Commit graph

688 commits

Author SHA1 Message Date
Hanno Becker dbd3e88479 Fix mbedtls_ssl_get_record_expansion() for CBC modes
`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.

Previously, 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 this bug. Fixes #1914.
2018-08-17 10:12:21 +01:00
Simon Butcher 7daacda940 Merge remote-tracking branch 'restricted/pr/494' into mbedtls-2.7 2018-07-24 23:40:53 +01:00
Simon Butcher d5a3ed36b8 Merge remote-tracking branch 'public/pr/1863' into mbedtls-2.7 2018-07-24 12:57:15 +01:00
Simon Butcher bc5ec41c01 Merge remote-tracking branch 'public/pr/1847' into mbedtls-2.7 2018-07-19 19:48:25 +01:00
Angus Gratton 8946b0dd30 Check for invalid short Alert messages
(Short Change Cipher Spec & Handshake messages are already checked for.)
2018-07-16 20:12:56 +01:00
Angus Gratton b91cb6e1e6 TLSv1.2: Treat zero-length fragments as invalid, unless they are application data
TLS v1.2 explicitly disallows other kinds of zero length fragments (earlier standards
don't mention zero-length fragments at all).
2018-07-16 20:12:55 +01:00
Angus Gratton 1ba8e911ec CBC mode: Allow zero-length message fragments (100% padding)
Fixes https://github.com/ARMmbed/mbedtls/issues/1632
2018-07-16 20:12:47 +01:00
Manuel Pégourié-Gonnard 7c34432b2d Avoid debug message that might leak length
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.
2018-07-12 10:18:37 +02:00
Manuel Pégourié-Gonnard aeeaaf271c Add counter-measure to cache-based Lucky 13
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.
2018-07-12 10:18:37 +02:00
Philippe Antoine 33e5c32a5b Fixes different off by ones 2018-07-09 10:39:02 +02:00
niisato a35dbf155c about a issue Replace "new" variable #1782 2018-06-29 11:17:41 +01:00
Andres Amaya Garcia 0fc4e0878e Document ssl_write_real() behaviour in detail 2018-06-21 19:29:49 +01:00
Simon Butcher bb5e1c3973 Fix multiple quality issues in the source
This PR fixes multiple issues in the source code to address issues raised by
tests/scripts/check-files.py. Specifically:
 * incorrect file permissions
 * missing newline at the end of files
 * trailing whitespace
 * Tabs present
 * TODOs in the souce code
2018-06-08 11:14:43 +01:00
Gilles Peskine bb07ca0bfb Fix Lucky13 attack protection when using HMAC-SHA-384
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 was correct for most supported hashes but not for
SHA-384. Adapt the formula to 128-byte blocks for SHA-384.
2018-06-06 17:23:31 +02:00
Andrzej Kurek 149f3a4d73 Change variable bytes_written to header_bytes in record decompression
The name is changed to better reflect the input, decompression case
2018-04-24 06:32:44 -04:00
Andrzej Kurek c3a3e2df0e ssl_tls: Fix invalid buffer sizes during compression / decompression
Adjust information passed to zlib to include already written data.
2018-04-23 08:39:13 -04:00
Jaeden Amero d8e0cec63b Merge remote-tracking branch 'upstream-public/pr/1464' into mbedtls-2.7-proposed 2018-04-03 18:27:54 +01:00
Jaeden Amero b5f53b1039 Merge remote-tracking branch 'upstream-public/pr/1401' into mbedtls-2.7-proposed 2018-04-03 12:09:45 +01:00
mohammad1603 29ed80f79f Fix compatibility problem in the printed message
Replace %zu with %lu and add cast for the printed value.
2018-04-02 07:34:26 -07:00
mohammad1603 44a6a688c8 Check whether INT_MAX larger than SIZE_MAX scenario
Check whether INT_MAX larger than SIZE_MAX scenario
2018-03-28 23:45:33 -07:00
mohammad1603 2ea2d686e2 Verify that f_send and f_recv send and receive the expected length
Verify that f_send and f_recv send and receive the expected length

