CIFS: Fix undefined behavior when mount fails

Fix double kfree() calls on the same pointers and cleanup mount code.

Reviewed-and-Tested-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 17 insertions, 27 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 131afadce0e0..d1ed7f9946d5 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -104,29 +104,23 @@ cifs_sb_deactive(struct super_block *sb)
 }
 
 static int
-cifs_read_super(struct super_block *sb, struct cifs_sb_info *cifs_sb,
-                void *data, struct smb_vol *volume_info, const char *devname,
-                int silent)
+cifs_read_super(struct super_block *sb, struct smb_vol *volume_info,
+                const char *devname, int silent)
 {
         struct inode *inode;
+        struct cifs_sb_info *cifs_sb;
         int rc = 0;
 
-        /* BB should we make this contingent on mount parm? */
-        sb->s_flags |= MS_NODIRATIME | MS_NOATIME;
-        sb->s_fs_info = cifs_sb;
+        cifs_sb = CIFS_SB(sb);
 
         spin_lock_init(&cifs_sb->tlink_tree_lock);
         cifs_sb->tlink_tree = RB_ROOT;
 
         rc = bdi_setup_and_register(&cifs_sb->bdi, "cifs", BDI_CAP_MAP_COPY);
-        if (rc) {
-                kfree(cifs_sb);
+        if (rc)
                 return rc;
-        }
-        cifs_sb->bdi.ra_pages = default_backing_dev_info.ra_pages;
 
-        if (data)
-                cifs_sb->mountdata = data;
+        cifs_sb->bdi.ra_pages = default_backing_dev_info.ra_pages;
 
         rc = cifs_mount(sb, cifs_sb, volume_info, devname);
 
@@ -179,15 +173,7 @@ out_no_root:
         cifs_umount(sb, cifs_sb);
 
 out_mount_failed:
-        if (cifs_sb) {
-                if (cifs_sb->mountdata) {
-                        kfree(cifs_sb->mountdata);
-                        cifs_sb->mountdata = NULL;
-                }
-                unload_nls(cifs_sb->local_nls);
-                bdi_destroy(&cifs_sb->bdi);
-                kfree(cifs_sb);
-        }
+        bdi_destroy(&cifs_sb->bdi);
         return rc;
 }
 
@@ -553,7 +539,6 @@ cifs_do_mount(struct file_system_type *fs_type,
         struct cifs_sb_info *cifs_sb;
         struct smb_vol *volume_info;
         struct dentry *root;
-        char *copied_data = NULL;
 
         cFYI(1, "Devname: %s flags: %d ", dev_name, flags);
 
@@ -576,20 +561,23 @@ cifs_do_mount(struct file_system_type *fs_type,
                 goto out;
         }
 
-        sb->s_flags = flags;
-
         /*
          * Copy mount params for use in submounts. Better to do
          * the copy here and deal with the error before cleanup gets
          * complicated post-mount.
          */
-        copied_data = kstrndup(data, PAGE_SIZE, GFP_KERNEL);
-        if (copied_data == NULL) {
+        cifs_sb->mountdata = kstrndup(data, PAGE_SIZE, GFP_KERNEL);
+        if (cifs_sb->mountdata == NULL) {
                 root = ERR_PTR(-ENOMEM);
                 goto err_out;
         }
 
-        rc = cifs_read_super(sb, cifs_sb, copied_data, volume_info, dev_name,
+        sb->s_flags = flags;
+        /* BB should we make this contingent on mount parm? */
+        sb->s_flags |= MS_NODIRATIME | MS_NOATIME;
+        sb->s_fs_info = cifs_sb;
+
+        rc = cifs_read_super(sb, volume_info, dev_name,
                              flags & MS_SILENT ? 1 : 0);
         if (rc) {
                 root = ERR_PTR(rc);
@@ -604,6 +592,8 @@ out:
         return root;
 
 err_out:
+        kfree(cifs_sb->mountdata);
+        unload_nls(cifs_sb->local_nls);
         kfree(cifs_sb);
         deactivate_locked_super(sb);
         cifs_cleanup_volume_info(&volume_info);