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From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	Balbir Singh <bsingharora@gmail.com>,
	Daniel Micay <danielmicay@gmail.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Rik van Riel <riel@redhat.com>,
	Casey Schaufler <casey@schaufler-ca.com>,
	PaX Team <pageexec@freemail.hu>,
	Brad Spengler <spender@grsecurity.net>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Tony Luck <tony.luck@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	x86@kernel.org, Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
	Mathias Krause <minipli@googlemail.com>, Jan Kara <jack@suse.cz>,
	Vitaly Wool <vitalywool@gmail.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Laura Abbott <labbott@fedoraproject.org>,
	linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	kernel-hardening@lists.openwall.com
Subject: [kernel-hardening] [PATCH v3 10/11] mm: SLAB hardened usercopy support
Date: Fri, 15 Jul 2016 14:44:24 -0700
Message-ID: <1468619065-3222-11-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1468619065-3222-1-git-send-email-keescook@chromium.org>

Under CONFIG_HARDENED_USERCOPY, this adds object size checking to the
SLAB allocator to catch any copies that may span objects.

Based on code from PaX and grsecurity.

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
---
 init/Kconfig |  1 +
 mm/slab.c    | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/init/Kconfig b/init/Kconfig
index f755a602d4a1..798c2020ee7c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1757,6 +1757,7 @@ choice
 
 config SLAB
 	bool "SLAB"
+	select HAVE_HARDENED_USERCOPY_ALLOCATOR
 	help
 	  The regular slab allocator that is established and known to work
 	  well in all environments. It organizes cache hot objects in
diff --git a/mm/slab.c b/mm/slab.c
index cc8bbc1e6bc9..5e2d5f349aca 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -4477,6 +4477,36 @@ static int __init slab_proc_init(void)
 module_init(slab_proc_init);
 #endif
 
+#ifdef CONFIG_HARDENED_USERCOPY
+/*
+ * Rejects objects that are incorrectly sized.
+ *
+ * Returns NULL if check passes, otherwise const char * to name of cache
+ * to indicate an error.
+ */
+const char *__check_heap_object(const void *ptr, unsigned long n,
+				struct page *page)
+{
+	struct kmem_cache *cachep;
+	unsigned int objnr;
+	unsigned long offset;
+
+	/* Find and validate object. */
+	cachep = page->slab_cache;
+	objnr = obj_to_index(cachep, page, (void *)ptr);
+	BUG_ON(objnr >= cachep->num);
+
+	/* Find offset within object. */
+	offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep);
+
+	/* Allow address range falling entirely within object size. */
+	if (offset <= cachep->object_size && n <= cachep->object_size - offset)
+		return NULL;
+
+	return cachep->name;
+}
+#endif /* CONFIG_HARDENED_USERCOPY */
+
 /**
  * ksize - get the actual amount of memory allocated for a given object
  * @objp: Pointer to the object
-- 
2.7.4

  parent reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-15 21:44 [kernel-hardening] [PATCH v3 00/11] mm: Hardened usercopy Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 01/11] mm: Implement stack frame object validation Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 02/11] mm: Hardened usercopy Kees Cook
2016-07-19  1:06   ` [kernel-hardening] " Laura Abbott
2016-07-19 18:48     ` Kees Cook
2016-07-19 22:00       ` [kernel-hardening] [PATCH] mm: Add is_migrate_cma_page Laura Abbott
2016-07-19 22:40         ` [kernel-hardening] " Kees Cook
2016-07-20 10:24       ` [kernel-hardening] Re: [PATCH v3 02/11] mm: Hardened usercopy Balbir Singh
2016-07-20 15:36         ` Laura Abbott
2016-07-19  1:52   ` Laura Abbott
2016-07-19 19:12     ` Kees Cook
2016-07-19 22:55       ` Kees Cook
2016-07-19  9:21   ` Christian Borntraeger
2016-07-19 19:31     ` Kees Cook
2016-07-19 20:14       ` Christian Borntraeger
2016-07-19 20:34         ` Kees Cook
2016-07-19 20:44           ` Christian Borntraeger
2016-07-21  6:52   ` Michael Ellerman
     [not found]   ` <5790711f.2350420a.b4287.2cc0SMTPIN_ADDED_BROKEN@mx.google.com>
2016-07-21 18:34     ` Kees Cook
2016-07-22 17:45       ` Josh Poimboeuf
2016-07-25  9:27         ` [kernel-hardening] " David Laight
2016-07-26  2:09           ` Michael Ellerman
2016-07-26  2:03         ` [kernel-hardening] " Michael Ellerman
2016-07-26  4:46           ` Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 03/11] x86/uaccess: Enable hardened usercopy Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 04/11] ARM: uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 05/11] arm64/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 06/11] ia64/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 07/11] powerpc/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 08/11] sparc/uaccess: " Kees Cook
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 09/11] s390/uaccess: " Kees Cook
2016-07-15 21:44 ` Kees Cook [this message]
2016-07-15 21:44 ` [kernel-hardening] [PATCH v3 11/11] mm: SLUB hardened usercopy support Kees Cook
2016-07-18  8:26 ` [kernel-hardening] Re: [PATCH v3 00/11] mm: Hardened usercopy Balbir Singh
2016-07-20  9:52 ` [kernel-hardening] " David Laight
2016-07-20 15:31   ` [kernel-hardening] " Kees Cook
2016-07-20 16:02     ` [kernel-hardening] " David Laight
2016-07-20 16:22       ` [kernel-hardening] " Rik van Riel
2016-07-20 17:44       ` Kees Cook

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