lookup_one_len: don't accept . and ..

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

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 937f9d50c84b..5f4cdf3ad913 100644
--- 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')