netfilter: ebtables: fix compat entry padding (9e8c8dab) · Commits · 戴 / test

On arm64, ebt_entry_{match,watcher,target} structs are 40 bytes long while on 32-bit arm these structs have a size of 36 bytes. COMPAT_XT_ALIGN() macro cannot be used here to determine the necessary padding for the CONFIG_COMPAT because it imposes an 8-byte boundary alignment, condition that is not found in 32-bit ebtables application. Signed-off-by:

Alin Nastac <alin.nastac@gmail.com> Acked-by:

Florian Westphal <fw@strlen.de> Signed-off-by:

Pablo Neira Ayuso <pablo@netfilter.org>

net/bridge/netfilter/ebtables.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -1610,16 +1610,16 @@ struct compat_ebt_entry_mwt {
		compat_uptr_t ptr;
		} u;
		compat_uint_t match_size;
		compat_uint_t data[0];
		compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace))));
		};

		/* account for possible padding between match_size and ->data */
		static int ebt_compat_entry_padsize(void)
		{
		BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
		COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
		return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
		COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
		BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
		sizeof(struct compat_ebt_entry_mwt));
		return (int) sizeof(struct ebt_entry_match) -
		sizeof(struct compat_ebt_entry_mwt);
		}

		static int ebt_compat_match_offset(const struct xt_match *match,

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