There are already 4 error paths in alloc_uid() that do incremental
rollbacks. I think it's time to merge them. This costs us 8 lines
of code :)
Maybe it would be better to merge this patch with the previous
one, but I remember that some time ago I sent a similar patch
(fixing the error path and cleaning it), but I was told to make
two patches in such cases.
Signed-off-by: Pavel Emelyanov <[email protected]>
---
diff --git a/kernel/user.c b/kernel/user.c
index 3549c4b..cb6c6f9 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -328,7 +328,7 @@ void free_uid(struct user_struct *up)
struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
{
struct hlist_head *hashent = uidhashentry(ns, uid);
- struct user_struct *up;
+ struct user_struct *up, *new;
/* Make uid_hash_find() + uids_user_create() + uid_hash_insert()
* atomic.
@@ -340,13 +340,9 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
spin_unlock_irq(&uidhash_lock);
if (!up) {
- struct user_struct *new;
-
new = kmem_cache_alloc(uid_cachep, GFP_KERNEL);
- if (!new) {
- uids_mutex_unlock();
- return NULL;
- }
+ if (!new)
+ goto out_unlock;
new->uid = uid;
atomic_set(&new->__count, 1);
@@ -362,28 +358,14 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
#endif
new->locked_shm = 0;
- if (alloc_uid_keyring(new, current) < 0) {
- kmem_cache_free(uid_cachep, new);
- uids_mutex_unlock();
- return NULL;
- }
+ if (alloc_uid_keyring(new, current) < 0)
+ goto out_free_user;
- if (sched_create_user(new) < 0) {
- key_put(new->uid_keyring);
- key_put(new->session_keyring);
- kmem_cache_free(uid_cachep, new);
- uids_mutex_unlock();
- return NULL;
- }
+ if (sched_create_user(new) < 0)
+ goto out_put_keys;
- if (uids_user_create(new)) {
- sched_destroy_user(new);
- key_put(new->uid_keyring);
- key_put(new->session_keyring);
- kmem_cache_free(uid_cachep, new);
- uids_mutex_unlock();
- return NULL;
- }
+ if (uids_user_create(new))
+ goto out_destoy_sched;
/*
* Before adding this, check whether we raced
@@ -411,6 +393,17 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
uids_mutex_unlock();
return up;
+
+out_destoy_sched:
+ sched_destroy_user(new);
+out_put_keys:
+ key_put(new->uid_keyring);
+ key_put(new->session_keyring);
+out_free_user:
+ kmem_cache_free(uid_cachep, new);
+out_unlock:
+ uids_mutex_unlock();
+ return NULL;
}
void switch_uid(struct user_struct *new_user)
--
1.5.3.4
-
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