fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START omfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE), but it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440). Later, omfs_make_empty() uses sbi->s_sys_blocksize - OMFS_DIR_START as the length argument to memset(). Since s_sys_blocksize is u32, a crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes an unsigned underflow there, wrapping to a value near 2^32. That drives a ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel memory far beyond the backing block buffer. Add the corresponding lower-bound check alongside the existing upper-bound check in omfs_fill_super(), so that malformed images are rejected during superblock validation before any filesystem data is processed.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
2.6.27
References 8
git.kernel.org
- stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54
- stable/c/5822a05a841a10794ad818620dd2af490b0705d3
- stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07
- stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51
- stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644
- stable/c/6561afc38398e3518a29c5eebb975c30468f98a6
- stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03
- stable/c/0621c385fda1376e967f37ccd534c26c3e511d14