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[4.14,175/343] 6lowpan: Off by one handling ->nexthdr

Message ID 20200124092943.039609589@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Jan. 24, 2020, 9:29 a.m. UTC 
From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit f57c4bbf34439531adccd7d3a4ecc14f409c1399 ]

NEXTHDR_MAX is 255.  What happens here is that we take a u8 value
"hdr->nexthdr" from the network and then look it up in
lowpan_nexthdr_nhcs[].  The problem is that if hdr->nexthdr is 0xff then
we read one element beyond the end of the array so the array needs to
be one element larger.

Fixes: 92aa7c65d295 ("6lowpan: add generic nhc layer interface")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Acked-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/6lowpan/nhc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c
index 4fa2fdda174d0..9e56fb98f33cf 100644
--- a/net/6lowpan/nhc.c
+++ b/net/6lowpan/nhc.c
@@ -18,7 +18,7 @@ 
 #include "nhc.h"
 
 static struct rb_root rb_root = RB_ROOT;
-static struct lowpan_nhc *lowpan_nexthdr_nhcs[NEXTHDR_MAX];
+static struct lowpan_nhc *lowpan_nexthdr_nhcs[NEXTHDR_MAX + 1];
 static DEFINE_SPINLOCK(lowpan_nhc_lock);
 
 static int lowpan_nhc_insert(struct lowpan_nhc *nhc)