From: Philipp Stanner <pstanner@redhat.com>
To: Kees Cook <keescook@chromium.org>,
Andy Shevchenko <andy@kernel.org>,
Eric Biederman <ebiederm@xmission.com>,
Christian Brauner <brauner@kernel.org>,
David Disseldorp <ddiss@suse.de>,
Luis Chamberlain <mcgrof@kernel.org>,
Siddh Raman Pant <code@siddh.me>,
Nick Alcock <nick.alcock@oracle.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
Zack Rusin <zackr@vmware.com>
Cc: VMware Graphics Reviewers <linux-graphics-maintainer@vmware.com>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
kexec@lists.infradead.org, linux-hardening@vger.kernel.org,
Philipp Stanner <pstanner@redhat.com>,
David Airlie <airlied@redhat.com>
Subject: [PATCH 1/5] string.h: add array-wrappers for (v)memdup_user()
Date: Wed, 30 Aug 2023 15:45:52 +0200 [thread overview]
Message-ID: <46f667e154393a930a97d2218d8e90286d93a062.1693386602.git.pstanner@redhat.com> (raw)
In-Reply-To: <cover.1693386602.git.pstanner@redhat.com>
Currently, user array duplications are sometimes done without an
overflow check. Sometimes the checks are done manually; sometimes the
array size is calculated with array_size() and sometimes by calculating
n * size directly in code.
Introduce wrappers for arrays for memdup_user() and vmemdup_user() to
provide a standardized and safe way for duplicating user arrays.
This is both for new code as well as replacing usage of (v)memdup_user()
in existing code that uses, e.g., n * size to calculate array sizes.
Suggested-by: David Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
include/linux/string.h | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/include/linux/string.h b/include/linux/string.h
index dbfc66400050..0e8e7a40bae7 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -6,6 +6,8 @@
#include <linux/types.h> /* for size_t */
#include <linux/stddef.h> /* for NULL */
#include <linux/errno.h> /* for E2BIG */
+#include <linux/overflow.h> /* for check_mul_overflow() */
+#include <linux/err.h> /* for ERR_PTR() */
#include <linux/stdarg.h>
#include <uapi/linux/string.h>
@@ -14,6 +16,46 @@ extern void *memdup_user(const void __user *, size_t);
extern void *vmemdup_user(const void __user *, size_t);
extern void *memdup_user_nul(const void __user *, size_t);
+/**
+ * memdup_array_user - duplicate array from user space
+ *
+ * @src: source address in user space
+ * @n: number of array members to copy
+ * @size: size of one array member
+ *
+ * Return: an ERR_PTR() on failure. Result is physically
+ * contiguous, to be freed by kfree().
+ */
+static inline void *memdup_array_user(const void __user *src, size_t n, size_t size)
+{
+ size_t nbytes;
+
+ if (unlikely(check_mul_overflow(n, size, &nbytes)))
+ return ERR_PTR(-EINVAL);
+
+ return memdup_user(src, nbytes);
+}
+
+/**
+ * vmemdup_array_user - duplicate array from user space
+ *
+ * @src: source address in user space
+ * @n: number of array members to copy
+ * @size: size of one array member
+ *
+ * Return: an ERR_PTR() on failure. Result may be not
+ * physically contiguous. Use kvfree() to free.
+ */
+static inline void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
+{
+ size_t nbytes;
+
+ if (unlikely(check_mul_overflow(n, size, &nbytes)))
+ return ERR_PTR(-EINVAL);
+
+ return vmemdup_user(src, nbytes);
+}
+
/*
* Include machine specific inline routines
*/
--
2.41.0
next prev parent reply other threads:[~2023-08-30 18:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 13:45 [PATCH 0/5] Introduce new wrappers to copy user-arrays Philipp Stanner
2023-08-30 13:45 ` Philipp Stanner [this message]
2023-08-30 14:11 ` [PATCH 1/5] string.h: add array-wrappers for (v)memdup_user() Andy Shevchenko
2023-08-30 14:19 ` pstanner
2023-08-30 14:29 ` Andy Shevchenko
2023-08-30 19:15 ` pstanner
2023-08-31 8:59 ` Andy Shevchenko
2023-08-31 12:16 ` Philipp Stanner
2023-08-31 12:22 ` Philipp Stanner
2023-08-31 13:16 ` Andy Shevchenko
2023-08-31 13:17 ` Andy Shevchenko
2023-08-30 14:15 ` Andy Shevchenko
2023-08-30 14:23 ` pstanner
2023-08-30 13:45 ` [PATCH 2/5] kernel: kexec: copy user-array safely Philipp Stanner
2023-08-30 13:45 ` [PATCH 3/5] kernel: watch_queue: " Philipp Stanner
2023-08-30 13:45 ` [PATCH 4/5] drm_lease.c: " Philipp Stanner
2023-08-30 13:45 ` [PATCH 5/5] drm: vmgfx_surface.c: " Philipp Stanner
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