* [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() [not found] <000000000000a9172705e7ffef2e@google.com> @ 2022-09-12 12:41 ` Tetsuo Handa 2022-09-12 12:44 ` Pablo Neira Ayuso 2022-09-15 20:19 ` Florian Westphal 0 siblings, 2 replies; 3+ messages in thread From: Tetsuo Handa @ 2022-09-12 12:41 UTC (permalink / raw) To: Pablo Neira Ayuso, Jozsef Kadlecsik, Florian Westphal Cc: syzbot, syzkaller-bugs, netfilter-devel, coreteam, Network Development syzbot is reporting underflow of nft_counters_enabled counter at nf_tables_addchain() [1], for commit 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error") missed that nf_tables_chain_destroy() after nft_basechain_init() in the error path of nf_tables_addchain() decrements the counter because nft_basechain_init() makes nft_is_base_chain() return true by setting NFT_CHAIN_BASE flag. Increment the counter immediately after returning from nft_basechain_init(). Link: https://syzkaller.appspot.com/bug?extid=b5d82a651b71cd8a75ab [1] Reported-by: syzbot <syzbot+b5d82a651b71cd8a75ab@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Tested-by: syzbot <syzbot+b5d82a651b71cd8a75ab@syzkaller.appspotmail.com> Fixes: 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error") --- net/netfilter/nf_tables_api.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 816052089b33..e062754dc6cc 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -2197,7 +2197,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, struct netlink_ext_ack *extack) { const struct nlattr * const *nla = ctx->nla; - struct nft_stats __percpu *stats = NULL; struct nft_table *table = ctx->table; struct nft_base_chain *basechain; struct net *net = ctx->net; @@ -2212,6 +2211,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, return -EOVERFLOW; if (nla[NFTA_CHAIN_HOOK]) { + struct nft_stats __percpu *stats = NULL; struct nft_chain_hook hook; if (flags & NFT_CHAIN_BINDING) @@ -2245,6 +2245,8 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, kfree(basechain); return err; } + if (stats) + static_branch_inc(&nft_counters_enabled); } else { if (flags & NFT_CHAIN_BASE) return -EINVAL; @@ -2319,9 +2321,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, goto err_unregister_hook; } - if (stats) - static_branch_inc(&nft_counters_enabled); - table->use++; return 0; -- 2.18.4 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() 2022-09-12 12:41 ` [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() Tetsuo Handa @ 2022-09-12 12:44 ` Pablo Neira Ayuso 2022-09-15 20:19 ` Florian Westphal 1 sibling, 0 replies; 3+ messages in thread From: Pablo Neira Ayuso @ 2022-09-12 12:44 UTC (permalink / raw) To: Tetsuo Handa Cc: Jozsef Kadlecsik, Florian Westphal, syzbot, syzkaller-bugs, netfilter-devel, coreteam, Network Development On Mon, Sep 12, 2022 at 09:41:00PM +0900, Tetsuo Handa wrote: > syzbot is reporting underflow of nft_counters_enabled counter at > nf_tables_addchain() [1], for commit 43eb8949cfdffa76 ("netfilter: > nf_tables: do not leave chain stats enabled on error") missed that > nf_tables_chain_destroy() after nft_basechain_init() in the error path of > nf_tables_addchain() decrements the counter because nft_basechain_init() > makes nft_is_base_chain() return true by setting NFT_CHAIN_BASE flag. > > Increment the counter immediately after returning from > nft_basechain_init(). Patch LGTM, thanks > Link: https://syzkaller.appspot.com/bug?extid=b5d82a651b71cd8a75ab [1] > Reported-by: syzbot <syzbot+b5d82a651b71cd8a75ab@syzkaller.appspotmail.com> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Tested-by: syzbot <syzbot+b5d82a651b71cd8a75ab@syzkaller.appspotmail.com> > Fixes: 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error") > --- > net/netfilter/nf_tables_api.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c > index 816052089b33..e062754dc6cc 100644 > --- a/net/netfilter/nf_tables_api.c > +++ b/net/netfilter/nf_tables_api.c > @@ -2197,7 +2197,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, > struct netlink_ext_ack *extack) > { > const struct nlattr * const *nla = ctx->nla; > - struct nft_stats __percpu *stats = NULL; > struct nft_table *table = ctx->table; > struct nft_base_chain *basechain; > struct net *net = ctx->net; > @@ -2212,6 +2211,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, > return -EOVERFLOW; > > if (nla[NFTA_CHAIN_HOOK]) { > + struct nft_stats __percpu *stats = NULL; > struct nft_chain_hook hook; > > if (flags & NFT_CHAIN_BINDING) > @@ -2245,6 +2245,8 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, > kfree(basechain); > return err; > } > + if (stats) > + static_branch_inc(&nft_counters_enabled); > } else { > if (flags & NFT_CHAIN_BASE) > return -EINVAL; > @@ -2319,9 +2321,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, > goto err_unregister_hook; > } > > - if (stats) > - static_branch_inc(&nft_counters_enabled); > - > table->use++; > > return 0; > -- > 2.18.4 > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() 2022-09-12 12:41 ` [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() Tetsuo Handa 2022-09-12 12:44 ` Pablo Neira Ayuso @ 2022-09-15 20:19 ` Florian Westphal 1 sibling, 0 replies; 3+ messages in thread From: Florian Westphal @ 2022-09-15 20:19 UTC (permalink / raw) To: Tetsuo Handa Cc: Pablo Neira Ayuso, Jozsef Kadlecsik, Florian Westphal, syzbot, syzkaller-bugs, netfilter-devel, coreteam, Network Development Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote: > syzbot is reporting underflow of nft_counters_enabled counter at > nf_tables_addchain() [1], for commit 43eb8949cfdffa76 ("netfilter: > nf_tables: do not leave chain stats enabled on error") missed that > nf_tables_chain_destroy() after nft_basechain_init() in the error path of > nf_tables_addchain() decrements the counter because nft_basechain_init() > makes nft_is_base_chain() return true by setting NFT_CHAIN_BASE flag. > > Increment the counter immediately after returning from > nft_basechain_init(). Applied, thanks. ^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-09-12 12:41 ` [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() Tetsuo Handa
2022-09-12 12:44 ` Pablo Neira Ayuso
2022-09-15 20:19 ` Florian Westphal
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