This option allows to test the constant-flow nature of selected code, using
MemSan and the fundamental observation behind ctgrind that the set of
operations allowed on undefined memory by dynamic analysers is the same as the
set of operations allowed on secret data to avoid leaking it to a local
attacker via side channels, namely, any operation except branching and
dereferencing.
(This isn't the full story, as on some CPUs some instructions have variable
execution depending on the inputs, most notably division and on some cores
multiplication. However, testing that no branch or memory access depends on
secret data is already a good start.)
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The dummy implementation is not constant-flow at all for now, it's just
here as a starting point and a support for developing the tests and putting
the infrastructure in place.
Depending on the implementation strategy, there might be various corner cases
depending on where the lengths fall relative to block boundaries. So it seems
safer to just test all possible lengths in a given range than to use only a
few randomly-chosen values.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The condition is a complex and repeated a few times. There were already some
inconsistencies in the repetitions as some of them forgot about DES.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
- it's 2020, there shouldn't be too many systems out there where SHA-1 is the
only available hash option, so its usefulness is limited
- OTOH testing configurations without SHA-2 reveal bugs that are not easy to
fix in a fully compatible way
So overall, the benefit/cost ratio is not good enough to justify keeping SHA-1
as a fallback option here.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This reverts commit 424210a93c.
This change was not safe enough for an LTS branch, as it might break code
that assumes it's safe to declare an object of type mbedtls_entropy_context
even when MBEDTLS_ENTROPY_C is undefined.
The build was failing in all.sh component test_no_drbg_no_sha2 because
entropy.h was referencing mbedtls_sha256_context but not including sha256.h
when SHA-256 and SHA-512 were both disabled. This broke query_config.c which
includes entropy.h (and actually all headers) unconditionally.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The dependency on a DRBG module was perhaps a bit strict for LTS branches, so
let's have an option that works with no DRBG when at least one SHA module is
present.
This changes the internal API of ecp_drbg_seed() by adding the size of the
MPI as a parameter. Re-computing the size from the number of limbs doesn't
work too well here as we're writing out to a fixed-size buffer and for some
curves (P-521) that would round up too much. Using mbedtls_mpi_get_len() is
not entirely satisfactory either as it would mean using a variable-length
encoding, with could open side channels.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The case of MBEDTLS_ECP_RESTARTABLE isn't handled correctly yet: in that case
the DRBG instance should persist when resuming the operation. This will be
addressed in the next commit.
When both CTR_DRBG and HMAC_DRBG are available, CTR_DRBG is preferred since
both are suitable but CTR_DRBG tends to be faster and I needed a tie-breaker.
There are currently three possible cases to test:
- NO_INTERNAL_RNG is set -> tested in test_ecp_no_internal_rng
- it's unset and CTR_DRBG is available -> tested in the default config
- it's unset and CTR_DRBG is disabled -> tested in
test_ecp_internal_rng_no_ctr_drbg
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
No effect so far, except on dependency checking, as the feature it's meant to
disable isn't implemented yet (so the descriptions in config.h and the
ChangeLog entry are anticipation for now).
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This will allow us to ship the LTS branches in a single archive
This commit was generated using the following script:
# ========================
#!/bin/sh
header1='\ * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later\
*\
* This file is provided under the Apache License 2.0, or the\
* GNU General Public License v2.0 or later.\
*\
* **********\
* Apache License 2.0:\
*\
* Licensed under the Apache License, Version 2.0 (the "License"); you may\
* not use this file except in compliance with the License.\
* You may obtain a copy of the License at\
*\
* http://www.apache.org/licenses/LICENSE-2.0\
*\
* Unless required by applicable law or agreed to in writing, software\
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT\
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\
* See the License for the specific language governing permissions and\
* limitations under the License.\
*\
* **********\
*\
* **********\
* GNU General Public License v2.0 or later:\
*\
* This program is free software; you can redistribute it and/or modify\
* it under the terms of the GNU General Public License as published by\
* the Free Software Foundation; either version 2 of the License, or\
* (at your option) any later version.\
*\
* This program is distributed in the hope that it will be useful,\
* but WITHOUT ANY WARRANTY; without even the implied warranty of\
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\
* GNU General Public License for more details.\
*\
* You should have received a copy of the GNU General Public License along\
* with this program; if not, write to the Free Software Foundation, Inc.,\
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.\
*\
* **********'
find -path './.git' -prune -o '(' -name '*.c' -o -name '*.cpp' -o -name '*.fmt' -o -name '*.h' ')' -print | xargs sed -i "
# Normalize the first line of the copyright headers (no text on the first line of a block comment)
/^\/\*.*Copyright.*Arm/I s/\/\*/&\n */
# Insert new copyright header
/SPDX-License-Identifier/ i\
$header1
# Delete old copyright header
/SPDX-License-Identifier/,$ {
# Delete lines until the one preceding the mbedtls declaration
N
1,/This file is part of/ {
/This file is part of/! D
}
}
"
# Format copyright header for inclusion into scripts
header2=$(echo "$header1" | sed 's/^\\\? \* \?/#/')
find -path './.git' -prune -o '(' -name '*.gdb' -o -name '*.pl' -o -name '*.py' -o -name '*.sh' ')' -print | xargs sed -i "
# Insert new copyright header
/SPDX-License-Identifier/ i\
$header2
# Delete old copyright header
/SPDX-License-Identifier/,$ {
# Delete lines until the one preceding the mbedtls declaration
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1,/This file is part of/ {
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"
# ========================
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
By convention, in the project, functions that have a
check or similar in the name return 0 if the check
succeeds, non-zero otherwise. Align with this for
mbedtls_ssl_chk_buf_ptr().
