Commit d24396c5 authored Nov 01, 2020 by Rustam Kovhaev Committed by Jan Kara Nov 26, 2020

reiserfs: add check for an invalid ih_entry_count

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>

parent 8fca3c8a

fs/reiserfs/stree.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -454,6 +454,12 @@ 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);
		}

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