diff options
author | Patrick McHardy <kaber@trash.net> | 2015-03-03 23:04:20 +0300 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2015-03-04 20:46:06 +0300 |
commit | 86f1ec32318159a24de349f0a38e79b9d2b3131a (patch) | |
tree | 6533fb1a3354201a635cf4dfdeaa143e2d3de12a /include/net | |
parent | 9889840f5988ecfd43b00c9abb83c1804e21406b (diff) | |
download | linux-86f1ec32318159a24de349f0a38e79b9d2b3131a.tar.xz |
netfilter: nf_tables: fix userdata length overflow
The NFT_USERDATA_MAXLEN is defined to 256, however we only have a u8
to store its size. Introduce a struct nft_userdata which contains a
length field and indicate its presence using a single bit in the rule.
The length field of struct nft_userdata is also a u8, however we don't
store zero sized data, so the actual length is udata->len + 1.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include/net')
-rw-r--r-- | include/net/netfilter/nf_tables.h | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 9eaaa7884586..decb9a095ae7 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -119,6 +119,22 @@ int nft_validate_data_load(const struct nft_ctx *ctx, enum nft_registers reg, const struct nft_data *data, enum nft_data_types type); + +/** + * struct nft_userdata - user defined data associated with an object + * + * @len: length of the data + * @data: content + * + * The presence of user data is indicated in an object specific fashion, + * so a length of zero can't occur and the value "len" indicates data + * of length len + 1. + */ +struct nft_userdata { + u8 len; + unsigned char data[0]; +}; + /** * struct nft_set_elem - generic representation of set elements * @@ -380,7 +396,7 @@ static inline void *nft_expr_priv(const struct nft_expr *expr) * @handle: rule handle * @genmask: generation mask * @dlen: length of expression data - * @ulen: length of user data (used for comments) + * @udata: user data is appended to the rule * @data: expression data */ struct nft_rule { @@ -388,7 +404,7 @@ struct nft_rule { u64 handle:42, genmask:2, dlen:12, - ulen:8; + udata:1; unsigned char data[] __attribute__((aligned(__alignof__(struct nft_expr)))); }; @@ -476,7 +492,7 @@ static inline struct nft_expr *nft_expr_last(const struct nft_rule *rule) return (struct nft_expr *)&rule->data[rule->dlen]; } -static inline void *nft_userdata(const struct nft_rule *rule) +static inline struct nft_userdata *nft_userdata(const struct nft_rule *rule) { return (void *)&rule->data[rule->dlen]; } |