Mercurial > dovecot > core-2.2
changeset 21952:e19e015f7449
auth: Make plaintext password comparisons safe against timing attacks
| author | Timo Sirainen <timo.sirainen@dovecot.fi> |
|---|---|
| date | Sun, 09 Apr 2017 00:50:15 +0300 |
| parents | 3ef988b95d96 |
| children | ec6539bd0690 |
| files | src/auth/password-scheme.c |
| diffstat | 1 files changed, 17 insertions(+), 5 deletions(-) [+] |
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--- a/src/auth/password-scheme.c Sun Apr 09 00:49:37 2017 +0300 +++ b/src/auth/password-scheme.c Sun Apr 09 00:50:15 2017 +0300 @@ -610,6 +610,18 @@ } static int +plain_verify(const char *plaintext, const char *user ATTR_UNUSED, + const unsigned char *raw_password, size_t size, + const char **error_r ATTR_UNUSED) +{ + size_t plaintext_len = strlen(plaintext); + + if (plaintext_len != size) + return 0; + return mem_equals_timing_safe(plaintext, raw_password, size) ? 1 : 0; +} + +static int plain_trunc_verify(const char *plaintext, const char *user ATTR_UNUSED, const unsigned char *raw_password, size_t size, const char **error_r) @@ -633,10 +645,10 @@ if (size-i == trunc_len && plaintext_len >= trunc_len) { /* possibly truncated password. allow the given password as long as the prefix matches. */ - return memcmp(raw_password+i, plaintext, trunc_len) == 0 ? 1 : 0; + return mem_equals_timing_safe(raw_password+i, plaintext, trunc_len) ? 1 : 0; } return plaintext_len == size-i && - memcmp(raw_password+i, plaintext, plaintext_len) == 0 ? 1 : 0; + mem_equals_timing_safe(raw_password+i, plaintext, plaintext_len) ? 1 : 0; } static void @@ -803,9 +815,9 @@ { "SSHA", PW_ENCODING_BASE64, 0, ssha_verify, ssha_generate }, { "SSHA256", PW_ENCODING_BASE64, 0, ssha256_verify, ssha256_generate }, { "SSHA512", PW_ENCODING_BASE64, 0, ssha512_verify, ssha512_generate }, - { "PLAIN", PW_ENCODING_NONE, 0, NULL, plain_generate }, - { "CLEAR", PW_ENCODING_NONE, 0, NULL, plain_generate }, - { "CLEARTEXT", PW_ENCODING_NONE, 0, NULL, plain_generate }, + { "PLAIN", PW_ENCODING_NONE, 0, plain_verify, plain_generate }, + { "CLEAR", PW_ENCODING_NONE, 0, plain_verify, plain_generate }, + { "CLEARTEXT", PW_ENCODING_NONE, 0, plain_verify, plain_generate }, { "PLAIN-TRUNC", PW_ENCODING_NONE, 0, plain_trunc_verify, plain_generate }, { "CRAM-MD5", PW_ENCODING_HEX, CRAM_MD5_CONTEXTLEN, NULL, cram_md5_generate },