By the standard (RFC 6066, Sect. 4), the Maximum Fragment Length (MFL)
extension limits the maximum record payload size, but not the maximum
datagram size. However, not inferring any limitations on the MTU when
setting the MFL means that a party has no means to dynamically inform
the peer about MTU limitations.
This commit changes the function ssl_get_remaining_payload_in_datagram()
to never return more than
MFL - { Total size of all records within the current datagram }
thereby limiting the MTU to MFL + { Maximum Record Expansion }.
The function ssl_free_buffered_record() frees a future epoch record, if
such is present. Previously, it was called in mbedtls_handshake_free(),
i.e. an unused buffered record would be cleared at the end of the handshake.
This commit moves the call to the function ssl_buffering_free() responsible
for freeing all buffering-related data, and which is called not only at
the end of the handshake, but at the end of every flight. In particular,
future record epochs won't be buffered across flight boundaries anymore,
and they shouldn't.
The previous code appended messages to flights only if their handshake type,
as derived from the first byte in the message, was different from
MBEDTLS_SSL_HS_HELLO_REQUEST. This check should only be performed
for handshake records, while CCS records should immediately be appended.
In SSLv3, the client sends a NoCertificate alert in response to
a CertificateRequest if it doesn't have a CRT. This previously
lead to failure in ssl_write_handshake_msg() which only accepted
handshake or CCS records.
The debugging functions
- mbedtls_debug_print_ret,
- mbedtls_debug_print_buf,
- mbedtls_debug_print_mpi, and
- mbedtls_debug_print_crt
return immediately if the SSL configuration bound to the
passed SSL context is NULL, has no debugging functions
configured, or if the debug threshold is below the debugging
level.
However, they do not check whether the provided SSL context
is not NULL before accessing the SSL configuration bound to it,
therefore leading to a segmentation fault if it is.
In contrast, the debugging function
- mbedtls_debug_print_msg
does check for ssl != NULL before accessing ssl->conf.
This commit unifies the checks by always returning immediately
if ssl == NULL.
The previous code appended messages to flights only if their handshake type,
as derived from the first byte in the message, was different from
MBEDTLS_SSL_HS_HELLO_REQUEST. This check should only be performed
for handshake records, while CCS records should immediately be appended.
In SSLv3, the client sends a NoCertificate alert in response to
a CertificateRequest if it doesn't have a CRT. This previously
lead to failure in ssl_write_handshake_msg() which only accepted
handshake or CCS records.
Previous commits introduced the field `total_bytes_buffered`
which is supposed to keep track of the cumulative size of
all heap allocated buffers used for the purpose of reassembly
and/or buffering of future messages.
However, the buffering of future epoch records were not reflected
in this field so far. This commit changes this, adding the length
of a future epoch record to `total_bytes_buffered` when it's buffered,
and subtracting it when it's freed.
This commit adds a static function ssl_buffer_make_space() which
takes a buffer size as an argument and attempts to free as many
future message bufffers as necessary to ensure that the desired
amount of buffering space is available without violating the
total buffering limit set by MBEDTLS_SSL_DTLS_MAX_BUFFERING.
If the next expected handshake message can't be reassembled because
buffered future messages have already used up too much of the available
space for buffering, free those future message buffers in order to
make space for the reassembly, starting with the handshake message
that's farthest in the future.
This commit adds a static function ssl_buffering_free_slot()
which allows to free a particular structure used to buffer
and/or reassembly some handshake message.
This commit introduces a compile time constant MBEDTLS_SSL_DTLS_MAX_BUFFERING
to mbedtls/config.h which allows the user to control the cumulative size of
all heap buffer allocated for the purpose of reassembling and buffering
handshake messages.
It is put to use by introducing a new field `total_bytes_buffered` to
the buffering substructure of `mbedtls_ssl_handshake_params` that keeps
track of the total size of heap allocated buffers for the purpose of
reassembly and buffering at any time. It is increased whenever a handshake
message is buffered or prepared for reassembly, and decreased when a
buffered or fully reassembled message is copied into the input buffer
and passed to the handshake logic layer.
This commit does not yet include future epoch record buffering into
account; this will be done in a subsequent commit.
Also, it is now conceivable that the reassembly of the next expected
handshake message fails because too much buffering space has already
been used up for future messages. This case currently leads to an
error, but instead, the stack should get rid of buffered messages
to be able to buffer the next one. This will need to be implemented
in one of the next commits.
A previous commit introduced the function ssl_prepare_reassembly_buffer()
which took a message length and a boolean flag indicating if a reassembly
bit map was needed, and attempted to heap-allocate a buffer of sufficient
size to hold both the message, its header, and potentially the reassembly
bitmap.
A subsequent commit is going to introduce a limit on the amount of heap
allocations allowed for the purpose of buffering, and this change will
need to know the reassembly buffer size before attempting the allocation.
To this end, this commit changes ssl_prepare_reassembly_buffer() into
ssl_get_reassembly_buffer_size() which solely computes the reassembly
buffer size, and performing the heap allocation manually in
ssl_buffer_message().
This commit moves the length and content check for CCS messages to
the function mbedtls_ssl_handle_message_type() which is called after
a record has been deprotected.
Previously, these checks were performed in the function
mbedtls_ssl_parse_change_cipher_spec(); however, now that
the arrival of out-of-order CCS messages is remembered
as a boolean flag, the check also has to happen when this
flag is set. Moving the length and content check to
mbedtls_ssl_handle_message_type() allows to treat both
checks uniformly.
Depends on the current transform, which might change when retransmitting a
flight containing a Finished message, so compute it only after the transform
is swapped.
This setting belongs to the individual connection, not to a configuration
shared by many connections. (If a default value is desired, that can be handled
by the application code that calls mbedtls_ssl_set_mtu().)
There are at least two ways in which this matters:
- per-connection settings can be adjusted if MTU estimates become available
during the lifetime of the connection
- it is at least conceivable that a server might recognize restricted clients
based on range of IPs and immediately set a lower MTU for them. This is much
easier to do with a per-connection setting than by maintaining multiple
near-duplicated ssl_config objects that differ only by the MTU setting.
The SSL context is passed to the reassembly preparation function
ssl_prepare_reassembly_buffer() solely for the purpose of allowing
debugging output. This commit marks the context as unused if
debugging is disabled (through !MBEDTLS_DEBUG_C).
This commit implements the buffering of a record from the next epoch.
- The buffering substructure of mbedtls_ssl_handshake_params
gets another field to hold a raw record (incl. header) from
a future epoch.
- If ssl_parse_record_header() sees a record from the next epoch,
it signals that it might be suitable for buffering by returning
MBEDTLS_ERR_SSL_EARLY_MESSAGE.
- If ssl_get_next_record() finds this error code, it passes control
to ssl_buffer_future_record() which may or may not decide to buffer
the record; it does so if
- a handshake is in progress,
- the record is a handshake record
- no record has already been buffered.
If these conditions are met, the record is backed up in the
aforementioned buffering substructure.
- If the current datagram is fully processed, ssl_load_buffered_record()
is called to check if a record has been buffered, and if yes,
if by now the its epoch is the current one; if yes, it copies
the record into the (empty! otherwise, ssl_load_buffered_record()
wouldn't have been called) input buffer.
This commit implements future handshake message buffering
and loading by implementing ssl_load_buffered_message()
and ssl_buffer_message().
Whenever a handshake message is received which is
- a future handshake message (i.e., the sequence number
is larger than the next expected one), or which is
- a proper fragment of the next expected handshake message,
ssl_buffer_message() is called, which does the following:
- Ignore message if its sequence number is too far ahead
of the next expected sequence number, as controlled by
the macro constant MBEDTLS_SSL_MAX_BUFFERED_HS.
- Otherwise, check if buffering for the message with the
respective sequence number has already commenced.
- If not, allocate space to back up the message within
the buffering substructure of mbedtls_ssl_handshake_params.
If the message is a proper fragment, allocate additional
space for a reassembly bitmap; if it is a full message,
omit the bitmap. In any case, fall throuh to the next case.
- If the message has already been buffered, check that
the header is the same, and add the current fragment
if the message is not yet complete (this excludes the
case where a future message has been received in a single
fragment, hence omitting the bitmap, and is afterwards
also received as a series of proper fragments; in this
case, the proper fragments will be ignored).
For loading buffered messages in ssl_load_buffered_message(),
the approach is the following:
- Check the first entry in the buffering window (the window
is always based at the next expected handshake message).
If buffering hasn't started or if reassembly is still
in progress, ignore. If the next expected message has been
fully received, copy it to the input buffer (which is empty,
as ssl_load_buffered_message() is only called in this case).
This commit returns the error code MBEDTLS_ERR_SSL_EARLY_MESSAGE
for proper handshake fragments, forwarding their treatment to
the buffering function ssl_buffer_message(); currently, though,
this function does not yet buffer or reassembly HS messages, so:
! This commit temporarily disables support for handshake reassembly !
This commit introduces helper functions
- ssl_get_hs_frag_len()
- ssl_get_hs_frag_off()
to parse the fragment length resp. fragment offset fields
in the handshake header.
Moreover, building on these helper functions, it adds a
function ssl_check_hs_header() checking the validity of
a DTLS handshake header with respect to the specification,
i.e. the indicated fragment must be a subrange of the total
handshake message, and the total handshake fragment length
(including header) must not exceed the record content size.
These checks were previously performed at a later stage during
ssl_reassemble_dtls_handshake().
This commit introduces a static helper function ssl_get_hs_total_len()
parsing the total message length field in the handshake header, and
puts it to use in mbedtls_ssl_prepare_handshake_record().
This commit introduces, but does not yet put to use, a sub-structure
of mbedtls_ssl_handshake_params::buffering that will be used for the
buffering and/or reassembly of handshake messages with handshake
sequence numbers that are greater or equal to the next expected
sequence number.
This commit introduces a sub-structure `buffering` within
mbedtls_ssl_handshake_params that shall contain all data
related to the reassembly and/or buffering of handshake
messages.
Currently, only buffering of CCS messages is implemented,
so the only member of this struct is the previously introduced
`seen_ccs` field.
This commit introduces a static function ssl_hs_is_proper_fragment()
to check if the current incoming handshake message is a proper fragment.
It is used within mbedtls_ssl_prepare_handshake_record() to decide whether
handshake reassembly through ssl_reassemble_dtls_handshake() is needed.
