CVE-2024-49884

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Source
https://cve.org/CVERecord?id=CVE-2024-49884
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-49884.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2024-49884
Downstream
Related
Published
2024-10-21T18:01:21Z
Modified
2026-08-12T03:30:14Z
Severity
  • 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
ext4: fix slab-use-after-free in ext4_split_extent_at()
Details

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix slab-use-after-free in ext4_split_extent_at()

We hit the following use-after-free:

================================================================== BUG: KASAN: slab-use-after-free in ext4_split_extent_at+0xba8/0xcc0 Read of size 2 at addr ffff88810548ed08 by task kworker/u20:0/40 CPU: 0 PID: 40 Comm: kworker/u20:0 Not tainted 6.9.0-dirty #724 Call Trace: kasan_report+0x93/0xc0 ext4_split_extent_at+0xba8/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...]

Allocated by task 40: __kmalloc_noprof+0x1ac/0x480 ext4_find_extent+0xf3b/0x1e70 ext4_ext_map_blocks+0x188/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...]

Freed by task 40: kfree+0xf1/0x2b0 ext4_find_extent+0xa71/0x1e70 ext4_ext_insert_extent+0xa22/0x3260 ext4_split_extent_at+0x3ef/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...]

The flow of issue triggering is as follows:

ext4_split_extent_at path = *ppath ext4_ext_insert_extent(ppath) ext4_ext_create_new_leaf(ppath) ext4_find_extent(orig_path) path = *orig_path read_extent_tree_block // return -ENOMEM or -EIO ext4_free_ext_path(path) kfree(path) *orig_path = NULL a. If err is -ENOMEM: ext4_ext_dirty(path + path->p_depth) // path use-after-free !!! b. If err is -EIO and we have EXT_DEBUG defined: ext4_ext_show_leaf(path) eh = path[depth].p_hdr // path also use-after-free !!!

So when trying to zeroout or fix the extent length, call ext4_find_extent() to update the path.

In addition we use *ppath directly as an ext4_ext_show_leaf() input to avoid possible use-after-free when EXT_DEBUG is defined, and to avoid unnecessary path updates.

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/49xxx/CVE-2024-49884.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
dfe5080939ea4686b3414b5d970a9b26733c57a4
Fixed
393a46f60ea4f249dc9d496d4eb2d542f5e11ade
Fixed
448100a29395b0c8b4c42967155849fe0fbe808f
Fixed
e52f933598b781d291b9297e39c463536da0e185
Fixed
cafcc1bd62934547c76abf46c6d0d54f135006fe
Fixed
a5401d4c3e2a3d25643c567d26e6de327774a2c9
Fixed
8fe117790b37c84c651e2bad9efc0e7fda73c0e3
Fixed
5d949ea75bb529ea6342e83465938a3b0ac51238
Fixed
915ac3630488af0ca194dc63b86d99802b4f6e18
Fixed
c26ab35702f8cd0cdc78f96aa5856bfb77be798f

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-49884.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
3.18.0
Fixed
4.19.323
Type
ECOSYSTEM
Events
Introduced
4.20.0
Fixed
5.4.290
Type
ECOSYSTEM
Events
Introduced
5.5.0
Fixed
5.10.227
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.168
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.113
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.55
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.10.14
Type
ECOSYSTEM
Events
Introduced
6.11.0
Fixed
6.11.3

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-49884.json"