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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Barebox List <barebox@lists.infradead.org>
Subject: [PATCH 1/2] net: nfs: Fix possible buffer overflow
Date: Mon,  2 Sep 2019 13:44:58 +0200	[thread overview]
Message-ID: <20190902114459.12171-2-s.hauer@pengutronix.de> (raw)
In-Reply-To: <20190902114459.12171-1-s.hauer@pengutronix.de>

nfs_readlink_reply() interprets a 32bit value directly received from the
network as length argument to memcpy() without any boundary checking.
Clamp the copy size at the end of the incoming packet.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 net/nfs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/nfs.c b/net/nfs.c
index 0a3021994a..63573098d7 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -502,7 +502,7 @@ static int nfs_readlink_reply(unsigned char *pkt, unsigned len)
 {
 	uint32_t *data;
 	char *path;
-	int rlen;
+	unsigned int rlen;
 	int ret;
 
 	ret = rpc_check_reply(pkt, 1);
@@ -515,6 +515,9 @@ static int nfs_readlink_reply(unsigned char *pkt, unsigned len)
 
 	rlen = ntohl(net_read_uint32(data)); /* new path length */
 
+	rlen = max_t(unsigned int, rlen,
+		     len - sizeof(struct rpc_reply) - sizeof(uint32_t));
+
 	data++;
 	path = (char *)data;
 
-- 
2.23.0


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  reply	other threads:[~2019-09-02 11:45 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-02 11:44 [PATCH 0/2] Fix buffer overflows in nfs code Sascha Hauer
2019-09-02 11:44 ` Sascha Hauer [this message]
2019-09-02 11:44 ` [PATCH 2/2] fs: nfs: Fix possible buffer overflow Sascha Hauer

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