Conflicts:
	ChangeLog
2018-03-22 14:56:28 -07:00
Gilles Peskine 21701305ce Robustness fix in mbedtls_ssl_derive_keys
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.
2018-03-20 18:41:25 +01:00
mohammad1603 b11af86daf Avoid wraparound on in_left
Avoid wraparound on in_left
2018-03-19 07:18:13 -07:00
Gilles Peskine 158fc33368 Merge remote-tracking branch 'upstream-public/pr/1296' into HEAD 2018-03-11 00:47:54 +01:00
mohammad1603 6085c721d2 Backport 2.7:Add guard to out_left to avoid negative values
Add guard to out_left to avoid negative values
2018-02-25 01:18:46 -08:00
Gilles Peskine 3f9cff20d7 Merge branch 'prr_424' into mbedtls-2.7-proposed 2018-02-22 16:07:32 +01:00
Jaeden Amero 784de59ccd Merge remote-tracking branch 'upstream-restricted/pr/410' into development-restricted
- Resolve ChangeLog conflicts
- Update Doxygen warning block in dhm.h to render correctly
- Prefix the exported identifier deprecated_constant_t with mbedtls_
2018-01-26 18:43:04 +00:00
Jaeden Amero 66954e1c1f Merge branch 'development' into development-restricted 2018-01-25 17:28:31 +00:00
Ron Eldor 5e9f14d4d9 Set correct minimal versions in default conf
Set `MBEDTLS_SSL_MIN_MAJOR_VERSION` and `MBEDTLS_SSL_MIN_MINOR_VERSION`
instead of `MBEDTLS_SSL_MAJOR_VERSION_3` and `MBEDTLS_SSL_MINOR_VERSION_1`
2018-01-22 22:06:44 +01:00
Gilles Peskine 9e4f77c606 New MD API: rename functions from _ext to _ret
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.
2018-01-22 11:54:42 +01:00
Gilles Peskine d91f2a26cb Merge branch 'development' into iotssl-1251-2.7
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.
2018-01-19 11:25:10 +01:00
Gilles Peskine 82d607eb9e Merge remote-tracking branch 'upstream-restricted/pr/433' into development-restricted 2017-12-19 19:20:27 +01:00
Manuel Pégourié-Gonnard d04c623ed6 Merge remote-tracking branch 'restricted/pr/403' into development-restricted
* 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
2017-12-19 11:31:20 +01:00
Manuel Pégourié-Gonnard b053efb295 Fix magic constant in previous commit 2017-12-19 10:03:46 +01:00
Manuel Pégourié-Gonnard 464147cadc Fix SSLv3 MAC computation
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.
2017-12-18 18:04:59 +01:00
Gilles Peskine 02e28fe0fd Merge remote-tracking branch 'upstream-restricted/pr/425' into development-restricted 2017-12-01 17:58:12 +01:00
Gilles Peskine 0960f0663e Merge branch 'development' into development-restricted 2017-11-29 21:07:55 +01:00
Gilles Peskine 0884f4811b Merge remote-tracking branch 'upstream-public/pr/1141' into development 2017-11-29 20:50:59 +01:00
Hanno Becker 1df4923eb1 Remove compile-time deprecation warning for TRUNCATED_HMAC_COMPAT 2017-11-29 16:55:56 +00:00
Gilles Peskine c753f5daf4 Merge remote-tracking branch 'upstream-restricted/pr/369' into development-restricted 2017-11-28 14:16:47 +01:00
Gilles Peskine 68306ed31f Merge remote-tracking branch 'upstream-public/pr/1094' into development 2017-11-23 20:02:46 +01:00
Hanno Becker 4c2ac7ef58 Deprecate MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT 2017-11-21 18:28:35 +00:00
Hanno Becker 563423fb21 Improve documentation of MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT option
Explain more clearly when this option should be used and which versions of Mbed
TLS build on the non-compliant implementation.
2017-11-21 17:20:17 +00:00
Hanno Becker e89353a6b4 Add fallback to non-compliant truncated HMAC for compatibiltiy
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.
2017-11-20 16:50:43 +00:00
Hanno Becker 81c7b18351 Don't truncate MAC key when truncated HMAC is negotiated
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.
2017-11-20 16:25:50 +00:00
Hanno Becker 992b6872f3 Fix heap corruption in ssl_decrypt_buf
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`.
2017-11-20 08:52:25 +00:00
Manuel Pégourié-Gonnard 888fedea06 Merge branch 'development' into development-restricted
* 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
  ...
2017-11-14 08:24:22 +01:00
Hanno Becker 21df7f90d2 Fix handling of HS msgs in mbedtls_ssl_read if renegotiation unused
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.
2017-10-17 11:03:26 +01:00
Hanno Becker b4ff0aafd9 Swap branches accepting/refusing renegotiation in in ssl_read 2017-10-17 11:03:04 +01:00
Hanno Becker 1a9a51c7cf Enhance documentation of ssl_write_hostname_ext, adapt ChangeLog.
Add a reference to the relevant RFC, adapt ChangeLog.
2017-10-06 11:58:50 +01:00