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From: Eric Biggers <ebiggers3@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: kernel-hardening@lists.openwall.com,
	David Windsor <dave@nullcore.net>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [kernel-hardening] [PATCH 17/23] dcache: define usercopy region in dentry_cache slab cache
Date: Mon, 19 Jun 2017 21:08:34 -0700	[thread overview]
Message-ID: <20170620040834.GB610@zzz.localdomain> (raw)
In-Reply-To: <1497915397-93805-18-git-send-email-keescook@chromium.org>

On Mon, Jun 19, 2017 at 04:36:31PM -0700, Kees Cook wrote:
> From: David Windsor <dave@nullcore.net>
> 
> When a dentry name is short enough, it can be stored directly in
> the dentry itself.  These dentry short names, stored in struct
> dentry.d_iname and therefore contained in the dentry_cache slab cache,
> need to be coped to/from userspace.
> 
> In support of usercopy hardening, this patch defines a region in
> the dentry_cache slab cache in which userspace copy operations
> are allowed.
> 
> This region is known as the slab cache's usercopy region.  Slab
> caches can now check that each copy operation involving cache-managed
> memory falls entirely within the slab's usercopy region.
> 
> This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY
> whitelisting code in the last public patch of grsecurity/PaX based on my
> understanding of the code. Changes or omissions from the original code are
> mine and don't reflect the original grsecurity/PaX code.
> 

For all these patches please mention *where* the data is being copied to/from
userspace.

> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index a48f54238273..97f4a0117b3b 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -151,6 +151,11 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *);
>  		sizeof(struct __struct), __alignof__(struct __struct),\
>  		(__flags), NULL)
>  
> +#define KMEM_CACHE_USERCOPY(__struct, __flags, __field) kmem_cache_create_usercopy(#__struct,\
> +		sizeof(struct __struct), __alignof__(struct __struct),\
> +		(__flags), offsetof(struct __struct, __field),\
> +		sizeof_field(struct __struct, __field), NULL)
> +

This helper macro should be added in the patch which adds
kmem_cache_create_usercopy(), not in this one.

- Eric

  reply	other threads:[~2017-06-20  4:08 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-19 23:36 [PATCH 00/23] Hardened usercopy whitelisting Kees Cook
2017-06-19 23:36 ` [PATCH 01/23] usercopy: Prepare for " Kees Cook
2017-06-19 23:36 ` [PATCH 02/23] usercopy: Enforce slab cache usercopy region boundaries Kees Cook
2017-06-19 23:36 ` [PATCH 03/23] vfs: define usercopy region in names_cache slab caches Kees Cook
2017-06-19 23:36 ` [PATCH 04/23] vfs: copy struct mount.mnt_id to userspace using put_user() Kees Cook
2017-06-19 23:36 ` [PATCH 05/23] befs: define usercopy region in befs_inode_cache slab cache Kees Cook
2017-06-19 23:36 ` [PATCH 06/23] cifs: define usercopy region in cifs_request " Kees Cook
2017-06-19 23:36 ` [PATCH 07/23] exofs: define usercopy region in exofs_inode_cache " Kees Cook
2017-06-19 23:36 ` [PATCH 08/23] ext2: define usercopy region in ext2_inode_cache " Kees Cook
2017-06-19 23:36 ` [PATCH 09/23] ext4: define usercopy region in ext4_inode_cache " Kees Cook
2017-06-19 23:36 ` [PATCH 10/23] vxfs: define usercopy region in vxfs_inode " Kees Cook
2017-06-19 23:36 ` [PATCH 11/23] jfs: define usercopy region in jfs_ip " Kees Cook
2017-06-19 23:36 ` [PATCH 12/23] orangefs: define usercopy region in orangefs_inode_cache " Kees Cook
2017-06-19 23:36 ` [PATCH 13/23] ufs: define usercopy region in ufs_inode_cache " Kees Cook
2017-06-19 23:36 ` [PATCH 14/23] fork: define usercopy region in thread_stack, task_struct, mm_struct slab caches Kees Cook
2017-06-19 23:36 ` [PATCH 15/23] net: define usercopy region in struct proto slab cache Kees Cook
2017-06-19 23:36 ` [PATCH 16/23] net: copy struct sctp_sock.autoclose to userspace using put_user() Kees Cook
2017-06-19 23:36 ` [PATCH 17/23] dcache: define usercopy region in dentry_cache slab cache Kees Cook
2017-06-20  4:08   ` Eric Biggers [this message]
2017-06-28 16:44     ` [kernel-hardening] " Kees Cook
2017-06-28 16:55       ` Eric Biggers
2017-06-19 23:36 ` [PATCH 18/23] scsi: define usercopy region in scsi_sense_cache " Kees Cook
2017-06-19 23:36 ` [PATCH 19/23] xfs: define usercopy region in xfs_inode " Kees Cook
2017-06-19 23:36 ` [PATCH 20/23] usercopy: convert kmalloc caches to usercopy caches Kees Cook
2017-06-19 23:36 ` [PATCH 21/23] usercopy: Restrict non-usercopy caches to size 0 Kees Cook
2017-06-20  4:04   ` [kernel-hardening] " Eric Biggers
2017-06-28 17:03     ` Kees Cook
2017-06-19 23:36 ` [PATCH 22/23] usercopy: split user-controlled slabs to separate caches Kees Cook
2017-06-20  4:24   ` [kernel-hardening] " Eric Biggers
2017-06-20  4:47   ` Eric Biggers
2017-06-20 22:27     ` Kees Cook
2017-06-20 20:24   ` Laura Abbott
2017-06-20 22:22     ` Kees Cook
2017-06-27  7:31       ` Michal Hocko
2017-06-27 22:07         ` Kees Cook
2017-06-28  8:54           ` Michal Hocko
2017-06-19 23:36 ` [PATCH 23/23] mm: Allow slab_nomerge to be set at build time Kees Cook
2017-06-20  4:09   ` [kernel-hardening] " Daniel Micay
2017-06-20 22:51     ` Kees Cook
2017-06-20  4:29   ` Eric Biggers
2017-06-20 23:09     ` Kees Cook
2017-06-20 19:41 ` [kernel-hardening] [PATCH 00/23] Hardened usercopy whitelisting Rik van Riel
2017-10-20 22:40 ` Paolo Bonzini
2017-10-20 23:25   ` Paolo Bonzini
2017-10-21  3:04     ` Kees Cook

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