The commit changes the behavior of the library in the (unnatural)
situation where proper fragments for a handshake message are followed
by a non-fragmented version of the same message. In this case,
the previous code invoked the handshake reassembly routine
ssl_reassemble_dtls_handshake(), while with this commit, the full
handshake message is directly forwarded to the user, no altering
the handshake reassembly state -- in particular, not freeing it.
As a remedy, freeing of a potential handshake reassembly structure
is now done as part of the handshake update function
mbedtls_ssl_update_handshake_status().
This commit adds a parameter to ssl_prepare_reassembly_buffer()
allowing to disable the allocation of space for a reassembly bitmap.
This will allow this function to be used for the allocation of buffers
for future handshake messages in case these need no fragmentation.
This commit moves the code-path preparing the handshake
reassembly buffer, consisting of header, message content,
and reassembly bitmap, to a separate function
ssl_prepare_reassembly_buffer().
This leads future HS messages to traverse the buffering
function ssl_buffer_message(), which however doesn't do
anything at the moment for HS messages. Since the error
code MBEDTLS_ERR_SSL_EARLY_MESSAGE is afterwards remapped
to MBEDTLS_ERR_SSL_CONTINUE_PROCESSING -- which is what
was returned prior to this commit when receiving a future
handshake message -- this commit therefore does not yet
introduce any change in observable behavior.
This commit implements support for remembering out-of-order
CCS messages. Specifically, a flag is set whenever a CCS message
is read which remains until the end of a flight, and when a
CCS message is expected and a CCS message has been seen in the
current flight, a synthesized CCS record is created.
This commit introduces a function ssl_record_is_in_progress()
to indicate if there is there is more data within the current
record to be processed. Further, it moves the corresponding
call from ssl_read_record_layer() to the parent function
mbedtls_ssl_read_record(). With this change, ssl_read_record_layer()
has the sole purpose of fetching and decoding a new record,
and hence this commit also renames it to ssl_get_next_record().
Subsequent commits will potentially inject buffered
messages after the last incoming message has been
consumed, but before a new one is fetched. As a
preparatory step to this, this commit moves the call
to ssl_consume_current_message() from ssl_read_record_layer()
to the calling function mbedtls_ssl_read_record().
The first part of the function ssl_read_record_layer() was
to mark the previous message as consumed. This commit moves
the corresponding code-path to a separate static function
ssl_consume_current_message().
This function was previously global because it was
used directly within ssl_parse_certificate_verify()
in library/ssl_srv.c. The previous commit removed
this dependency, replacing the call by a call to
the global parent function mbedtls_ssl_read_record().
This renders mbedtls_ssl_read_record_layer() internal
and therefore allows to make it static, and accordingly
rename it as ssl_read_record_layer().
Usually, debug messages beginning with "=> and "<="
match up and indicate entering of and returning from
functions, respectively. This commit fixes one exception
to this rule in mbedtls_ssl_read_record(), which sometimes
printed two messages of the form "<= XXX".
Previously, mbedtls_ssl_read_record() always updated the handshake
checksum in case a handshake record was received. While desirable
most of the time, for the CertificateVerify message the checksum
update must only happen after the message has been fully processed,
because the validation requires the handshake digest up to but
excluding the CertificateVerify itself. As a remedy, the bulk
of mbedtls_ssl_read_record() was previously duplicated within
ssl_parse_certificate_verify(), hardening maintenance in case
mbedtls_ssl_read_record() is subject to changes.
This commit adds a boolean parameter to mbedtls_ssl_read_record()
indicating whether the checksum should be updated in case of a
handshake message or not. This allows using it also for
ssl_parse_certificate_verify(), manually updating the checksum
after the message has been processed.
This for example lead to the following corner case bug:
The code attempted to piggy-back a Finished message at
the end of a datagram where precisely 12 bytes of payload
were still available. This lead to an empty Finished fragment
being sent, and when mbedtls_ssl_flight_transmit() was called
again, it believed that it was just starting to send the
Finished message, thereby calling ssl_swap_epochs() which
had already happened in the call sending the empty fragment.
Therefore, the second call would send the 'rest' of the
Finished message with wrong epoch.
This commit adds a public function
`mbedtls_ssl_conf_datagram_packing()`
that allows to allow / forbid the packing of multiple
records within a single datagram.
The `partial` argument is only used when DTLS and same port
client reconnect are enabled. This commit marks the variable
as unused if that's not the case.
If neither the maximum fragment length extension nor DTLS
are used, the SSL context argument is unnecessary as the
maximum payload length is hardcoded as MBEDTLS_SSL_MAX_CONTENT_LEN.
This commit finally enables datagram packing by modifying the
record preparation function ssl_write_record() to not always
calling mbedtls_ssl_flush_output().
The packing of multiple records within a single datagram works
by increasing the pointer `out_hdr` (pointing to the beginning
of the next outgoing record) within the datagram buffer, as
long as space is available and no flush was mandatory.
This commit does not yet change the code's behavior of always
flushing after preparing a record, but it introduces the logic
of increasing `out_hdr` after preparing the record, and resetting
it after the flush has been completed.
Previously, the record sequence number was incremented at the
end of each successful call to mbedtls_ssl_flush_output(),
which works as long as there is precisely one such call for
each outgoing record.
When packing multiple records into a single datagram, this
property is no longer true, and instead the increment of the
record sequence number must happen after the record has been
prepared, and not after it has been dispatched.
This commit moves the code for incrementing the record sequence
number from mbedtls_ssl_flush_output() to ssl_write_record().
This commit is another step towards supporting the packing of
multiple records within a single datagram.
Previously, the incremental outgoing record sequence number was
statically stored within the record buffer, at its final place
within the record header. This slightly increased efficiency
as it was not necessary to copy the sequence number when writing
outgoing records.
When allowing multiple records within a single datagram, it is
necessary to allow the position of the current record within the
datagram buffer to be flexible; in particular, there is no static
address for the record sequence number field within the record header.
This commit introduces an additional field `cur_out_ctr` within
the main SSL context structure `mbedtls_ssl_context` to keep track
of the outgoing record sequence number independent of the buffer used
for the current record / datagram. Whenever a new record is written,
this sequence number is copied to the the address `out_ctr` of the
sequence number header field within the current outgoing record.
The SSL/TLS module maintains a number of internally used pointers
`out_hdr`, `out_len`, `out_iv`, ..., indicating where to write the
various parts of the record header.
These pointers have to be kept in sync and sometimes need update:
Most notably, the `out_msg` pointer should always point to the
beginning of the record payload, and its offset from the pointer
`out_iv` pointing to the end of the record header is determined
by the length of the explicit IV used in the current record
protection mechanism.
This commit introduces functions deducing these pointers from
the pointers `out_hdr` / `in_hdr` to the beginning of the header
of the current outgoing / incoming record.
The flexibility gained by these functions will subsequently
be used to allow shifting of `out_hdr` for the purpose of
packing multiple records into a single datagram.
For now, just check that it causes us to fragment. More tests are coming in
follow-up commits to ensure we respect the exact value set, including when
renegotiating.
Note: no interop tests in ssl-opt.sh for now, as some of them make us run into
bugs in (the CI's default versions of) OpenSSL and GnuTLS, so interop tests
will be added later once the situation is clarified. <- TODO
This will allow fragmentation to always happen in the same place, always from
a buffer distinct from ssl->out_msg, and with the same way of resuming after
returning WANT_WRITE
- take advantage of the fact that we're only called for first send
- put all sanity checks at the top
- rename and constify shortcut variables
- improve comments
`mbedtls_ssl_get_record_expansion()` is supposed to return the maximum
difference between the size of a protected record and the size of the
encapsulated plaintext.
It had the following two bugs:
(1) It did not consider the new ChaChaPoly ciphersuites, returning
the error code #MBEDTLS_ERR_SSL_INTERNAL_ERROR in this case.
(2) It did not correctly estimate the maximum record expansion in case
of CBC ciphersuites in (D)TLS versions 1.1 and higher, in which
case the ciphertext is prefixed by an explicit IV.
This commit fixes both bugs.
In `mbedtls_ccm_self_test()`, enforce input and output
buffers sent to the ccm API to be contigous and aligned,
by copying the test vectors to buffers on the stack.
In ecp_mul_comb(), if (!p_eq_g && grp->T == NULL) and then ecp_precompute_comb() fails (which can
happen due to OOM), then the new array of points T will be leaked (as it's newly allocated, but
hasn't been asigned to grp->T yet).
Symptom was a memory leak in ECDHE key exchange under low memory conditions.
Address review comments:
1. add `mbedtls_cipher_init()` after freeing context, in test code
2. style comments
3. set `ctx->iv_size = 0` in case `IV == NULL && iv_len == 0`
The length to the debug message could conceivably leak through the time it
takes to print it, and that length would in turn reveal whether padding was
correct or not.
The basis for the Lucky 13 family of attacks is for an attacker to be able to
distinguish between (long) valid TLS-CBC padding and invalid TLS-CBC padding.
Since our code sets padlen = 0 for invalid padding, the length of the input to
the HMAC function, and the location where we read the MAC, give information
about that.
A local attacker could gain information about that by observing via a
cache attack whether the bytes at the end of the record (at the location of
would-be padding) have been read during MAC verification (computation +
comparison).
Let's make sure they're always read.
The basis for the Lucky 13 family of attacks is for an attacker to be able to
distinguish between (long) valid TLS-CBC padding and invalid TLS-CBC padding.
Since our code sets padlen = 0 for invalid padding, the length of the input to
the HMAC function gives information about that.
Information about this length (modulo the MD/SHA block size) can be deduced
from how much MD/SHA padding (this is distinct from TLS-CBC padding) is used.
If MD/SHA padding is read from a (static) buffer, a local attacker could get
information about how much is used via a cache attack targeting that buffer.
Let's get rid of this buffer. Now the only buffer used is the internal MD/SHA
one, which is always read fully by the process() function.
Move definition of `MBEDTLS_CIPHER_MODE_STREAM` to header file
(`mbedtls_cipher_internal.h`), because it is used by more than
one file. Raised by TrinityTonic in #1719
The IAR compiler doesn't like it when we assign an int to an enum variable.
