From: Stijn Tintel <stijn@linux-ipv6.be>
Date: Thu, 13 May 2021 20:08:47 +0000 (+0300)
Subject: bcachefs: avoid out-of-bounds in split_devs
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ffcf9ec78c133fb85ff13d8119ff404e11820834;p=linux.git

bcachefs: avoid out-of-bounds in split_devs

Calling mount with an empty source string causes an out-of-bounds error
in split_devs. Check the length of the source string to avoid this.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index b00f352011321..5eef67358cfb0 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -32,6 +32,7 @@
 #include <linux/random.h>
 #include <linux/seq_file.h>
 #include <linux/statfs.h>
+#include <linux/string.h>
 #include <linux/xattr.h>
 
 static struct kmem_cache *bch2_inode_cache;
@@ -1324,6 +1325,9 @@ static char **split_devs(const char *_dev_name, unsigned *nr)
 	char *dev_name = NULL, **devs = NULL, *s;
 	size_t i, nr_devs = 0;
 
+	if (strlen(_dev_name) == 0)
+		return NULL;
+
 	dev_name = kstrdup(_dev_name, GFP_KERNEL);
 	if (!dev_name)
 		return NULL;