From: Gabriel Krisman Bertazi <krisman@collabora.com>
Date: Sun, 28 Apr 2019 19:10:21 +0000 (-0400)
Subject: ext2fs: fix potential null dereference in utf8nlookup
X-Git-Tag: v1.45.1-rc1~24
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=dea1e527ebfa689ed0a0a6bc78a4f640c1fe192e;p=tools%2Fe2fsprogs.git

ext2fs: fix potential null dereference in utf8nlookup

Delay the access of data->offset until after the null check.  This was
reported by 0-day on the kernel version of the script.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/lib/ext2fs/nls_utf8-norm.c b/lib/ext2fs/nls_utf8-norm.c
index 5a91573..98c6700 100644
--- a/lib/ext2fs/nls_utf8-norm.c
+++ b/lib/ext2fs/nls_utf8-norm.c
@@ -335,7 +335,7 @@ utf8hangul(const char *str, unsigned char *hangul)
 static utf8leaf_t *utf8nlookup(const struct utf8data *data,
 			       unsigned char *hangul, const char *s, size_t len)
 {
-	utf8trie_t	*trie = utf8data + data->offset;
+	utf8trie_t	*trie;
 	int		offlen;
 	int		offset;
 	int		mask;
@@ -345,6 +345,8 @@ static utf8leaf_t *utf8nlookup(const struct utf8data *data,
 		return NULL;
 	if (len == 0)
 		return NULL;
+
+	trie = utf8data + data->offset;
 	node = 1;
 	while (node) {
 		offlen = (*trie & OFFLEN) >> OFFLEN_SHIFT;