Описание
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix data corruption by fallocate
When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size.
Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily.
The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size.
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix data corruption by fallocate
When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size.
Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily.
The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size.
v1: https://www.spinics.net/lists/linux-fsdevel/msg193999.html v2: https://lore.kernel.org/linux-fsdevel/20210525093034.GB4112@quack2.suse.cz/T/
Ссылки
- https://nvd.nist.gov/vuln/detail/CVE-2021-47114
- https://git.kernel.org/stable/c/0a31dd6fd2f4e7db538fb6eb1f06973d81f8dd3b
- https://git.kernel.org/stable/c/33e03adafb29eedae1bae9cdb50c1385279fcf65
- https://git.kernel.org/stable/c/624fa7baa3788dc9e57840ba5b94bc22b03cda57
- https://git.kernel.org/stable/c/6bba4471f0cc1296fe3c2089b9e52442d3074b2e
- https://git.kernel.org/stable/c/a1700479524bb9cb5e8ae720236a6fabd003acae
- https://git.kernel.org/stable/c/c8d5faee46242c3f33b8a71a4d7d52214785bfcc
- https://git.kernel.org/stable/c/cc2edb99ea606a45182b5ea38cc8f4e583aa0774
- https://git.kernel.org/stable/c/cec4e857ffaa8c447f51cd8ab4e72350077b6770
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size. Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily. qemu-img convert -p -t none -T none -f qcow2 $qcow_image \ -O qcow2 -o compat=1.1 $qcow_image.conv The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size. fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 65536) = 0 fallocate(11, 0,...
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size. Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily. qemu-img convert -p -t none -T none -f qcow2 $qcow_image \ -O qcow2 -o compat=1.1 $qcow_image.conv The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size. fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 65536) = 0 fallocate(11, 0,...
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size. Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily. qemu-img convert -p -t none -T none -f qcow2 $qcow_image \ -O qcow2 -o compat=1.1 $qcow_image.conv The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size. fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 655
In the Linux kernel, the following vulnerability has been resolved: o ...
Уязвимость функции __ocfs2_change_file_space() модуля fs/ocfs2/file.c поддержки файловой системы ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании