From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
David Windsor <dave@nullcore.net>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org,
linux-mm@kvack.org, kernel-hardening@lists.openwall.com
Subject: [PATCH v3 05/31] vfs: Define usercopy region in names_cache slab caches
Date: Wed, 20 Sep 2017 13:45:11 -0700 [thread overview]
Message-ID: <1505940337-79069-6-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1505940337-79069-1-git-send-email-keescook@chromium.org>
From: David Windsor <dave@nullcore.net>
VFS pathnames are stored in the names_cache slab cache, either inline
or across an entire allocation entry (when approaching PATH_MAX). These
are copied to/from userspace, so they must be entirely whitelisted.
cache object allocation:
include/linux/fs.h:
#define __getname() kmem_cache_alloc(names_cachep, GFP_KERNEL)
example usage trace:
strncpy_from_user+0x4d/0x170
getname_flags+0x6f/0x1f0
user_path_at_empty+0x23/0x40
do_mount+0x69/0xda0
SyS_mount+0x83/0xd0
fs/namei.c:
getname_flags(...):
...
result = __getname();
...
kname = (char *)result->iname;
result->name = kname;
len = strncpy_from_user(kname, filename, EMBEDDED_NAME_MAX);
...
if (unlikely(len == EMBEDDED_NAME_MAX)) {
const size_t size = offsetof(struct filename, iname[1]);
kname = (char *)result;
result = kzalloc(size, GFP_KERNEL);
...
result->name = kname;
len = strncpy_from_user(kname, filename, PATH_MAX);
In support of usercopy hardening, this patch defines the entire cache
object in the names_cache slab cache as whitelisted, since it may entirely
hold name strings to be copied to/from userspace.
This patch is verbatim 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@nullcore.net>
[kees: adjust commit log, add usage trace]
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/dcache.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 5f5e7c1fcf4b..34ef9a9169be 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3642,8 +3642,8 @@ void __init vfs_caches_init_early(void)
void __init vfs_caches_init(void)
{
- names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
dcache_init();
inode_init();
--
2.7.4
--
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next prev parent reply other threads:[~2017-09-20 20:46 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-20 20:45 [PATCH v3 00/31] Hardened usercopy whitelisting Kees Cook
2017-09-20 20:45 ` [PATCH v3 01/31] usercopy: Prepare for " Kees Cook
2017-09-21 15:21 ` Christopher Lameter
2017-09-20 20:45 ` [PATCH v3 02/31] usercopy: Enforce slab cache usercopy region boundaries Kees Cook
2017-09-21 15:23 ` Christopher Lameter
2017-09-20 20:45 ` [PATCH v3 03/31] usercopy: Mark kmalloc caches as usercopy caches Kees Cook
2017-09-21 15:27 ` Christopher Lameter
2017-09-21 15:40 ` [kernel-hardening] " Kees Cook
2017-09-21 16:04 ` Christopher Lameter
2017-09-21 18:26 ` Kees Cook
2017-09-20 20:45 ` [PATCH v3 04/31] dcache: Define usercopy region in dentry_cache slab cache Kees Cook
2017-09-20 20:45 ` Kees Cook [this message]
2017-09-20 20:45 ` [PATCH v3 06/31] vfs: Copy struct mount.mnt_id to userspace using put_user() Kees Cook
2017-09-20 20:45 ` [PATCH v3 07/31] ext4: Define usercopy region in ext4_inode_cache slab cache Kees Cook
2017-09-20 20:45 ` [PATCH v3 08/31] ext2: Define usercopy region in ext2_inode_cache " Kees Cook
2017-09-20 20:45 ` [PATCH v3 09/31] jfs: Define usercopy region in jfs_ip " Kees Cook
2017-09-22 2:54 ` Dave Kleikamp
2017-09-20 20:45 ` [PATCH v3 10/31] befs: Define usercopy region in befs_inode_cache " Kees Cook
2017-09-21 9:34 ` Luis de Bethencourt
2017-09-20 20:45 ` [PATCH v3 11/31] exofs: Define usercopy region in exofs_inode_cache " Kees Cook
2017-09-20 20:45 ` [PATCH v3 12/31] orangefs: Define usercopy region in orangefs_inode_cache " Kees Cook
2017-09-20 20:45 ` [PATCH v3 13/31] ufs: Define usercopy region in ufs_inode_cache " Kees Cook
2017-09-20 20:45 ` [PATCH v3 14/31] vxfs: Define usercopy region in vxfs_inode " Kees Cook
2017-09-20 20:56 ` Christoph Hellwig
2017-09-20 21:21 ` Kees Cook
2017-09-20 23:22 ` Christoph Hellwig
2017-09-20 20:45 ` [PATCH v3 15/31] xfs: Define usercopy region in xfs_inode " Kees Cook
2017-09-20 20:45 ` [PATCH v3 16/31] cifs: Define usercopy region in cifs_request " Kees Cook
2017-09-20 20:45 ` [PATCH v3 17/31] scsi: Define usercopy region in scsi_sense_cache " Kees Cook
2017-09-20 20:45 ` [PATCH v3 18/31] net: Define usercopy region in struct proto " Kees Cook
2017-09-20 20:45 ` [PATCH v3 19/31] ip: Define usercopy region in IP " Kees Cook
2017-09-20 20:45 ` [PATCH v3 20/31] caif: Define usercopy region in caif " Kees Cook
2017-09-20 20:45 ` [PATCH v3 21/31] sctp: Define usercopy region in SCTP " Kees Cook
2017-09-20 20:45 ` [PATCH v3 22/31] sctp: Copy struct sctp_sock.autoclose to userspace using put_user() Kees Cook
2017-09-20 20:45 ` [PATCH v3 23/31] net: Restrict unwhitelisted proto caches to size 0 Kees Cook
2017-09-20 20:45 ` [PATCH v3 24/31] fork: Define usercopy region in mm_struct slab caches Kees Cook
2017-09-20 20:45 ` [PATCH v3 25/31] fork: Define usercopy region in thread_stack " Kees Cook
2017-09-20 20:45 ` [PATCH v3 26/31] fork: Provide usercopy whitelisting for task_struct Kees Cook
2017-09-20 20:45 ` [PATCH v3 27/31] x86: Implement thread_struct whitelist for hardened usercopy Kees Cook
2017-09-20 20:45 ` [PATCH v3 28/31] arm64: " Kees Cook
2017-09-20 20:45 ` [PATCH v3 29/31] arm: " Kees Cook
2017-09-20 20:45 ` [PATCH v3 30/31] usercopy: Restrict non-usercopy caches to size 0 Kees Cook
2017-09-20 20:45 ` [PATCH v3 31/31] lkdtm: Update usercopy tests for whitelisting Kees Cook
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