From 520aa7414bb590f39d0d1591b06018e60cbc7cf4 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 12 Feb 2015 22:15:31 +0100 Subject: [PATCH] netfilter: nft_compat: fix module refcount underflow Feb 12 18:20:42 nfdev kernel: ------------[ cut here ]------------ Feb 12 18:20:42 nfdev kernel: WARNING: CPU: 4 PID: 4359 at kernel/module.c:963 module_put+0x9b/0xba() Feb 12 18:20:42 nfdev kernel: CPU: 4 PID: 4359 Comm: ebtables-compat Tainted: G W 3.19.0-rc6+ #43 [...] Feb 12 18:20:42 nfdev kernel: Call Trace: Feb 12 18:20:42 nfdev kernel: [] dump_stack+0x4c/0x65 Feb 12 18:20:42 nfdev kernel: [] warn_slowpath_common+0x9c/0xb6 Feb 12 18:20:42 nfdev kernel: [] ? module_put+0x9b/0xba Feb 12 18:20:42 nfdev kernel: [] warn_slowpath_null+0x15/0x17 Feb 12 18:20:42 nfdev kernel: [] module_put+0x9b/0xba Feb 12 18:20:42 nfdev kernel: [] nft_match_destroy+0x45/0x4c Feb 12 18:20:42 nfdev kernel: [] nf_tables_rule_destroy+0x28/0x70 Reported-by: Arturo Borrero Gonzalez Signed-off-by: Pablo Neira Ayuso Tested-by: Arturo Borrero Gonzalez --- net/netfilter/nft_compat.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c index 265e190..b636486 100644 --- a/net/netfilter/nft_compat.c +++ b/net/netfilter/nft_compat.c @@ -578,8 +578,12 @@ nft_match_select_ops(const struct nft_ctx *ctx, struct xt_match *match = nft_match->ops.data; if (strcmp(match->name, mt_name) == 0 && - match->revision == rev && match->family == family) + match->revision == rev && match->family == family) { + if (!try_module_get(match->me)) + return ERR_PTR(-ENOENT); + return &nft_match->ops; + } } match = xt_request_find_match(family, mt_name, rev); @@ -648,8 +652,12 @@ nft_target_select_ops(const struct nft_ctx *ctx, struct xt_target *target = nft_target->ops.data; if (strcmp(target->name, tg_name) == 0 && - target->revision == rev && target->family == family) + target->revision == rev && target->family == family) { + if (!try_module_get(target->me)) + return ERR_PTR(-ENOENT); + return &nft_target->ops; + } } target = xt_request_find_target(family, tg_name, rev); -- 2.7.4