5.10-stable review patch. If anyone has any objections, please let me know.
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From: Namjae Jeon linkinjeon@kernel.org
commit 02dffe9ab092fc4c8800aee68cb7eafd37a980c4 upstream.
There is no check if stream size and start_clu are invalid. If start_clu is EOF cluster and stream size is 4096, It will cause uninit value access. because ei->hint_femp.eidx could be 128(if cluster size is 4K) and wrong hint will allocate next cluster. and this cluster will be same with the cluster that is allocated by exfat_extend_valid_size(). The previous patch will check invalid start_clu, but for clarity, initialize hint_femp.eidx to zero.
Cc: stable@vger.kernel.org Reported-by: syzbot+01218003be74b5e1213a@syzkaller.appspotmail.com Tested-by: syzbot+01218003be74b5e1213a@syzkaller.appspotmail.com Reviewed-by: Yuezhang Mo Yuezhang.Mo@sony.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/exfat/namei.c | 1 + 1 file changed, 1 insertion(+)
--- a/fs/exfat/namei.c +++ b/fs/exfat/namei.c @@ -356,6 +356,7 @@ static int exfat_find_empty_entry(struct if (ei->start_clu == EXFAT_EOF_CLUSTER) { ei->start_clu = clu.dir; p_dir->dir = clu.dir; + hint_femp.eidx = 0; }
/* append to the FAT chain */