Commit graph

19 commits

Author SHA1 Message Date
Janos Follath
b62bad442e Bidnum Mod: fix check in setup
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>
2022-11-25 17:55:00 +00:00
Minos Galanakis
8b375451c5 bignum_mod: Refactored mbedtls_mpi_mod_read/write()
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>
2022-11-25 17:55:00 +00:00
Minos Galanakis
aed832ac16 bignum_mod: Adjusted input checking for mbedtls_mpi_mod_residue_setup()
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>
2022-11-25 17:55:00 +00:00
Minos Galanakis
a17ad48e2d bignum_mod: Fixed an issue with input checking in mpi_mod_residue_setup
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>
2022-11-25 17:55:00 +00:00
Minos Galanakis
81f4b11010 bignum_mod: Added mbedtls_mpi_mod_read/write() IO functions
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>
2022-11-25 17:55:00 +00:00
Janos Follath
5933f691a2 Add merge slots to Bignum files
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>
2022-11-02 17:27:25 +00:00
Minos Galanakis
4d4c98b1b9 bignum_mod: mbedtls_mpi_mod_modulus_setup() refactoring.
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>
2022-10-27 17:47:26 +01:00
Minos Galanakis
771c47055f bignum_mod: Style changes
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>
2022-10-27 12:36:24 +01:00
Minos Galanakis
8b33363315 bignum_mod: Updated modulus lifecycle with mm and rr.
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>
2022-10-27 11:43:54 +01:00
Minos Galanakis
760f5d6b6b bignum_mod: Updated mbedtls_mpi_mod_modulus_setup/free with new fields
At the current state, those fields are initialised to 0, NULL.

Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
2022-10-27 11:43:54 +01:00
Gilles Peskine
945b23c46f Include platform.h unconditionally: automatic part
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>
2022-09-15 20:33:07 +02:00
Janos Follath
a95f204cd3 Improve documentation
Co-authored-by: Tom Cosgrove <81633263+tom-cosgrove-arm@users.noreply.github.com>
Co-authored-by: Werner Lewis <werner.wmlewis@gmail.com>
Co-authored-by: Minos Galanakis <minos.galanakis@arm.com>

Signed-off-by: Janos Follath <janos.follath@arm.com>
2022-08-19 13:11:22 +01:00
Janos Follath
b7a88eca42 Bignum: Apply naming conventions
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>
2022-08-19 13:11:22 +01:00
Janos Follath
6b8a4ad0d8 Bignum: update const qualifiers
While at it, mark parameters based on their role.

Signed-off-by: Janos Follath <janos.follath@arm.com>
2022-08-19 13:11:22 +01:00
Janos Follath
ed5c8d3d1e Bignum: make modulus value const
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>
2022-08-15 11:50:22 +01:00
Gabor Mezei
fd65e82753
Rename structure elements
Use better names for structure elements and adopting the convention of
the other modules.

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
2022-08-12 18:09:12 +02:00
Janos Follath
56a10f97ba Bignum: remove unnecessary NULL pointer checks
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>
2022-08-11 15:19:00 +01:00
Janos Follath
296ea66442 Bignum: clean up use of enums
- 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>
2022-08-11 14:58:29 +01:00
Janos Follath
d1baedb786 Bignum: extract bignum_mod.h functions
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>
2022-08-09 13:44:53 +01:00
Renamed from library/bignum_new.c (Browse further)