cifs: check MaxPathNameComponentLength != 0 before using it

[mirror_ubuntu-artful-kernel.git] / fs / cifs / dir.c

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 56366e9840769dd8a45250ec3a7b65097c979ff9..81ba6e0d88d8f3ec1d1c8b2e81e695819537c921 100644 (file)
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -194,15 +194,21 @@ cifs_bp_rename_retry:
 }
 
 /*
+ * Don't allow path components longer than the server max.
  * Don't allow the separator character in a path component.
  * The VFS will not allow "/", but "\" is allowed by posix.
  */
 static int
-check_name(struct dentry *direntry)
+check_name(struct dentry *direntry, struct cifs_tcon *tcon)
 {
        struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
        int i;
 
+       if (unlikely(tcon->fsAttrInfo.MaxPathNameComponentLength &&
+                    direntry->d_name.len >
+                    le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength)))
+               return -ENAMETOOLONG;
+
        if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
                for (i = 0; i < direntry->d_name.len; i++) {
                        if (direntry->d_name.name[i] == '\\') {
@@ -500,10 +506,6 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
                return finish_no_open(file, res);
        }
 
-       rc = check_name(direntry);
-       if (rc)
-               return rc;
-
        xid = get_xid();
 
        cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
@@ -516,6 +518,11 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
        }
 
        tcon = tlink_tcon(tlink);
+
+       rc = check_name(direntry, tcon);
+       if (rc)
+               goto out;
+
        server = tcon->ses->server;
 
        if (server->ops->new_lease_key)
@@ -776,7 +783,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
        }
        pTcon = tlink_tcon(tlink);
 
-       rc = check_name(direntry);
+       rc = check_name(direntry, pTcon);
        if (rc)
                goto lookup_out;