Merge branch 'fixes-v4.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull key handling fixes from James Morris:
 "This includes a fix for the capabilities code from Colin King, and a
  set of further fixes for the keys subsystem. From David:

   - Fix a bunch of places where kernel drivers may access revoked
     user-type keys and don't do it correctly.

   - Fix some ecryptfs bits.

   - Fix big_key to require CONFIG_CRYPTO.

   - Fix a couple of bugs in the asymmetric key type.

   - Fix a race between updating and finding negative keys.

   - Prevent add_key() from updating uninstantiated keys.

   - Make loading of key flags and expiry time atomic when not holding
     locks"

* 'fixes-v4.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  commoncap: move assignment of fs_ns to avoid null pointer dereference
  pkcs7: Prevent NULL pointer dereference, since sinfo is not always set.
  KEYS: load key flags and expiry time atomically in proc_keys_show()
  KEYS: Load key expiry time atomically in keyring_search_iterator()
  KEYS: load key flags and expiry time atomically in key_validate()
  KEYS: don't let add_key() update an uninstantiated key
  KEYS: Fix race between updating and finding a negative key
  KEYS: checking the input id parameters before finding asymmetric key
  KEYS: Fix the wrong index when checking the existence of second id
  security/keys: BIG_KEY requires CONFIG_CRYPTO
  ecryptfs: fix dereference of NULL user_key_payload
  fscrypt: fix dereference of NULL user_key_payload
  lib/digsig: fix dereference of NULL user_key_payload
  FS-Cache: fix dereference of NULL user_key_payload
  KEYS: encrypted: fix dereference of NULL user_key_payload

1 files changed, 17 insertions, 7 deletions

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 9c351bf757b2..3fbc0ff79699 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -84,11 +84,16 @@ struct ecryptfs_page_crypt_context {
 static inline struct ecryptfs_auth_tok *
 ecryptfs_get_encrypted_key_payload_data(struct key *key)
 {
-	if (key->type == &key_type_encrypted)
-		return (struct ecryptfs_auth_tok *)
-			(&((struct encrypted_key_payload *)key->payload.data[0])->payload_data);
-	else
+	struct encrypted_key_payload *payload;
+
+	if (key->type != &key_type_encrypted)
 		return NULL;
+
+	payload = key->payload.data[0];
+	if (!payload)
+		return ERR_PTR(-EKEYREVOKED);
+
+	return (struct ecryptfs_auth_tok *)payload->payload_data;
 }
 
 static inline struct key *ecryptfs_get_encrypted_key(char *sig)
@@ -114,12 +119,17 @@ static inline struct ecryptfs_auth_tok *
 ecryptfs_get_key_payload_data(struct key *key)
 {
 	struct ecryptfs_auth_tok *auth_tok;
+	struct user_key_payload *ukp;
 
 	auth_tok = ecryptfs_get_encrypted_key_payload_data(key);
-	if (!auth_tok)
-		return (struct ecryptfs_auth_tok *)user_key_payload_locked(key)->data;
-	else
+	if (auth_tok)
 		return auth_tok;
+
+	ukp = user_key_payload_locked(key);
+	if (!ukp)
+		return ERR_PTR(-EKEYREVOKED);
+
+	return (struct ecryptfs_auth_tok *)ukp->data;
 }
 
 #define ECRYPTFS_MAX_KEYSET_SIZE 1024