netfilter: x_tables: guard option walkers against 1-byte tail reads

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[ Upstream commit cfe770220a ]

When the last byte of options is a non-single-byte option kind, walkers
that advance with i += op[i + 1] ? : 1 can read op[i + 1] past the end
of the option area.

Add an explicit i == optlen - 1 check before dereferencing op[i + 1]
in xt_tcpudp and xt_dccp option walkers.

Fixes: 2e4e6a17af ("[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables")
Signed-off-by: David Dull <monderasdor@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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David Dull 2026-03-07 20:26:21 +02:00 • committed by Greg Kroah-Hartman

parent e047f6fbb9

commit bc18551c61

2 changed files with 6 additions and 4 deletions

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4

net/netfilter/xt_dccp.c

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6

net/netfilter/xt_tcpudp.c

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