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Date: Thu, 31 May 2018 17:42:25 -0700
From: Kees Cook <keescook@...omium.org>
To: Matthew Wilcox <mawilcox@...rosoft.com>
Cc: Kees Cook <keescook@...omium.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Matthew Wilcox <willy@...radead.org>,
LKML <linux-kernel@...r.kernel.org>,
Linux-MM <linux-mm@...ck.org>,
Kernel Hardening <kernel-hardening@...ts.openwall.com>
Subject: [PATCH v3 08/16] device: Use overflow helpers for devm_kmalloc()
Use the overflow helpers both in existing multiplication-using inlines as
well as the addition-overflow case in the core allocation routine.
Signed-off-by: Kees Cook <keescook@...omium.org>
---
drivers/base/devres.c | 7 ++++++-
include/linux/device.h | 8 ++++++--
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 95b67281cd2a..f98a097e73f2 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -84,9 +84,14 @@ static struct devres_group * node_to_group(struct devres_node *node)
static __always_inline struct devres * alloc_dr(dr_release_t release,
size_t size, gfp_t gfp, int nid)
{
- size_t tot_size = sizeof(struct devres) + size;
+ size_t tot_size;
struct devres *dr;
+ /* We must catch any near-SIZE_MAX cases that could overflow. */
+ if (unlikely(check_add_overflow(sizeof(struct devres), size,
+ &tot_size)))
+ return NULL;
+
dr = kmalloc_node_track_caller(tot_size, gfp, nid);
if (unlikely(!dr))
return NULL;
diff --git a/include/linux/device.h b/include/linux/device.h
index 477956990f5e..897efa647203 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -25,6 +25,7 @@
#include <linux/ratelimit.h>
#include <linux/uidgid.h>
#include <linux/gfp.h>
+#include <linux/overflow.h>
#include <asm/device.h>
struct device;
@@ -668,9 +669,12 @@ static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
static inline void *devm_kmalloc_array(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
- if (size != 0 && n > SIZE_MAX / size)
+ size_t bytes;
+
+ if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
- return devm_kmalloc(dev, n * size, flags);
+
+ return devm_kmalloc(dev, bytes, flags);
}
static inline void *devm_kcalloc(struct device *dev,
size_t n, size_t size, gfp_t flags)
--
2.17.0
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