Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6

[safe/jmp/linux-2.6] / security / keys / request_key.c

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index ac49c8a..f5ec9ac 100644 (file)
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -58,6 +58,38 @@ void complete_request_key(struct key_construction *cons, int error)
 }
 EXPORT_SYMBOL(complete_request_key);
 
+static int umh_keys_init(struct subprocess_info *info)
+{
+       struct cred *cred = (struct cred*)current_cred();
+       struct key *keyring = info->data;
+       /*
+        * This is called in context of freshly forked kthread before
+        * kernel_execve(), we can just change our ->session_keyring.
+        */
+       return install_session_keyring_to_cred(cred, keyring);
+}
+
+static void umh_keys_cleanup(struct subprocess_info *info)
+{
+       struct key *keyring = info->data;
+       key_put(keyring);
+}
+
+static int call_usermodehelper_keys(char *path, char **argv, char **envp,
+                        struct key *session_keyring, enum umh_wait wait)
+{
+       gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
+       struct subprocess_info *info =
+               call_usermodehelper_setup(path, argv, envp, gfp_mask);
+
+       if (!info)
+               return -ENOMEM;
+
+       call_usermodehelper_setfns(info, umh_keys_init, umh_keys_cleanup,
+                                       key_get(session_keyring));
+       return call_usermodehelper_exec(info, wait);
+}
+
 /*
  * request userspace finish the construction of a key
  * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
@@ -299,6 +331,7 @@ static int construct_alloc_key(struct key_type *type,
                               struct key_user *user,
                               struct key **_key)
 {
+       struct keyring_list *prealloc;
        const struct cred *cred = current_cred();
        struct key *key;
        key_ref_t key_ref;
@@ -306,6 +339,7 @@ static int construct_alloc_key(struct key_type *type,
 
        kenter("%s,%s,,,", type->name, description);
 
+       *_key = NULL;
        mutex_lock(&user->cons_lock);
 
        key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
@@ -315,8 +349,12 @@ static int construct_alloc_key(struct key_type *type,
 
        set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
 
-       if (dest_keyring)
-               down_write(&dest_keyring->sem);
+       if (dest_keyring) {
+               ret = __key_link_begin(dest_keyring, type, description,
+                                      &prealloc);
+               if (ret < 0)
+                       goto link_prealloc_failed;
+       }
 
        /* attach the key to the destination keyring under lock, but we do need
         * to do another check just in case someone beat us to it whilst we
@@ -328,11 +366,11 @@ static int construct_alloc_key(struct key_type *type,
                goto key_already_present;
 
        if (dest_keyring)
-               __key_link(dest_keyring, key);
+               __key_link(dest_keyring, key, &prealloc);
 
        mutex_unlock(&key_construction_mutex);
        if (dest_keyring)
-               up_write(&dest_keyring->sem);
+               __key_link_end(dest_keyring, type, prealloc);
        mutex_unlock(&user->cons_lock);
        *_key = key;
        kleave(" = 0 [%d]", key_serial(key));
@@ -341,27 +379,36 @@ static int construct_alloc_key(struct key_type *type,
        /* the key is now present - we tell the caller that we found it by
         * returning -EINPROGRESS  */
 key_already_present:
+       key_put(key);
        mutex_unlock(&key_construction_mutex);
-       ret = 0;
+       key = key_ref_to_ptr(key_ref);
        if (dest_keyring) {
-               ret = __key_link(dest_keyring, key_ref_to_ptr(key_ref));
-               up_write(&dest_keyring->sem);
+               ret = __key_link_check_live_key(dest_keyring, key);
+               if (ret == 0)
+                       __key_link(dest_keyring, key, &prealloc);
+               __key_link_end(dest_keyring, type, prealloc);
+               if (ret < 0)
+                       goto link_check_failed;
        }
        mutex_unlock(&user->cons_lock);
-       key_put(key);
-       if (ret < 0) {
-               key_ref_put(key_ref);
-               *_key = NULL;
-               kleave(" = %d [link]", ret);
-               return ret;
-       }
-       *_key = key = key_ref_to_ptr(key_ref);
+       *_key = key;
        kleave(" = -EINPROGRESS [%d]", key_serial(key));
        return -EINPROGRESS;
 
+link_check_failed:
+       mutex_unlock(&user->cons_lock);
+       key_put(key);
+       kleave(" = %d [linkcheck]", ret);
+       return ret;
+
+link_prealloc_failed:
+       up_write(&dest_keyring->sem);
+       mutex_unlock(&user->cons_lock);
+       kleave(" = %d [prelink]", ret);
+       return ret;
+
 alloc_failed:
        mutex_unlock(&user->cons_lock);
-       *_key = NULL;
        kleave(" = %ld", PTR_ERR(key));
        return PTR_ERR(key);
 }