From 1b2552cbdbe099b51aaffa486c042b0a7bf0a808 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 11 Apr 2022 14:15:54 -0500 Subject: [PATCH] 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: "Eric W. Biederman" --- fs/exec.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 75eb6e0ee7b2..9c5260e74517 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -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);