lookup_one_len: don't accept . and ..

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 937f9d5..5f4cdf3 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2131,6 +2131,11 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
        if (!len)
                return ERR_PTR(-EACCES);
 
+       if (unlikely(name[0] == '.')) {
+               if (len < 2 || (len == 2 && name[1] == '.'))
+                       return ERR_PTR(-EACCES);
+       }
+
        while (len--) {
                c = *(const unsigned char *)name++;
                if (c == '/' || c == '\0')