Problem Description:

Several file systems were not properly initializing the d_off field of the dirent structures returned by VOP_READDIR. In particular, tmpfs(5), smbfs(5), autofs(5) and mqueuefs(5) were failing to do so. As a result, eight uninitialized kernel stack bytes may be leaked to userspace by these file systems. This problem is not present in FreeBSD 11.

Additionally, msdosfs(5) was failing to zero-fill a pair of padding fields in the dirent structure, resulting in a leak of three uninitialized bytes.

Impact:

Kernel stack disclosures may leak sensitive information which could be used to compromise the security of the system.

ge 12.2 lt 12.2_3

ge 12.1 lt 12.1_13

ge 11.4 lt 11.4_7