Subject: + userns-unshare_usernscred-should-not-populate-cred-on-failure.patch added to -mm tree
To: oleg@xxxxxxxxxx,dhowells@xxxxxxxxxx,ebiederm@xxxxxxxxxxxx,luto@xxxxxxxxxxxxxx,pmatouse@xxxxxxxxxx,stable@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 06 Aug 2013 15:44:45 -0700
The patch titled
Subject: userns: unshare_userns(&cred) should not populate cred on failure
has been added to the -mm tree. Its filename is
userns-unshare_usernscred-should-not-populate-cred-on-failure.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userns-unshare_usernscred-should-not-populate-cred-on-failure.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userns-unshare_usernscred-should-not-populate-cred-on-failure.patch
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From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: userns: unshare_userns(&cred) should not populate cred on failure
unshare_userns(new_cred) does *new_cred = prepare_creds() before
create_user_ns() which can fail. However, the caller expects that it
doesn't need to take care of new_cred if unshare_userns() fails.
We could change the single caller, sys_unshare(), but I think it would be
more clean to avoid the side effects on failure, so with this patch
unshare_userns() does put_cred() itself and initializes *new_cred only if
create_user_ns() succeeeds.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Petr Matousek <pmatouse@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/user_namespace.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff -puN kernel/user_namespace.c~userns-unshare_usernscred-should-not-populate-cred-on-failure kernel/user_namespace.c
--- a/kernel/user_namespace.c~userns-unshare_usernscred-should-not-populate-cred-on-failure
+++ a/kernel/user_namespace.c
@@ -105,16 +105,21 @@ int create_user_ns(struct cred *new)
int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
{
struct cred *cred;
+ int err = -ENOMEM;
if (!(unshare_flags & CLONE_NEWUSER))
return 0;
cred = prepare_creds();
- if (!cred)
- return -ENOMEM;
+ if (cred) {
+ err = create_user_ns(cred);
+ if (err)
+ put_cred(cred);
+ else
+ *new_cred = cred;
+ }
- *new_cred = cred;
- return create_user_ns(cred);
+ return err;
}
void free_user_ns(struct user_namespace *ns)
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
userns-unshare_usernscred-should-not-populate-cred-on-failure.patch
x86-get_unmapped_area-use-proper-mmap-base-for-bottom-up-direction.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
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.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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