fs/cifs: make share unaccessible at root level mountable
if, when mounting //HOST/share/sub/dir/foo we can query /sub/dir/foo but
not any of the path components above:
- store the /sub/dir/foo prefix in the cifs super_block info
- in the superblock, set root dentry to the subpath dentry (instead of
the share root)
- set a flag in the superblock to remember it
- use prefixpath when building path from a dentry
fixes bso#8950
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index eb24653..7ae0328 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3485,6 +3485,44 @@
return volume_info;
}
+static int
+cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
+ unsigned int xid,
+ struct cifs_tcon *tcon,
+ struct cifs_sb_info *cifs_sb,
+ char *full_path)
+{
+ int rc;
+ char *s;
+ char sep, tmp;
+
+ sep = CIFS_DIR_SEP(cifs_sb);
+ s = full_path;
+
+ rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
+ while (rc == 0) {
+ /* skip separators */
+ while (*s == sep)
+ s++;
+ if (!*s)
+ break;
+ /* next separator */
+ while (*s && *s != sep)
+ s++;
+
+ /*
+ * temporarily null-terminate the path at the end of
+ * the current component
+ */
+ tmp = *s;
+ *s = 0;
+ rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
+ full_path);
+ *s = tmp;
+ }
+ return rc;
+}
+
int
cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
{
@@ -3622,6 +3660,16 @@
kfree(full_path);
goto mount_fail_check;
}
+
+ rc = cifs_are_all_path_components_accessible(server,
+ xid, tcon, cifs_sb,
+ full_path);
+ if (rc != 0) {
+ cifs_dbg(VFS, "cannot query dirs between root and final path, "
+ "enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+ rc = 0;
+ }
kfree(full_path);
}
@@ -3891,6 +3939,7 @@
bdi_destroy(&cifs_sb->bdi);
kfree(cifs_sb->mountdata);
+ kfree(cifs_sb->prepath);
call_rcu(&cifs_sb->rcu, delayed_free);
}