In the new bignum files (bignum_core.c, bignum_mod_raw.c and
bignum_mod.c) the loop variables are declared in the loop head wherever
this change is beneficial.
There are loops where the loop variable is used after the end of the
loop (this might not be good practice, but that is out of scope for this
commit) and others where there are several loop variables and declaring
them there would hurt readability.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The modulus value won't change during normal operations, make this clear
in the struct and the function signatures.
This won't prevent the caller from modifying the passed buffer, but
might give a hint and reinforces the message of the documentation.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Skip reading if output pointer is NULL even if the length of the input buffer is 0.
The memory sanitizer will mark this as an error.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
These functions have full documentation in the header. Maintaing two
copies does not worth the effort and having an out of sync reduced
duplicate is not helpful.
Signed-off-by: Janos Follath <janos.follath@arm.com>
This used to resize MPIs in the legacy interface, which is not
needed/possible as the new interface has fixed size MPIs.
Inlining this function makes the code easier to read and maintain, while
there is no obvious drawback to it.
Signed-off-by: Janos Follath <janos.follath@arm.com>
A null pointer dereference, or null pointer plus small offset, is a
clean runtime error in most environments. So it's not particularly
useful to protect against this.
While at it make a null pointer check that is actually necessary more
robust.
Signed-off-by: Janos Follath <janos.follath@arm.com>
- Made use of enums in struct and function declaration
- All enums are handled by switch case now
- If the switch does nothing on default, omit the default case to make
compiler warnings more powerful
- The two enums are now disjoint and the value 1 is skipped to make
mistakes easier to detect
Signed-off-by: Janos Follath <janos.follath@arm.com>
The code will make the decision based on availability of MD, not of
MD+this_hash. The later would only be possible at runtime (the hash
isn't known until then, that's the whole point of MD), so we'd need to
have both MD-based and PSA-based code paths in a single build, which
would have a very negative impact on code size. So, instead, we choose
based on the presence of MD, which is know at compile time, so we only
have one of the two code paths in each build.
Adjust the macros so that they match the logic of the code using them.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Test coverage not there yet, as the entire test_suite_pkcs1_v21 is
skipped so far - dependencies to be adjusted in a future commit.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This allows callers not to worry with md_info and makes it easier to
provide a PSA version for when MD_C is not available.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This will also make it easier to provide a PSA-based version for when MD
is not available.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Some of them no longer need md_ctx, some of those no longer need the
exit dance that was used to free it, or need it on a smaller scope.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This is a first step towards making a version of this function that
uses PSA when MD is not available.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Looking at the bigger picture it is clear that if `ssl->session` is NULL,
there will be a failure much earlier, and that is well protected from,
however, the practice of dereferencing a pointer which has not been
verified in prior for validity goes against secure coding practices.
Signed-off-by: Leonid Rozenboim <leonid.rozenboim@oracle.com>
Extract functions declared in bignum_mod.h into a source file with a
matching name.
We are doing this because:
- This is a general best practice/convention
- We hope that this will make resolving merge conflicts in the future
easier
- Having them in a unified source file is a premature optimisation at
this point
This makes library/bignum_new.c empty and therefore it is deleted.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Extract functions declared in bignum_mod_raw.h into a source file with a
matching name.
We are doing this because:
- This is a general best practice/convention
- We hope that this will make resolving merge conflicts in the future
easier
- Having them in a unified source file is a premature optimisation at
this point
Signed-off-by: Janos Follath <janos.follath@arm.com>
Extract functions declared in bignum_core.h into a source file with a
matching name.
We are doing this because:
- This is a general best practice/convention
- We hope that this will make resolving merge conflicts in the future
easier
- Having them in a unified source file is a premature optimisation at
this point
Signed-off-by: Janos Follath <janos.follath@arm.com>
This reverts commit 62c5901f0a5061a8825e19c77f88c91fea235078.
Reverting commit due the macros are meant to be local and not following the
naming convention.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
Unfortunately reusing the new function from the signed constant time
comparison is not trivial.
One option would be to do temporary conditional swaps which would prevent
qualifying input to const. Another way would be to add an additional
flag for the sign and make it an integral part of the computation, which
would defeat the purpose of having an unsigned core comparison.
Going with two separate function for now and the signed version can be
retired/compiled out with the legacy API eventually.
The new function in theory could be placed into either
`library/constant_time.c` or `library/bignum_new.c`. Going with the
first as the other functions in the second are not constant time yet and
this distinction seems more valuable for new (as opposed to belonging to
the `_core` functions.
Signed-off-by: Janos Follath <janos.follath@arm.com>
- We don't check for NULL pointers this deep in the library
- Accessing a NULL pointer when the limb number is 0 as a mistake is the
very similar to any other out of bounds access
- We could potentially mandate at least 1 limb representation for 0 but
we either would need to enforce it or the implementation would be less
robust.
- Allowing zero limb representation - (NULL, 0) in particular - for zero
is present in the legacy interface, if we disallow it, the
compatibility code will need to deal with this (more code size and
opportunities for mistakes)
In summary, interpreting (NULL, 0) as the number zero in the core
interface is the least of the two evils.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The test case where there were extra limbs in the MPI failed and this
commit contains the corresponding fix as well. (We used to use the
minimum required limbs instead of the actual limbs present.)
Signed-off-by: Janos Follath <janos.follath@arm.com>
