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CVE-2022-49707

Vulnérabilité moyenne dans Linux (Linux)

CVSS 5.5 · Moyenne
EPSS 0.3%
Linux•Linux•Versions : <0dc2fca8e4f9ac4a40e8424a10163369cca0cc06, <b55c3cd102a6f48b90e61c44f7f3dda8c290c694, 0, 5.4.200, 5.19, 4.9.320, <=4.9.*, <=5.10.*, <=4.14.*, 5.18.6, 5.15.49, 4.14.285, <=5.18.*, <=5.4.*, <fba54289176702a7caac0b64738406775817f451, <=4.19.*, <bfd004a1d3a062aac300523d406ac1f3e5f1a82c, <7c921328ac760bba780bdace41f4cd045f7f1405, <b9747263b13e5290ac4d63bec47e38f701303cad, 1c6bd7173d66b3dfdefcedb38cabc1fb03997509, <33b1bba31f4c784d33d2c2517964bdccdc9204cd, 5.10.124, <3.7, <=*, 3.7, <=5.15.*, 4.19.249, <af75c481a2e45e70f62f5942c93695e95bf7bd21

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: add reserved GDT blocks check We capture a NULL pointer issue when resizing a corrupt ext4 image which is freshly clear resize_inode feature (not run e2fsck). It could be simply reproduced by following steps. The problem is because of the resize_inode feature was cleared, and it will convert the filesystem to meta_bg mode in ext4_resize_fs(), but the es->s_reserved_gdt_blocks was not reduced to zero, so could we mistakenly call reserve_backup_gdb() and passing an uninitialized resize_inode to it when adding new group descriptors. mkfs.ext4 /dev/sda 3G tune2fs -O ^resize_inode /dev/sda #forget to run requested e2fsck mount /dev/sda /mnt resize2fs /dev/sda 8G ======== BUG: kernel NULL pointer dereference, address: 0000000000000028 CPU: 19 PID: 3243 Comm: resize2fs Not tainted 5.18.0-rc7-00001-gfde086c5ebfd #748 ... RIP: 0010:ext4_flex_group_add+0xe08/0x2570 ... Call Trace: <TASK> ext4_resize_fs+0xbec/0x1660 __ext4_ioctl+0x1749/0x24e0 ext4_ioctl+0x12/0x20 __x64_sys_ioctl+0xa6/0x110 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2dd739617b ======== The fix is simple, add a check in ext4_resize_begin() to make sure that the es->s_reserved_gdt_blocks is zero when the resize_inode feature is disabled.

Gravité et risque d'exploitation

CVE-2022-49707 obtient un score CVSS de 5.5/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.28 %, ce qui la place devant 19.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <0dc2fca8e4f9ac4a40e8424a10163369cca0cc06, <b55c3cd102a6f48b90e61c44f7f3dda8c290c694, 0, 5.4.200, 5.19, 4.9.320, <=4.9.*, <=5.10.*, <=4.14.*, 5.18.6, 5.15.49, 4.14.285, <=5.18.*, <=5.4.*, <fba54289176702a7caac0b64738406775817f451, <=4.19.*, <bfd004a1d3a062aac300523d406ac1f3e5f1a82c, <7c921328ac760bba780bdace41f4cd045f7f1405, <b9747263b13e5290ac4d63bec47e38f701303cad, 1c6bd7173d66b3dfdefcedb38cabc1fb03997509, <33b1bba31f4c784d33d2c2517964bdccdc9204cd, 5.10.124, <3.7, <=*, 3.7, <=5.15.*, 4.19.249, <af75c481a2e45e70f62f5942c93695e95bf7bd21) 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

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