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CVE-2023-52986

bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener A listening socket linked to a sockmap has its sk_prot overridden. It points to one of the struct proto variants in tcp_bpf_prots. The variant depends on the socket's family and which sockmap programs are attached. A child socket cloned from a TCP listener initially inherits their sk_prot. But before cloning is finished, we restore the child's proto to the listener's original non-tcp_bpf_prots one. This happens in tcp_create_openreq_child -> tcp_bpf_clone. Today, in tcp_bpf_clone we detect if the child's proto should be restored by checking only for the TCP_BPF_BASE proto variant. This is not correct. The sk_prot of listening socket linked to a sockmap can point to to any variant in tcp_bpf_prots. If the listeners sk_prot happens to be not the TCP_BPF_BASE variant, then the child socket unintentionally is left if the inherited sk_prot by tcp_bpf_clone. This leads to issues like infinite recursion on close [1], because the child state is otherwise not set up for use with tcp_bpf_prot operations. Adjust the check in tcp_bpf_clone to detect all of tcp_bpf_prots variants. Note that it wouldn't be sufficient to check the socket state when overriding the sk_prot in tcp_bpf_update_proto in order to always use the TCP_BPF_BASE variant for listening sockets. Since commit b8b8315e39ff ("bpf, sockmap: Remove unhash handler for BPF sockmap usage") it is possible for a socket to transition to TCP_LISTEN state while already linked to a sockmap, e.g. connect() -> insert into map -> connect(AF_UNSPEC) -> listen(). [1]: https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected e80251555f0befd1271e74b080bccf0ff0348bfc before 9bd6074e1872d22190a8da30e796cbf937d334f0; affected e80251555f0befd1271e74b080bccf0ff0348bfc before c681d7a4ed3d360de0574f4d6b7305a8de8dc54f; affected e80251555f0befd1271e74b080bccf0ff0348bfc before 12b0ec7c6953e1602957926439e5297095d7d065; affected e80251555f0befd1271e74b080bccf0ff0348bfc before ddce1e091757d0259107c6c0c7262df201de2b66
Linux / Linuxaffected 5.7; unaffected 0 before 5.7; unaffected 5.10.168 through 5.10.*; unaffected 5.15.93 through 5.15.*; unaffected 6.1.11 through 6.1.*; unaffected 6.2 through *

CWE

No CWE identifiers supplied.

References