CVE-2022-48726

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/ucma: Protect mc during concurrent multicast leaves Partially revert the commit mentioned in the Fixes line to make sure that allocation and erasing multicast struct are locked. BUG: KASAN: use-after-free in ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline] BUG: KASAN: use-after-free in ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579 Read of size 8 at addr ffff88801bb74b00 by task syz-executor.1/25529 CPU: 0 PID: 25529 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247 __kasan_report mm/kasan/report.c:433 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline] ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579 ucma_destroy_id+0x1e6/0x280 drivers/infiniband/core/ucma.c:614 ucma_write+0x25c/0x350 drivers/infiniband/core/ucma.c:1732 vfs_write+0x28e/0xae0 fs/read_write.c:588 ksys_write+0x1ee/0x250 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Currently the xarray search can touch a concurrently freeing mc as the xa_for_each() is not surrounded by any lock. Rather than hold the lock for a full scan hold it only for the effected items, which is usually an empty list.

Gravité et risque d'exploitation

CVE-2022-48726 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.24 %, ce qui la place devant 13.9 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <2923948ffe0835f7114e948b35bcc42bc9b3baa1, <=*, <75c610212b9f1756b9384911d3a2c347eee8031c, <=5.15.*, <5.10, 95fe51096b7adf1d1e7315c49c75e2f75f162584, 5.17, <=5.10.*, 0, <ee2477e8ccd3d978eeac0dc5a981b286d9bb7b0a, 5.10.99, 5.15.22, 5.10, <=5.16.*, <36e8169ec973359f671f9ec7213547059cae972e, 5.16.8) 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/75c610212b9f1756b9384911d3a2c347eee8031c
• https://git.kernel.org/stable/c/2923948ffe0835f7114e948b35bcc42bc9b3baa1
• https://git.kernel.org/stable/c/ee2477e8ccd3d978eeac0dc5a981b286d9bb7b0a
• https://git.kernel.org/stable/c/36e8169ec973359f671f9ec7213547059cae972e