CVE-2022-50636

Description

In the Linux kernel, the following vulnerability has been resolved: PCI: Fix pci_device_is_present() for VFs by checking PF pci_device_is_present() previously didn't work for VFs because it reads the Vendor and Device ID, which are 0xffff for VFs, which looks like they aren't present. Check the PF instead. Wei Gong reported that if virtio I/O is in progress when the driver is unbound or "0" is written to /sys/.../sriov_numvfs, the virtio I/O operation hangs, which may result in output like this: task:bash state:D stack: 0 pid: 1773 ppid: 1241 flags:0x00004002 Call Trace: schedule+0x4f/0xc0 blk_mq_freeze_queue_wait+0x69/0xa0 blk_mq_freeze_queue+0x1b/0x20 blk_cleanup_queue+0x3d/0xd0 virtblk_remove+0x3c/0xb0 [virtio_blk] virtio_dev_remove+0x4b/0x80 ... device_unregister+0x1b/0x60 unregister_virtio_device+0x18/0x30 virtio_pci_remove+0x41/0x80 pci_device_remove+0x3e/0xb0 This happened because pci_device_is_present(VF) returned "false" in virtio_pci_remove(), so it called virtio_break_device(). The broken vq meant that vring_interrupt() skipped the vq.callback() that would have completed the virtio I/O operation via virtblk_done(). [bhelgaas: commit log, simplify to always use pci_physfn(), add stable tag]

Gravité et risque d'exploitation

CVE-2022-50636 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 0.21 %, ce qui la place devant 10.6 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, 8496e85c20e7836b3dec97780e40f420a3ae2801, <3.13, <81565e51ccaf6fff8910e997ee22e16b5e1dabc3, 0, 4.14.303, 4.19.270, <=5.10.*, <=4.14.*, 5.15.87, <=6.0.*, 5.4.229, <=5.4.*, <643d77fda08d06f863af35e80a7e517ea61d9629, <f4b44c7766dae2b8681f621941cabe9f14066d59, <98b04dd0b4577894520493d96bc4623387767445, 3.13, <=4.19.*, <99ef6cc791584495987dd11b14769b450dfa5820, 6.1.4, 5.10.163, <=*, <=5.15.*, <65bd0962992abd42e77a05e68c7b40e7c73726d1, <67fd41bbb0f51aa648a47f728b99e6f1fa2ccc34, 6.0.18, <518573988a2f14f517403db2ece5ddaefba21e94, 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.

Références

• https://git.kernel.org/stable/c/f4b44c7766dae2b8681f621941cabe9f14066d59
• https://git.kernel.org/stable/c/643d77fda08d06f863af35e80a7e517ea61d9629
• https://git.kernel.org/stable/c/65bd0962992abd42e77a05e68c7b40e7c73726d1
• https://git.kernel.org/stable/c/99ef6cc791584495987dd11b14769b450dfa5820
• https://git.kernel.org/stable/c/67fd41bbb0f51aa648a47f728b99e6f1fa2ccc34
• https://git.kernel.org/stable/c/81565e51ccaf6fff8910e997ee22e16b5e1dabc3
• https://git.kernel.org/stable/c/518573988a2f14f517403db2ece5ddaefba21e94
• https://git.kernel.org/stable/c/98b04dd0b4577894520493d96bc4623387767445