Received-SPF: pass (google.com: domain of linux-bluetooth-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Ildar Kamaletdinov <i.kamaletdinov@omp.ru>
To:     <linux-bluetooth@vger.kernel.org>
CC:     Ildar Kamaletdinov <i.kamaletdinov@omp.ru>
Subject: [PATCH BlueZ 3/7] tools: Fix signed integer overflow in btsnoop.c
Date:   Fri, 1 Apr 2022 14:14:04 +0300
Message-ID: <20220401111408.3961844-4-i.kamaletdinov@omp.ru>
In-Reply-To: <20220401111408.3961844-1-i.kamaletdinov@omp.ru>
References: <20220401111408.3961844-1-i.kamaletdinov@omp.ru>
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
Content-Type:   text/plain; charset=US-ASCII
Precedence: bulk

If malformed packet is proceed with zero 'size' field we will face with
wrong behaviour of write() call. Value 'toread - 1' gives wrong sign
for value 'written' (-1) in write() call. To prevent this we should
check that 'toread' is not equal to zero.

Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.
---
 tools/btsnoop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/btsnoop.c b/tools/btsnoop.c
index 738027dfc..a0d6cf356 100644
--- a/tools/btsnoop.c
+++ b/tools/btsnoop.c
@@ -193,7 +193,7 @@ next_packet:
 	flags = be32toh(input_pkt[select_input].flags);
 
 	len = read(input_fd[select_input], buf, toread);
-	if (len < 0 || len != (ssize_t) toread) {
+	if (toread == 0 || len < 0 || len != (ssize_t) toread) {
 		close(input_fd[select_input]);
 		input_fd[select_input] = -1;
 		goto next_packet;
-- 
2.35.1