CVE-2024-49882

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Source
https://cve.org/CVERecord?id=CVE-2024-49882
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-49882.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2024-49882
Downstream
Related
Published
2024-10-21T18:01:20Z
Modified
2026-08-12T03:30:18Z
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 double brelse() the buffer of the extents path
Details

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

ext4: fix double brelse() the buffer of the extents path

In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows:

split2 map split1

ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice

Finally got the following WARRNING when removing the buffer from lru:

============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...]

Database specific 
{
    "cna_assigner":  "Linux",
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/49xxx/CVE-2024-49882.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
ecb94f5fdf4b72547fca022421a9dca1672bddd4
Fixed
d4574bda63906bf69660e001470bfe1a0ac524ae
Fixed
f9fd47c9d9548f9e47fa60098eab99dde175401d
Fixed
b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e
Fixed
32bbb59e3f18facd7201bef110010bf35819b8c3
Fixed
78bbc3d15b6f443acb26e94418c445bac940d414
Fixed
68a69cf60660c73990c1875f94a5551600b04775
Fixed
7633407ca4ab8be2916ab214eb44ccebc6a50e1a
Fixed
230ee0535d01478bad9a3037292043f39b9be10b
Fixed
dcaa6c31134c0f515600111c38ed7750003e1b9c

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-49882.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
3.7.0
Fixed
4.19.323
Type
ECOSYSTEM
Events
Introduced
4.20.0
Fixed
5.4.285
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-2024-49882.json"