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From: Sasha Levin <>
Cc: Dan Carpenter <>,
	Jukka Rissanen <>,
	Alexander Aring <>,
	Marcel Holtmann <>,
	Sasha Levin <>,,,
Subject: [PATCH AUTOSEL 4.9 120/251] 6lowpan: Off by one handling ->nexthdr
Date: Thu, 16 Jan 2020 12:34:29 -0500
Message-ID: <> (raw)
In-Reply-To: <>

From: Dan Carpenter <>

[ 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 <>
Acked-by: Jukka Rissanen <>
Acked-by: Alexander Aring <>
Signed-off-by: Marcel Holtmann <>
Signed-off-by: Sasha Levin <>
 net/6lowpan/nhc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c
index 7008d53e455c..e61679bf0908 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)

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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
2020-01-16 17:34 ` Sasha Levin [this message]
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 150/251] inet: frags: call inet_frags_fini() after unregister_pernet_subsys() Sasha Levin

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