From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 23 Aug 2007 16:16:11 +0000 (+0000)
Subject: Fix combo_decrypt() to throw an error for zero-length input when using a
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=0c57c249b5cba28f46a391babb7de24a8d6f5e18;p=users%2Fbernd%2Fpostgres.git

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.
---

diff --git a/contrib/pgcrypto/px.c b/contrib/pgcrypto/px.c
index 456d3ed894..70c4685d15 100644
--- a/contrib/pgcrypto/px.c
+++ b/contrib/pgcrypto/px.c
@@ -185,6 +185,18 @@ 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 -1;
+		
+		/* without padding, report empty result */
+		*rlen = 0;
+		return 0;
+	}
+
 	bs = px_cipher_block_size(c);
 	if (bs > 1 && (dlen % bs) != 0)
 		goto block_error;