Zeroize local MAC variables used for CBC+HMAC cipher suites. In encryption,
this is just good hygiene but probably not needed for security since the
data protected by the MAC that could leak is about to be transmitted anyway.
In DTLS decryption, this could be a security issue since an adversary could
learn the MAC of data that they were trying to inject. At least with
encrypt-then-MAC, the adversary could then easily inject a datagram with
a corrected packet. TLS would still be safe since the receiver would close
the connection after the bad MAC.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
All function declaration provided by ssl_invasive.h is needed only for
testing purposes and all of them are provided by constant_time.h as well.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
There were multiple functions called mbedtls_cf_size_bool_eq. They had exactly
the same behavior, so move the one in bignum.c and remove the other.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
exchange groups of the byte reading macros with MBEDTLS_PUT_UINTxyz
and then shift the pointer afterwards. Easier to read as you can
see how big the data is that you are putting in, and in the case of
UINT32 AND UINT64 it saves some vertical space.
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
The previous commits cherry picked from the changes made with relation
to the development branch. This commit makes the appropriate chnages to
the files not present in the development branch.
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
byte shifting opertations throughout library/ were only replaced with
the byte reading macros when an 0xff mask was being used.
The byte reading macros are now more widley used, however they have not
been used in all cases of a byte shift operation, as it detracted from
the immediate readability or otherwise did not seem appropriate.
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
The CHAR macros casted to an unsigned char which in this project
is garunteed to be 8 bits - the same as uint8_t (which BYTE casts
to) therefore, instances of CHAR have been swapped with BYTE and
the number of macros have been cut down
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
These cast to an unsigned char rather than a uint8_t
like with MBEDTLS_BYTE_x
These save alot of space and will improve maintence by
replacing the appropriate code with MBEDTLS_CHAR_x
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
As per tests/scripts/check-names.sh, macros in
library/ header files should be prefixed with
MBEDTLS_
The macro functions in common.h where also indented
to comply with the same test
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
To improve readability by saving horizontal and vertical space.
Removed unecessary & 0xFF.
Byte reading macros implemented in library/common.h, All files
containing "& 0xff" were modified.
Comments/Documentation not yet added to the macro definitions.
Fixes#4274
Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
The sequence of calls starts-update-starts-update-finish is not a
guaranteed valid way to abort an operation and start a new one. Our
software implementation just happens to support it, but alt
implementations may very well not support it.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
MinGW and older windows compilers cannot cope with %zu or %lld (there is
a workaround for MinGW, but it involves linking more code, there is no
workaround for Windows compilers prior to 2013). Attempt to work around
this by defining printf specifiers for size_t per platform for the
compilers that cannot use the C99 specifiers.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
Fixes for printf format specifiers, where they have been flagged as
invalid sizes by coverity, and new build flags to enable catching these
errors when building using CMake. Note that this patch uses %zu, which
requires C99 or later.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
Mbed TLS requires users of DTLS to configure timer callbacks
needed to implement the wait-and-retransmit logic of DTLS.
Previously, the presence of these timer callbacks was checked
at every invocation of `mbedtls_ssl_fetch_input()`, so lowest
layer of the messaging stack interfacing with the underlying
transport.
This commit removes this recurring check and instead checks the
presence of timers once at the beginning of the handshake.
The main rationale for this change is that it is a step towards
separating the various layers of the messaging stack more cleanly:
datagram layer, record layer, message layer, retransmission layer.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
According to https://www.bearssl.org/ctmul.html even single-precision
multiplication is not constant-time on some older platforms.
An added benefit of the new code is that it removes the somewhat mysterious
constant 0x1ff - which was selected because at that point the maximum value of
padlen was 256. The new code is perhaps a bit more readable for that reason.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The previous code used comparison operators >= and == that are quite likely to
be compiled to branches by some compilers on some architectures (with some
optimisation levels).
For example, take the following function:
void old_update( size_t data_len, size_t *padlen )
{
*padlen *= ( data_len >= *padlen + 1 );
}
With Clang 3.8, let's compile it for the Arm v6-M architecture:
% clang --target=arm-none-eabi -march=armv6-m -Os foo.c -S -o - |
sed -n '/^old_update:$/,/\.size/p'
old_update:
.fnstart
@ BB#0:
.save {r4, lr}
push {r4, lr}
ldr r2, [r1]
adds r4, r2, #1
movs r3, #0
cmp r4, r0
bls .LBB0_2
@ BB#1:
mov r2, r3
.LBB0_2:
str r2, [r1]
pop {r4, pc}
.Lfunc_end0:
.size old_update, .Lfunc_end0-old_update
We can see an unbalanced secret-dependant branch, resulting in a total
execution time depends on the value of the secret (here padlen) in a
straightforward way.
The new version, based on bit operations, doesn't have this issue:
new_update:
.fnstart
@ BB#0:
ldr r2, [r1]
subs r0, r0, #1
subs r0, r0, r2
asrs r0, r0, #31
bics r2, r0
str r2, [r1]
bx lr
.Lfunc_end1:
.size new_update, .Lfunc_end1-new_update
(As a bonus, it's smaller and uses less stack.)
While there's no formal guarantee that the version based on bit operations in
C won't be translated using branches by the compiler, experiments tend to show
that's the case [1], and it is commonly accepted knowledge in the practical
crypto community that if we want to sick to C, bit operations are the safest
bet [2].
[1] https://github.com/mpg/ct/blob/master/results
[2] https://github.com/veorq/cryptocoding
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
* development:
Update copyright notices to use Linux Foundation guidance
Undef ASSERT before defining it to ensure that no previous definition has sneaked in through included files.
Add ChangeLog entry for X.509 CN-type vulnerability
Improve documentation of cn in x509_crt_verify()
Fix comparison between different name types
Add test: DNS names should not match IP addresses
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
ssl-opt.sh: remove old buildbot-specific condition
ssl-opt.sh: add proxy to all DTLS tests
Signed-off-by: Dan Handley <dan.handley@arm.com>
The tests are supposed to be failing now (in all.sh component
test_memsan_constant_flow), but they don't as apparently MemSan doesn't
complain when the src argument of memcpy() is uninitialized, see
https://github.com/google/sanitizers/issues/1296
The next commit will add an option to test constant flow with valgrind, which
will hopefully correctly flag the current non-constant-flow implementation.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This paves the way for a constant-flow implementation of HMAC checking, by
making sure that the comparison happens at a constant address. The missing
step is obviously to copy the HMAC from the secret offset to this temporary
buffer with constant flow, which will be done in the next few commits.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
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>
