CVE-2023-52986
Vulnérabilité non évaluée dans Linux (Linux)
Description
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/
Gravité et risque d'exploitation
CVE-2023-52986 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.28 %, ce qui la place devant 19.3 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 5.7, <=6.1.*, <=*, 5.10.168, 6.1.11, <=5.15.*, <12b0ec7c6953e1602957926439e5297095d7d065, <5.7, <=5.10.*, 5.15.93, e80251555f0befd1271e74b080bccf0ff0348bfc, 0, <ddce1e091757d0259107c6c0c7262df201de2b66, <9bd6074e1872d22190a8da30e796cbf937d334f0, <c681d7a4ed3d360de0574f4d6b7305a8de8dc54f, 6.2) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.