Starting with commit 49e94e3, the do/while loop in
`rsa_prepare_blinding()` was changed to a `do...while(0)`, which
prevents retry from being effective and leaves dead code.
Restore the while condition to retry, and lift the calls to finish the
computation out of the while loop by by observing that they are
performed only when `mbedtls_mpi_inv_mod()` returns zero.
Signed-off-by: Peter Kolbus <peter.kolbus@garmin.com>
* mbedtls-2.7: (28 commits)
A different approach of signed-to-unsigned comparison
Update the copy of tests/data_files/server2-sha256.crt in certs.c
Fix bug in redirection of unit test outputs
Backport e2k support to mbedtls-2.7
Don't forget to free G, P, Q, ctr_drbg, and entropy
Regenerate server2-sha256.crt with a PrintableString issuer
Regenerate test client certificates with a PrintableString issuer
cert_write: support all hash algorithms
compat.sh: stop using allow_sha1
compat.sh: quit using SHA-1 certificates
compat.sh: enable CBC-SHA-2 suites for GnuTLS
Fix license header in pre-commit hook
Update copyright notices to use Linux Foundation guidance
Fix building on NetBSD 9.0
Remove obsolete buildbot reference in compat.sh
Fix misuse of printf in shell script
Fix added proxy command when IPv6 is used
Simplify test syntax
Fix logic error in setting client port
ssl-opt.sh: include test name in log files
...
As a result, the copyright of contributors other than Arm is now
acknowledged, and the years of publishing are no longer tracked in the
source files.
Also remove the now-redundant lines declaring that the files are part of
MbedTLS.
This commit was generated using the following script:
# ========================
#!/bin/sh
# Find files
find '(' -path './.git' -o -path './3rdparty' ')' -prune -o -type f -print | xargs sed -bi '
# Replace copyright attribution line
s/Copyright.*Arm.*/Copyright The Mbed TLS Contributors/I
# Remove redundant declaration and the preceding line
$!N
/This file is part of Mbed TLS/Id
P
D
'
# ========================
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
inv_mod() already returns a specific error code if the value is not
invertible, so no need to check in advance that it is. Also, this is a
preparation for blinding the call to inv_mod(), which is made easier by
avoiding the redundancy (otherwise the call to gcd() would need to be blinded
too).
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\
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* 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
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1,/This file is part of/ {
/This file is part of/! D
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"
# 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
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1,/This file is part of/ {
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# ========================
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
The code assumed that `int x = - (unsigned) u` with 0 <= u < INT_MAX
sets `x` to the negative of u, but actually this calculates
(UINT_MAX - u) and then converts this value to int, which overflows.
Cast to int before applying the unary minus operator to guarantee the
desired behavior.
The code was making two unsequenced reads from volatile locations.
This is undefined behavior. It was probably harmless because we didn't
care in what order the reads happened and the reads were from ordinary
memory, but UB is UB and IAR8 complained.
Get rid of the variable p. This makes it more apparent where the code
accesses the buffer at an offset whose value is sensitive.
No intended behavior change in this commit.
Rather than doing the quadratic-time constant-memory-trace on the
whole working buffer, do it on the section of the buffer where the
data to copy has to lie, which can be significantly smaller if the
output buffer is significantly smaller than the working buffer, e.g.
for TLS RSA ciphersuites (48 bytes vs MBEDTLS_MPI_MAX_SIZE).
In mbedtls_rsa_rsaes_pkcs1_v15_decrypt, use size_greater_than (which
is based on bitwise operations) instead of the < operator to compare
sizes when the values being compared must not leak. Some compilers
compile < to a branch at least under some circumstances (observed with
gcc 5.4 for arm-gnueabi -O9 on a toy program).
Replace memmove(to, to + offset, length) by a functionally equivalent
function that strives to make the same memory access patterns
regardless of the value of length. This fixes an information leak
through timing (especially timing of memory accesses via cache probes)
that leads to a Bleichenbacher-style attack on PKCS#1 v1.5 decryption
using the plaintext length as the observable.
mbedtls_rsa_rsaes_pkcs1_v15_decrypt takes care not to reveal whether
the padding is valid or not, even through timing or memory access
patterns. This is a defense against an attack published by
Bleichenbacher. The attacker can also obtain the same information by
observing the length of the plaintext. The current implementation
leaks the length of the plaintext through timing and memory access
patterns.
This commit is a first step towards fixing this leak. It reduces the
leak to a single memmove call inside the working buffer.
Make the function more robust by taking an arbitrary zero/nonzero
argument instead of insisting on zero/all-bits-one. Update and fix its
documentation.
mbedtls_rsa_rsaes_pkcs1_v15_decrypt took care of calculating the
padding length without leaking the amount of padding or the validity
of the padding. However it then skipped the copying of the data if the
padding was invalid, which could allow an adversary to find out
whether the padding was valid through precise timing measurements,
especially if for a local attacker who could observe memory access via
cache timings.
Avoid this leak by always copying from the decryption buffer to the
output buffer, even when the padding is invalid. With invalid padding,
copy the same amount of data as what is expected on valid padding: the
minimum valid padding size if this fits in the output buffer,
otherwise the output buffer size. To avoid leaking payload data from
an unsuccessful decryption, zero the decryption buffer before copying
if the padding was invalid.
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.
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.
If RSA-CRT is used for signing, and if an attacker can cause a glitch
in one of the two computations modulo P or Q, the difference between
the faulty and the correct signature (which is not secret) will be
divisible by P or Q, but not by both, allowing to recover the private
key by taking the GCD with the public RSA modulus N. This is known as
the Bellcore Glitch Attack. Verifying the RSA signature before handing
it out is a countermeasure against it.
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.
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.
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).
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.
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.
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.
