ghsa-gcmg-mgh2-gvc3
Vulnerability from github
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: 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.
{
"affected": [],
"aliases": [
"CVE-2022-49707"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-26T07:01:46Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: add reserved GDT blocks check\n\nWe capture a NULL pointer issue when resizing a corrupt ext4 image which\nis freshly clear resize_inode feature (not run e2fsck). It could be\nsimply reproduced by following steps. The problem is because of the\nresize_inode feature was cleared, and it will convert the filesystem to\nmeta_bg mode in ext4_resize_fs(), but the es-\u003es_reserved_gdt_blocks was\nnot reduced to zero, so could we mistakenly call reserve_backup_gdb()\nand passing an uninitialized resize_inode to it when adding new group\ndescriptors.\n\n mkfs.ext4 /dev/sda 3G\n tune2fs -O ^resize_inode /dev/sda #forget to run requested e2fsck\n mount /dev/sda /mnt\n resize2fs /dev/sda 8G\n\n ========\n BUG: kernel NULL pointer dereference, address: 0000000000000028\n CPU: 19 PID: 3243 Comm: resize2fs Not tainted 5.18.0-rc7-00001-gfde086c5ebfd #748\n ...\n RIP: 0010:ext4_flex_group_add+0xe08/0x2570\n ...\n Call Trace:\n \u003cTASK\u003e\n ext4_resize_fs+0xbec/0x1660\n __ext4_ioctl+0x1749/0x24e0\n ext4_ioctl+0x12/0x20\n __x64_sys_ioctl+0xa6/0x110\n do_syscall_64+0x3b/0x90\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n RIP: 0033:0x7f2dd739617b\n ========\n\nThe fix is simple, add a check in ext4_resize_begin() to make sure that\nthe es-\u003es_reserved_gdt_blocks is zero when the resize_inode feature is\ndisabled.",
"id": "GHSA-gcmg-mgh2-gvc3",
"modified": "2025-03-12T00:31:49Z",
"published": "2025-03-12T00:31:49Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49707"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0dc2fca8e4f9ac4a40e8424a10163369cca0cc06"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/33b1bba31f4c784d33d2c2517964bdccdc9204cd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7c921328ac760bba780bdace41f4cd045f7f1405"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/af75c481a2e45e70f62f5942c93695e95bf7bd21"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b55c3cd102a6f48b90e61c44f7f3dda8c290c694"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b9747263b13e5290ac4d63bec47e38f701303cad"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bfd004a1d3a062aac300523d406ac1f3e5f1a82c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fba54289176702a7caac0b64738406775817f451"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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