From: Rustam Kovhaev <rkovhaev@xxxxxxxxx> [ Upstream commit d24396c5290ba8ab04ba505176874c4e04a2d53c ] when directory item has an invalid value set for ih_entry_count it might trigger use-after-free or out-of-bounds read in bin_search_in_dir_item() ih_entry_count * IH_SIZE for directory item should not be larger than ih_item_len Link: https://lore.kernel.org/r/20201101140958.3650143-1-rkovhaev@xxxxxxxxx Reported-and-tested-by: syzbot+83b6f7cf9922cae5c4d7@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://syzkaller.appspot.com/bug?extid=83b6f7cf9922cae5c4d7 Signed-off-by: Rustam Kovhaev <rkovhaev@xxxxxxxxx> Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/reiserfs/stree.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c index 5f5fff0688776..25b2aed9af0b3 100644 --- a/fs/reiserfs/stree.c +++ b/fs/reiserfs/stree.c @@ -453,6 +453,12 @@ static int is_leaf(char *buf, int blocksize, struct buffer_head *bh) "(second one): %h", ih); return 0; } + if (is_direntry_le_ih(ih) && (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE))) { + reiserfs_warning(NULL, "reiserfs-5093", + "item entry count seems wrong %h", + ih); + return 0; + } prev_location = ih_location(ih); } -- 2.27.0
