[glibc] Avoid unbound alloca usage in *-crypt routines (#804792)
Jeffrey Law
law at fedoraproject.org
Thu Mar 29 18:46:55 UTC 2012
commit 5022ed713cfd314910f7aadd4bdc9dd972b71953
Author: Jeff Law <law at redhat.com>
Date: Thu Mar 29 12:46:29 2012 -0600
Avoid unbound alloca usage in *-crypt routines (#804792)
glibc-rh804792.patch | 217 ++++++++++++++++++++++++++++++++++++++++++++++++++
glibc.spec | 4 +
2 files changed, 221 insertions(+), 0 deletions(-)
---
diff --git a/glibc-rh804792.patch b/glibc-rh804792.patch
new file mode 100644
index 0000000..d91ae6f
--- /dev/null
+++ b/glibc-rh804792.patch
@@ -0,0 +1,217 @@
+2012-03-29 Jeff Law <law at 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;
+ }
+
+
+
diff --git a/glibc.spec b/glibc.spec
index 78de6d0..e13f243 100644
--- a/glibc.spec
+++ b/glibc.spec
@@ -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 at 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 at redhat.com> - 2.15-29
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