From b918bf86c65632a5716308d8a613f5538a770927 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 23 Aug 2007 16:15:51 +0000
Subject: [PATCH] Fix combo_decrypt() to throw an error for zero-length input
when using a padded encryption scheme. Formerly it would try to access
res[(unsigned) -1], which resulted in core dumps on 64-bit machines, and was
certainly trouble waiting to happen on 32-bit machines (though in at least
the known case it was harmless because that byte would be overwritten after
return). Per report from Ken Colson; fix by Marko Kreen.
---
contrib/pgcrypto/px.c | 15 ++++++++++++++-
contrib/pgcrypto/px.h | 3 ++-
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/contrib/pgcrypto/px.c b/contrib/pgcrypto/px.c
index 0374b1c0276..81222873b69 100644
--- a/contrib/pgcrypto/px.c
+++ b/contrib/pgcrypto/px.c
@@ -26,7 +26,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
- * $PostgreSQL: pgsql/contrib/pgcrypto/px.c,v 1.15 2005/10/15 02:49:06 momjian Exp $
+ * $PostgreSQL: pgsql/contrib/pgcrypto/px.c,v 1.16 2007/08/23 16:15:51 tgl Exp $
*/
#include "postgres.h"
@@ -58,6 +58,7 @@ static const struct error_desc px_err_list[] = {
{PXE_BAD_SALT_ROUNDS, "Incorrect number of rounds"},
{PXE_MCRYPT_INTERNAL, "mcrypt internal error"},
{PXE_NO_RANDOM, "No strong random source"},
+ {PXE_DECRYPT_FAILED, "Decryption failed"},
{PXE_PGP_CORRUPT_DATA, "Wrong key or corrupt data"},
{PXE_PGP_CORRUPT_ARMOR, "Corrupt ascii-armor"},
{PXE_PGP_UNSUPPORTED_COMPR, "Unsupported compression algorithm"},
@@ -279,6 +280,18 @@ combo_decrypt(PX_Combo * cx, const uint8 *data, unsigned dlen,
PX_Cipher *c = cx->cipher;
+ /* decide whether zero-length input is allowed */
+ if (dlen == 0)
+ {
+ /* with padding, empty ciphertext is not allowed */
+ if (cx->padding)
+ return PXE_DECRYPT_FAILED;
+
+ /* without padding, report empty result */
+ *rlen = 0;
+ return 0;
+ }
+
bs = px_cipher_block_size(c);
if (bs > 1 && (dlen % bs) != 0)
goto block_error;
diff --git a/contrib/pgcrypto/px.h b/contrib/pgcrypto/px.h
index 412728e53d0..257d6015bc3 100644
--- a/contrib/pgcrypto/px.h
+++ b/contrib/pgcrypto/px.h
@@ -26,7 +26,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
- * $PostgreSQL: pgsql/contrib/pgcrypto/px.h,v 1.17 2007/04/06 05:36:50 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/pgcrypto/px.h,v 1.18 2007/08/23 16:15:51 tgl Exp $
*/
#ifndef __PX_H
@@ -78,6 +78,7 @@ void px_free(void *p);
#define PXE_BAD_SALT_ROUNDS -15
#define PXE_MCRYPT_INTERNAL -16
#define PXE_NO_RANDOM -17
+#define PXE_DECRYPT_FAILED -18
#define PXE_MBUF_SHORT_READ -50
--
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