diff options
Diffstat (limited to 'thirdparty/mbedtls/library/pk_wrap.c')
| -rw-r--r-- | thirdparty/mbedtls/library/pk_wrap.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/thirdparty/mbedtls/library/pk_wrap.c b/thirdparty/mbedtls/library/pk_wrap.c index 14c6d3f99c..dd460a6a0c 100644 --- a/thirdparty/mbedtls/library/pk_wrap.c +++ b/thirdparty/mbedtls/library/pk_wrap.c @@ -53,7 +53,23 @@ static int rsa_can_do(mbedtls_pk_type_t type) static size_t rsa_get_bitlen(const void *ctx) { const mbedtls_rsa_context *rsa = (const mbedtls_rsa_context *) ctx; - return 8 * mbedtls_rsa_get_len(rsa); + /* Unfortunately, the rsa.h interface does not have a direct way + * to access the bit-length that works with MBEDTLS_RSA_ALT. + * So we have to do a little work here. + */ + mbedtls_mpi N; + mbedtls_mpi_init(&N); + int ret = mbedtls_rsa_export(rsa, &N, NULL, NULL, NULL, NULL); + /* If the export fails for some reason (e.g. the RSA_ALT implementation + * does not support export, or there is not enough memory), + * we have no way of returning an error from this function. + * As a fallback, return the byte-length converted in bits, which is + * the correct value if the modulus size is a multiple of 8 bits, which + * is very often the case in practice. */ + size_t bitlen = (ret == 0 ? mbedtls_mpi_bitlen(&N) : + 8 * mbedtls_rsa_get_len(rsa)); + mbedtls_mpi_free(&N); + return bitlen; } static int rsa_verify_wrap(void *ctx, mbedtls_md_type_t md_alg, |