diff options
| author | Florian Westphal <fw@strlen.de> | 2022-05-20 00:02:03 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-05-27 11:16:33 +0200 |
| commit | ffd219efd9ee1ceccc7ccfa9361fd40705680fc3 (patch) | |
| tree | 24deb559efab08e0288c735ac82d50435b6e69ca /net/netfilter | |
| parent | 02ded5a173619b11728b8bf75a3fd995a2c1ff28 (diff) | |
netfilter: nfnetlink: fix warn in nfnetlink_unbind
syzbot reports following warn:
WARNING: CPU: 0 PID: 3600 at net/netfilter/nfnetlink.c:703 nfnetlink_unbind+0x357/0x3b0 net/netfilter/nfnetlink.c:694
The syzbot generated program does this:
socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER) = 3
setsockopt(3, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, [1], 4) = 0
... which triggers 'WARN_ON_ONCE(nfnlnet->ctnetlink_listeners == 0)' check.
Instead of counting, just enable reporting for every bind request
and check if we still have listeners on unbind.
While at it, also add the needed bounds check on nfnl_group2type[]
access.
Reported-by: <syzbot+4903218f7fba0a2d6226@syzkaller.appspotmail.com>
Reported-by: <syzbot+afd2d80e495f96049571@syzkaller.appspotmail.com>
Fixes: 2794cdb0b97b ("netfilter: nfnetlink: allow to detect if ctnetlink listeners exist")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/nfnetlink.c | 24 |
1 files changed, 5 insertions, 19 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index ad3bbe34ca88..2f7c477fc9e7 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -45,7 +45,6 @@ MODULE_DESCRIPTION("Netfilter messages via netlink socket"); static unsigned int nfnetlink_pernet_id __read_mostly; struct nfnl_net { - unsigned int ctnetlink_listeners; struct sock *nfnl; }; @@ -673,18 +672,8 @@ static int nfnetlink_bind(struct net *net, int group) #ifdef CONFIG_NF_CONNTRACK_EVENTS if (type == NFNL_SUBSYS_CTNETLINK) { - struct nfnl_net *nfnlnet = nfnl_pernet(net); - nfnl_lock(NFNL_SUBSYS_CTNETLINK); - - if (WARN_ON_ONCE(nfnlnet->ctnetlink_listeners == UINT_MAX)) { - nfnl_unlock(NFNL_SUBSYS_CTNETLINK); - return -EOVERFLOW; - } - - nfnlnet->ctnetlink_listeners++; - if (nfnlnet->ctnetlink_listeners == 1) - WRITE_ONCE(net->ct.ctnetlink_has_listener, true); + WRITE_ONCE(net->ct.ctnetlink_has_listener, true); nfnl_unlock(NFNL_SUBSYS_CTNETLINK); } #endif @@ -694,15 +683,12 @@ static int nfnetlink_bind(struct net *net, int group) static void nfnetlink_unbind(struct net *net, int group) { #ifdef CONFIG_NF_CONNTRACK_EVENTS - int type = nfnl_group2type[group]; - - if (type == NFNL_SUBSYS_CTNETLINK) { - struct nfnl_net *nfnlnet = nfnl_pernet(net); + if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) + return; + if (nfnl_group2type[group] == NFNL_SUBSYS_CTNETLINK) { nfnl_lock(NFNL_SUBSYS_CTNETLINK); - WARN_ON_ONCE(nfnlnet->ctnetlink_listeners == 0); - nfnlnet->ctnetlink_listeners--; - if (nfnlnet->ctnetlink_listeners == 0) + if (!nfnetlink_has_listeners(net, group)) WRITE_ONCE(net->ct.ctnetlink_has_listener, false); nfnl_unlock(NFNL_SUBSYS_CTNETLINK); } |