Merge tag 'ecryptfs-4.0-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs

Pull eCryptfs fixes from Tyler Hicks:
 "Fixes for proper ioctl handling and an untriggerable buffer overflow

   - The eCryptfs ioctl handling functions should only pass known-good
     ioctl commands to the lower filesystem

   - A static checker found a potential buffer overflow.  Upon
     inspection, it is not triggerable due to input validation performed
     on the mount parameters"

* tag 'ecryptfs-4.0-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
  eCryptfs: don't pass fs-specific ioctl commands through
  eCryptfs: ensure copy to crypt_stat->cipher does not overrun

4 files changed, 34 insertions, 8 deletions

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 90d1882b306f..5ba029e627cc 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -124,7 +124,7 @@ ecryptfs_get_key_payload_data(struct key *key)
 }
 
 #define ECRYPTFS_MAX_KEYSET_SIZE 1024
-#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32
+#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 31
 #define ECRYPTFS_MAX_NUM_ENC_KEYS 64
 #define ECRYPTFS_MAX_IV_BYTES 16        /* 128 bits */
 #define ECRYPTFS_SALT_BYTES 2
@@ -237,7 +237,7 @@ struct ecryptfs_crypt_stat {
         struct crypto_ablkcipher *tfm;
         struct crypto_hash *hash_tfm; /* Crypto context for generating
                                        * the initialization vectors */
-        unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
+        unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
         unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
         unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
         struct list_head keysig_list;
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index b07731e68c0b..fd39bad6f1bd 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -303,9 +303,22 @@ ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         struct file *lower_file = ecryptfs_file_to_lower(file);
         long rc = -ENOTTY;
 
-        if (lower_file->f_op->unlocked_ioctl)
+        if (!lower_file->f_op->unlocked_ioctl)
+                return rc;
+
+        switch (cmd) {
+        case FITRIM:
+        case FS_IOC_GETFLAGS:
+        case FS_IOC_SETFLAGS:
+        case FS_IOC_GETVERSION:
+        case FS_IOC_SETVERSION:
                 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
-        return rc;
+                fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+                return rc;
+        default:
+                return rc;
+        }
 }
 
 #ifdef CONFIG_COMPAT
@@ -315,9 +328,22 @@ ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         struct file *lower_file = ecryptfs_file_to_lower(file);
         long rc = -ENOIOCTLCMD;
 
-        if (lower_file->f_op->compat_ioctl)
+        if (!lower_file->f_op->compat_ioctl)
+                return rc;
+
+        switch (cmd) {
+        case FITRIM:
+        case FS_IOC32_GETFLAGS:
+        case FS_IOC32_SETFLAGS:
+        case FS_IOC32_GETVERSION:
+        case FS_IOC32_SETVERSION:
                 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
-        return rc;
+                fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+                return rc;
+        default:
+                return rc;
+        }
 }
 #endif
 
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 917bd5c9776a..6bd67e2011f0 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -891,7 +891,7 @@ struct ecryptfs_parse_tag_70_packet_silly_stack {
         struct blkcipher_desc desc;
         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
         char iv[ECRYPTFS_MAX_IV_BYTES];
-        char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
+        char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
 };
 
 /**
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 1895d60f4122..c095d3264259 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -407,7 +407,7 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
         if (!cipher_name_set) {
                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 
-                BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+                BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
                 strcpy(mount_crypt_stat->global_default_cipher_name,
                        ECRYPTFS_DEFAULT_CIPHER);
         }