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Avoid unbound alloca usage in *-crypt routines (#804792)

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Jeff Law 2012-03-29 12:46:29 -06:00
parent d004e5468f
commit 5022ed713c
2 changed files with 221 additions and 0 deletions
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217
glibc-rh804792.patch Normal file
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@ -0,0 +1,217 @@
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.
diff -rup c/crypt/md5-crypt.c d/crypt/md5-crypt.c
--- c/crypt/md5-crypt.c 2012-01-01 05:16:32.000000000 -0700
+++ d/crypt/md5-crypt.c 2012-03-27 11:37:24.035574503 -0600
@@ -108,6 +108,7 @@ __md5_crypt_r (key, salt, buffer, buflen
char *cp;
char *copied_key = NULL;
char *copied_salt = NULL;
+ char *free_key = NULL;
/* Find beginning of salt string. The prefix should normally always
be present. Just in case it is not. */
@@ -120,7 +121,17 @@ __md5_crypt_r (key, salt, buffer, buflen
if ((key - (char *) 0) % __alignof__ (md5_uint32) != 0)
{
- char *tmp = (char *) alloca (key_len + __alignof__ (md5_uint32));
+ char *tmp;
+
+ if (__libc_use_alloca (key_len + __alignof__ (md5_uint32)))
+ tmp = (char *) alloca (key_len + __alignof__ (md5_uint32));
+ else
+ {
+ free_key = tmp = (char *) malloc (key_len + __alignof__ (md5_uint32));
+ if (tmp == NULL)
+ return NULL;
+ }
+
key = copied_key =
memcpy (tmp + __alignof__ (md5_uint32)
- (tmp - (char *) 0) % __alignof__ (md5_uint32),
@@ -142,7 +158,10 @@ __md5_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
@@ -296,6 +315,7 @@ __md5_crypt_r (key, salt, buffer, buflen
if (copied_salt != NULL)
memset (copied_salt, '\0', salt_len);
+ free (free_key);
return buffer;
}
diff -rup c/crypt/sha256-crypt.c d/crypt/sha256-crypt.c
--- c/crypt/sha256-crypt.c 2012-01-01 05:16:32.000000000 -0700
+++ d/crypt/sha256-crypt.c 2012-03-27 11:58:55.823809542 -0600
@@ -123,6 +123,9 @@ __sha256_crypt_r (key, salt, buffer, buf
/* 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. */
@@ -149,7 +152,17 @@ __sha256_crypt_r (key, salt, buffer, buf
if ((key - (char *) 0) % __alignof__ (uint32_t) != 0)
{
- char *tmp = (char *) alloca (key_len + __alignof__ (uint32_t));
+ char *tmp;
+
+ if (__libc_use_alloca (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),
@@ -160,6 +179,7 @@ __sha256_crypt_r (key, salt, buffer, buf
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),
@@ -171,7 +191,10 @@ __sha256_crypt_r (key, salt, buffer, buf
/* 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
@@ -233,8 +256,19 @@ __sha256_crypt_r (key, salt, buffer, buf
/* Finish the digest. */
sha256_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result);
- /* Create byte sequence P. */
- cp = p_bytes = alloca (key_len);
+ /* Create byte sequence P. */
+ 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);
@@ -362,6 +401,8 @@ __sha256_crypt_r (key, salt, buffer, buf
if (copied_salt != NULL)
memset (copied_salt, '\0', salt_len);
+ free (free_key);
+ free (free_pbytes);
return buffer;
}
diff -rup c/crypt/sha512-crypt.c d/crypt/sha512-crypt.c
--- c/crypt/sha512-crypt.c 2012-01-01 05:16:32.000000000 -0700
+++ d/crypt/sha512-crypt.c 2012-03-27 12:10:08.895097239 -0600
@@ -123,6 +123,9 @@ __sha512_crypt_r (key, salt, buffer, buf
/* 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. */
@@ -149,7 +152,17 @@ __sha512_crypt_r (key, salt, buffer, buf
if ((key - (char *) 0) % __alignof__ (uint64_t) != 0)
{
- char *tmp = (char *) alloca (key_len + __alignof__ (uint64_t));
+ char *tmp;
+
+ if (__libc_use_alloca (key_len + __alignof__ (uint64_t)))
+ tmp = alloca_account (key_len + __alignof__ (uint64_t), alloca_used);
+ else
+ {
+ free_key = tmp = (char *) malloc (key_len + __alignof__ (uint64_t));
+ if (tmp == NULL)
+ return NULL;
+ }
+
key = copied_key =
memcpy (tmp + __alignof__ (uint64_t)
- (tmp - (char *) 0) % __alignof__ (uint64_t),
@@ -171,7 +190,10 @@ __sha512_crypt_r (key, salt, buffer, buf
/* 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
@@ -233,8 +255,19 @@ __sha512_crypt_r (key, salt, buffer, buf
/* Finish the digest. */
sha512_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result);
- /* Create byte sequence P. */
- cp = p_bytes = alloca (key_len);
+ /* Create byte sequence P. */
+ 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 >= 64; cnt -= 64)
cp = mempcpy (cp, temp_result, 64);
memcpy (cp, temp_result, cnt);
@@ -374,6 +412,8 @@ __sha512_crypt_r (key, salt, buffer, buf
if (copied_salt != NULL)
memset (copied_salt, '\0', salt_len);
+ free (free_key);
+ free (free_pbytes);
return buffer;
}

4
glibc.spec
View File

@ -125,6 +125,8 @@ Patch45 : %{name}-rh803286.patch
Patch46 : %{name}-rh806403.patch
# Submitted upstream, BZ 13594
Patch47 : %{name}-rh806070.patch
# Submitted upstream
Patch48 : %{name}-rh804792.patch
Buildroot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@ -391,6 +393,7 @@ rm -rf %{glibcportsdir}
%patch45 -p1
%patch46 -p1
%patch47 -p1
%patch48 -p1
# A lot of programs still misuse memcpy when they have to use
# memmove. The memcpy implementation below is not tolerant at
@ -1244,6 +1247,7 @@ rm -f *.filelist*
%changelog
* Tue Mar 27 2012 Jeff Law <law@redhat.com> - 2.15-30
- Avoid unbound alloca usage in *-crypt routines (#804792)
- Fix data race in nscd (#806070)
* Fri Mar 23 2012 Jeff Law <law@redhat.com> - 2.15-29