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit adds an error condition for bad user configurations
and updates the number of SSL module errors in error.h.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit adds a macro for buffer bounds checks in the SSL
module. It takes the buffer's current and end position as the
first argument(s), followed by the needed space; if the
available space is too small, it returns an SSL_BUFFER_TOO_SMALL
error.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Additional sanity checks in check_config.h to ensure:
* if test certificates are included (MBEDTLS_CERTS_C) there must be also be
support for the core X509 feature (MBEDTLS_X509_USE_C). This has a
secondary dependency on the public key abstraction layer (MBEDTLS_PK_C),
necessary as the certificates will either be signed by RSA or ECDSA, and
therefore need to be part of the library.
* if any of the TLS protocols are defined (MBEDTLS_SSL_PROTO_xxx) then a
key exchange method must also be defined (MBEDTLS_KEY_EXCHANGE_xxx).
Anyone who knows the library will probably not make these mistakes or will
quickly diagnose and fix them, but it is possible to compile and link both
configurations if you build only the library and not the example programs, and
therefore users may not realise immediately that there's a mistake, only
discovering it at runtime.
These checks may therefore save someone some time.
Signed-off-by: Simon Butcher <simon.butcher@arm.com>
* origin/mbedtls-2.16:
Fix some pylint warnings
Enable more test cases without MBEDTLS_MEMORY_DEBUG
More accurate test case description
Clarify that the "FATAL" message is expected
Note that mbedtls_ctr_drbg_seed() must not be called twice
Fix CTR_DRBG benchmark
Changelog entry for xxx_drbg_set_entropy_len before xxx_drbg_seed
CTR_DRBG: support set_entropy_len() before seed()
CTR_DRBG: Don't use functions before they're defined
HMAC_DRBG: support set_entropy_len() before seed()
The signature of mbedtls_mpi_cmp_mpi_ct() meant to support using it in
place of mbedtls_mpi_cmp_mpi(). This meant full comparison functionality
and a signed result.
To make the function more universal and friendly to constant time
coding, we change the result type to unsigned. Theoretically, we could
encode the comparison result in an unsigned value, but it would be less
intuitive.
Therefore we won't be able to represent the result as unsigned anymore
and the functionality will be constrained to checking if the first
operand is less than the second. This is sufficient to support the
current use case and to check any relationship between MPIs.
The only drawback is that we need to call the function twice when
checking for equality, but this can be optimised later if an when it is
needed.
You can't reuse a CTR_DRBG context without free()ing it and
re-init()ing it. This generally happened to work, but was never
guaranteed. It could have failed with alternative implementations of
the AES module because mbedtls_ctr_drbg_seed() calls
mbedtls_aes_init() on a context which is already initialized if
mbedtls_ctr_drbg_seed() hasn't been called before, plausibly causing a
memory leak.
Calling free() and seed() with no intervening init fails when
MBEDTLS_THREADING_C is enabled and all-bits-zero is not a valid mutex
representation.
mbedtls_ctr_drbg_seed() always set the entropy length to the default,
so a call to mbedtls_ctr_drbg_set_entropy_len() before seed() had no
effect. Change this to the more intuitive behavior that
set_entropy_len() sets the entropy length and seed() respects that and
only uses the default entropy length if there was no call to
set_entropy_len().
The former test-only function mbedtls_ctr_drbg_seed_entropy_len() is
no longer used, but keep it for strict ABI compatibility.
mbedtls_hmac_drbg_seed() always set the entropy length to the default,
so a call to mbedtls_hmac_drbg_set_entropy_len() before seed() had no
effect. Change this to the more intuitive behavior that
set_entropy_len() sets the entropy length and seed() respects that and
only uses the default entropy length if there was no call to
set_entropy_len().
The documentation of HMAC_DRBG erroneously claimed that
mbedtls_hmac_drbg_set_entropy_len() had an impact on the initial
seeding. This is in fact not the case: mbedtls_hmac_drbg_seed() forces
the entropy length to its chosen value. Fix the documentation.
The documentation of CTR_DRBG erroneously claimed that
mbedtls_ctr_drbg_set_entropy_len() had an impact on the initial
seeding. This is in fact not the case: mbedtls_ctr_drbg_seed() forces
the initial seeding to grab MBEDTLS_CTR_DRBG_ENTROPY_LEN bytes of
entropy. Fix the documentation and rewrite the discussion of the
entropy length and the security strength accordingly.
Explain how MBEDTLS_CTR_DRBG_ENTROPY_LEN is set next to the security
strength statement, rather than giving a partial explanation (current
setting only) in the documentation of MBEDTLS_CTR_DRBG_ENTROPY_LEN.
NIST and many other sources call it a "personalization string", and
certainly not "device-specific identifiers" which is actually somewhat
misleading since this is just one of many things that might go into a
personalization string.
Improve the formatting and writing of the documentation based on what
had been done for CTR_DRBG.
Document the maximum size and nullability of some buffer parameters.
