CVE-2023-53619

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> netfilter: conntrack: Avoid nf_ct_helper_hash uses after free<br /> <br /> If nf_conntrack_init_start() fails (for example due to a<br /> register_nf_conntrack_bpf() failure), the nf_conntrack_helper_fini()<br /> clean-up path frees the nf_ct_helper_hash map.<br /> <br /> When built with NF_CONNTRACK=y, further netfilter modules (e.g:<br /> netfilter_conntrack_ftp) can still be loaded and call<br /> nf_conntrack_helpers_register(), independently of whether nf_conntrack<br /> initialized correctly. This accesses the nf_ct_helper_hash dangling<br /> pointer and causes a uaf, possibly leading to random memory corruption.<br /> <br /> This patch guards nf_conntrack_helper_register() from accessing a freed<br /> or uninitialized nf_ct_helper_hash pointer and fixes possible<br /> uses-after-free when loading a conntrack module.