"C:\builds\ws\mbedtls-restricted-pr\library\ecp.c",509 Error[Pe188]:
enumerated type mixed with another type
* development: (180 commits)
Change the library version to 2.11.0
Fix version in ChangeLog for fix for #552
Add ChangeLog entry for clang version fix. Issue #1072
Compilation warning fixes on 32b platfrom with IAR
Revert "Turn on MBEDTLS_SSL_ASYNC_PRIVATE by default"
Fix for missing len var when XTS config'd and CTR not
ssl_server2: handle mbedtls_x509_dn_gets failure
Fix harmless use of uninitialized memory in ssl_parse_encrypted_pms
SSL async tests: add a few test cases for error in decrypt
Fix memory leak in ssl_server2 with SNI + async callback
SNI + SSL async callback: make all keys async
ssl_async_resume: free the operation context on error
ssl_server2: get op_name from context in ssl_async_resume as well
Clarify "as directed here" in SSL async callback documentation
SSL async callbacks documentation: clarify resource cleanup
Async callback: use mbedtls_pk_check_pair to compare keys
Rename mbedtls_ssl_async_{get,set}_data for clarity
Fix copypasta in the async callback documentation
SSL async callback: cert is not always from mbedtls_ssl_conf_own_cert
ssl_async_set_key: detect if ctx->slots overflows
...
The TLS layer is checking for mode, such as GCM, CCM, CBC, STREAM. ChachaPoly
needs to have its own mode, even if it's used just one cipher, in order to
allow consistent handling of mode in the TLS layer.
* development: (182 commits)
Change the library version to 2.11.0
Fix version in ChangeLog for fix for #552
Add ChangeLog entry for clang version fix. Issue #1072
Compilation warning fixes on 32b platfrom with IAR
Revert "Turn on MBEDTLS_SSL_ASYNC_PRIVATE by default"
Fix for missing len var when XTS config'd and CTR not
ssl_server2: handle mbedtls_x509_dn_gets failure
Fix harmless use of uninitialized memory in ssl_parse_encrypted_pms
SSL async tests: add a few test cases for error in decrypt
Fix memory leak in ssl_server2 with SNI + async callback
SNI + SSL async callback: make all keys async
ssl_async_resume: free the operation context on error
ssl_server2: get op_name from context in ssl_async_resume as well
Clarify "as directed here" in SSL async callback documentation
SSL async callbacks documentation: clarify resource cleanup
Async callback: use mbedtls_pk_check_pair to compare keys
Rename mbedtls_ssl_async_{get,set}_data for clarity
Fix copypasta in the async callback documentation
SSL async callback: cert is not always from mbedtls_ssl_conf_own_cert
ssl_async_set_key: detect if ctx->slots overflows
...
For the situation where the mbedTLS device has limited RAM, but the
other end of the connection doesn't support the max_fragment_length
extension. To be spec-compliant, mbedTLS has to keep a 16384 byte
incoming buffer. However the outgoing buffer can be made smaller without
breaking spec compliance, and we save some RAM.
See comments in include/mbedtls/config.h for some more details.
(The lower limit of outgoing buffer size is the buffer size used during
handshake/cert negotiation. As the handshake is half-duplex it might
even be possible to store this data in the "incoming" buffer during the
handshake, which would save even more RAM - but it would also be a lot
hackier and error-prone. I didn't really explore this possibility, but
thought I'd mention it here in case someone sees this later on a mission
to jam mbedTLS into an even tinier RAM footprint.)
Fix compilation warnings with IAR toolchain, on 32 bit platform.
Reported by rahmanih in #683
This is based on work by Ron Eldor in PR #750, some of which was independently
fixed by Azim Khan and already merged in PR #1646.
The AES XTS self-test was using a variable len, which was declared only when CTR
was enabled. Changed the declaration of len to be conditional on CTR and XTS.
The AES OFB self-test made use of a variable `offset` but failed to have a
preprocessor condition around it, so unless CTR and CBC were enabled, the
variable would be undeclared.
In ssl_parse_encrypted_pms, some operational failures from
ssl_decrypt_encrypted_pms lead to diff being set to a value that
depended on some uninitialized unsigned char and size_t values. This didn't
affect the behavior of the program (assuming an implementation with no
trap values for size_t) because all that matters is whether diff is 0,
but Valgrind rightfully complained about the use of uninitialized
memory. Behave nicely and initialize the offending memory.
THe function `mbedtls_gf128mul_x_ble()` doesn't multiply by x, x^4, and
x^8. Update the function description to properly describe what the function
does.
mbedtls_aes_crypt_xts() currently takes a `bits_length` parameter, unlike
the other block modes. Change the parameter to accept a bytes length
instead, as the `bits_length` parameter is not actually ever used in the
current implementation.
Add a new context structure for XTS. Adjust the API for XTS to use the new
context structure, including tests suites and the benchmark program. Update
Doxgen documentation accordingly.
AES-XEX is a building block for other cryptographic standards and not yet a
standard in and of itself. We'll just provide the standardized AES-XTS
algorithm, and not AES-XEX. The AES-XTS algorithm and interface provided
can be used to perform the AES-XEX algorithm when the length of the input
is a multiple of the AES block size.
If we're unlucky with memory placement, gf128mul_table_bbe may spread over
two cache lines and this would leak b >> 63 to a cache timing attack.
Instead, take an approach that is less likely to make different memory
loads depending on the value of b >> 63 and is also unlikely to be compiled
to a condition.
XTS mode is fully known as "xor-encrypt-xor with ciphertext-stealing".
This is the generalization of the XEX mode.
This implementation is limited to an 8-bits (1 byte) boundary, which
doesn't seem to be what was thought considering some test vectors [1].
This commit comes with tests, extracted from [1], and benchmarks.
Although, benchmarks aren't really nice here, as they work with a buffer
of a multiple of 16 bytes, which isn't a challenge for XTS compared to
XEX.
[1] http://csrc.nist.gov/groups/STM/cavp/documents/aes/XTSTestVectors.zip
As seen from the first benchmark run, AES-XEX was running pourly (even
slower than AES-CBC). This commit doubles the performances of the
current implementation.
XEX mode, known as "xor-encrypt-xor", is the simple case of the XTS
mode, known as "XEX with ciphertext stealing". When the buffers to be
encrypted/decrypted have a length divisible by the length of a standard
AES block (16), XTS is exactly like XEX.
It's undesirable to have users of the SSL layer check for an error code
specific to a lower-level layer, both out of general layering principles, and
also because if we later make another crypto module gain resume capabilities,
we would need to change the contract again (checking for a new module-specific
error code).
When MBEDTLS_PLATFORM_MEMORY is defined but MBEDTLS_PLATFORM_FREE_MACRO or
MBEDTLS_PLATFORM_CALLOC_MACRO are not defined then the actual functions
used to allocate and free memory are stored in function pointers.
These pointers are exposed to the caller, and it means that the caller
and the library have to share a data section.
In TF-A, we execute in a very constrained environment, where some images
are executed from ROM and other images are executed from SRAM. The
images that are executed from ROM cannot be modified. The SRAM size
is very small and we are moving libraries to the ROM that can be shared
between the different SRAM images. These SRAM images could import all the
symbols used in mbedtls, but it would create an undesirable hard binary
dependency between the different images. For this reason, all the library
functions in ROM are accesed using a jump table whose base address is
known, allowing the images to execute with different versions of the ROM.
This commit changes the function pointers to actual functions,
so that the SRAM images only have to use the new exported symbols
(mbedtls_calloc and mbedtls_free) using the jump table. In
our scenario, mbedtls_platform_set_calloc_free is called from
mbedtls_memory_buffer_alloc_init which initializes the function pointers
to the internal buffer_alloc_calloc and buffer_alloc_free functions.
No functional changes to mbedtls_memory_buffer_alloc_init.
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
Summary of merge conflicts:
include/mbedtls/ecdh.h -> documentation style
include/mbedtls/ecdsa.h -> documentation style
include/mbedtls/ecp.h -> alt style, new error codes, documentation style
include/mbedtls/error.h -> new error codes
library/error.c -> new error codes (generated anyway)
library/ecp.c:
- code of an extracted function was changed
library/ssl_cli.c:
- code addition on one side near code change on the other side
(ciphersuite validation)
library/x509_crt.c -> various things
- top fo file: helper structure added near old zeroize removed
- documentation of find_parent_in()'s signature: improved on one side,
added arguments on the other side
- documentation of find_parent()'s signature: same as above
- verify_chain(): variables initialised later to give compiler an
opportunity to warn us if not initialised on a code path
- find_parent(): funcion structure completely changed, for some reason git
tried to insert a paragraph of the old structure...
- merge_flags_with_cb(): data structure changed, one line was fixed with a
cast to keep MSVC happy, this cast is already in the new version
- in verify_restratable(): adjacent independent changes (function
signature on one line, variable type on the next)
programs/ssl/ssl_client2.c:
- testing for IN_PROGRESS return code near idle() (event-driven):
don't wait for data in the the socket if ECP_IN_PROGRESS
tests/data_files/Makefile: adjacent independent additions
tests/suites/test_suite_ecdsa.data: adjacent independent additions
tests/suites/test_suite_x509parse.data: adjacent independent additions
* development: (1059 commits)
Change symlink to hardlink to avoid permission issues
Fix out-of-tree testing symlinks on Windows
Updated version number to 2.10.0 for release
Add a disabled CMAC define in the no-entropy configuration
Adapt the ARIA test cases for new ECB function
Fix file permissions for ssl.h
Add ChangeLog entry for PR#1651
Fix MicroBlaze register typo.
Fix typo in doc and copy missing warning
Fix edit mistake in cipher_wrap.c
Update CTR doc for the 64-bit block cipher
Update CTR doc for other 128-bit block ciphers
Slightly tune ARIA CTR documentation
Remove double declaration of mbedtls_ssl_list_ciphersuites
Update CTR documentation
Use zeroize function from new platform_util
Move to new header style for ALT implementations
Add ifdef for selftest in header file
Fix typo in comments
Use more appropriate type for local variable
...
Adds error handling into mbedtls_aes_crypt_ofb for AES errors, a self-test
for the OFB mode using NIST SP 800-38A test vectors and adds a check to
potential return errors in setting the AES encryption key in the OFB test
suite.
* development: (97 commits)
Updated version number to 2.10.0 for release
Add a disabled CMAC define in the no-entropy configuration
Adapt the ARIA test cases for new ECB function
Fix file permissions for ssl.h
Add ChangeLog entry for PR#1651
Fix MicroBlaze register typo.
Fix typo in doc and copy missing warning
Fix edit mistake in cipher_wrap.c
Update CTR doc for the 64-bit block cipher
Update CTR doc for other 128-bit block ciphers
Slightly tune ARIA CTR documentation
Remove double declaration of mbedtls_ssl_list_ciphersuites
Update CTR documentation
Use zeroize function from new platform_util
Move to new header style for ALT implementations
Add ifdef for selftest in header file
Fix typo in comments
Use more appropriate type for local variable
Remove useless parameter from function
Wipe sensitive info from the stack
...
