From: Daniel Gustafsson <dgustafsson@postgresql.org>
Date: Tue, 30 Jan 2024 10:15:46 +0000 (+0100)
Subject: pgcrypto: Fix check for buffer size
X-Git-Tag: REL_14_11~14
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=54717fcaad759312b2ff8588e146977f529e7798;p=postgresql.git

pgcrypto: Fix check for buffer size

The code copying the PGP block into the temp buffer failed to
account for the extra 2 bytes in the buffer which are needed
for the prefix. If the block was oversized, subsequent checks
of the prefix would have exceeded the buffer size.  Since the
block sizes are hardcoded in the list of supported ciphers it
can be verified that there is no live bug here. Backpatch all
the way for consistency though, as this bug is old.

Author: Mikhail Gribkov <youzhick@gmail.com>
Discussion: https://postgr.es/m/CAMEv5_uWvcMCMdRFDsJLz2Q8g16HEa9xWyfrkr+FYMMFJhawOw@mail.gmail.com
Backpatch-through: v12
---

diff --git a/contrib/pgcrypto/pgp-decrypt.c b/contrib/pgcrypto/pgp-decrypt.c
index d12dcad1945..e1ea5b3e58d 100644
--- a/contrib/pgcrypto/pgp-decrypt.c
+++ b/contrib/pgcrypto/pgp-decrypt.c
@@ -250,7 +250,8 @@ prefix_init(void **priv_p, void *arg, PullFilter *src)
 	uint8		tmpbuf[PGP_MAX_BLOCK + 2];
 
 	len = pgp_get_cipher_block_size(ctx->cipher_algo);
-	if (len > sizeof(tmpbuf))
+	/* Make sure we have space for prefix */
+	if (len > PGP_MAX_BLOCK)
 		return PXE_BUG;
 
 	res = pullf_read_max(src, len + 2, &buf, tmpbuf);