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| author | Jeff Law <law@redhat.com> | 2012-03-30 09:45:44 -0600 |
|---|---|---|
| committer | Jeff Law <law@redhat.com> | 2012-03-30 09:51:27 -0600 |
| commit | b8dc394ddfd58bc5d0fe9ecfc970fc42b789a9df (patch) | |
| tree | 5c0fd054db74a8ae8ad36c478b4f030b9da7b2fd /crypt/sha256-crypt.c | |
| parent | 966977f1b72123bdd5187a60e9b50eaa70312d90 (diff) | |
| download | glibc-b8dc394ddfd58bc5d0fe9ecfc970fc42b789a9df.tar.gz glibc-b8dc394ddfd58bc5d0fe9ecfc970fc42b789a9df.tar.xz glibc-b8dc394ddfd58bc5d0fe9ecfc970fc42b789a9df.zip | |
2012-03-29 Jeff Law <law@redhat.com>
* crypt/md5-crypt.c (__md5_crypt_r): Avoid unbounded alloca uses due to long keys. * crypt/sha256-crypt.c (__sha256_crypt_r): Likewise. * crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.
Diffstat (limited to 'crypt/sha256-crypt.c')
| -rw-r--r-- | crypt/sha256-crypt.c | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/crypt/sha256-crypt.c b/crypt/sha256-crypt.c index eb2585b527..440933ac01 100644 --- a/crypt/sha256-crypt.c +++ b/crypt/sha256-crypt.c @@ -1,5 +1,5 @@ /* One way encryption based on SHA256 sum. - Copyright (C) 2007, 2009 Free Software Foundation, Inc. + Copyright (C) 2007, 2009, 2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2007. @@ -122,6 +122,9 @@ __sha256_crypt_r (key, salt, buffer, buflen) /* Default number of rounds. */ size_t rounds = ROUNDS_DEFAULT; bool rounds_custom = false; + size_t alloca_used = 0; + char *free_key = NULL; + char *free_pbytes = NULL; /* Find beginning of salt string. The prefix should normally always be present. Just in case it is not. */ @@ -148,7 +151,17 @@ __sha256_crypt_r (key, salt, buffer, buflen) if ((key - (char *) 0) % __alignof__ (uint32_t) != 0) { - char *tmp = (char *) alloca (key_len + __alignof__ (uint32_t)); + char *tmp; + + if (__libc_use_alloca (alloca_used + key_len + __alignof__ (uint32_t))) + tmp = alloca_account (key_len + __alignof__ (uint32_t), alloca_used); + else + { + free_key = tmp = (char *) malloc (key_len + __alignof__ (uint32_t)); + if (tmp == NULL) + return NULL; + } + key = copied_key = memcpy (tmp + __alignof__ (uint32_t) - (tmp - (char *) 0) % __alignof__ (uint32_t), @@ -159,6 +172,7 @@ __sha256_crypt_r (key, salt, buffer, buflen) if ((salt - (char *) 0) % __alignof__ (uint32_t) != 0) { char *tmp = (char *) alloca (salt_len + __alignof__ (uint32_t)); + alloca_used += salt_len + __alignof__ (uint32_t); salt = copied_salt = memcpy (tmp + __alignof__ (uint32_t) - (tmp - (char *) 0) % __alignof__ (uint32_t), @@ -170,7 +184,10 @@ __sha256_crypt_r (key, salt, buffer, buflen) /* Initialize libfreebl3. */ NSSLOWInitContext *nss_ictx = NSSLOW_Init (); if (nss_ictx == NULL) - return NULL; + { + free (free_key); + return NULL; + } NSSLOWHASHContext *nss_ctx = NULL; NSSLOWHASHContext *nss_alt_ctx = NULL; #else @@ -233,7 +250,18 @@ __sha256_crypt_r (key, salt, buffer, buflen) sha256_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result); /* Create byte sequence P. */ - cp = p_bytes = alloca (key_len); + if (__libc_use_alloca (alloca_used + key_len)) + cp = p_bytes = (char *) alloca (key_len); + else + { + free_pbytes = cp = p_bytes = (char *)malloc (key_len); + if (free_pbytes == NULL) + { + free (free_key); + return NULL; + } + } + for (cnt = key_len; cnt >= 32; cnt -= 32) cp = mempcpy (cp, temp_result, 32); memcpy (cp, temp_result, cnt); @@ -361,6 +389,8 @@ __sha256_crypt_r (key, salt, buffer, buflen) if (copied_salt != NULL) memset (copied_salt, '\0', salt_len); + free (free_key); + free (free_pbytes); return buffer; } |