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 <viro@xxxxxxxxxxxxxxxxxx> --- 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 = {
