Commits
Liping Zhang committed 4b512e1c1f8
netfilter: nft_compat: fix crash when related match/target module is removed We "cache" the loaded match/target modules and reuse them, but when the modules are removed, we still point to them. Then we may end up with invalid memory references when using iptables-compat to add rules later. Input the following commands will reproduce the kernel crash: # iptables-compat -A INPUT -j LOG # iptables-compat -D INPUT -j LOG # rmmod xt_LOG # iptables-compat -A INPUT -j LOG BUG: unable to handle kernel paging request at ffffffffa05a9010 IP: [<ffffffff813f783e>] strcmp+0xe/0x30 Call Trace: [<ffffffffa05acc43>] nft_target_select_ops+0x83/0x1f0 [nft_compat] [<ffffffffa058a177>] nf_tables_expr_parse+0x147/0x1f0 [nf_tables] [<ffffffffa058e541>] nf_tables_newrule+0x301/0x810 [nf_tables] [<ffffffff8141ca00>] ? nla_parse+0x20/0x100 [<ffffffffa057fa8f>] nfnetlink_rcv+0x33f/0x53d [nfnetlink] [<ffffffffa057f94b>] ? nfnetlink_rcv+0x1fb/0x53d [nfnetlink] [<ffffffff817116b8>] netlink_unicast+0x178/0x220 [<ffffffff81711a5b>] netlink_sendmsg+0x2fb/0x3a0 [<ffffffff816b7fc8>] sock_sendmsg+0x38/0x50 [<ffffffff816b8a7e>] ___sys_sendmsg+0x28e/0x2a0 [<ffffffff816bcb7e>] ? release_sock+0x1e/0xb0 [<ffffffff81804ac5>] ? _raw_spin_unlock_bh+0x35/0x40 [<ffffffff816bcbe2>] ? release_sock+0x82/0xb0 [<ffffffff816b93d4>] __sys_sendmsg+0x54/0x90 [<ffffffff816b9422>] SyS_sendmsg+0x12/0x20 [<ffffffff81805172>] entry_SYSCALL_64_fastpath+0x1a/0xa9 So when nobody use the related match/target module, there's no need to "cache" it. And nft_[match|target]_release are useless anymore, remove them. Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>