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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 105/238] ipmr: fix incorrect parameter validation in the ip_mroute_getsockopt() function
Date: Sun, 24 Mar 2024 19:38:13 -0400
Message-ID: <20240324234027.1354210-106-sashal@kernel.org>
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From: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>

[ Upstream commit 5c3be3e0eb44b7f978bb6cbb20ad956adb93f736 ]

The 'olr' variable can't be negative when assigned the result of
'min_t' because all 'min_t' parameters are cast to unsigned int,
and then the minimum one is chosen.

To fix the logic, check 'olr' as read from 'optlen',
where the types of relevant variables are (signed) int.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/ipmr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index cdc0a1781fd28..db184cb826b95 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1574,9 +1574,11 @@ int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
 
 	if (copy_from_sockptr(&olr, optlen, sizeof(int)))
 		return -EFAULT;
-	olr = min_t(unsigned int, olr, sizeof(int));
 	if (olr < 0)
 		return -EINVAL;
+
+	olr = min_t(unsigned int, olr, sizeof(int));
+
 	if (copy_to_sockptr(optlen, &olr, sizeof(int)))
 		return -EFAULT;
 	if (copy_to_sockptr(optval, &val, olr))
-- 
2.43.0