Motivation is similar to NO_UDBL_DIVISION.
The alternative implementation of 64-bit mult is straightforward and aims at
obvious correctness. Also, visual examination of the generate assembly show
that it's quite efficient with clang, armcc5 and arm-clang. However current
GCC generates fairly inefficient code for it.
I tried to rework the code in order to make GCC generate more efficient code.
Unfortunately the only way to do that is to get rid of 64-bit add and handle
the carry manually, but this causes other compilers to generate less efficient
code with branches, which is not acceptable from a side-channel point of view.
So let's keep the obvious code that works for most compilers and hope future
versions of GCC learn to manage registers in a sensible way in that context.
See https://bugs.launchpad.net/gcc-arm-embedded/+bug/1775263
- in x509_profile_check_pk_alg
- in x509_profile_check_md_alg
- in x509_profile_check_key
and in ssl_cli.c : unsigned char gets promoted to signed integer
Allowing DECRYPT with crypt_and_tag is a risk as people might fail to check
the tag correctly (or at all). So force them to use auth_decrypt() instead.
See also https://github.com/ARMmbed/mbedtls/pull/1668
When MBEDTLS_TIMING_C was not defined in config.h, but the MemSan
memory sanitizer was activated, entropy_poll.c used memset without
declaring it. Fix this by including string.h unconditionally.
As a protection against the Lucky Thirteen attack, the TLS code for
CBC decryption in encrypt-then-MAC mode performs extra MAC
calculations to compensate for variations in message size due to
padding. The amount of extra MAC calculation to perform was based on
the assumption that the bulk of the time is spent in processing
64-byte blocks, which is correct for most supported hashes but not for
SHA-384. Correct the amount of extra work for SHA-384 (and SHA-512
which is currently not used in TLS, and MD2 although no one should
care about that).
Fix IAR compiler warnings
Two warnings have been fixed:
1. code 'if( len <= 0xFFFFFFFF )' gave warning 'pointless integer comparison'.
This was fixed by wraping the condition in '#if SIZE_MAX > 0xFFFFFFFF'.
2. code 'diff |= A[i] ^ B[i];' gave warning 'the order of volatile accesses is undefined in'.
This was fixed by read the volatile data in temporary variables before the computation.
Explain IAR warning on volatile access
Consistent use of CMAKE_C_COMPILER_ID
The cast to void was motivated by the assumption that the functions only
return non-zero when passed bad arguments, but that might not be true of
alternative implementation, for example on hardware failure.
- need HW failure codes too
- re-use relevant poly codes for chachapoly to save on limited space
Values were chosen to leave 3 free slots at the end of the NET odd range.
That's what it is. So we shouldn't set a block size != 1.
While at it, move call to chachapoly_update() closer to the one for GCM, as
they are similar (AEAD).
This reduces clutter, making the functions more readable.
Also, it makes lcov see each line as covered. This is not cheating, as the
lines that were previously seen as not covered are not supposed to be reached
anyway (failing branches of the selftests).
Thanks to this and previous test suite enhancements, lcov now sees chacha20.c
and poly1305.c at 100% line coverage, and for chachapoly.c only two lines are
not covered (error returns from lower-level module that should never happen
except perhaps if an alternative implementation returns an unexpected error).
This module used (len, pointer) while (pointer, len) is more common in the
rest of the library, in particular it's what's used in the GCM API that
very comparable to it, so switch to (pointer, len) for consistency.
Note that the crypt_and_tag() and auth_decrypt() functions were already using
the same convention as GCM, so this also increases intra-module consistency.
This module used (len, pointer) while (pointer, len) is more common in the
rest of the library, in particular it's what's used in the CMAC API that is
very comparable to Poly1305, so switch to (pointer, len) for consistency.
In addition to making the APIs of the various AEAD modules more consistent
with each other, it's useful to have an auth_decrypt() function so that we can
safely check the tag ourselves, as the user might otherwise do it in an
insecure way (or even forget to do it altogether).
While the old name is explicit and aligned with the RFC, it's also very long,
so with the mbedtls_ prefix prepended we get a 31-char prefix to each
identifier, which quickly conflicts with our 80-column policy.
The new name is shorter, it's what a lot of people use when speaking about
that construction anyway, and hopefully should not introduce confusion at
it seems unlikely that variants other than 20/1305 be standardised in the
foreseeable future.
- in .h files: only put the context declaration inside the #ifdef _ALT
(this was changed in 2.9.0, ie after the original PR)
- in .c file: only leave selftest out of _ALT: even though some function are
trivial to build from other parts, alt implementors might want to go another
way about them (for efficiency or other reasons)
I refactored some code into the function mbedtls_constant_time_memcmp
in commit 7aad291 but this function is only used by GCM and
AEAD_ChaCha20_Poly1305 to check the tags. So this function is now
only enabled if either of these two ciphers is enabled.
This change permits users of the ChaCha20/Poly1305 algorithms
(and the AEAD construction thereof) to pass NULL pointers for
data that they do not need, and avoids the need to provide a valid
buffer for data that is not used.
This implementation is based off the description in RFC 7539.
The ChaCha20 code is also updated to provide a means of generating
keystream blocks with arbitrary counter values. This is used to
generated the one-time Poly1305 key in the AEAD construction.
* development: (504 commits)
Fix minor code style issues
Add the uodate to the soversion to the ChangeLog
Fix the ChangeLog for clarity, english and credit
Update version to 2.9.0
ecp: Fix binary compatibility with group ID
Changelog entry
Change accepted ciphersuite versions when parsing server hello
Remove preprocessor directives around platform_util.h include
Fix style for mbedtls_mpi_zeroize()
Improve mbedtls_platform_zeroize() docs
mbedtls_zeroize -> mbedtls_platform_zeroize in docs
Reword config.h docs for MBEDTLS_PLATFORM_ZEROIZE_ALT
Organize CMakeLists targets in alphabetical order
Organize output objs in alfabetical order in Makefile
Regenerate errors after ecp.h updates
Update ecp.h
Change variable bytes_written to header_bytes in record decompression
Update ecp.h
Update ecp.h
Update ecp.h
...
Rename to mbedtls_ssl_get_async_operation_data and
mbedtls_ssl_set_async_operation_data so that they're about
"async operation data" and not about some not-obvious "data".
When a handshake step starts an asynchronous operation, the
application needs to know which SSL connection the operation is for,
so that when the operation completes, the application can wake that
connection up. Therefore the async start callbacks need to take the
SSL context as an argument. It isn't enough to let them set a cookie
in the SSL connection, the application needs to be able to find the
right SSL connection later.
Also pass the SSL context to the other callbacks for consistency. Add
a new field to the handshake that the application can use to store a
per-connection context. This new field replaces the former
context (operation_ctx) that was created by the start function and
passed to the resume function.
Add a boolean flag to the handshake structure to track whether an
asynchronous operation is in progress. This is more robust than
relying on the application to set a non-null application context.
Change the signature of mbedtls_ssl_handshake_free again. Now take the
whole SSL context as argument and not just the configuration and the
handshake substructure.
This is in preparation for changing the asynchronous cancel callback
to take the SSL context as an argument.
In the refactoring of ssl_parse_encrypted_pms, I advertently broke the
case when decryption signalled an error, with the variable ret getting
overwritten before calculating diff. Move the calculation of diff
immediately after getting the return code to make the connection more
obvious. Also move the calculation of mask immediately after the
calculation of diff, which doesn't change the behavior, because I find
the code clearer that way.
Conflict resolution:
* ChangeLog: put the new entry from my branch in the proper place.
* include/mbedtls/error.h: counted high-level module error codes again.
* include/mbedtls/ssl.h: picked different numeric codes for the
concurrently added errors; made the new error a full sentence per
current standards.
* library/error.c: ran scripts/generate_errors.pl.
* library/ssl_srv.c:
* ssl_prepare_server_key_exchange "DHE key exchanges": the conflict
was due to style corrections in development
(4cb1f4d49c) which I merged with
my refactoring.
* ssl_prepare_server_key_exchange "For key exchanges involving the
server signing", first case, variable declarations: merged line
by line:
* dig_signed_len: added in async
* signature_len: removed in async
* hashlen: type changed to size_t in development
* hash: size changed to MBEDTLS_MD_MAX_SIZE in async
* ret: added in async
* ssl_prepare_server_key_exchange "For key exchanges involving the
server signing", first cae comment: the conflict was due to style
corrections in development (4cb1f4d49c)
which I merged with my comment changes made as part of refactoring
the function.
* ssl_prepare_server_key_exchange "Compute the hash to be signed" if
`md_alg != MBEDTLS_MD_NONE`: conflict between
ebd652fe2d
"ssl_write_server_key_exchange: calculate hashlen explicitly" and
46f5a3e9b4 "Check return codes from
MD in ssl code". I took the code from commit
ca1d742904 made on top of development
which makes mbedtls_ssl_get_key_exchange_md_ssl_tls return the
hash length.
* programs/ssl/ssl_server2.c: multiple conflicts between the introduction
of MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS and new auxiliary functions and
definitions for async support, and the introduction of idle().
* definitions before main: concurrent additions, kept both.
* main, just after `handshake:`: in the loop around
mbedtls_ssl_handshake(), merge the addition of support for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS and SSL_ASYNC_INJECT_ERROR_CANCEL
with the addition of the idle() call.
* main, if `opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM`: take the
code from development and add a check for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS.
* main, loop around mbedtls_ssl_read() in the datagram case:
take the code from development and add a check for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS; revert to a do...while loop.
* main, loop around mbedtls_ssl_write() in the datagram case:
take the code from development and add a check for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS; revert to a do...while loop.
In mbedtls_ssl_get_key_exchange_md_tls1_2, add an output parameter for
the hash length. The code that calls this function can currently do
without it, but it will need the hash length in the future, when
adding support for a third-party callback to calculate the signature
of the hash.
Reorganize ssl_parse_encrypted_pms so that it first prepares the
ciphertext to decrypt, then decrypts it, then returns either the
decrypted premaster secret or random data in an appropriate manner.
This is in preparation for allowing the private key operation to be
offloaded to an external cryptographic module which can operate
asynchronously. The refactored code no longer calculates state before
the decryption that needs to be saved until after the decryption,
which allows the decryption to be started and later resumed.
Use the public key to extract metadata rather than the public key.
Don't abort early if there is no private key.
This is in preparation for allowing the private key operation to be
offloaded to an external cryptographic module.
