From 0be286cd6de995d6249508ebde6cfb8066045d77 Mon Sep 17 00:00:00 2001
From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Sat, 30 Jan 2021 11:08:21 +0100
Subject: [PATCH] fs: fat: must not write directory '.' and '..'
Directories or files called '.' or '..' cannot be created or written to
in any directory. Move the test to normalize_longname() to check this
early.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
fs/fat/fat_write.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index a9b9fa5d68..8945649977 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -1259,8 +1259,10 @@ again:
static int normalize_longname(char *l_filename, const char *filename)
{
const char *p, illegal[] = "<>:\"/\\|?*";
+ size_t len;
- if (strlen(filename) >= VFAT_MAXLEN_BYTES)
+ len = strlen(filename);
+ if (!len || len >= VFAT_MAXLEN_BYTES || filename[len - 1] == '.')
return -1;
for (p = filename; *p; ++p) {
@@ -1348,15 +1350,6 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
char shortname[SHORT_NAME_SIZE];
int ndent;
- if (itr->is_root) {
- /* root dir cannot have "." or ".." */
- if (!strcmp(l_filename, ".") ||
- !strcmp(l_filename, "..")) {
- ret = -EINVAL;
- goto exit;
- }
- }
-
if (pos) {
/* No hole allowed */
ret = -EINVAL;
--
2.39.5