0001-Null-terminate-the-output-buffer-of-LZ4Stream_gets.patch

From 587873da2b563c59b281051c2636cda667abf099 Mon Sep 17 00:00:00 2001
From: Georgios Kokolatos <gkokolatos@pm.me>
Date: Fri, 5 May 2023 09:47:02 +0000
Subject: [PATCH] Null terminate the output buffer of LZ4Stream_gets

LZ4Stream_gets did not null terminate its output buffer. Its callers expected
the buffer to be null terminated so they passed it around to functions such as
sscanf with unintended consequences.

Reported-by: Alexander Lakhin<exclusion@gmail.com>
---
 src/bin/pg_dump/compress_lz4.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/bin/pg_dump/compress_lz4.c b/src/bin/pg_dump/compress_lz4.c
index 423e1b7976..26c9a8b280 100644
--- a/src/bin/pg_dump/compress_lz4.c
+++ b/src/bin/pg_dump/compress_lz4.c
@@ -459,6 +459,10 @@ LZ4Stream_read_internal(LZ4State *state, void *ptr, int ptrsize, bool eol_flag)
 	if (!LZ4Stream_init(state, size, false /* decompressing */ ))
 		return -1;
 
+	/* No work needs to be done for a zero-sized output buffer */
+	if (size <= 0)
+		return 0;
+
 	/* Verify that there is enough space in the outbuf */
 	if (size > state->buflen)
 	{
@@ -636,7 +640,12 @@ LZ4Stream_gets(char *ptr, int size, CompressFileHandle *CFH)
 	LZ4State   *state = (LZ4State *) CFH->private_data;
 	int			ret;
 
-	ret = LZ4Stream_read_internal(state, ptr, size, true);
+	Assert(size > 1);
+
+	/* Our caller expects the return string to be NULL terminated */
+	memset(ptr, '\0', size);
+
+	ret = LZ4Stream_read_internal(state, ptr, size - 1, true);
 	if (ret < 0 || (ret == 0 && !LZ4Stream_eof(CFH)))
 		pg_fatal("could not read from input file: %s", LZ4Stream_get_error(CFH));
 
-- 
2.34.1