Florian Westphal ffd219efd9 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: 2794cdb0b9 ("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>
2022-05-27 11:16:33 +02:00

Linux kernel
============

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There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
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