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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Barebox List <barebox@lists.infradead.org>
Subject: [PATCH 2/2] fs: nfs: Fix possible buffer overflow
Date: Mon,  2 Sep 2019 13:44:59 +0200	[thread overview]
Message-ID: <20190902114459.12171-3-s.hauer@pengutronix.de> (raw)
In-Reply-To: <20190902114459.12171-1-s.hauer@pengutronix.de>

nfs_readlink_req() 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>
---
 fs/nfs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/nfs.c b/fs/nfs.c
index d606ccd1e9..0ad07aa3f2 100644
--- a/fs/nfs.c
+++ b/fs/nfs.c
@@ -1023,6 +1023,10 @@ static int nfs_readlink_req(struct nfs_priv *npriv, struct nfs_fh *fh,
 	p = nfs_read_post_op_attr(p, NULL);
 
 	len = ntoh32(net_read_uint32(p)); /* new path length */
+
+	len = max_t(unsigned int, len,
+		    nfs_packet->len - sizeof(struct rpc_reply) - sizeof(uint32_t));
+
 	p++;
 
 	*target = xzalloc(len + 1);
-- 
2.23.0


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      parent 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 ` [PATCH 1/2] net: nfs: Fix possible buffer overflow Sascha Hauer
2019-09-02 11:44 ` Sascha Hauer [this message]

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