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authorPaolo Abeni <pabeni@redhat.com>2018-02-08 12:19:00 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2018-02-14 20:44:42 +0100
commit01ea306f2ac2baff98d472da719193e738759d93 (patch)
treef640a388b5930e52613e7109c177ac6d6f7e05fe /net/ipv4/ip_sockglue.c
parentnetfilter: ipt_CLUSTERIP: fix a race condition of proc file creation (diff)
downloadlinux-dev-01ea306f2ac2baff98d472da719193e738759d93.tar.xz
linux-dev-01ea306f2ac2baff98d472da719193e738759d93.zip
netfilter: drop outermost socket lock in getsockopt()
The Syzbot reported a possible deadlock in the netfilter area caused by rtnl lock, xt lock and socket lock being acquired with a different order on different code paths, leading to the following backtrace: Reviewed-by: Xin Long <lucien.xin@gmail.com> ====================================================== WARNING: possible circular locking dependency detected 4.15.0+ #301 Not tainted ------------------------------------------------------ syzkaller233489/4179 is trying to acquire lock: (rtnl_mutex){+.+.}, at: [<0000000048e996fd>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 but task is already holding lock: (&xt[i].mutex){+.+.}, at: [<00000000328553a2>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1041 which lock already depends on the new lock. === Since commit 3f34cfae1230 ("netfilter: on sockopt() acquire sock lock only in the required scope"), we already acquire the socket lock in the innermost scope, where needed. In such commit I forgot to remove the outer-most socket lock from the getsockopt() path, this commit addresses the issues dropping it now. v1 -> v2: fix bad subj, added relavant 'fixes' tag Fixes: 22265a5c3c10 ("netfilter: xt_TEE: resolve oif using netdevice notifiers") Fixes: 202f59afd441 ("netfilter: ipt_CLUSTERIP: do not hold dev") Fixes: 3f34cfae1230 ("netfilter: on sockopt() acquire sock lock only in the required scope") Reported-by: syzbot+ddde1c7b7ff7442d7f2d@syzkaller.appspotmail.com Suggested-by: Florian Westphal <fw@strlen.de> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv4/ip_sockglue.c')
-rw-r--r--net/ipv4/ip_sockglue.c7
1 files changed, 1 insertions, 6 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 008be04ac1cc..9c41a0cef1a5 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1567,10 +1567,7 @@ int ip_getsockopt(struct sock *sk, int level,
if (get_user(len, optlen))
return -EFAULT;
- lock_sock(sk);
- err = nf_getsockopt(sk, PF_INET, optname, optval,
- &len);
- release_sock(sk);
+ err = nf_getsockopt(sk, PF_INET, optname, optval, &len);
if (err >= 0)
err = put_user(len, optlen);
return err;
@@ -1602,9 +1599,7 @@ int compat_ip_getsockopt(struct sock *sk, int level, int optname,
if (get_user(len, optlen))
return -EFAULT;
- lock_sock(sk);
err = compat_nf_getsockopt(sk, PF_INET, optname, optval, &len);
- release_sock(sk);
if (err >= 0)
err = put_user(len, optlen);
return err;