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Message-Id: <1497915397-93805-11-git-send-email-keescook@chromium.org> Date: Mon, 19 Jun 2017 16:36:24 -0700 From: Kees Cook <keescook@...omium.org> To: kernel-hardening@...ts.openwall.com Cc: Kees Cook <keescook@...omium.org>, David Windsor <dave@...lcore.net>, linux-mm@...ck.org, linux-kernel@...r.kernel.org Subject: [PATCH 10/23] vxfs: define usercopy region in vxfs_inode slab cache From: David Windsor <dave@...lcore.net> The vxfs symlink pathnames, stored in struct vxfs_inode_info.vii_immed.vi_immed and therefore contained in the vxfs_inode slab cache, need to be copied to/from userspace. In support of usercopy hardening, this patch defines a region in the vxfs_inode 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. Signed-off-by: David Windsor <dave@...lcore.net> [kees: adjust commit log] Signed-off-by: Kees Cook <keescook@...omium.org> --- fs/freevxfs/vxfs_super.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c index 455ce5b77e9b..c143e18d5a65 100644 --- a/fs/freevxfs/vxfs_super.c +++ b/fs/freevxfs/vxfs_super.c @@ -332,9 +332,13 @@ vxfs_init(void) { int rv; - vxfs_inode_cachep = kmem_cache_create("vxfs_inode", + vxfs_inode_cachep = kmem_cache_create_usercopy("vxfs_inode", sizeof(struct vxfs_inode_info), 0, - SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL); + SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, + offsetof(struct vxfs_inode_info, vii_immed.vi_immed), + sizeof_field(struct vxfs_inode_info, + vii_immed.vi_immed), + NULL); if (!vxfs_inode_cachep) return -ENOMEM; rv = register_filesystem(&vxfs_fs_type); -- 2.7.4
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