On Tue, Jun 02, 2020 at 01:03:05PM +0800, butt3rflyh4ck wrote:
> I report a bug (in linux-5.7.0-rc7) found by syzkaller.
>
> kernel config:
> https://github.com/butterflyhack/syzkaller-fuzz/blob/master/config-v5.7.0-rc7
>
> and can reproduce.
>
> A param->string held by exfat_mount_options.
Humm...
First of all, exfat_free() ought to call exfat_free_upcase_table().
What's more, WTF bother with that kstrdup(), anyway? Just steal the string
and be done with that...
Signed-off-by: Al Viro <[email protected]>
---
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 0565d5539d57..01cd7ed1614d 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -259,9 +259,8 @@ static int exfat_parse_param(struct fs_context *fc, struct
fs_parameter *param)
break;
case Opt_charset:
exfat_free_iocharset(sbi);
- opts->iocharset = kstrdup(param->string, GFP_KERNEL);
- if (!opts->iocharset)
- return -ENOMEM;
+ opts->iocharset = param->string;
+ param->string = NULL;
break;
case Opt_errors:
opts->errors = result.uint_32;
@@ -611,7 +610,10 @@ static int exfat_get_tree(struct fs_context *fc)
static void exfat_free(struct fs_context *fc)
{
- kfree(fc->s_fs_info);
+ struct exfat_sb_info *sbi = fc->s_fs_info;
+
+ exfat_free_iocharset(sbi);
+ kfree(sbi);
}
static const struct fs_context_operations exfat_context_ops = {
