diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h index 0b247248b032..fd5c4dbf72ca 100644 --- a/include/net/netfilter/nf_conntrack_extend.h +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -38,7 +38,6 @@ enum nf_ct_ext_id { struct nf_ct_ext { u8 offset[NF_CT_EXT_NUM]; u8 len; - unsigned int gen_id; char data[] __aligned(8); }; @@ -52,8 +51,6 @@ static inline bool nf_ct_ext_exist(const struct nf_conn *ct, u8 id) return (ct->ext && __nf_ct_ext_exist(ct->ext, id)); } -void *__nf_ct_ext_find(const struct nf_ct_ext *ext, u8 id); - static inline void *nf_ct_ext_find(const struct nf_conn *ct, u8 id) { struct nf_ct_ext *ext = ct->ext; @@ -61,19 +58,10 @@ static inline void *nf_ct_ext_find(const struct nf_conn *ct, u8 id) if (!ext || !__nf_ct_ext_exist(ext, id)) return NULL; - if (unlikely(ext->gen_id)) - return __nf_ct_ext_find(ext, id); - return (void *)ct->ext + ct->ext->offset[id]; } /* Add this type, returns pointer to data or NULL. */ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp); -/* ext genid. if ext->id != ext_genid, extensions cannot be used - * anymore unless conntrack has CONFIRMED bit set. - */ -extern atomic_t nf_conntrack_ext_genid; -void nf_ct_ext_bump_genid(void); - #endif /* _NF_CONNTRACK_EXTEND_H */ diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 7c135fe3dd03..91255fd3b35d 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -840,33 +840,6 @@ static void __nf_conntrack_hash_insert(struct nf_conn *ct, &nf_conntrack_hash[reply_hash]); } -static bool nf_ct_ext_valid_pre(const struct nf_ct_ext *ext) -{ - /* if ext->gen_id is not equal to nf_conntrack_ext_genid, some extensions - * may contain stale pointers to e.g. helper that has been removed. - * - * The helper can't clear this because the nf_conn object isn't in - * any hash and synchronize_rcu() isn't enough because associated skb - * might sit in a queue. - */ - return !ext || ext->gen_id == atomic_read(&nf_conntrack_ext_genid); -} - -static bool nf_ct_ext_valid_post(struct nf_ct_ext *ext) -{ - if (!ext) - return true; - - if (ext->gen_id != atomic_read(&nf_conntrack_ext_genid)) - return false; - - /* inserted into conntrack table, nf_ct_iterate_cleanup() - * will find it. Disable nf_ct_ext_find() id check. - */ - WRITE_ONCE(ext->gen_id, 0); - return true; -} - int nf_conntrack_hash_check_insert(struct nf_conn *ct) { @@ -882,9 +855,6 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct) zone = nf_ct_zone(ct); - if (!nf_ct_ext_valid_pre(ct->ext)) - return -EAGAIN; - local_bh_disable(); do { sequence = read_seqcount_begin(&nf_conntrack_generation); @@ -918,18 +888,6 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct) goto chaintoolong; } - /* If genid has changed, we can't insert anymore because ct - * extensions could have stale pointers and nf_ct_iterate_destroy - * might have completed its table scan already. - * - * Increment of the ext genid right after this check is fine: - * nf_ct_iterate_destroy blocks until locks are released. - */ - if (!nf_ct_ext_valid_post(ct->ext)) { - err = -EAGAIN; - goto out; - } - smp_wmb(); /* The caller holds a reference to this object */ refcount_set(&ct->ct_general.use, 2); @@ -1257,11 +1215,6 @@ __nf_conntrack_confirm(struct sk_buff *skb) return NF_DROP; } - if (!nf_ct_ext_valid_pre(ct->ext)) { - NF_CT_STAT_INC(net, insert_failed); - goto dying; - } - /* We have to check the DYING flag after unlink to prevent * a race against nf_ct_get_next_corpse() possibly called from * user context, else we insert an already 'dead' hash, blocking @@ -1324,16 +1277,6 @@ __nf_conntrack_confirm(struct sk_buff *skb) nf_conntrack_double_unlock(hash, reply_hash); local_bh_enable(); - /* ext area is still valid (rcu read lock is held, - * but will go out of scope soon, we need to remove - * this conntrack again. - */ - if (!nf_ct_ext_valid_post(ct->ext)) { - nf_ct_kill(ct); - NF_CT_STAT_INC_ATOMIC(net, drop); - return NF_DROP; - } - help = nfct_help(ct); if (help && help->helper) nf_conntrack_event_cache(IPCT_HELPER, ct); @@ -2441,13 +2384,11 @@ nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data) */ synchronize_net(); - nf_ct_ext_bump_genid(); iter_data.data = data; nf_ct_iterate_cleanup(iter, &iter_data); /* Another cpu might be in a rcu read section with - * rcu protected pointer cleared in iter callback - * or hidden via nf_ct_ext_bump_genid() above. + * rcu protected pointer cleared in iter callback. * * Wait until those are done. */ diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c index dd62cc12e775..0da105e1ded9 100644 --- a/net/netfilter/nf_conntrack_extend.c +++ b/net/netfilter/nf_conntrack_extend.c @@ -27,8 +27,6 @@ #define NF_CT_EXT_PREALLOC 128u /* conntrack events are on by default */ -atomic_t nf_conntrack_ext_genid __read_mostly = ATOMIC_INIT(1); - static const u8 nf_ct_ext_type_len[NF_CT_EXT_NUM] = { [NF_CT_EXT_HELPER] = sizeof(struct nf_conn_help), #if IS_ENABLED(CONFIG_NF_NAT) @@ -118,10 +116,8 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) if (!new) return NULL; - if (!ct->ext) { + if (!ct->ext) memset(new->offset, 0, sizeof(new->offset)); - new->gen_id = atomic_read(&nf_conntrack_ext_genid); - } new->offset[id] = newoff; new->len = newlen; @@ -131,29 +127,3 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) return (void *)new + newoff; } EXPORT_SYMBOL(nf_ct_ext_add); - -/* Use nf_ct_ext_find wrapper. This is only useful for unconfirmed entries. */ -void *__nf_ct_ext_find(const struct nf_ct_ext *ext, u8 id) -{ - unsigned int gen_id = atomic_read(&nf_conntrack_ext_genid); - unsigned int this_id = READ_ONCE(ext->gen_id); - - if (!__nf_ct_ext_exist(ext, id)) - return NULL; - - if (this_id == 0 || ext->gen_id == gen_id) - return (void *)ext + ext->offset[id]; - - return NULL; -} -EXPORT_SYMBOL(__nf_ct_ext_find); - -void nf_ct_ext_bump_genid(void) -{ - unsigned int value = atomic_inc_return(&nf_conntrack_ext_genid); - - if (value == UINT_MAX) - atomic_set(&nf_conntrack_ext_genid, 1); - - msleep(HZ); -}