tree b179ba94101ce895d6348e542705ea619ef037a1
parent a20600762300154bb6ed99eea6b16abd1163dbea
author Alexey Dobriyan <adobriyan@gmail.com> 1524261363 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1529521366 +0900

proc: revalidate kernel thread inodes to root:root

[ Upstream commit 2e0ad552f5f8cd0fda02bc45fcd2b89821c62fd1 ]

task_dump_owner() has the following code:

	mm = task->mm;
	if (mm) {
		if (get_dumpable(mm) != SUID_DUMP_USER) {
			uid = ...
		}
	}

Check for ->mm is buggy -- kernel thread might be borrowing mm
and inode will go to some random uid:gid pair.

Link: http://lkml.kernel.org/r/20180412220109.GA20978@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>