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-rw-r--r--include/linux/key.h2
-rw-r--r--security/keys/internal.h2
-rw-r--r--security/keys/key.c2
-rw-r--r--security/keys/keyring.c23
-rw-r--r--security/keys/process_keys.c6
5 files changed, 23 insertions, 12 deletions
diff --git a/include/linux/key.h b/include/linux/key.h
index 044114185120..e315e16b6ff8 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -187,6 +187,7 @@ struct key {
 #define KEY_FLAG_BUILTIN	8	/* set if key is built in to the kernel */
 #define KEY_FLAG_ROOT_CAN_INVAL	9	/* set if key can be invalidated by root without permission */
 #define KEY_FLAG_KEEP		10	/* set if key should not be removed */
+#define KEY_FLAG_UID_KEYRING	11	/* set if key is a user or user session keyring */
 
 	/* the key type and key description string
 	 * - the desc is used to match a key against search criteria
@@ -243,6 +244,7 @@ extern struct key *key_alloc(struct key_type *type,
 #define KEY_ALLOC_NOT_IN_QUOTA		0x0002	/* not in quota */
 #define KEY_ALLOC_BUILT_IN		0x0004	/* Key is built into kernel */
 #define KEY_ALLOC_BYPASS_RESTRICTION	0x0008	/* Override the check on restricted keyrings */
+#define KEY_ALLOC_UID_KEYRING		0x0010	/* allocating a user or user session keyring */
 
 extern void key_revoke(struct key *key);
 extern void key_invalidate(struct key *key);
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 1c02c6547038..503adbae7b0d 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -141,7 +141,7 @@ extern key_ref_t keyring_search_aux(key_ref_t keyring_ref,
 extern key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx);
 extern key_ref_t search_process_keyrings(struct keyring_search_context *ctx);
 
-extern struct key *find_keyring_by_name(const char *name, bool skip_perm_check);
+extern struct key *find_keyring_by_name(const char *name, bool uid_keyring);
 
 extern int install_user_keyrings(void);
 extern int install_thread_keyring_to_cred(struct cred *);
diff --git a/security/keys/key.c b/security/keys/key.c
index 83da68d98b40..e5c0896c3a8f 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -302,6 +302,8 @@ struct key *key_alloc(struct key_type *type, const char *desc,
 		key->flags |= 1 << KEY_FLAG_IN_QUOTA;
 	if (flags & KEY_ALLOC_BUILT_IN)
 		key->flags |= 1 << KEY_FLAG_BUILTIN;
+	if (flags & KEY_ALLOC_UID_KEYRING)
+		key->flags |= 1 << KEY_FLAG_UID_KEYRING;
 
 #ifdef KEY_DEBUGGING
 	key->magic = KEY_DEBUG_MAGIC;
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 94f038967c17..4fa82a8a9c0e 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -1097,15 +1097,15 @@ found:
 /*
  * Find a keyring with the specified name.
  *
- * All named keyrings in the current user namespace are searched, provided they
- * grant Search permission directly to the caller (unless this check is
- * skipped).  Keyrings whose usage points have reached zero or who have been
- * revoked are skipped.
+ * Only keyrings that have nonzero refcount, are not revoked, and are owned by a
+ * user in the current user namespace are considered.  If @uid_keyring is %true,
+ * the keyring additionally must have been allocated as a user or user session
+ * keyring; otherwise, it must grant Search permission directly to the caller.
  *
  * Returns a pointer to the keyring with the keyring's refcount having being
  * incremented on success.  -ENOKEY is returned if a key could not be found.
  */
-struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
+struct key *find_keyring_by_name(const char *name, bool uid_keyring)
 {
 	struct key *keyring;
 	int bucket;
@@ -1133,10 +1133,15 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
 			if (strcmp(keyring->description, name) != 0)
 				continue;
 
-			if (!skip_perm_check &&
-			    key_permission(make_key_ref(keyring, 0),
-					   KEY_NEED_SEARCH) < 0)
-				continue;
+			if (uid_keyring) {
+				if (!test_bit(KEY_FLAG_UID_KEYRING,
+					      &keyring->flags))
+					continue;
+			} else {
+				if (key_permission(make_key_ref(keyring, 0),
+						   KEY_NEED_SEARCH) < 0)
+					continue;
+			}
 
 			/* we've got a match but we might end up racing with
 			 * key_cleanup() if the keyring is currently 'dead'
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 86bced9fdbdf..293d3598153b 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -77,7 +77,8 @@ int install_user_keyrings(void)
 		if (IS_ERR(uid_keyring)) {
 			uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
 						    cred, user_keyring_perm,
-						    KEY_ALLOC_IN_QUOTA,
+						    KEY_ALLOC_UID_KEYRING |
+							KEY_ALLOC_IN_QUOTA,
 						    NULL, NULL);
 			if (IS_ERR(uid_keyring)) {
 				ret = PTR_ERR(uid_keyring);
@@ -94,7 +95,8 @@ int install_user_keyrings(void)
 			session_keyring =
 				keyring_alloc(buf, user->uid, INVALID_GID,
 					      cred, user_keyring_perm,
-					      KEY_ALLOC_IN_QUOTA,
+					      KEY_ALLOC_UID_KEYRING |
+						  KEY_ALLOC_IN_QUOTA,
 					      NULL, NULL);
 			if (IS_ERR(session_keyring)) {
 				ret = PTR_ERR(session_keyring);