linux-kernel - Re: [PATCH] ext34: ensure do_split leaves enough free space in both blocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 17 Sep 2007 12:21:40 -0500
From:	Eric Sandeen <sandeen@...deen.net>
To:	Eric Sandeen <sandeen@...hat.com>
CC:	ext4 development <linux-ext4@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	hooanon05@...oo.co.jp, Andrew Morton <akpm@...l.org>
Subject: Re: [PATCH] ext34: ensure do_split leaves enough free space in both
 blocks

Eric Sandeen wrote:
> The do_split() function for htree dir blocks is intended to split a
> leaf block to make room for a new entry.  It sorts the entries in the
> original block by hash value, then moves the last half of the entries to 
> the new block - without accounting for how much space this actually moves.  
> (IOW, it moves half of the entry *count* not half of the entry *space*).
> If by chance we have both large & small entries, and we move only the 
> smallest entries, and we have a large new entry to insert, we may not have 
> created enough space for it.

(btw, the upshot of this is that in add_dirent_to_buf(),
memcpy(de->name, name, namelen) will overshoot the buffer and actually
corrupt memory.)

:(

-Eric
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/