netdev - [PATCH iproute2-next 1/1] tc: flower: Fix buffer overflow on large labels

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Date:   Sun, 5 Dec 2021 15:20:25 +0200
From:   Paul Blakey <paulb@...dia.com>
To:     Paul Blakey <paulb@...dia.com>, Oz Shlomo <ozsh@...dia.com>,
        Roi Dayan <roid@...dia.com>, <netdev@...r.kernel.org>,
        David Ahern <dsahern@...il.com>,
        Stephen Hemminger <stephen@...workplumber.org>
CC:     Simon Horman <simon.horman@...ronome.com>
Subject: [PATCH iproute2-next 1/1] tc: flower: Fix buffer overflow on large labels

Buffer is 64bytes, but label printing can take 66bytes printing
in hex, and will overflow when setting the string delimiter ('\0').

Fix that by increasing the print buffer size.

Example of overflowing ct_label:
ct_label 11111111111111111111111111111111/11111111111111111111111111111111

Fixes: 2fffb1c03056 ("tc: flower: Add matching on conntrack info")
Signed-off-by: Paul Blakey <paulb@...dia.com>
---
 tc/f_flower.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tc/f_flower.c b/tc/f_flower.c
index 7f78195f..6d70b92a 100644
--- a/tc/f_flower.c
+++ b/tc/f_flower.c
@@ -2195,7 +2195,7 @@ static void flower_print_ct_label(struct rtattr *attr,
 	const unsigned char *str;
 	bool print_mask = false;
 	int data_len, i;
-	SPRINT_BUF(out);
+	char out[128];
 	char *p;
 
 	if (!attr)
-- 
2.30.1