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fork: Stop allowing kthreads to call execve

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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" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2022-04-11 14:15:54 -05:00
parent 753550eb0c
commit 1b2552cbdb
1 changed files with 3 additions and 3 deletions

6
fs/exec.c
View File

@ -1308,7 +1308,7 @@ int begin_new_exec(struct linux_binprm * bprm)
if (retval) if (retval)
goto out_unlock; goto out_unlock;
me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC |
PF_NOFREEZE | PF_NO_SETAFFINITY); PF_NOFREEZE | PF_NO_SETAFFINITY);
flush_thread(); flush_thread();
me->personality &= ~bprm->per_clear; me->personality &= ~bprm->per_clear;
@ -1953,8 +1953,8 @@ int kernel_execve(const char *kernel_filename,
int fd = AT_FDCWD; int fd = AT_FDCWD;
int retval; int retval;
if (WARN_ON_ONCE((current->flags & PF_KTHREAD) && /* It is non-sense for kernel threads to call execve */
(current->worker_private))) if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
return -EINVAL; return -EINVAL;
filename = getname_kernel(kernel_filename); filename = getname_kernel(kernel_filename);