[PATCH] keys: sort out key quota system

Add the ability for key creation to overrun the user's quota in some
circumstances - notably when a session keyring is created and assigned to a
process that didn't previously have one.

This means it's still possible to log in, should PAM require the creation of a
new session keyring, and fix an overburdened key quota.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 7 deletions

diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 4d9825f9962c..32150cf7c37f 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -77,7 +77,8 @@ int alloc_uid_keyring(struct user_struct *user,
         /* concoct a default session keyring */
         sprintf(buf, "_uid_ses.%u", user->uid);
 
-        session_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, ctx, 0, NULL);
+        session_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, ctx,
+                                        KEY_ALLOC_IN_QUOTA, NULL);
         if (IS_ERR(session_keyring)) {
                 ret = PTR_ERR(session_keyring);
                 goto error;
@@ -87,8 +88,8 @@ int alloc_uid_keyring(struct user_struct *user,
          * keyring */
         sprintf(buf, "_uid.%u", user->uid);
 
-        uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, ctx, 0,
-                                    session_keyring);
+        uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, ctx,
+                                    KEY_ALLOC_IN_QUOTA, session_keyring);
         if (IS_ERR(uid_keyring)) {
                 key_put(session_keyring);
                 ret = PTR_ERR(uid_keyring);
@@ -144,7 +145,8 @@ int install_thread_keyring(struct task_struct *tsk)
 
         sprintf(buf, "_tid.%u", tsk->pid);
 
-        keyring = keyring_alloc(buf, tsk->uid, tsk->gid, tsk, 1, NULL);
+        keyring = keyring_alloc(buf, tsk->uid, tsk->gid, tsk,
+                                KEY_ALLOC_QUOTA_OVERRUN, NULL);
         if (IS_ERR(keyring)) {
                 ret = PTR_ERR(keyring);
                 goto error;
@@ -178,7 +180,8 @@ int install_process_keyring(struct task_struct *tsk)
         if (!tsk->signal->process_keyring) {
                 sprintf(buf, "_pid.%u", tsk->tgid);
 
-                keyring = keyring_alloc(buf, tsk->uid, tsk->gid, tsk, 1, NULL);
+                keyring = keyring_alloc(buf, tsk->uid, tsk->gid, tsk,
+                                        KEY_ALLOC_QUOTA_OVERRUN, NULL);
                 if (IS_ERR(keyring)) {
                         ret = PTR_ERR(keyring);
                         goto error;
@@ -209,6 +212,7 @@ error:
 static int install_session_keyring(struct task_struct *tsk,
                                    struct key *keyring)
 {
+        unsigned long flags;
         struct key *old;
         char buf[20];
 
@@ -218,7 +222,12 @@ static int install_session_keyring(struct task_struct *tsk,
         if (!keyring) {
                 sprintf(buf, "_ses.%u", tsk->tgid);
 
-                keyring = keyring_alloc(buf, tsk->uid, tsk->gid, tsk, 1, NULL);
+                flags = KEY_ALLOC_QUOTA_OVERRUN;
+                if (tsk->signal->session_keyring)
+                        flags = KEY_ALLOC_IN_QUOTA;
+
+                keyring = keyring_alloc(buf, tsk->uid, tsk->gid, tsk,
+                                        flags, NULL);
                 if (IS_ERR(keyring))
                         return PTR_ERR(keyring);
         }
@@ -728,7 +737,8 @@ long join_session_keyring(const char *name)
         keyring = find_keyring_by_name(name, 0);
         if (PTR_ERR(keyring) == -ENOKEY) {
                 /* not found - try and create a new one */
-                keyring = keyring_alloc(name, tsk->uid, tsk->gid, tsk, 0, NULL);
+                keyring = keyring_alloc(name, tsk->uid, tsk->gid, tsk,
+                                        KEY_ALLOC_IN_QUOTA, NULL);
                 if (IS_ERR(keyring)) {
                         ret = PTR_ERR(keyring);
                         goto error2;