mirror/mbedtls
1
0
Fork 0
mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-01-25 18:35:28 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Document invariants of MPI objects

Browse Source 
Note that s must be +1 for zero.

Note that p may be NULL for zero, when n is 0.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine 2022-11-09 21:55:33 +01:00
parent 72ee1e3f3c
commit 128895775d
1 changed files with 21 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
include/mbedtls/bignum.h
View File

@ -188,9 +188,27 @@ extern "C" {
*/
typedef struct mbedtls_mpi
{
int MBEDTLS_PRIVATE(s); /*!< Sign: -1 if the mpi is negative, 1 otherwise */
size_t MBEDTLS_PRIVATE(n); /*!< total # of limbs */
mbedtls_mpi_uint *MBEDTLS_PRIVATE(p); /*!< pointer to limbs */
/** Sign: -1 if the mpi is negative, 1 otherwise.
*
* The number 0 must be represented with `s = +1`. Although many library
* functions treat all-limbs-zero as equivalent to a valid representation
* of 0 regardless of the sign bit, there are exceptions, so bignum
* functions and external callers must always set \c s to +1 for the
* number zero.
*
* Note that this implies that calloc() or `... = {0}` does not create
* a valid MPI representation. You must call mbedtls_mpi_init().
*/
int MBEDTLS_PRIVATE(s);
/** Total number of limbs in \c p. */
size_t MBEDTLS_PRIVATE(n);
/** Pointer to limbs.
*
* This may be \c NULL if \c n is 0.
*/
mbedtls_mpi_uint *MBEDTLS_PRIVATE(p);
}
mbedtls_mpi;