Re: BUG #16476: pgp_sym_encrypt_bytea with compress-level=6 :Wrong key or corrupt data

At Thu, 11 Jun 2020 22:17:26 +0900, Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in 
> >
> > The reproducer becomes not to fail with the attached patch.
> 
> 
> I put an assertion in the patch, but that is not appropriare. It shoud be
> an ereport instead. I’ll fix that later.

Fixed.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center
From 1f5003c164cf529a79d1f56e4c43d5867c3a345e Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyoga.ntt@gmail.com>
Date: Thu, 11 Jun 2020 20:29:23 +0900
Subject: [PATCH v2] Make sure to consume stream-terminating packet

When a compressed stream ends with a full packet, it must be
terminated by a normal empty packet.  Make sure to consume such
packets.
---
 contrib/pgcrypto/pgp-compress.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/contrib/pgcrypto/pgp-compress.c b/contrib/pgcrypto/pgp-compress.c
index 0505bdee92..296afb3324 100644
--- a/contrib/pgcrypto/pgp-compress.c
+++ b/contrib/pgcrypto/pgp-compress.c
@@ -286,7 +286,29 @@ restart:
 
     dec->buf_data = dec->buf_len - dec->stream.avail_out;
     if (res == Z_STREAM_END)
+    {
+        uint8 *tmp;
+
+        /*
+         * A stream must be terminated by a normal packet. If the last stream
+         * packet in the source stream is a full packet, a normal empty packet
+         * must follow. Since the underlying packet reader doesn't know that
+         * the compressed stream has been ended, we need to to consume the
+         * terminating packet here. This read doesn't harm even if the stream
+         * has already ended.
+         */
+        res = pullf_read(src, 1, &tmp);
+
+        if (res < 0)
+            return res;
+        else if (res > 0)
+        {
+            px_debug("decompress_read: extra bytes after end of stream");
+            return PXE_PGP_CORRUPT_DATA;
+        }
+        
         dec->eof = 1;
+    }
     goto restart;
 }
 
-- 
2.18.2