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pgcrypto: Detect and report too-short crypt() salts.

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Certain short salts crashed the backend or disclosed a few bytes of
backend memory.  For existing salt-induced error conditions, emit a
message saying as much.  Back-patch to 9.0 (all supported versions).

Josh Kupershmidt

Security: CVE-2015-5288
This commit is contained in:
Noah Misch
2015-10-05 10:06:29 -04:00
parent bd90147680
commit 4d6752277e
9 changed files with 103 additions and 6 deletions
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19
contrib/pgcrypto/crypt-blowfish.c
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@ -602,6 +602,17 @@ _crypt_blowfish_rn(const char *key, const char *setting,
if (size < 7 + 22 + 31 + 1)
return NULL;
/*
* Blowfish salt value must be formatted as follows: "$2a$" or "$2x$", a
* two digit cost parameter, "$", and 22 digits from the alphabet
* "./0-9A-Za-z". -- from the PHP crypt docs. Apparently we enforce a few
* more restrictions on the count in the salt as well.
*/
if (strlen(setting) < 29)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid salt")));
if (setting[0] != '$' ||
setting[1] != '2' ||
(setting[2] != 'a' && setting[2] != 'x') ||
@ -611,14 +622,18 @@ _crypt_blowfish_rn(const char *key, const char *setting,
(setting[4] == '3' && setting[5] > '1') ||
setting[6] != '$')
{
return NULL;
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid salt")));
}
count = (BF_word) 1 << ((setting[4] - '0') * 10 + (setting[5] - '0'));
if (count < 16 || BF_decode(data.binary.salt, &setting[7], 16))
{
px_memset(data.binary.salt, 0, sizeof(data.binary.salt));
return NULL;
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid salt")));
}
BF_swap(data.binary.salt, 4);