Call mbedtls_mpi_mod_raw_canonical_to_modulus_rep instead of assuming that
anything that isn't MBEDTLS_MPI_MOD_REP_MONTGOMERY is canonical.
mbedtls_mpi_mod_write should get the same treatment, but I'm holding off
until https://github.com/Mbed-TLS/mbedtls/issues/6679 is done.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Require equality for the number of limbs in the modulus and the residue.
This makes these functions consistent with residue_setup().
Signed-off-by: Janos Follath <janos.follath@arm.com>
The function isn't documented as accepting null pointer, and there's no
reason why it should be. Just let it dereference the pointer.
The null/zero checks are only marginally useful: they validate that m
and r are properly populated objects, not freshly initialized ones. For
that, it's enough to check that the pointers aren't null or that the
sizes aren't zero, we don't need to check both.
Also, use separate if statements for unrelated checks.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The external representation before included more than just endianness
(like reading in Mongtomery curve scalars or converting hashes to
numbers in a standard compliant way).
These are higher level concepts and are out of scope for Bignum and for
the modulus structure.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The external representation before included more than just endianness
(like reading in Mongtomery curve scalars or converting hashes to
numbers in a standard compliant way).
These are higher level concepts and are out of scope for Bignum and for
the modulus structure.
Passing endianness as a parameter is a step towards removing it from the
modulus structure.
Signed-off-by: Janos Follath <janos.follath@arm.com>
In theory we could allow residues to have more allocated limbs than the
modulus, but we might or might not need it in the end.
Go for the simpler option for now and we can extend it later if we
really need it.
Signed-off-by: Janos Follath <janos.follath@arm.com>
We want to make sure that the value has at least as many limbs allocated
as the modulus as we need this to be able to do any operations in
constant time.
An invariant of the API is that the residue values are canonical, make
sure that the residue is compared to the entire modulus.
Signed-off-by: Janos Follath <janos.follath@arm.com>
This patch adjusts the I/O methods and the tests.
Documentation has also been updated to be more clear.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
This patch adjusts the logic of the size checking of the method,
and refactors the tests. Documentation has also been updated.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
This patch is inverting the input type checking logic in the method,
in order to ensure that residue < modulus.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
This patch adds input and ouput fucntions in the `bignum_mod` layer.
The data will be automatically converted between Cannonical and
Montgomery representation if required.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
Legacy Bignum is excluded as it doesn't get regular extensions like new
ones.
Each slot uses comments of their respective filetype. Since .data files
don't have a syntax for comments, dummy test cases are used. (These test
cases will never be executed and no noise will be added to tests.)
Signed-off-by: Janos Follath <janos.follath@arm.com>
This patch addresses more review comments, and fixes
a circular depedency in the `mbedtls_mpi_mod_modulus_setup()`.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
This patch addresses review comments with regards to style of
`mbedtls_mpi_mod_modulus_setup/free()`.
It also removes a test check which was triggering a use-after-free.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
This patch updates the `mbedtls_mpi_mod_modulus_setup/free()`
methods to precalculate mm and rr(Montgomery const squared) during
setup and zeroize it during free.
A static `set_mont_const_square()` is added to manage the memory allocation
and parameter checking before invoking the
`mbedtls_mpi_core_get_mont_r2_unsafe()`
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
We used to include platform.h only when MBEDTLS_PLATFORM_C was enabled, and
to define ad hoc replacements for mbedtls_xxx functions on a case-by-case
basis when MBEDTLS_PLATFORM_C was disabled. The only reason for this
complication was to allow building individual source modules without copying
platform.h. This is not something we support or recommend anymore, so get
rid of the complication: include platform.h unconditionally.
There should be no change in behavior since just including the header should
not change the behavior of a program.
This commit replaces most occurrences of conditional inclusion of
platform.h, using the following code:
```
perl -i -0777 -pe 's!#if.*\n#include "mbedtls/platform.h"\n(#else.*\n(#define (mbedtls|MBEDTLS)_.*\n|#include <(stdarg|stddef|stdio|stdlib|string|time)\.h>\n)*)?#endif.*!#include "mbedtls/platform.h"!mg' $(git grep -l '#include "mbedtls/platform.h"')
```
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Numbers:
- A, B for mbedtls_mpi_uint* operands
- a, b for mbedtls_mpi_uint operands
- X or x for result
- HAC references where applicable
Lengths:
- Reserve size or length for length/size in bytes or byte buffers.
- For length of mbedtls_mpi_uint* buffers use limbs
- Length parameters are qualified if possible (eg. input_length or
a_limbs)
Setup functions:
- The parameters match the corresponding structure member's name
- The structure to set up is a standard lower case name even if in other
functions different naming conventions would apply
Scope of changes/conventions:
- bignum_core
- bignum_mod
- bignum_mod_raw
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>
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>
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>
