SUSE: CVE-2023-52523: SUSE Linux Security Advisory
Description
In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Reject sk_msg egress redirects to non-TCP sockets With a SOCKMAP/SOCKHASH map and an sk_msg program user can steer messages sent from one TCP socket (s1) to actually egress from another TCP socket (s2): tcp_bpf_sendmsg(s1) // = sk_prot->sendmsg tcp_bpf_send_verdict(s1) // __SK_REDIRECT case tcp_bpf_sendmsg_redir(s2) tcp_bpf_push_locked(s2) tcp_bpf_push(s2) tcp_rate_check_app_limited(s2) // expects tcp_sock tcp_sendmsg_locked(s2) // ditto There is a hard-coded assumption in the call-chain, that the egress socket (s2) is a TCP socket. However in commit 122e6c79efe1 ("sock_map: Update sock type checks for UDP") we have enabled redirects to non-TCP sockets. This was done for the sake of BPF sk_skb programs. There was no indention to support sk_msg send-to-egress use case. As a result, attempts to send-to-egress through a non-TCP socket lead to a crash due to invalid downcast from sock to tcp_sock: BUG: kernel NULL pointer dereference, address: 000000000000002f ... Call Trace: <TASK> ? show_regs+0x60/0x70 ? __die+0x1f/0x70 ? page_fault_oops+0x80/0x160 ? do_user_addr_fault+0x2d7/0x800 ? rcu_is_watching+0x11/0x50 ? exc_page_fault+0x70/0x1c0 ? asm_exc_page_fault+0x27/0x30 ? tcp_tso_segs+0x14/0xa0 tcp_write_xmit+0x67/0xce0 __tcp_push_pending_frames+0x32/0xf0 tcp_push+0x107/0x140 tcp_sendmsg_locked+0x99f/0xbb0 tcp_bpf_push+0x19d/0x3a0 tcp_bpf_sendmsg_redir+0x55/0xd0 tcp_bpf_send_verdict+0x407/0x550 tcp_bpf_sendmsg+0x1a1/0x390 inet_sendmsg+0x6a/0x70 sock_sendmsg+0x9d/0xc0 ? sockfd_lookup_light+0x12/0x80 __sys_sendto+0x10e/0x160 ? syscall_enter_from_user_mode+0x20/0x60 ? __this_cpu_preempt_check+0x13/0x20 ? lockdep_hardirqs_on+0x82/0x110 __x64_sys_sendto+0x1f/0x30 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Reject selecting a non-TCP sockets as redirect target from a BPF sk_msg program to prevent the crash. When attempted, user will receive an EACCES error from send/sendto/sendmsg() syscall.
Solution(s)
- suse-upgrade-cluster-md-kmp-64kb
- suse-upgrade-cluster-md-kmp-default
- suse-upgrade-cluster-md-kmp-rt
- suse-upgrade-dlm-kmp-64kb
- suse-upgrade-dlm-kmp-default
- suse-upgrade-dlm-kmp-rt
- suse-upgrade-dtb-allwinner
- suse-upgrade-dtb-altera
- suse-upgrade-dtb-amazon
- suse-upgrade-dtb-amd
- suse-upgrade-dtb-amlogic
- suse-upgrade-dtb-apm
- suse-upgrade-dtb-apple
- suse-upgrade-dtb-arm
- suse-upgrade-dtb-broadcom
- suse-upgrade-dtb-cavium
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- suse-upgrade-kernel-64kb-devel
- suse-upgrade-kernel-64kb-extra
- suse-upgrade-kernel-64kb-livepatch-devel
- suse-upgrade-kernel-64kb-optional
- suse-upgrade-kernel-debug
- suse-upgrade-kernel-debug-devel
- suse-upgrade-kernel-debug-livepatch-devel
- suse-upgrade-kernel-debug-vdso
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- suse-upgrade-kernel-default-livepatch-devel
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- suse-upgrade-kernel-rt-extra
- suse-upgrade-kernel-rt-livepatch
- suse-upgrade-kernel-rt-livepatch-devel
- suse-upgrade-kernel-rt-optional
- suse-upgrade-kernel-rt-vdso
- suse-upgrade-kernel-rt_debug
- suse-upgrade-kernel-rt_debug-devel
- suse-upgrade-kernel-rt_debug-livepatch-devel
- suse-upgrade-kernel-rt_debug-vdso
- suse-upgrade-kernel-source
- suse-upgrade-kernel-source-rt
- suse-upgrade-kernel-source-vanilla
- suse-upgrade-kernel-syms
- suse-upgrade-kernel-syms-rt
- suse-upgrade-kernel-zfcpdump
- suse-upgrade-kselftests-kmp-64kb
- suse-upgrade-kselftests-kmp-default
- suse-upgrade-kselftests-kmp-rt
- suse-upgrade-ocfs2-kmp-64kb
- suse-upgrade-ocfs2-kmp-default
- suse-upgrade-ocfs2-kmp-rt
- suse-upgrade-reiserfs-kmp-64kb
- suse-upgrade-reiserfs-kmp-default
- suse-upgrade-reiserfs-kmp-rt
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