linux-kernel - Re: [PATCH 5/5] alloc_tag: config to store page allocation tag refs in page flags

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <ZsOeVSlToyhsyDGD@casper.infradead.org>
Date: Mon, 19 Aug 2024 20:34:45 +0100
From: Matthew Wilcox <willy@...radead.org>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: akpm@...ux-foundation.org, kent.overstreet@...ux.dev, corbet@....net,
	arnd@...db.de, mcgrof@...nel.org, rppt@...nel.org,
	paulmck@...nel.org, thuth@...hat.com, tglx@...utronix.de,
	bp@...en8.de, xiongwei.song@...driver.com, ardb@...nel.org,
	david@...hat.com, vbabka@...e.cz, mhocko@...e.com,
	hannes@...xchg.org, roman.gushchin@...ux.dev, dave@...olabs.net,
	liam.howlett@...cle.com, pasha.tatashin@...een.com,
	souravpanda@...gle.com, keescook@...omium.org, dennis@...nel.org,
	jhubbard@...dia.com, yuzhao@...gle.com, vvvvvv@...gle.com,
	rostedt@...dmis.org, iamjoonsoo.kim@....com, rientjes@...gle.com,
	minchan@...gle.com, kaleshsingh@...gle.com,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arch@...r.kernel.org, linux-mm@...ck.org,
	linux-modules@...r.kernel.org, kernel-team@...roid.com
Subject: Re: [PATCH 5/5] alloc_tag: config to store page allocation tag refs
 in page flags

On Mon, Aug 19, 2024 at 08:15:11AM -0700, Suren Baghdasaryan wrote:
> @@ -91,7 +97,7 @@
>  #endif
>  
>  #if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \
> -	KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
> +	KASAN_TAG_WIDTH + ALLOC_TAG_REF_WIDTH + LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
>  #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
>  #else
>  #define LAST_CPUPID_WIDTH 0

So if ALLOC_TAG_REF_WIDTH is big enough, it's going to force last_cpupid
into struct page.  That will misalign struct page and disable HVO --
with no warning!