From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> stable inclusion from stable-v5.10.146 commit 710e3f526bd23a0d33435dedc52c3144de284378 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0VX Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 921ebde3c0d22c8cba74ce8eb3cc4626abff1ccd ] 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") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> --- 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 b8e7e1c5c08a..d65c47bcbfc9 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -2001,7 +2001,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, u8 policy, u32 flags) { 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; @@ -2015,6 +2014,7 @@ 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) @@ -2047,6 +2047,8 @@ 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; @@ -2121,9 +2123,6 @@ 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; -- 2.25.1