diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/common/crypto.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/src/common/crypto.c b/src/common/crypto.c index 7768cc37b..5b5fb755b 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -748,19 +748,23 @@ crypto_pk_public_exponent_ok(crypto_pk_t *env) return BN_is_word(env->key->e, 65537); } -/** Compare the public-key components of a and b. Return -1 if a\<b, 0 - * if a==b, and 1 if a\>b. +/** Compare the public-key components of a and b. Return -1 if a\<b, + * 0 if a==b, and 1 if a\>b. A NULL key is considered to be less than + * all non-NULL keys, and equal to itself. + * + * Note that this may leak information about the keys through timing. */ int crypto_pk_cmp_keys(crypto_pk_t *a, crypto_pk_t *b) { int result; + char a_is_non_null = (a != NULL) && (a->key != NULL); + char b_is_non_null = (b != NULL) && (b->key != NULL); + char an_argument_is_null = !a_is_non_null | !b_is_non_null; - if (!a || !b) - return -1; - - if (!a->key || !b->key) - return -1; + result = tor_memcmp(&a_is_non_null, &b_is_non_null, sizeof(a_is_non_null)); + if (an_argument_is_null) + return result; tor_assert(PUBLIC_KEY_OK(a)); tor_assert(PUBLIC_KEY_OK(b)); |