Implement SSL asynchronous private operation for the case of a
signature operation in a server.
This is a first implementation. It is functional, but the code is not
clean, with heavy reliance on goto.
The pk layer can infer the hash length from the hash type. Calculate
it explicitly here anyway because it's needed for debugging purposes,
and it's needed for the upcoming feature allowing the signature
operation to be offloaded to an external cryptographic processor, as
the offloading code will need to know what length hash to copy.
New compile-time option MBEDTLS_SSL_ASYNC_PRIVATE_C, enabling
callbacks to replace private key operations. These callbacks allow the
SSL stack to make an asynchronous call to an external cryptographic
module instead of calling the cryptography layer inside the library.
The call is asynchronous in that it may return the new status code
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS, in which case the SSL stack returns
and can be later called where it left off.
This commit introduces the configuration option. Later commits will
implement the feature proper.
This function is declared in ssl_internal.h, so this is not a public
API change.
This is in preparation for mbedtls_ssl_handshake_free needing to call
methods from the config structure.
In SSL, don't use mbedtls_pk_ec or mbedtls_pk_rsa on a private
signature or decryption key (as opposed to a public key or a key used
for DH/ECDH). Extract the data (it's the same data) from the public
key object instead. This way the code works even if the private key is
opaque or if there is no private key object at all.
Specifically, with an EC key, when checking whether the curve in a
server key matches the handshake parameters, rely only on the offered
certificate and not on the metadata of the private key.
* public/pr/1380:
Update ChangeLog for #1380
Generate RSA keys according to FIPS 186-4
Generate primes according to FIPS 186-4
Avoid small private exponents during RSA key generation
Change mbedtls_zeroize() implementation to use memset() instead of a
custom implementation for performance reasons. Furthermore, we would
also like to prevent as much as we can compiler optimisations that
remove zeroization code.
The implementation of mbedtls_zeroize() now uses a volatile function
pointer to memset() as suggested by Colin Percival at:
http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html
Add a new macro MBEDTLS_UTILS_ZEROIZE that allows users to configure
mbedtls_zeroize() to an alternative definition when defined. If the
macro is not defined, then mbed TLS will use the default definition of
the function.
This commit removes all the static occurrencies of the function
mbedtls_zeroize() in each of the individual .c modules. Instead the
function has been moved to utils.h that is included in each of the
modules.
The new header contains common information across various mbed TLS
modules and avoids code duplication. To start, utils.h currently only
contains the mbedtls_zeroize() function.
The specification requires that P and Q are not too close. The specification
also requires that you generate a P and stick with it, generating new Qs until
you have found a pair that works. In practice, it turns out that sometimes a
particular P results in it being very unlikely a Q can be found matching all
the constraints. So we keep the original behavior where a new P and Q are
generated every round.
The specification requires that numbers are the raw entropy (except for odd/
even) and at least 2^(nbits-0.5). If not, new random bits need to be used for
the next number. Similarly, if the number is not prime new random bits need to
be used.
Attacks against RSA exist for small D. [Wiener] established this for
D < N^0.25. [Boneh] suggests the bound should be N^0.5.
Multiple possible values of D might exist for the same set of E, P, Q. The
attack works when there exists any possible D that is small. To make sure that
the generated key is not susceptible to attack, we need to make sure we have
found the smallest possible D, and then check that D is big enough. The
Carmichael function λ of p*q is lcm(p-1, q-1), so we can apply Carmichael's
theorem to show that D = d mod λ(n) is the smallest.
[Wiener] Michael J. Wiener, "Cryptanalysis of Short RSA Secret Exponents"
[Boneh] Dan Boneh and Glenn Durfee, "Cryptanalysis of RSA with Private Key d Less than N^0.292"
Clang-Msan is known to report spurious errors when MBEDTLS_AESNI_C is
enabled, due to the use of assembly code. The error reports don't
mention AES, so they can be difficult to trace back to the use of
AES-NI. Warn about this potential problem at compile time.
Zeroing out an fd_set before calling FD_ZERO on it is in principle
useless, but without it some memory sanitizers think the fd_set is
still uninitialized after FD_ZERO (e.g. clang-msan/Glibc/x86_64 where
FD_ZERO is implemented in assembly). Make the zeroing conditional on
using a memory sanitizer.
The initialization via FD_SET is not seen by memory sanitizers if
FD_SET is implemented through assembly. Additionally zeroizing the
respective fd_set's before calling FD_SET contents the sanitizers
and comes at a negligible computational overhead.
In mbedtls_ssl_derive_keys, don't call mbedtls_md_hmac_starts in
ciphersuites that don't use HMAC. This doesn't change the behavior of
the code, but avoids relying on an uncaught error when attempting to
start an HMAC operation that hadn't been initialized.
Clarify what MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH and
MBEDTLS_ERR_PK_SIG_LEN_MISMATCH mean. Add comments to highlight that
this indicates that a valid signature is present, unlike other error
codes. See
https://github.com/ARMmbed/mbedtls/pull/1149#discussion_r178130705
Conflict resolution:
* ChangeLog
* tests/data_files/Makefile: concurrent additions, order irrelevant
* tests/data_files/test-ca.opensslconf: concurrent additions, order irrelevant
* tests/scripts/all.sh: one comment change conflicted with a code
addition. In addition some of the additions in the
iotssl-1381-x509-verify-refactor-restricted branch need support for
keep-going mode, this will be added in a subsequent commit.
The relevant ASN.1 definitions for a PKCS#8 encoded Elliptic Curve key are:
PrivateKeyInfo ::= SEQUENCE {
version Version,
privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
privateKey PrivateKey,
attributes [0] IMPLICIT Attributes OPTIONAL
}
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL
}
ECParameters ::= CHOICE {
namedCurve OBJECT IDENTIFIER
-- implicitCurve NULL
-- specifiedCurve SpecifiedECDomain
}
ECPrivateKey ::= SEQUENCE {
version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
privateKey OCTET STRING,
parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
publicKey [1] BIT STRING OPTIONAL
}
Because of the two optional fields, there are 4 possible variants that need to
be parsed: no optional fields, only parameters, only public key, and both
optional fields. Previously mbedTLS was unable to parse keys with "only
parameters". Also, only "only public key" was tested. There was a test for "no
optional fields", but it was labelled incorrectly as SEC.1 and not run because
of a great renaming mixup.
check-names.sh reserves the prefix MBEDTLS_ for macros defined in
config.h so this name (or check-names.sh) had to change.
This is also more flexible because it allows for platforms that don't have
an EINTR equivalent or have multiple such values.
Also, introduce MBEDTLS_EINTR locally in net_sockets.c
for the platform-dependent return code macro used by
the `select` call to indicate that the poll was interrupted
by a signal handler: On Unix, the corresponding macro is EINTR,
while on Windows, it's WSAEINTR.
If the select UNIX system call is interrupted by a signal handler,
it is not automatically restarted but returns EINTR. This commit
modifies the use of select in mbedtls_net_poll from net_sockets.c
to retry the select call in this case.
Found by running:
CC=clang cmake -D CMAKE_BUILD_TYPE="Check"
tests/scripts/depend-pkalgs.pl
(Also tested with same command but CC=gcc)
Another PR will address improving all.sh and/or the depend-xxx.pl scripts
themselves to catch this kind of thing.
library\x509_crt.c(2137): warning C4267: 'function' : conversion from 'size_t' to 'int', possible loss of data
library\x509_crt.c(2265): warning C4267: 'function' : conversion from 'size_t' to 'int', possible loss of data
* development: (557 commits)
Add attribution for #1351 report
Adapt version_features.c
Note incompatibility of truncated HMAC extension in ChangeLog
Add LinkLibraryDependencies to VS2010 app template
Add ChangeLog entry for PR #1382
MD: Make deprecated functions not inline
Add ChangeLog entry for PR #1384
Have Visual Studio handle linking to mbedTLS.lib internally
Mention in ChangeLog that this fixes#1351
Add issue number to ChangeLog
Note in the changelog that this fixes an interoperability issue.
Style fix in ChangeLog
Add ChangeLog entries for PR #1168 and #1362
Add ChangeLog entry for PR #1165
ctr_drbg: Typo fix in the file description comment.
dhm: Fix typo in RFC 5114 constants
tests_suite_pkparse: new PKCS8-v2 keys with PRF != SHA1
data_files/pkcs8-v2: add keys generated with PRF != SHA1
tests/pkcs5/pbkdf2_hmac: extend array to accommodate longer results
tests/pkcs5/pbkdf2_hmac: add unit tests for additional SHA algorithms
...
Fix warnings from gcc -O -Wall about `ret` used uninitialized in
CMAC selftest auxiliary functions. The variable was indeed
uninitialized if the function was called with num_tests=0 (which
never happens).
Use specific instructions for moving bytes around in a word. This speeds
things up, and as a side-effect, slightly lowers code size.
ARIA_P3 and ARIA_P1 are now 1 single-cycle instruction each (those
instructions are available in all architecture versions starting from v6-M).
Note: ARIA_P3 was already translated to a single instruction by Clang 3.8 and
armclang 6.5, but not arm-gcc 5.4 nor armcc 5.06.
ARIA_P2 is already efficiently translated to the minimal number of
instruction (1 in ARM mode, 2 in thumb mode) by all tested compilers
Manually compiled and inspected generated code with the following compilers:
arm-gcc 5.4, clang 3.8, armcc 5.06 (with and without --gnu), armclang 6.5.
Size reduction (arm-none-eabi-gcc -march=armv6-m -mthumb -Os): 5288 -> 5044 B
Effect on executing time of self-tests on a few boards:
FRDM-K64F (Cortex-M4): 444 -> 385 us (-13%)
LPC1768 (Cortex-M3): 488 -> 432 us (-11%)
FRDM-KL64Z (Cortex-M0): 1429 -> 1134 us (-20%)
Measured using a config.h with no cipher mode and the following program with
aria.c and aria.h copy-pasted to the online compiler:
#include "mbed.h"
#include "aria.h"
int main() {
Timer t;
t.start();
int ret = mbedtls_aria_self_test(0);
t.stop();
printf("ret = %d; time = %d us\n", ret, t.read_us());
}
(A similar commit for Arm follows.)
Use specific instructions for moving bytes around in a word. This speeds
things up, and as a side-effect, slightly lowers code size.
ARIA_P3 (aka reverse byte order) is now 1 instruction on x86, which speeds up
key schedule. (Clang 3.8 finds this but GCC 5.4 doesn't.)
