From: Rustam Kovhaev rkovhaev@gmail.com
[ 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@gmail.com Reported-and-tested-by: syzbot+83b6f7cf9922cae5c4d7@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=83b6f7cf9922cae5c4d7 Signed-off-by: Rustam Kovhaev rkovhaev@gmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- fs/reiserfs/stree.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c index e3a4cbad9620c..33b78ee9fb9e2 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); }