netfilter: nft_compat: add more restrictions on netlink attributes

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[ Upstream commit cda26c6459 ]

As far as I can see nothing bad can happen when NFTA_TARGET/MATCH_NAME
are too large because this calls x_tables helpers which check for the
length, but it seems better to already reject it during netlink parsing.

Rest of the changes avoid silent u8/u16 truncations.

For _TYPE, its expected to be only 1 or 0. In x_tables world, this
variable is set by kernel, for IPT_SO_GET_REVISION_TARGET its 1, for
all others its set to 0.

As older versions of nf_tables permitted any value except 1 to mean 'match',
keep this as-is but sanitize the value for consistency.

Fixes: 0ca743a559 ("netfilter: nf_tables: add compatibility layer for x_tables")
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Florian Westphal 2022-08-19 16:16:07 +02:00 • committed by Sasha Levin

parent 3d0994ed0a

commit 63fece123b

1 changed files with 10 additions and 3 deletions

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net/netfilter/nft_compat.c

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