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For IPCTNL_MSG_EXP_GET, if the CTA_EXPECT_MASTER attr is specified, then the NLM_F_DUMP request will dump the expectations related to this connection tracking. But we forget to check whether the conntrack has nf_conn_help or not, so if nfct_help(ct) is NULL, oops will happen: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: ctnetlink_exp_ct_dump_table+0xf9/0x1e0 [nf_conntrack_netlink] Call Trace: ? ctnetlink_exp_ct_dump_table+0x75/0x1e0 [nf_conntrack_netlink] netlink_dump+0x124/0x2a0 __netlink_dump_start+0x161/0x190 ctnetlink_dump_exp_ct+0x16c/0x1bc [nf_conntrack_netlink] ? ctnetlink_exp_fill_info.constprop.33+0xf0/0xf0 [nf_conntrack_netlink] ? ctnetlink_glue_seqadj+0x20/0x20 [nf_conntrack_netlink] ctnetlink_get_expect+0x32e/0x370 [nf_conntrack_netlink] ? debug_lockdep_rcu_enabled+0x1d/0x20 nfnetlink_rcv_msg+0x60a/0x6a9 [nfnetlink] ? nfnetlink_rcv_msg+0x1b9/0x6a9 [nfnetlink] [...] Signed-off-by: Liping Zhang <zlpnobody@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.