b855d416dc
nft_cmp_fast is used for equality comparisions of size <= 4. For comparisions of size < 4 byte a mask is calculated that is applied to both the data from userspace (during initialization) and the register value (during runtime). Both values are stored using (in effect) memcpy to a memory area that is then interpreted as u32 by nft_cmp_fast. This works fine on little endian since smaller types have the same base address, however on big endian this is not true and the smaller types are interpreted as a big number with trailing zero bytes. The mask therefore must not include the lower bytes, but the higher bytes on big endian. Add a helper function that does a cpu_to_le32 to switch the bytes on big endian. Since we're dealing with a mask of just consequitive bits, this works out fine. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
53 lines
1.3 KiB
C
53 lines
1.3 KiB
C
#ifndef _NET_NF_TABLES_CORE_H
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#define _NET_NF_TABLES_CORE_H
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int nf_tables_core_module_init(void);
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void nf_tables_core_module_exit(void);
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int nft_immediate_module_init(void);
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void nft_immediate_module_exit(void);
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struct nft_cmp_fast_expr {
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u32 data;
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enum nft_registers sreg:8;
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u8 len;
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};
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/* Calculate the mask for the nft_cmp_fast expression. On big endian the
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* mask needs to include the *upper* bytes when interpreting that data as
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* something smaller than the full u32, therefore a cpu_to_le32 is done.
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*/
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static inline u32 nft_cmp_fast_mask(unsigned int len)
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{
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return cpu_to_le32(~0U >> (FIELD_SIZEOF(struct nft_cmp_fast_expr,
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data) * BITS_PER_BYTE - len));
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}
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extern const struct nft_expr_ops nft_cmp_fast_ops;
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int nft_cmp_module_init(void);
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void nft_cmp_module_exit(void);
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int nft_lookup_module_init(void);
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void nft_lookup_module_exit(void);
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int nft_bitwise_module_init(void);
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void nft_bitwise_module_exit(void);
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int nft_byteorder_module_init(void);
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void nft_byteorder_module_exit(void);
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struct nft_payload {
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enum nft_payload_bases base:8;
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u8 offset;
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u8 len;
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enum nft_registers dreg:8;
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};
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extern const struct nft_expr_ops nft_payload_fast_ops;
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int nft_payload_module_init(void);
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void nft_payload_module_exit(void);
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#endif /* _NET_NF_TABLES_CORE_H */
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