I couldn't find an Intel equivalent of ARM's ret16 (aka ARIA_P1), so I made it
two instructions, which is still much better than the code generated with
the previous mask-shift-or definition, and speeds up en/decryption. (Neither
Clang 3.8 nor GCC 5.4 find this.)
Before:
O aria.o ins
s 7976 43,865
2 10520 37,631
3 13040 28,146
After:
O aria.o ins
s 7768 33,497
2 9816 28,268
3 11432 20,829
For measurement method, see previous commit:
"aria: turn macro into static inline function"
This decreases the size with -Os by nearly 1k while
not hurting performance too much with -O2 and -O3
Before:
O aria.o ins
s 8784 41,408
2 11112 37,001
3 13096 27,438
After:
O aria.o ins
s 7976 43,865
2 10520 37,631
3 13040 28,146
(See previous commit for measurement details.)
Besides documenting types better and so on, this give the compiler more room
to optimise either for size or performance.
Here are some before/after measurements of:
- size of aria.o in bytes (less is better)
- instruction count for the selftest function (less is better)
with various -O flags.
Before:
O aria.o ins
s 10896 37,256
2 11176 37,199
3 12248 27,752
After:
O aria.o ins
s 8784 41,408
2 11112 37,001
3 13096 27,438
The new version allows the compiler to reach smaller size with -Os while
maintaining (actually slightly improving) performance with -O2 and -O3.
Measurements were done on x86_64 (but since this is mainly about inlining
code, this should transpose well to other platforms) using the following
helper program and script, after disabling CBC, CFB and CTR in config.h, in
order to focus on the core functions.
==> st.c <==
#include "mbedtls/aria.h"
int main( void ) {
return mbedtls_aria_self_test( 0 );
}
==> p.sh <==
#!/bin/sh
set -eu
ccount () {
(
valgrind --tool=callgrind --dump-line=no --callgrind-out-file=/dev/null --collect-atstart=no --toggle-collect=main $1
) 2>&1 | sed -n -e 's/.*refs: *\([0-9,]*\)/\1/p'
}
printf "O\taria.o\tins\n"
for O in s 2 3; do
GCC="gcc -Wall -Wextra -Werror -Iinclude"
$GCC -O$O -c library/aria.c
$GCC -O1 st.c aria.o -o st
./st
SIZE=$( du -b aria.o | cut -f1 )
INS=$( ccount ./st )
printf "$O\t$SIZE\t$INS\n"
done
We're not absolutely consistent in the rest of the library, but we tend to use
C99-style comments less often.
Change to use C89-style comments everywhere except for end-of-line comments
Those suites were defined in ciphersuite_definitions[] but not included in
ciphersuite_preference[] which meant they couldn't be negotiated unless
explicitly added by the user. Add them so that they're usable by default like
any other suite.
In 2.7.0, we replaced a number of MD functions with deprecated inline
versions. This causes ABI compatibility issues, as the functions are no
longer guaranteed to be callable when built into a shared library.
Instead, deprecate the functions without also inlining them, to help
maintain ABI backwards compatibility.
Add missing MBEDTLS_DEPRECATED_REMOVED guards around the definitions
of mbedtls_aes_decrypt and mbedtls_aes_encrypt.
This fixes the build under -Wmissing-prototypes -Werror.
Fixes#1388
Currently only SHA1 is supported as PRF algorithm for PBKDF2
(PKCS#5 v2.0).
This means that keys encrypted and authenticated using
another algorithm of the SHA family cannot be decrypted.
This deficiency has become particularly incumbent now that
PKIs created with OpenSSL1.1 are encrypting keys using
hmacSHA256 by default (OpenSSL1.0 used PKCS#5 v1.0 by default
and even if v2 was forced, it would still use hmacSHA1).
Enable support for all the digest algorithms of the SHA
family for PKCS#5 v2.0.
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
1. Style issues fixes - remove redundant spacing.
2. Remove depency of `MBEDTLS_RSA_C` in `pk_parse_public_keyfile_rsa()`
tests, as the function itself is dependent on it.
- Rephrase file/function/parameter/enum/define/error descriptions into full
and clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Add full standard name in file description.
GitHub PR: #1316
- Rephrase file/function/parameter/enum/define/error descriptions into full
and clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Rephrase the descriptions of all md_alg and hashlen parameters.
GitHub PR: #1327
- Rephrase file/function/parameter/enum/define/error descriptions into full
and clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Standardize defines documentation
GitHub PR: #1323
- Rephrase function/parameter/enum/define/error descriptions into full and
clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
GitHub PR: #1306
- Rephrase function/parameter/enum/define/error descriptions into full and
clear sentences.
- Make sure to adhering to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Fix iv_len values per the standard.
GitHub PR: #1305
- Separate "\file" blocks from copyright, so that Doxygen doesn't repeat
the copyright information in all the Detailed Descriptions.
- Improve phrasing and clarity of functions, parameters, defines and enums.
GitHub PR: #1292
A new test for mbedtls_timing_alarm(0) was introduced in PR 1136, which also
fixed it on Unix. Apparently test results on MinGW were not checked at that
point, so we missed that this new test was also failing on this platform.
Add MBEDTLS_ERR_XXX_HW_ACCEL_FAILED error codes for all cryptography
modules where the software implementation can be replaced by a hardware
implementation.
This does not include the individual message digest modules since they
currently have no way to return error codes.
This does include the higher-level md, cipher and pk modules since
alternative implementations and even algorithms can be plugged in at
runtime.
This commit allows users to provide alternative implementations of the
ECJPAKE interface through the configuration option MBEDTLS_ECJPAKE_ALT.
When set, the user must add `ecjpake_alt.h` declaring the same
interface as `ecjpake.h`, as well as add some compilation unit which
implements the functionality. This is in line with the preexisting
support for alternative implementations of other modules.
The corner cases fixed include:
* Allocating a buffer of size 0. With this change, the allocator now
returns a NULL pointer in this case. Note that changes in pem.c and
x509_crl.c were required to fix tests that did not work under this
assumption.
* Initialising the allocator with less memory than required for headers.
* Fix header chain checks for uninitialised allocator.
The _ext suffix suggests "new arguments", but the new functions have
the same arguments. Use _ret instead, to convey that the difference is
that the new functions return a value.
Conflict resolution:
* ChangeLog: put the new entries in their rightful place.
* library/x509write_crt.c: the change in development was whitespace
only, so use the one from the iotssl-1251 feature branch.
This commit adds some explicit downcasts from `size_t` to `uint8_t` in
the RSASSA signature encoding function `rsa_rsassa_pkcs1_v15_encode`.
The truncation is safe as it has been checked beforehand that the
respective values are in the range of a `uint8_t`.
1) `mbedtls_rsa_import_raw` used an uninitialized return
value when it was called without any input parameters.
While not sensible, this is allowed and should be a
succeeding no-op.
2) The MPI test for prime generation missed a return value
check for a call to `mbedtls_mpi_shift_r`. This is neither
critical nor new but should be fixed.
3) Both the RSA keygeneration example program and the
RSA test suites contained code initializing an RSA context
after a potentially failing call to CTR DRBG initialization,
leaving the corresponding RSA context free call in the
cleanup section of the respective function orphaned.
While this defect existed before, Coverity picked up on
it again because of newly introduced MPI's that were
also wrongly initialized only after the call to CTR DRBG
init. The commit fixes both the old and the new issue
by moving the initializtion of both the RSA context and
all MPI's prior to the first potentially failing call.
A previous commit changed the record encryption function
`ssl_encrypt_buf` to compute the MAC in a temporary buffer
and copying the relevant part of it (which is strictly smaller
if the truncated HMAC extension is used) to the outgoing message
buffer. However, the change was only made in case Encrypt-Then-MAC
was enabled, but not in case of MAC-Then-Encrypt. While this
doesn't constitute a problem, for the sake of uniformity this
commit changes `ssl_encrypt_buf` to compute the MAC in a temporary
buffer in this case, too.
The function `mbedtls_rsa_complete` is supposed to guarantee that
RSA operations will complete without failure. In contrast, it does
not ensure consistency of parameters, which is the task of the
checking functions `rsa_check_pubkey` and `rsa_check_privkey`.
Previously, the maximum allowed size of the RSA modulus was checked
in `mbedtls_rsa_check_pubkey`. However, exceeding this size would lead
to failure of some RSA operations, hence this check belongs to
`mbedtls_rsa_complete` rather than `mbedtls_rsa_check_pubkey`.
This commit moves it accordingly.
The function `pk_get_rsapubkey` originally performed some basic
sanity checks (e.g. on the size of public exponent) on the parsed
RSA public key by a call to `mbedtls_rsa_check_pubkey`.
This check was dropped because it is not possible to thoroughly
check full parameter sanity (i.e. that (-)^E is a bijection on Z/NZ).
Still, for the sake of not silently changing existing behavior,
this commit puts back the call to `mbedtls_rsa_check_pubkey`.
- Adapt the change in all.sh to the new keep-going mode
- Restore alphabetical order of configuration flags for
alternative implementations in config.h and rebuild
library/version_features.c
`mbedtls_rsa_deduce_primes` implicitly casts the result of a call to
`mbedtls_mpi_lsb` to a `uint16_t`. This is safe because of the size
of MPI's used in the library, but still may have compilers complain
about it. This commit makes the cast explicit.
Conflict resolution: additions in the same places as
upstream-public/pr/865, both adding into lexicographically sorted
lists, resolved by taking the additions in lexicographic order.
* development:
Timing self test: shorten redundant tests
Timing self test: increased duration
Timing self test: increased tolerance
Timing unit tests: more protection against infinite loops
Unit test for mbedtls_timing_hardclock
New timing unit tests
selftest: allow excluding a subset of the tests
selftest: allow running a subset of the tests
selftest: refactor to separate the list of tests from the logic
Timing self test: print some diagnosis information
mbedtls_timing_get_timer: don't use uninitialized memory
timing interface documentation: minor clarifications
Timing: fix mbedtls_set_alarm(0) on Unix/POSIX
* public/pr/1136:
Timing self test: shorten redundant tests
Timing self test: increased duration
Timing self test: increased tolerance
Timing unit tests: more protection against infinite loops
Unit test for mbedtls_timing_hardclock
New timing unit tests
selftest: allow excluding a subset of the tests
selftest: allow running a subset of the tests
selftest: refactor to separate the list of tests from the logic
Timing self test: print some diagnosis information
mbedtls_timing_get_timer: don't use uninitialized memory
timing interface documentation: minor clarifications
Timing: fix mbedtls_set_alarm(0) on Unix/POSIX
1. Surround the generate keys with
`#if ! defined(MBEDTLS_CMAC_ALT) || defined(MBEDTLS_SELF_TEST)`
to resolve build issue when `MBEDTLS_SELF_TEST` is defined for
alternative CMAC as well
2. Update ChangeLog
Increase the duration of the self test, otherwise it tends to fail on
a busy machine even with the recently upped tolerance. But run the
loop only once, it's enough for a simple smoke test.
mbedtls_timing_self_test fails annoyingly often when running on a busy
machine such as can be expected of a continous integration system.
