diff options
Diffstat (limited to 'thirdparty/mbedtls/library/bignum_core.h')
| -rw-r--r-- | thirdparty/mbedtls/library/bignum_core.h | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/thirdparty/mbedtls/library/bignum_core.h b/thirdparty/mbedtls/library/bignum_core.h index 92c8d47db5..cf6485a148 100644 --- a/thirdparty/mbedtls/library/bignum_core.h +++ b/thirdparty/mbedtls/library/bignum_core.h @@ -90,6 +90,27 @@ #define GET_BYTE(X, i) \ (((X)[(i) / ciL] >> (((i) % ciL) * 8)) & 0xff) +/* Constants to identify whether a value is public or secret. If a parameter is marked as secret by + * this constant, the function must be constant time with respect to the parameter. + * + * This is only needed for functions with the _optionally_safe postfix. All other functions have + * fixed behavior that can't be changed at runtime and are constant time with respect to their + * parameters as prescribed by their documentation or by conventions in their module's documentation. + * + * Parameters should be named X_public where X is the name of the + * corresponding input parameter. + * + * Implementation should always check using + * if (X_public == MBEDTLS_MPI_IS_PUBLIC) { + * // unsafe path + * } else { + * // safe path + * } + * not the other way round, in order to prevent misuse. (This is, if a value + * other than the two below is passed, default to the safe path.) */ +#define MBEDTLS_MPI_IS_PUBLIC 0x2a2a2a2a +#define MBEDTLS_MPI_IS_SECRET 0 + /** Count leading zero bits in a given integer. * * \warning The result is undefined if \p a == 0 @@ -605,6 +626,42 @@ int mbedtls_mpi_core_random(mbedtls_mpi_uint *X, size_t mbedtls_mpi_core_exp_mod_working_limbs(size_t AN_limbs, size_t E_limbs); /** + * \brief Perform a modular exponentiation with public or secret exponent: + * X = A^E mod N, where \p A is already in Montgomery form. + * + * \warning This function is not constant time with respect to \p E (the exponent). + * + * \p X may be aliased to \p A, but not to \p RR or \p E, even if \p E_limbs == + * \p AN_limbs. + * + * \param[out] X The destination MPI, as a little endian array of length + * \p AN_limbs. + * \param[in] A The base MPI, as a little endian array of length \p AN_limbs. + * Must be in Montgomery form. + * \param[in] N The modulus, as a little endian array of length \p AN_limbs. + * \param AN_limbs The number of limbs in \p X, \p A, \p N, \p RR. + * \param[in] E The exponent, as a little endian array of length \p E_limbs. + * \param E_limbs The number of limbs in \p E. + * \param[in] RR The precomputed residue of 2^{2*biL} modulo N, as a little + * endian array of length \p AN_limbs. + * \param[in,out] T Temporary storage of at least the number of limbs returned + * by `mbedtls_mpi_core_exp_mod_working_limbs()`. + * Its initial content is unused and its final content is + * indeterminate. + * It must not alias or otherwise overlap any of the other + * parameters. + * It is up to the caller to zeroize \p T when it is no + * longer needed, and before freeing it if it was dynamically + * allocated. + */ +void mbedtls_mpi_core_exp_mod_unsafe(mbedtls_mpi_uint *X, + const mbedtls_mpi_uint *A, + const mbedtls_mpi_uint *N, size_t AN_limbs, + const mbedtls_mpi_uint *E, size_t E_limbs, + const mbedtls_mpi_uint *RR, + mbedtls_mpi_uint *T); + +/** * \brief Perform a modular exponentiation with secret exponent: * X = A^E mod N, where \p A is already in Montgomery form. * @@ -760,4 +817,17 @@ void mbedtls_mpi_core_from_mont_rep(mbedtls_mpi_uint *X, mbedtls_mpi_uint mm, mbedtls_mpi_uint *T); +/* + * Can't define thread local variables with our abstraction layer: do nothing if threading is on. + */ +#if defined(MBEDTLS_TEST_HOOKS) && !defined(MBEDTLS_THREADING_C) +extern int mbedtls_mpi_optionally_safe_codepath; + +static inline void mbedtls_mpi_optionally_safe_codepath_reset(void) +{ + // Set to a default that is neither MBEDTLS_MPI_IS_PUBLIC nor MBEDTLS_MPI_IS_SECRET + mbedtls_mpi_optionally_safe_codepath = MBEDTLS_MPI_IS_PUBLIC + MBEDTLS_MPI_IS_SECRET + 1; +} +#endif + #endif /* MBEDTLS_BIGNUM_CORE_H */ |