2025-07-04 13:37:44
Linux
PUBLISHED
In the Linux kernel, the following vulnerability has been resolved:
jfs: validate AG parameters in dbMount() to prevent crashes
Validate db_agheight, db_agwidth, and db_agstart in dbMount to catch
corrupted metadata early and avoid undefined behavior in dbAllocAG.
Limits are derived from L2LPERCTL, LPERCTL/MAXAG, and CTLTREESIZE:
- agheight: 0 to L2LPERCTL/2 (0 to 5) ensures shift
(L2LPERCTL - 2*agheight) >= 0.
- agwidth: 1 to min(LPERCTL/MAXAG, 2^(L2LPERCTL - 2*agheight))
ensures agperlev >= 1.
- Ranges: 1-8 (agheight 0-3), 1-4 (agheight 4), 1 (agheight 5).
- LPERCTL/MAXAG = 1024/128 = 8 limits leaves per AG;
2^(10 - 2*agheight) prevents division to 0.
- agstart: 0 to CTLTREESIZE-1 - agwidth*(MAXAG-1) keeps ti within
stree (size 1365).
- Ranges: 0-1237 (agwidth 1), 0-348 (agwidth 8).
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:1400:9
shift exponent -335544310 is negative
CPU: 0 UID: 0 PID: 5822 Comm: syz-executor130 Not tainted 6.14.0-rc5-syzkaller #0
Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace: