eCryptfs: write lock requested keys

A requested key is write locked in order to prevent modifications on the
authentication token while it is being used.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index d95dd50..03e609c 100644 (file)
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -516,10 +516,11 @@ ecryptfs_find_global_auth_tok_for_sig(
                        goto out_invalid_auth_tok;
                }
 
+               down_write(&(walker->global_auth_tok_key->sem));
                rc = ecryptfs_verify_auth_tok_from_key(
                                walker->global_auth_tok_key, auth_tok);
                if (rc)
-                       goto out_invalid_auth_tok;
+                       goto out_invalid_auth_tok_unlock;
 
                (*auth_tok_key) = walker->global_auth_tok_key;
                key_get(*auth_tok_key);
@@ -527,6 +528,8 @@ ecryptfs_find_global_auth_tok_for_sig(
        }
        rc = -ENOENT;
        goto out;
+out_invalid_auth_tok_unlock:
+       up_write(&(walker->global_auth_tok_key->sem));
 out_invalid_auth_tok:
        printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
        walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
@@ -869,8 +872,10 @@ out_free_unlock:
 out_unlock:
        mutex_unlock(s->tfm_mutex);
 out:
-       if (auth_tok_key)
+       if (auth_tok_key) {
+               up_write(&(auth_tok_key->sem));
                key_put(auth_tok_key);
+       }
        kfree(s);
        return rc;
 }
@@ -1106,8 +1111,10 @@ out:
                (*filename_size) = 0;
                (*filename) = NULL;
        }
-       if (auth_tok_key)
+       if (auth_tok_key) {
+               up_write(&(auth_tok_key->sem));
                key_put(auth_tok_key);
+       }
        kfree(s);
        return rc;
 }
@@ -1638,9 +1645,10 @@ int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
                (*auth_tok_key) = NULL;
                goto out;
        }
-
+       down_write(&(*auth_tok_key)->sem);
        rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
        if (rc) {
+               up_write(&(*auth_tok_key)->sem);
                key_put(*auth_tok_key);
                (*auth_tok_key) = NULL;
                goto out;
@@ -1865,6 +1873,7 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
 find_next_matching_auth_tok:
        found_auth_tok = 0;
        if (auth_tok_key) {
+               up_write(&(auth_tok_key->sem));
                key_put(auth_tok_key);
                auth_tok_key = NULL;
        }
@@ -1951,8 +1960,10 @@ found_matching_auth_tok:
 out_wipe_list:
        wipe_auth_tok_list(&auth_tok_list);
 out:
-       if (auth_tok_key)
+       if (auth_tok_key) {
+               up_write(&(auth_tok_key->sem));
                key_put(auth_tok_key);
+       }
        return rc;
 }
 
@@ -2446,6 +2457,7 @@ ecryptfs_generate_key_packet_set(char *dest_base,
                        rc = -EINVAL;
                        goto out_free;
                }
+               up_write(&(auth_tok_key->sem));
                key_put(auth_tok_key);
                auth_tok_key = NULL;
        }
@@ -2460,8 +2472,10 @@ out_free:
 out:
        if (rc)
                (*len) = 0;
-       if (auth_tok_key)
+       if (auth_tok_key) {
+               up_write(&(auth_tok_key->sem));
                key_put(auth_tok_key);
+       }
 
        mutex_unlock(&crypt_stat->keysig_list_mutex);
        return rc;

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 520d05f..c27c0ec 100644 (file)
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -254,8 +254,10 @@ static int ecryptfs_init_global_auth_toks(
                               "option: [%s]\n", global_auth_tok->sig);
                        global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
                        goto out;
-               } else
+               } else {
                        global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
+                       up_write(&(global_auth_tok->global_auth_tok_key)->sem);
+               }
        }
 out:
        return rc;