CVE-2025-37858

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.

• linux linux kernel (< 5.4.293) • linux linux kernel (>= 5.5 < 5.10.237) • linux linux kernel (>= 5.11 < 5.15.181) • linux linux kernel (>= 5.16 < 6.1.135) • linux linux kernel (>= 6.2 < 6.6.88) • linux linux kernel (>= 6.7 < 6.12.24) • linux linux kernel (>= 6.13 < 6.13.12) • linux linux kernel (>= 6.14 < 6.14.3) • debian debian linux 11.0