Subject: + pidns-fix-vfork-after-unshareclone_newpid.patch added to -mm tree
To: oleg@xxxxxxxxxx,ebiederm@xxxxxxxxxxxx,luto@xxxxxxxxxxxxxx,stable@xxxxxxxxxxxxxxx,walters@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 23 Aug 2013 16:20:20 -0700
The patch titled
Subject: pidns: fix vfork() after unshare(CLONE_NEWPID)
has been added to the -mm tree. Its filename is
pidns-fix-vfork-after-unshareclone_newpid.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/pidns-fix-vfork-after-unshareclone_newpid.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/pidns-fix-vfork-after-unshareclone_newpid.patch
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From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: pidns: fix vfork() after unshare(CLONE_NEWPID)
8382fcac ("pidns: Outlaw thread creation after unshare(CLONE_NEWPID)")
nacks CLONE_VM if the forking process unshared pid_ns, this obviously
breaks vfork:
int main(void)
{
assert(unshare(CLONE_NEWUSER | CLONE_NEWPID) == 0);
assert(vfork() >= 0);
_exit(0);
return 0;
}
fails without this patch.
Change this check to use CLONE_SIGHAND instead. This also forbids
CLONE_THREAD automatically, and this is what the comment implies.
We could probably even drop CLONE_SIGHAND and use CLONE_THREAD, but it
would be safer to not do this. The current check denies CLONE_SIGHAND
implicitely and there is no reason to change this.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reported-by: Colin Walters <walters@xxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff -puN kernel/fork.c~pidns-fix-vfork-after-unshareclone_newpid kernel/fork.c
--- a/kernel/fork.c~pidns-fix-vfork-after-unshareclone_newpid
+++ a/kernel/fork.c
@@ -1173,10 +1173,11 @@ static struct task_struct *copy_process(
return ERR_PTR(-EINVAL);
/*
- * If the new process will be in a different pid namespace
- * don't allow the creation of threads.
+ * If the new process will be in a different pid namespace don't
+ * allow it to share a thread group or signal handlers with the
+ * forking task.
*/
- if ((clone_flags & (CLONE_VM|CLONE_NEWPID)) &&
+ if ((clone_flags & (CLONE_SIGHAND | CLONE_NEWPID)) &&
(task_active_pid_ns(current) != current->nsproxy->pid_ns))
return ERR_PTR(-EINVAL);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
pidns-fix-vfork-after-unshareclone_newpid.patch
pidns-kill-the-unnecessary-clone_newpid-in-copy_process.patch
fork-unify-and-tighten-up-clone_newuser-clone_newpid-checks.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
mm-mempolicy-turn-vma_set_policy-into-vma_dup_policy.patch
mm-shift-vm_grows-check-from-mmap_region-to-do_mmap_pgoff-v2.patch
mm-do_mmap_pgoff-cleanup-the-usage-of-file_inode.patch
mm-mmap_region-kill-correct_wcount-inode-use-allow_write_access.patch
kernel-wide-fix-missing-validations-on-__get-__put-__copy_to-__copy_from_user.patch
task_work-minor-cleanups.patch
task_work-documentation.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
__ptrace_may_access-should-not-deny-sub-threads.patch
signals-eventpoll-set-saved_sigmask-at-the-start.patch
move-exit_task_namespaces-outside-of-exit_notify-fix.patch
exec-introduce-exec_binprm-for-depth-==-0-code.patch
exec-kill-int-depth-in-search_binary_handler.patch
exec-proc_exec_connector-should-be-called-only-once.patch
exec-move-allow_write_access-fput-to-exec_binprm.patch
exec-kill-load_binary-=-null-check-in-search_binary_handler.patch
exec-cleanup-the-config_modules-logic.patch
exec-dont-retry-if-request_module-fails.patch
exec-cleanup-the-error-handling-in-search_binary_handler.patch
linux-next.patch
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