Bug 2363759 (CVE-2023-53101)
| Summary: | CVE-2023-53101 kernel: ext4: zero i_disksize when initializing the bootloader inode | ||
|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | dfreiber, drow, jburrell, vkumar |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: ext4: zero i_disksize when initializing the bootloader inode If the boot loader inode has never been used before, the EXT4_IOC_SWAP_BOOT inode will initialize it, including setting the i_size to 0. However, if the "never before used" boot loader has a non-zero i_size, then i_disksize will be non-zero, and the inconsistency between i_size and i_disksize can trigger a kernel warning: WARNING: CPU: 0 PID: 2580 at fs/ext4/file.c:319 CPU: 0 PID: 2580 Comm: bb Not tainted 6.3.0-rc1-00004-g703695902cfa RIP: 0010:ext4_file_write_iter+0xbc7/0xd10 Call Trace: vfs_write+0x3b1/0x5c0 ksys_write+0x77/0x160 __x64_sys_write+0x22/0x30 do_syscall_64+0x39/0x80 Reproducer: 1. create corrupted image and mount it: mke2fs -t ext4 /tmp/foo.img 200 debugfs -wR "sif <5> size 25700" /tmp/foo.img mount -t ext4 /tmp/foo.img /mnt cd /mnt echo 123 > file 2. Run the reproducer program: posix_memalign(&buf, 1024, 1024) fd = open("file", O_RDWR | O_DIRECT); ioctl(fd, EXT4_IOC_SWAP_BOOT); write(fd, buf, 1024); Fix this by setting i_disksize as well as i_size to zero when initiaizing the boot loader inode.