In the Linux kernel, the following vulnerability has been resolved: fs/jfs: Prevent integer overflow in AG size calculation The JFS filesystem calculates allocation group (AG) size using 1 << l2agsize in dbExtendFS(). When l2agsize exceeds 31 (possible with >2TB aggregates on 32-bit systems), this 32-bit shift operation causes undefined behavior and improper AG sizing. On 32-bit architectures: - Left-shifting 1 by 32+ bits results in 0 due to integer overflow - This creates invalid AG sizes (0 or garbage values) in sbi->bmap->db_agsize - Subsequent block allocations would reference invalid AG structures - Could lead to: - Filesystem corruption during extend operations - Kernel crashes due to invalid memory accesses - Security vulnerabilities via malformed on-disk structures Fix by casting to s64 before shifting: bmp->db_agsize = (s64)1 << l2agsize; This ensures 64-bit arithmetic even on 32-bit architectures. The cast matches the data type of db_agsize (s64) and follows similar patterns in JFS block calculation code. Found by Linux Verification Center (linuxtesting.org) with SVACE.
2025-05-09T07:16:06.827
2025-11-12T20:09:28.507
Analyzed
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSSv3.1: 5.5 (MEDIUM)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | linux | linux_kernel | < 5.4.293 | Yes |
| Operating System | linux | linux_kernel | < 5.10.237 | Yes |
| Operating System | linux | linux_kernel | < 5.15.181 | Yes |
| Operating System | linux | linux_kernel | < 6.1.135 | Yes |
| Operating System | linux | linux_kernel | < 6.6.88 | Yes |
| Operating System | linux | linux_kernel | < 6.12.24 | Yes |
| Operating System | linux | linux_kernel | < 6.13.12 | Yes |
| Operating System | linux | linux_kernel | < 6.14.3 | Yes |
| Operating System | debian | debian_linux | 11.0 | Yes |