fs/adfs: validate nzones in adfs_validate_bblk()

Summary

In the Linux kernel, the following vulnerability has been resolved: fs/adfs: validate nzones in adfs_validate_bblk() Reject ADFS disc records with a zero zone count during boot block validation, before the disc record is used. When nzones is 0, adfs_read_map() passes it to kmalloc_array(0, ...) which returns ZERO_SIZE_PTR, and adfs_map_layout() then writes to dm[-1], causing an out-of-bounds write before the allocated buffer. adfs_validate_dr0() already rejects nzones != 1 for old-format images. Add the equivalent check to adfs_validate_bblk() for new-format images so that a crafted image with nzones == 0 is rejected at probe time. Found by syzkaller.

Timeline

1. Jun 24, 2026, 4:29 PM UTCCVE published

Affected versions

• Linux Linux

  Version range not reported

• Linux Linux

  5.6

References 8