Increase the tolerances in the delay test, to reduce the chance of
failures that are only due to missing a deadline on a busy machine.
Print some not-very-nice-looking but helpful diagnosis information if
the timing selftest fails. Since the failures tend to be due to heavy
system load that's hard to reproduce, this information is necessary to
understand what's going on.
mbedtls_timing_get_timer with reset=1 is called both to initialize a
timer object and to reset an already-initialized object. In an
initial call, the content of the data structure is indeterminate, so
the code should not read from it. This could crash if signed overflows
trap, for example.
As a consequence, on reset, we can't return the previously elapsed
time as was previously done on Windows. Return 0 as was done on Unix.
The POSIX/Unix implementation of mbedtls_set_alarm did not set the
mbedtls_timing_alarmed flag when called with 0, which was inconsistent
with what the documentation implied and with the Windows behavior.
* restricted/pr/403:
Correct record header size in case of TLS
Don't allocate space for DTLS header if DTLS is disabled
Improve debugging output
Adapt ChangeLog
Add run-time check for handshake message size in ssl_write_record
Add run-time check for record content size in ssl_encrypt_buf
Add compile-time checks for size of record content and payload
* development:
Don't split error code description across multiple lines
Register new error code in error.h
Move deprecation to separate section in ChangeLog
Extend scope of ERR_RSA_UNSUPPORTED_OPERATION error code
Adapt RSA test suite
Adapt ChangeLog
Deprecate usage of RSA primitives with wrong key type
* restricted/pr/397:
Don't split error code description across multiple lines
Register new error code in error.h
Move deprecation to separate section in ChangeLog
Extend scope of ERR_RSA_UNSUPPORTED_OPERATION error code
Adapt RSA test suite
Adapt ChangeLog
Deprecate usage of RSA primitives with wrong key type
In a previous PR (Fix heap corruption in implementation of truncated HMAC
extension #425) the place where MAC is computed was changed from the end of
the SSL I/O buffer to a local buffer (then (part of) the content of the local
buffer is either copied to the output buffer of compare to the input buffer).
Unfortunately, this change was made only for TLS 1.0 and later, leaving SSL
3.0 in an inconsistent state due to ssl_mac() still writing to the old,
hard-coded location, which, for MAC verification, resulted in later comparing
the end of the input buffer (containing the computed MAC) to the local buffer
(uninitialised), most likely resulting in MAC verification failure, hence no
interop (even with ourselves).
This commit completes the move to using a local buffer by using this strategy
for SSL 3.0 too. Fortunately ssl_mac() was static so it's not a problem to
change its signature.
Fix missing definition of mbedtls_zeroize when MBEDTLS_FS_IO is
disabled in the configuration.
Introduced by e7707228b4
Merge remote-tracking branch 'upstream-public/pr/1062' into development
In case truncated HMAC must be used but the Mbed TLS peer hasn't been updated
yet, one can use the compile-time option MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT to
temporarily fall back to the old, non-compliant implementation of the truncated
HMAC extension.
The truncated HMAC extension as described in
https://tools.ietf.org/html/rfc6066.html#section-7 specifies that when truncated
HMAC is used, only the HMAC output should be truncated, while the HMAC key
generation stays unmodified. This commit fixes Mbed TLS's behavior of also
truncating the key, potentially leading to compatibility issues with peers
running other stacks than Mbed TLS.
Details:
The keys for the MAC are pieces of the keyblock that's generated from the
master secret in `mbedtls_ssl_derive_keys` through the PRF, their size being
specified as the size of the digest used for the MAC, regardless of whether
truncated HMAC is enabled or not.
/----- MD size ------\ /------- MD size ----\
Keyblock +----------------------+----------------------+------------------+---
now | MAC enc key | MAC dec key | Enc key | ...
(correct) +----------------------+----------------------+------------------+---
In the previous code, when truncated HMAC was enabled, the HMAC keys
were truncated to 10 bytes:
/-10 bytes-\ /-10 bytes-\
Keyblock +-------------+-------------+------------------+---
previously | MAC enc key | MAC dec key | Enc key | ...
(wrong) +-------------+-------------+------------------+---
The reason for this was that a single variable `transform->maclen` was used for
both the keysize and the size of the final MAC, and its value was reduced from
the MD size to 10 bytes in case truncated HMAC was negotiated.
This commit fixes this by introducing a temporary variable `mac_key_len` which
permanently holds the MD size irrespective of the presence of truncated HMAC,
and using this temporary to obtain the MAC key chunks from the keyblock.
Previously, MAC validation for an incoming record proceeded as follows:
1) Make a copy of the MAC contained in the record;
2) Compute the expected MAC in place, overwriting the presented one;
3) Compare both.
This resulted in a record buffer overflow if truncated MAC was used, as in this
case the record buffer only reserved 10 bytes for the MAC, but the MAC
computation routine in 2) always wrote a full digest.
For specially crafted records, this could be used to perform a controlled write of
up to 6 bytes past the boundary of the heap buffer holding the record, thereby
corrupting the heap structures and potentially leading to a crash or remote code
execution.
This commit fixes this by making the following change:
1) Compute the expected MAC in a temporary buffer that has the size of the
underlying message digest.
2) Compare to this to the MAC contained in the record, potentially
restricting to the first 10 bytes if truncated HMAC is used.
A similar fix is applied to the encryption routine `ssl_encrypt_buf`.
* development: (30 commits)
update README file (#1144)
Fix typo in asn1.h
Improve leap year test names in x509parse.data
Correctly handle leap year in x509_date_is_valid()
Renegotiation: Add tests for SigAlg ext parsing
Parse Signature Algorithm ext when renegotiating
Minor style fix
config.pl get: be better behaved
config.pl get: don't rewrite config.h; detect write errors
Fixed "config.pl get" for options with no value
Fix typo and bracketing in macro args
Ensure failed test_suite output is sent to stdout
Remove use of GNU sed features from ssl-opt.sh
Fix typos in ssl-opt.sh comments
Add ssl-opt.sh test to check gmt_unix_time is good
Extend ssl-opt.h so that run_test takes function
Always print gmt_unix_time in TLS client
Restored note about using minimum functionality in makefiles
Note in README that GNU make is required
Fix changelog for ssl_server2.c usage fix
...
Fix the x509_get_subject_alt_name() function to not accept invalid
tags. The problem was that the ASN.1 class for tags consists of two
bits. Simply doing bit-wise and of the CONTEXT_SPECIFIC macro with the
input tag has the potential of accepting tag values 0x10 (private)
which would indicate that the certificate has an incorrect format.
This commit fixes a comparison of ssl_session->encrypt_then_mac against the
ETM-unrelated constant MBEDTLS_SSL_EXTENDED_MS_DISABLED. Instead,
MBEDTLS_SSL_ETM_DISABLED should be used.
The typo is has no functional effect since both constants have the same value 0.
Remove a check introduced in the previous buffer overflow fix with keys of
size 8N+1 which the subsequent fix for buffer start calculations made
redundant.
Added a changelog entry for the buffer start calculation fix.
For a key of size 8N+1, check that the first byte after applying the
public key operation is 0 (it could have been 1 instead). The code was
incorrectly doing a no-op check instead, which led to invalid
signatures being accepted. Not a security flaw, since you would need the
private key to craft such an invalid signature, but a bug nonetheless.
The check introduced by the previous security fix was off by one. It
fixed the buffer overflow but was not compliant with the definition of
PSS which technically led to accepting some invalid signatures (but
not signatures made without the private key).
I don't think this can cause a crash as the member accessed is in the
beginning of the context, so wouldn't be outside of valid memory if the actual
context was RSA.
Also, the mismatch will be caught later when checking signature, so the cert
chain will be rejected anyway.
Fix buffer overflow in RSA-PSS signature verification when the hash is
too large for the key size. Found by Seth Terashima, Qualcomm.
Added a non-regression test and a positive test with the smallest
permitted key size for a SHA-512 hash.
The function mbedtls_ecp_gen_keypair_base did not wipe the stack buffer used to
hold the private exponent before returning. This commit fixes this by not using
a stack buffer in the first place but instead calling mpi_fill_random directly
to acquire the necessary random MPI.
This commit modifies mpi_read_binary to always allocate the minimum number of
limbs required to hold the entire buffer provided to the function, regardless of
its content. Previously, leading zero bytes in the input data were detected and
used to reduce memory footprint and time, but this non-constant behavior turned
out to be non-tolerable for the cryptographic applications this function is used
for.
Previously, if `MBEDTLS_SSL_RENEGOTIATION` was disabled, incoming handshake
messages in `mbedtls_ssl_read` (expecting application data) lead to the
connection being closed. This commit fixes this, restricting the
`MBEDTLS_SSL_RENEGOTIATION`-guard to the code-paths responsible for accepting
renegotiation requests and aborting renegotiation attempts after too many
unexpected records have been received.
1) use `pk_get_rsapubkey` instead of reimplementing the parsing
2) rename the key files, according to their type and key size
3) comment in the data_files/Makefile hoe the keys were generated
4) Fix issue of failure parsing pkcs#1 DER format parsing, missed in previous commit
Signature algorithm extension was skipped when renegotiation was in
progress, causing the signature algorithm not to be known when
renegotiating, and failing the handshake. Fix removes the renegotiation
step check before parsing the extension.
As the optional RSA parameters DP, DQ and QP are effectively discarded (they are only considered for their length to
ensure that the key fills the entire buffer), it is not necessary to read them into separate MPI's.
The number of loop iterations per candidate in `mbedtls_deduce_primes` was off
by one. This commit corrects this and removes a toy non-example from the RSA
test suite, as it seems difficult to have the function fail on small values of N
even if D,E are corrupted.
Signature algorithm extension was skipped when renegotiation was in
progress, causing the signature algorithm not to be known when
renegotiating, and failing the handshake. Fix removes the renegotiation
step check before parsing the extension.
