ovl: allow filenames with comma

Allow option separator (comma) to be escaped with backslash.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 45 insertions, 3 deletions

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index b92bd1829cf7..eee7a62e1c0e 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -462,11 +462,34 @@ static const match_table_t ovl_tokens = {
         {OPT_ERR,                       NULL}
 };
 
+static char *ovl_next_opt(char **s)
+{
+        char *sbegin = *s;
+        char *p;
+
+        if (sbegin == NULL)
+                return NULL;
+
+        for (p = sbegin; *p; p++) {
+                if (*p == '\\') {
+                        p++;
+                        if (!*p)
+                                break;
+                } else if (*p == ',') {
+                        *p = '\0';
+                        *s = p + 1;
+                        return sbegin;
+                }
+        }
+        *s = NULL;
+        return sbegin;
+}
+
 static int ovl_parse_opt(char *opt, struct ovl_config *config)
 {
         char *p;
 
-        while ((p = strsep(&opt, ",")) != NULL) {
+        while ((p = ovl_next_opt(&opt)) != NULL) {
                 int token;
                 substring_t args[MAX_OPT_ARGS];
 
@@ -554,15 +577,34 @@ out_dput:
         goto out_unlock;
 }
 
+static void ovl_unescape(char *s)
+{
+        char *d = s;
+
+        for (;; s++, d++) {
+                if (*s == '\\')
+                        s++;
+                *d = *s;
+                if (!*s)
+                        break;
+        }
+}
+
 static int ovl_mount_dir(const char *name, struct path *path)
 {
         int err;
+        char *tmp = kstrdup(name, GFP_KERNEL);
+
+        if (!tmp)
+                return -ENOMEM;
 
-        err = kern_path(name, LOOKUP_FOLLOW, path);
+        ovl_unescape(tmp);
+        err = kern_path(tmp, LOOKUP_FOLLOW, path);
         if (err) {
-                pr_err("overlayfs: failed to resolve '%s': %i\n", name, err);
+                pr_err("overlayfs: failed to resolve '%s': %i\n", tmp, err);
                 err = -EINVAL;
         }
+        kfree(tmp);
         return err;
 }