fs/9p: Fix invalid mount options/args

Without this fix, if any invalid mount options/args are passed while mouting
the 9p fs, no error (-EINVAL) is returned and default arg value is assigned.

This fix returns -EINVAL when an invalid arguement is found while parsing
mount options.

Signed-off-by: Prem Karat <prem.karat@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 34 insertions, 9 deletions

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 8b7c6be2450b..ef9661886112 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -78,6 +78,25 @@ static const match_table_t tokens = {
         {Opt_err, NULL}
 };
 
+/* Interpret mount options for cache mode */
+static int get_cache_mode(char *s)
+{
+        int version = -EINVAL;
+
+        if (!strcmp(s, "loose")) {
+                version = CACHE_LOOSE;
+                P9_DPRINTK(P9_DEBUG_9P, "Cache mode: loose\n");
+        } else if (!strcmp(s, "fscache")) {
+                version = CACHE_FSCACHE;
+                P9_DPRINTK(P9_DEBUG_9P, "Cache mode: fscache\n");
+        } else if (!strcmp(s, "none")) {
+                version = CACHE_NONE;
+                P9_DPRINTK(P9_DEBUG_9P, "Cache mode: none\n");
+        } else
+                printk(KERN_INFO "9p: Unknown Cache mode %s.\n", s);
+        return version;
+}
+
 /**
  * v9fs_parse_options - parse mount options into session structure
  * @v9ses: existing v9fs session information
@@ -97,7 +116,7 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
         /* setup defaults */
         v9ses->afid = ~0;
         v9ses->debug = 0;
-        v9ses->cache = 0;
+        v9ses->cache = CACHE_NONE;
 #ifdef CONFIG_9P_FSCACHE
         v9ses->cachetag = NULL;
 #endif
@@ -171,13 +190,13 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
                                   "problem allocating copy of cache arg\n");
                                 goto free_and_return;
                         }
+                        ret = get_cache_mode(s);
+                        if (ret == -EINVAL) {
+                                kfree(s);
+                                goto free_and_return;
+                        }
 
-                        if (strcmp(s, "loose") == 0)
-                                v9ses->cache = CACHE_LOOSE;
-                        else if (strcmp(s, "fscache") == 0)
-                                v9ses->cache = CACHE_FSCACHE;
-                        else
-                                v9ses->cache = CACHE_NONE;
+                        v9ses->cache = ret;
                         kfree(s);
                         break;
 
@@ -200,9 +219,15 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
                         } else {
                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
                                 v9ses->uid = simple_strtoul(s, &e, 10);
-                                if (*e != '\0')
-                                        v9ses->uid = ~0;
+                                if (*e != '\0') {
+                                        ret = -EINVAL;
+                                        printk(KERN_INFO "9p: Unknown access "
+                                                        "argument %s.\n", s);
+                                        kfree(s);
+                                        goto free_and_return;
+                                }
                         }
+
                         kfree(s);
                         break;