Commit 1b2552cb authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

fork: Stop allowing kthreads to call execve 

Now that kernel_execve is no longer called from kernel threads stop
supporting kernel threads calling kernel_execve.

Remove the code for converting a kthread to a normal thread in execve.

Document the restriction that kthreads may not call kernel_execve by
having kernel_execve fail if called by a kthread.

Link: https://lkml.kernel.org/r/20220506141512.516114-7-ebiederm@xmission.com


Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 753550eb

fs/exec.c

+3 −3
Original line number Diff line number Diff line
@@ -1308,7 +1308,7 @@ int begin_new_exec(struct linux_binprm * bprm) 
	if (retval)

		goto out_unlock;



	me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |

	me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC |

					PF_NOFREEZE | PF_NO_SETAFFINITY);

	flush_thread();

	me->personality &= ~bprm->per_clear;
@@ -1953,8 +1953,8 @@ int kernel_execve(const char *kernel_filename, 
	int fd = AT_FDCWD;

	int retval;



	if (WARN_ON_ONCE((current->flags & PF_KTHREAD) &&

			(current->worker_private)))

	/* It is non-sense for kernel threads to call execve */

	if (WARN_ON_ONCE(current->flags & PF_KTHREAD))

		return -EINVAL;



	filename = getname_kernel(kernel_filename);