Merge tag 'ecryptfs-3.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs

Pull eCryptfs fixes from Tyler Hicks:
 "Fixes for filename decryption and encrypted view plus a cleanup

   - The filename decryption routines were, at times, writing a zero
     byte one character past the end of the filename buffer

   - The encrypted view feature attempted, and failed, to roll its own
     form of enforcing a read-only mount instead of letting the VFS
     enforce it"

* tag 'ecryptfs-3.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
  eCryptfs: Remove buggy and unnecessary write in file name decode routine
  eCryptfs: Remove unnecessary casts when parsing packet lengths
  eCryptfs: Force RO mount when encrypted view is enabled

4 files changed, 16 insertions, 19 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index c2d6604667b0..719e1ce1c609 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1917,7 +1917,6 @@ ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
                         break;
                 case 2:
                         dst[dst_byte_offset++] |= (src_byte);
-                        dst[dst_byte_offset] = 0;
                         current_bit_offset = 0;
                         break;
                 }
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 80154ec4f8c2..6f4e659f508f 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -190,23 +190,11 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
 {
         int rc = 0;
         struct ecryptfs_crypt_stat *crypt_stat = NULL;
-        struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
         struct dentry *ecryptfs_dentry = file->f_path.dentry;
         /* Private value of ecryptfs_dentry allocated in
          * ecryptfs_lookup() */
         struct ecryptfs_file_info *file_info;
 
-        mount_crypt_stat = &ecryptfs_superblock_to_private(
-                ecryptfs_dentry->d_sb)->mount_crypt_stat;
-        if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
-            && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
-                || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
-                || (file->f_flags & O_APPEND))) {
-                printk(KERN_WARNING "Mount has encrypted view enabled; "
-                       "files may only be read\n");
-                rc = -EPERM;
-                goto out;
-        }
         /* Released in ecryptfs_release or end of function if failure */
         file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
         ecryptfs_set_file_private(file, file_info);
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 635e8e16a5b7..917bd5c9776a 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -100,12 +100,12 @@ int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
         (*size) = 0;
         if (data[0] < 192) {
                 /* One-byte length */
-                (*size) = (unsigned char)data[0];
+                (*size) = data[0];
                 (*length_size) = 1;
         } else if (data[0] < 224) {
                 /* Two-byte length */
-                (*size) = (((unsigned char)(data[0]) - 192) * 256);
-                (*size) += ((unsigned char)(data[1]) + 192);
+                (*size) = (data[0] - 192) * 256;
+                (*size) += data[1] + 192;
                 (*length_size) = 2;
         } else if (data[0] == 255) {
                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index c4cd1fd86cc2..d9eb84bda559 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -493,6 +493,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
 {
         struct super_block *s;
         struct ecryptfs_sb_info *sbi;
+        struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
         struct ecryptfs_dentry_info *root_info;
         const char *err = "Getting sb failed";
         struct inode *inode;
@@ -511,6 +512,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
                 err = "Error parsing options";
                 goto out;
         }
+        mount_crypt_stat = &sbi->mount_crypt_stat;
 
         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
         if (IS_ERR(s)) {
@@ -557,11 +559,19 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
 
         /**
          * Set the POSIX ACL flag based on whether they're enabled in the lower
-         * mount. Force a read-only eCryptfs mount if the lower mount is ro.
-         * Allow a ro eCryptfs mount even when the lower mount is rw.
+         * mount.
          */
         s->s_flags = flags & ~MS_POSIXACL;
-        s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
+        s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
+
+        /**
+         * Force a read-only eCryptfs mount when:
+         *   1) The lower mount is ro
+         *   2) The ecryptfs_encrypted_view mount option is specified
+         */
+        if (path.dentry->d_sb->s_flags & MS_RDONLY ||
+            mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+                s->s_flags |= MS_RDONLY;
 
         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
         s->s_blocksize = path.dentry->d_sb->s_blocksize;