linux-kernel - Re: [PATCH v3 08/35] mm: prevent slabobj_ext allocations for slabobj_ext and kmem

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]

Date: Thu, 15 Feb 2024 22:44:02 +0100
From: Vlastimil Babka <vbabka@...e.cz>
To: Suren Baghdasaryan <surenb@...gle.com>, akpm@...ux-foundation.org
Cc: kent.overstreet@...ux.dev, mhocko@...e.com, hannes@...xchg.org,
 roman.gushchin@...ux.dev, mgorman@...e.de, dave@...olabs.net,
 willy@...radead.org, liam.howlett@...cle.com, corbet@....net,
 void@...ifault.com, peterz@...radead.org, juri.lelli@...hat.com,
 catalin.marinas@....com, will@...nel.org, arnd@...db.de, tglx@...utronix.de,
 mingo@...hat.com, dave.hansen@...ux.intel.com, x86@...nel.org,
 peterx@...hat.com, david@...hat.com, axboe@...nel.dk, mcgrof@...nel.org,
 masahiroy@...nel.org, nathan@...nel.org, dennis@...nel.org, tj@...nel.org,
 muchun.song@...ux.dev, rppt@...nel.org, paulmck@...nel.org,
 pasha.tatashin@...een.com, yosryahmed@...gle.com, yuzhao@...gle.com,
 dhowells@...hat.com, hughd@...gle.com, andreyknvl@...il.com,
 keescook@...omium.org, ndesaulniers@...gle.com, vvvvvv@...gle.com,
 gregkh@...uxfoundation.org, ebiggers@...gle.com, ytcoode@...il.com,
 vincent.guittot@...aro.org, dietmar.eggemann@....com, rostedt@...dmis.org,
 bsegall@...gle.com, bristot@...hat.com, vschneid@...hat.com, cl@...ux.com,
 penberg@...nel.org, iamjoonsoo.kim@....com, 42.hyeyoo@...il.com,
 glider@...gle.com, elver@...gle.com, dvyukov@...gle.com,
 shakeelb@...gle.com, songmuchun@...edance.com, jbaron@...mai.com,
 rientjes@...gle.com, minchan@...gle.com, kaleshsingh@...gle.com,
 kernel-team@...roid.com, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, iommu@...ts.linux.dev,
 linux-arch@...r.kernel.org, linux-fsdevel@...r.kernel.org,
 linux-mm@...ck.org, linux-modules@...r.kernel.org,
 kasan-dev@...glegroups.com, cgroups@...r.kernel.org
Subject: Re: [PATCH v3 08/35] mm: prevent slabobj_ext allocations for
 slabobj_ext and kmem_cache objects

On 2/12/24 22:38, Suren Baghdasaryan wrote:
> Use __GFP_NO_OBJ_EXT to prevent recursions when allocating slabobj_ext
> objects. Also prevent slabobj_ext allocations for kmem_cache objects.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
> ---
>  mm/slab.h        | 6 ++++++
>  mm/slab_common.c | 2 ++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/mm/slab.h b/mm/slab.h
> index 436a126486b5..f4ff635091e4 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -589,6 +589,12 @@ prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p)
>  	if (!need_slab_obj_ext())
>  		return NULL;
>  
> +	if (s->flags & SLAB_NO_OBJ_EXT)
> +		return NULL;
> +
> +	if (flags & __GFP_NO_OBJ_EXT)
> +		return NULL;

Since we agreed to postpone this function, when it appears later it can have
those in.

>  	slab = virt_to_slab(p);
>  	if (!slab_obj_exts(slab) &&
>  	    WARN(alloc_slab_obj_exts(slab, s, flags, false),
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 6bfa1810da5e..83fec2dd2e2d 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -218,6 +218,8 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
>  	void *vec;
>  
>  	gfp &= ~OBJCGS_CLEAR_MASK;
> +	/* Prevent recursive extension vector allocation */
> +	gfp |= __GFP_NO_OBJ_EXT;

And this could become part of 6/35 mm: introduce __GFP_NO_OBJ_EXT ... ?

>  	vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
>  			   slab_nid(slab));
>  	if (!vec)