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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Alexey Kodanev <aleksei.kodanev@bell-sw.com>,
	Jack Wang <jinpu.wang@ionos.com>,
	Leon Romanovsky <leon@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.8 572/715] RDMA/rtrs-clt: Check strnlen return len in sysfs mpath_policy_store()
Date: Sun, 24 Mar 2024 18:32:31 -0400
Message-ID: <20240324223455.1342824-573-sashal@kernel.org>
In-Reply-To: <20240324223455.1342824-1-sashal@kernel.org>
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From: Alexey Kodanev <aleksei.kodanev@bell-sw.com>

[ Upstream commit 7a7b7f575a25aa68ee934ee8107294487efcb3fe ]

strnlen() may return 0 (e.g. for "\0\n" string), it's better to
check the result of strnlen() before using 'len - 1' expression
for the 'buf' array index.

Detected using the static analysis tool - Svace.

Fixes: dc3b66a0ce70 ("RDMA/rtrs-clt: Add a minimum latency multipath policy")
Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com>
Link: https://lore.kernel.org/r/20240221113204.147478-1-aleksei.kodanev@bell-sw.com
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
index d3c436ead6946..4aa80c9388f05 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
@@ -133,7 +133,7 @@ static ssize_t mpath_policy_store(struct device *dev,
 
 	/* distinguish "mi" and "min-latency" with length */
 	len = strnlen(buf, NAME_MAX);
-	if (buf[len - 1] == '\n')
+	if (len && buf[len - 1] == '\n')
 		len--;
 
 	if (!strncasecmp(buf, "round-robin", 11) ||
-- 
2.43.0