CVE-2024-49883

CVE Details

Release Date:

2024-10-21

Description

In the Linux kernel, the following vulnerability has been resolved:\next4: aovid use-after-free in ext4_ext_insert_extent()\nAs Ojaswin mentioned in Link, in ext4_ext_insert_extent(), if the path is\nreallocated in ext4_ext_create_new_leaf(), we'll use the stale path and\ncause UAF. Below is a sample trace with dummy values:\next4_ext_insert_extent\npath = *ppath = 2000\next4_ext_create_new_leaf(ppath)\next4_find_extent(ppath)\npath = *ppath = 2000\nif (depth > path[0].p_maxdepth)\nkfree(path = 2000);\n*ppath = path = NULL;\npath = kcalloc() = 3000\n*ppath = 3000;\nreturn path;\n/* here path is still 2000, UAF! */\neh = path[depth].p_hdr\n==================================================================\nBUG: KASAN: slab-use-after-free in ext4_ext_insert_extent+0x26d4/0x3330\nRead of size 8 at addr ffff8881027bf7d0 by task kworker/u36:1/179\nCPU: 3 UID: 0 PID: 179 Comm: kworker/u6:1 Not tainted 6.11.0-rc2-dirty #866\nCall Trace:\n\next4_ext_insert_extent+0x26d4/0x3330\next4_ext_map_blocks+0xe22/0x2d40\next4_map_blocks+0x71e/0x1700\next4_do_writepages+0x1290/0x2800\n[...]\nAllocated by task 179:\next4_find_extent+0x81c/0x1f70\next4_ext_map_blocks+0x146/0x2d40\next4_map_blocks+0x71e/0x1700\next4_do_writepages+0x1290/0x2800\next4_writepages+0x26d/0x4e0\ndo_writepages+0x175/0x700\n[...]\nFreed by task 179:\nkfree+0xcb/0x240\next4_find_extent+0x7c0/0x1f70\next4_ext_insert_extent+0xa26/0x3330\next4_ext_map_blocks+0xe22/0x2d40\next4_map_blocks+0x71e/0x1700\next4_do_writepages+0x1290/0x2800\next4_writepages+0x26d/0x4e0\ndo_writepages+0x175/0x700\n[...]\n==================================================================\nSo use *ppath to update the path to avoid the above problem.

See more information about CVE-2024-49883 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality:	None
Integrity:	None
Availability:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12884	2024-12-16
Oracle Linux version 8 (kernel-uek)	ELSA-2024-12884	2024-12-16