cifs: cifsroot: add more err checking

make cifs more verbose about buffer size errors
and add some comments

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifsroot.c b/fs/cifs/cifsroot.c
index 8760d9c..37edbfb 100644 (file)
--- a/fs/cifs/cifsroot.c
+++ b/fs/cifs/cifsroot.c
@@ -24,6 +24,7 @@ static char root_opts[1024] __initdata = DEFAULT_MNT_OPTS;
 
 static __be32 __init parse_srvaddr(char *start, char *end)
 {
+       /* TODO: ipv6 support */
        char addr[sizeof("aaa.bbb.ccc.ddd")];
        int i = 0;
 
@@ -50,14 +51,24 @@ static int __init cifs_root_setup(char *line)
                if (!s || s[1] == '\0')
                        return 1;
 
+               /* make s point to ',' or '\0' at end of line */
                s = strchrnul(s, ',');
+               /* len is strlen(unc) + '\0' */
                len = s - line + 1;
-               if (len <= sizeof(root_dev)) {
-                       strlcpy(root_dev, line, len);
-                       srvaddr = parse_srvaddr(&line[2], s);
-                       if (*s) {
-                               snprintf(root_opts, sizeof(root_opts), "%s,%s",
+               if (len > sizeof(root_dev)) {
+                       printk(KERN_ERR "Root-CIFS: UNC path too long\n");
+                       return 1;
+               }
+               strlcpy(root_dev, line, len);
+               srvaddr = parse_srvaddr(&line[2], s);
+               if (*s) {
+                       int n = snprintf(root_opts,
+                                        sizeof(root_opts), "%s,%s",
                                         DEFAULT_MNT_OPTS, s + 1);
+                       if (n >= sizeof(root_opts)) {
+                               printk(KERN_ERR "Root-CIFS: mount options string too long\n");
+                               root_opts[sizeof(root_opts)-1] = '\0';
+                               return 1;
                        }
                }
        }