CVE - CVE-2024-49880

CVE-ID
CVE-2024-49880	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0d80d2b8bf613398baf7185009e35f9d0459ecb0 URL:https://git.kernel.org/stable/c/0d80d2b8bf613398baf7185009e35f9d0459ecb0 MISC:https://git.kernel.org/stable/c/6121258c2b33ceac3d21f6a221452692c465df88 URL:https://git.kernel.org/stable/c/6121258c2b33ceac3d21f6a221452692c465df88 MISC:https://git.kernel.org/stable/c/acb559d6826116cc113598640d105094620c2526 URL:https://git.kernel.org/stable/c/acb559d6826116cc113598640d105094620c2526
Assigning CNA
kernel.org
Date Record Created
20241021	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20241021)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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