diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2023-06-28 16:24:27 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-08-16 18:27:30 +0200 |
commit | f3f0f95a023370561a9b4d2028308f8452f1e7d1 (patch) | |
tree | 6d04f01ddcc70e6647eb737283b830d96b10bf07 /include | |
parent | c21fddce7e450b737a77cd918e55969076143bb0 (diff) | |
download | linux-f3f0f95a023370561a9b4d2028308f8452f1e7d1.tar.gz |
netfilter: nf_tables: report use refcount overflow
commit 1689f25924ada8fe14a4a82c38925d04994c7142 upstream. Overflow use refcount checks are not complete. Add helper function to deal with object reference counter tracking. Report -EMFILE in case UINT_MAX is reached. nft_use_dec() splats in case that reference counter underflows, which should not ever happen. Add nft_use_inc_restore() and nft_use_dec_restore() which are used to restore reference counter from error and abort paths. Use u32 in nft_flowtable and nft_object since helper functions cannot work on bitfields. Remove the few early incomplete checks now that the helper functions are in place and used to check for refcount overflow. Fixes: 96518518cc41 ("netfilter: add nftables") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/net/netfilter/nf_tables.h | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index f3a37cacb32c..c752b6f50979 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -1192,6 +1192,29 @@ int __nft_release_basechain(struct nft_ctx *ctx); unsigned int nft_do_chain(struct nft_pktinfo *pkt, void *priv); +static inline bool nft_use_inc(u32 *use) +{ + if (*use == UINT_MAX) + return false; + + (*use)++; + + return true; +} + +static inline void nft_use_dec(u32 *use) +{ + WARN_ON_ONCE((*use)-- == 0); +} + +/* For error and abort path: restore use counter to previous state. */ +static inline void nft_use_inc_restore(u32 *use) +{ + WARN_ON_ONCE(!nft_use_inc(use)); +} + +#define nft_use_dec_restore nft_use_dec + /** * struct nft_table - nf_tables table * @@ -1275,8 +1298,8 @@ struct nft_object { struct list_head list; struct rhlist_head rhlhead; struct nft_object_hash_key key; - u32 genmask:2, - use:30; + u32 genmask:2; + u32 use; u64 handle; u16 udlen; u8 *udata; @@ -1378,8 +1401,8 @@ struct nft_flowtable { char *name; int hooknum; int ops_len; - u32 genmask:2, - use:30; + u32 genmask:2; + u32 use; u64 handle; /* runtime data below here */ struct list_head hook_list ____cacheline_aligned; |