This commit splits off the RSA helper functions into separate headers and
compilation units to have a clearer separation of the public RSA interface,
intended to be used by end-users, and the helper functions which are publicly
provided only for the benefit of designers of alternative RSA implementations.
1) move the change into Features from Changes, in the changLog
2) Change the feature alternative configuration MBEDTLS_ECDH_ALT
definition to function alternative defintions
MBEDTLS_ECDH_COMPUTE_SHARED_ALT and MBEDTLS_ECDH_GEN_PUBLIC_ALT
1) update ChangLog to have new feature in Features instead of Changes
2) Change MBEDTLS_ECDSA_ALT to function specific alternative definitions:
MBEDTLS_ECDSA_SIGN_ALT, MBEDTLS_ECDSA_VERIFY_ALT and MBEDTLS_ECDSA_GENKEY_ALT
It is not necessary to pass a CSPRNG to `mbedtls_rsa_deduce_moduli`, as there
exist well-working static strategies, and even if a PRNG is preferred, a
non-secure one would be sufficient.
Further, the implementation is changed to use a static strategy for the choice
of candidates which according to some benchmarks even performs better than the
previous one using random candidate choices.
This commit reconciles the code path responsible for resending the
final DTLS handshake flight with the path for handling resending of
the other flights.
This commit restricts WANT_READ to indicate that no data is available on the
underlying transport. To signal the need for further processing - which was
previously also handled through this error code - a new internal error code
MBEDTLS_ERR_SSL_CONTINUE_PROCESSING is introduced.
DTLS records from previous epochs were incorrectly checked against the
current epoch transform's minimal content length, leading to the
rejection of entire datagrams. This commit fixed that and adapts two
test cases accordingly.
Internal reference: IOTSSL-1417
- Enhances the documentation of mbedtls_ssl_get_bytes_avail (return
the number of bytes left in the current application data record, if
there is any).
- Introduces a new public function mbedtls_ssl_check_pending for
checking whether any data in the internal buffers still needs to be
processed. This is necessary for users implementing event-driven IO
to decide when they can safely idle until they receive further
events from the underlying transport.
Give a note on the debugging output on the following occasions:
(1) The timer expires in mbedtls_ssl_fetch_input
(2) There's more than one records within a single datagram
Change ssl_parse_server_hello() so that the parsed first four random
bytes from the ServerHello message are printed by the TLS client as
a Unix timestamp regardless of whether MBEDTLS_DEBUG_C is defined. The
debug message will only be printed if debug_level is 3 or higher.
Unconditionally enabling the debug print enabled testing of this value.
Change ssl_parse_server_hello() so that the parsed first four random
bytes from the ServerHello message are printed by the TLS client as
a Unix timestamp regardless of whether MBEDTLS_DEBUG_C is defined. The
debug message will only be printed if debug_level is 3 or higher.
Unconditionally enabling the debug print enabled testing of this value.
Further, state explicitly that wrong key types need not be supported by alternative RSA implementations, and that those
may instead return the newly introduced error code MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION.
This commit returns to using constant macros instead of global variables for the DHM group constants. Further, macros
providing the binary encoding of the primes from RFC 3526 and RFC 7919 are added. The hex-string macros are deprecated.
This commit modifies the PKCS1 v1.5 signature verification function `mbedtls_rsa_rsassa_pkcs1_v15_verify` to prepare the
expected PKCS1-v1.5-encoded hash using the function also used by the signing routine `mbedtls_rsa_rsassa_pkcs1_v15_sign`
and comparing it to the provided byte-string afterwards. This comes at the benefits of (1) avoiding any error-prone
parsing, (2) removing the dependency of the RSA module on the ASN.1 parsing module, and (3) reducing code size.
This commit moves the code preparing PKCS1 v1.5 encoded hashes from `mbedtls_rsa_rsassa_pkcs1_v15_sign` to a separate
non-public function `rsa_rsassa_pkcs1_v15_encode`. This code-path will then be re-used by the signature verification function
`mbetls_rsa_rsassa_pkcs1_v15_verify` in a later commit.
Original intention was to be allowed to perform in-place operations like changing the byte-order before importing
parameters into an HSM. Now a copy is needed in this case, but there's no more danger of a user expecting the arguments
to be left untouched.
State explicitly that `pk_parse_pkcs8_undencrypted_der` and `pk_parse_key_pkcs8_encrypted_der` are not responsible for
zeroizing and freeing the provided key buffer.
This commit changes the implementation of `mbedtls_rsa_get_len` to return
`ctx->len` instead of always re-computing the modulus' byte-size via
`mbedtls_mpi_size`.
Although the variable ret was initialised to an error, the
MBEDTLS_MPI_CHK macro was overwriting it. Therefore it ended up being
0 whenewer the bignum computation was successfull and stayed 0
independently of the actual check.
This commit renames the test-only flag MBEDTLS_ENTROPY_HAVE_STRONG to ENTROPY_HAVE_STRONG to make it more transparent
that it's an internal flag, and also to content the testscript tests/scripts/check-names.pl which previously complained
about the macro occurring in a comment in `entropy.c` without being defined in a library file.
This commit removes extension-writing code for X.509 non-v3 certificates from
mbedtls_x509write_crt_der. Previously, even if no extensions were present an
empty sequence would have been added.
Fix compilation error on Mingw32 when `_TRUNCATE` is defined. Use
`_TRUNCATE` only if `__MINGW32__` not defined. Fix suggested by
Thomas Glanzmann and Nick Wilson on issue #355
* mbedtls-2.6: (27 commits)
Update version number to 2.6.0
Fix language in Changelog for clarity
Improve documentation of PKCS1 decryption functions
Fix style and missing item in ChangeLog
Add credit to Changelog to fix for #666
Fix naked call to time() with platform call
Fix ChangeLog for duplication after merge
Rename time and index parameter to avoid name conflict.
Correct comment
Adapt ChangeLog
Reliably zeroize sensitive data in AES sample application
Reliably zeroize sensitive data in Crypt-and-Hash sample application
Fix potential integer overflow parsing DER CRT
Fix potential integer overflow parsing DER CRL
Move the git scripts to correct path
Update after @sbutcher-arm comments
Fix slash direction for linux path
Add note for the git_hoos README file
Pre push hook script
Check return code of mbedtls_mpi_fill_random
...
The stack buffer used to hold the decrypted key in pk_parse_pkcs8_encrypted_der
was statically sized to 2048 bytes, which is not enough for DER encoded 4096bit
RSA keys.
This commit resolves the problem by performing the key-decryption in-place,
circumventing the introduction of another stack or heap copy of the key.
There are two situations where pk_parse_pkcs8_encrypted_der is invoked:
1. When processing a PEM-encoded encrypted key in mbedtls_pk_parse_key.
This does not need adaption since the PEM context used to hold the decoded
key is already constructed and owned by mbedtls_pk_parse_key.
2. When processing a DER-encoded encrypted key in mbedtls_pk_parse_key.
In this case, mbedtls_pk_parse_key calls pk_parse_pkcs8_encrypted_der with
the buffer provided by the user, which is declared const. The commit
therefore adds a small code paths making a copy of the keybuffer before
calling pk_parse_pkcs8_encrypted_der.
If CRT is not used, the helper fields CRT are not assumed to be present in the
RSA context structure, so do the verification directly in this case. If CRT is
used, verification could be done using CRT, but we're sticking to ordinary
verification for uniformity.
This commit adds the function mbedtls_rsa_validate_crt for validating a set of CRT parameters. The function
mbedtls_rsa_check_crt is simplified accordingly.
If rsm != NULL then the curve type has to be Short Weierstrass, as we don't
implement restartable Montgomery now. If and when we do, then it's better to
check for the subcontext only, and not for the curve type.
Exactly one of three ways will be used, so make that clear by using an
if 1 else if 2 else 3 structure.
While at it, don't initialize variables at declaration, just to make extra
sure they're properly initialized afterwards in all code paths.
As done by previous commits for ECC and ECDSA:
- use explicit state assignments rather than increment
- always place the state update right before the operation label
This will make it easier to add restart support for other operations later if
desired.
SSL-specific changes:
- remove useless states: when the last restartable operation on a message is
complete, ssl->state is incremented already, so we don't need any additional
state update: ecrs_state is only meant to complement ssl->state
- rename remaining states consistently as <message>_<operation>
- move some labels closer to the actual operation when possible (no assignment
to variables used after the label between its previous and current position)
Systematically assign state just before the next operation that may return,
rather that just after the previous one. This makes things more local. (For
example, previously precompute_comb() has to handle a state reset for
mul_comb_core(), a kind of coupling that's best avoided.)
Note that this change doesn't move the location of state updates relative
to any potential return point, which is all that matters.
Incrementing the state is error-prone as we can end up doing it too many times
(loops) or not enough (skipped branches), or just make programming mistakes
(eg. the state was incremented twice at the end, so it ended up with a value
not in the enum...)
This is the first step of the rework, the next one will rationalize where the
state assignments are done.
Primality testing is guarded by the configuration flag MBEDTLS_GENPRIME and used in the new RSA helper functions. This
commit adds a corresponding preprocessor directive.
The call would anyway check for pointer equality and return early, but it
doesn't hurt to save a function call, and also this follows more uniformly the
pattern that those two lines go together:
#if defined(MBEDTLS_ECP_RESTARTBLE)
if( rs_ctx != NULL && ...
Alternative RSA implementations can be provided by defining MBEDTLS_RSA_ALT in
config.h, defining an mbedtls_rsa_context struct in a new file rsa_alt.h and
re-implementing the RSA interface specified in rsa.h.
Through the previous reworkings, the adherence to the interface is the only
implementation obligation - in particular, implementors are free to use a
different layout for the RSA context structure.
Child was almost redundant as it's already saved in ver_chain, except it was
multiplexed to also indicate whether an operation is in progress. This commit
removes it and introduces an explicit state variable instead.
This state can be useful later if we start returning IN_PROGRESS at other
points than find_parent() (for example when checking CRL).
Note that the state goes none -> find_parent and stays there until the context
is free(), as it's only on the first call that nothing was in progress.
Some parts were already implicitly using this as the two ifdefs were nested,
and some others didn't, which resulted in compile errors in some configs. This
fixes those errors and saves a bit of code+RAM that was previously wasted when
ECP_RESTARTABLE was defined but ECDSA_C wasn't
Previously we kept the ecdsa context created by the PK layer for ECDSA
operations on ECKEY in the ecdsa_restart_ctx structure, which was wrong, and
caused by the fact that we didn't have a proper handling of restart
sub-contexts in the PK layer.
