In the Linux kernel, the following vulnerability has been resolved:
ext4: fix off by one issue in alloc_flex_gd()
Wesley reported an issue:
==================================================================
EXT4-fs (dm-5): resizing filesystem from 7168 to 786432 blocks
------------[ cut here ]------------
kernel BUG at fs/ext4/resize.c:324!
CPU: 9 UID: 0 PID: 3576 Comm: resize2fs Not tainted 6.11.0+ #27
RIP: 0010:ext4_resize_fs+0x1212/0x12d0
Call Trace:
__ext4_ioctl+0x4e0/0x1800
ext4_ioctl+0x12/0x20
__x64_sys_ioctl+0x99/0xd0
x64_sys_call+0x1206/0x20d0
do_syscall_64+0x72/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e
==================================================================
While reviewing the patch, Honza found that when adjusting resize_bg in
alloc_flex_gd(), it was possible for flex_gd->resize_bg to be bigger than
flexbg_size.
The reproduction of the problem requires the following:
o_group = flexbg_size * 2 * n;
o_size = (o_group + 1) * group_size;
n_group: [o_group + flexbg_size, o_group + flexbg_size * 2)
o_size = (n_group + 1) * group_size;
Take n=0,flexbg_size=16 as an example:
last:15
|o---------------|--------------n-|
o_group:0 resize to n_group:30
The corresponding reproducer is:
img=test.img
rm -f $img
truncate -s 600M $img
mkfs.ext4 -F $img -b 1024 -G 16 8M
dev=`losetup -f --show $img`
mkdir -p /tmp/test
mount $dev /tmp/test
resize2fs $dev 248M
Delete the problematic plus 1 to fix the issue, and add a WARN_ON_ONCE()
to prevent the issue from happening again.
[ Note: another reproucer which this commit fixes is:
img=test.img
rm -f $img
truncate -s 25MiB $img
mkfs.ext4 -b 4096 -E nodiscard,lazy_itable_init=0,lazy_journal_init=0 $img
truncate -s 3GiB $img
dev=`losetup -f --show $img`
mkdir -p /tmp/test
mount $dev /tmp/test
resize2fs $dev 3G
umount $dev
losetup -d $dev
-- TYT ]
References
Configurations
Configuration 1 (hide)
|
History
25 Oct 2024, 14:42
Type | Values Removed | Values Added |
---|---|---|
References | () https://git.kernel.org/stable/c/0d80d2b8bf613398baf7185009e35f9d0459ecb0 - Patch | |
References | () https://git.kernel.org/stable/c/6121258c2b33ceac3d21f6a221452692c465df88 - Patch | |
References | () https://git.kernel.org/stable/c/acb559d6826116cc113598640d105094620c2526 - Patch | |
CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* |
|
CWE | CWE-193 | |
First Time |
Linux linux Kernel
Linux |
|
CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
23 Oct 2024, 15:13
Type | Values Removed | Values Added |
---|---|---|
Summary |
|
21 Oct 2024, 18:15
Type | Values Removed | Values Added |
---|---|---|
New CVE |
Information
Published : 2024-10-21 18:15
Updated : 2024-10-25 14:42
NVD link : CVE-2024-49880
Mitre link : CVE-2024-49880
CVE.ORG link : CVE-2024-49880
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-193
Off-by-one Error