[020/101] fs/9p: Fix invalid mount options/args

[Greg KH]

2.6.33-longterm review patch.  If anyone has any objections, please let us know.

------------------

From: Prem Karat <prem.karat@xxxxxxxxxxxxxxxxxx>

commit a2dd43bb0d7b9ce28f8a39254c25840c0730498e upstream.

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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Eric Van Hensbergen <ericvh@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/9p/v9fs.c |   43 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 9 deletions(-)

--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -75,6 +75,25 @@ 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
@@ -94,7 +113,7 @@ static int v9fs_parse_options(struct v9f
 	/* setup defaults */
 	v9ses->afid = ~0;
 	v9ses->debug = 0;
-	v9ses->cache = 0;
+	v9ses->cache = CACHE_NONE;
 #ifdef CONFIG_9P_FSCACHE
 	v9ses->cachetag = NULL;
 #endif
@@ -168,13 +187,13 @@ static int v9fs_parse_options(struct v9f
 				  "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;
 
@@ -195,9 +214,15 @@ static int v9fs_parse_options(struct v9f
 			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;
 


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