cifs: clean up handling of unc= option

Make sure we free any existing memory allocated for vol->UNC, just in
case someone passes in multiple unc= options.

Get rid of the check for too long a UNC. The check for >300 bytes seems
arbitrary. We later copy this into the tcon->treeName, for instance and
it's a lot shorter than 300 bytes.

Eliminate an extra kmalloc and copy as well. Just set the vol->UNC
directly with the contents of match_strdup.

Establish that the UNC should be stored with '\\' delimiters. Use
convert_delimiter to change it in place in the vol->UNC.

Finally, move the check for a malformed UNC into
cifs_parse_mount_options so we can catch that situation earlier.

Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 12 insertions, 27 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index f3276239e075..9c5c8b8c19fe 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1566,29 +1566,15 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
                         got_ip = true;
                         break;
                 case Opt_unc:
-                        string = match_strdup(args);
-                        if (string == NULL)
+                        kfree(vol->UNC);
+                        vol->UNC = match_strdup(args);
+                        if (vol->UNC == NULL)
                                 goto out_nomem;
 
-                        temp_len = strnlen(string, 300);
-                        if (temp_len  == 300) {
-                                printk(KERN_WARNING "CIFS: UNC name too long\n");
-                                goto cifs_parse_mount_err;
-                        }
-
-                        vol->UNC = kmalloc(temp_len+1, GFP_KERNEL);
-                        if (vol->UNC == NULL) {
-                                printk(KERN_WARNING "CIFS: no memory for UNC\n");
-                                goto cifs_parse_mount_err;
-                        }
-                        strcpy(vol->UNC, string);
-
-                        if (strncmp(string, "//", 2) == 0) {
-                                vol->UNC[0] = '\\';
-                                vol->UNC[1] = '\\';
-                        } else if (strncmp(string, "\\\\", 2) != 0) {
+                        convert_delimiter(vol->UNC, '\\');
+                        if (vol->UNC[0] != '\\' || vol->UNC[1] != '\\') {
                                 printk(KERN_WARNING "CIFS: UNC Path does not "
-                                                    "begin with // or \\\\\n");
+                                                "begin with // or \\\\\n");
                                 goto cifs_parse_mount_err;
                         }
 
@@ -1813,6 +1799,12 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
                 goto cifs_parse_mount_err;
         }
 
+        /* make sure UNC has a share name */
+        if (!strchr(vol->UNC + 3, '\\')) {
+                cERROR(1, "Malformed UNC. Unable to find share name.");
+                goto cifs_parse_mount_err;
+        }
+
         if (!got_ip) {
                 /* No ip= option specified? Try to get it from UNC */
                 if (!cifs_convert_address(dstaddr, &vol->UNC[2],
@@ -2575,13 +2567,6 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)
                 }
         }
 
-        if (strchr(volume_info->UNC + 3, '\\') == NULL
-            && strchr(volume_info->UNC + 3, '/') == NULL) {
-                cERROR(1, "Missing share name");
-                rc = -ENODEV;
-                goto out_fail;
-        }
-
         /*
          * BB Do we need to wrap session_mutex around this TCon call and Unix
          * SetFS as we do on SessSetup and reconnect?