Merge tag 'topic/vmemdup-user-array-2023-10-24-1' of...

Merge tag 'topic/vmemdup-user-array-2023-10-24-1' of git://anongit.freedesktop.org/drm/drm into drm-next

vmemdup-user-array API and changes with it.

This is just a process PR to merge the topic branch into drm-next, this contains some core kernel and drm changes.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231024010905.646830-1-airlied@redhat.com

drivers/gpu/drm/drm_lease.c

@@ -510,8 +510,8 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	/* Handle leased objects, if any */
 	idr_init(&leases);
 	if (object_count != 0) {
-		object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
-					 array_size(object_count, sizeof(__u32)));
+		object_ids = memdup_array_user(u64_to_user_ptr(cl->object_ids),
+					       object_count, sizeof(__u32));
 		if (IS_ERR(object_ids)) {
 			ret = PTR_ERR(object_ids);
 			idr_destroy(&leases);

drivers/gpu/drm/vmwgfx/vmwgfx_surface.c

@@ -774,9 +774,9 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
 	       sizeof(metadata->mip_levels));
 	metadata->num_sizes = num_sizes;
 	metadata->sizes =
-		memdup_user((struct drm_vmw_size __user *)(unsigned long)
+		memdup_array_user((struct drm_vmw_size __user *)(unsigned long)
 			    req->size_addr,
-			    sizeof(*metadata->sizes) * metadata->num_sizes);
+			    metadata->num_sizes, sizeof(*metadata->sizes));
 	if (IS_ERR(metadata->sizes)) {
 		ret = PTR_ERR(metadata->sizes);
 		goto out_no_sizes;

include/linux/string.h

@@ -5,7 +5,9 @@
 #include <linux/compiler.h>	/* for inline */
 #include <linux/types.h>	/* for size_t */
 #include <linux/stddef.h>	/* for NULL */
+#include <linux/err.h>		/* for ERR_PTR() */
 #include <linux/errno.h>	/* for E2BIG */
+#include <linux/overflow.h>	/* for check_mul_overflow() */
 #include <linux/stdarg.h>
 #include <uapi/linux/string.h>
 
@@ -14,6 +16,44 @@ 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 (check_mul_overflow(n, size, &nbytes))
+		return ERR_PTR(-EOVERFLOW);
+
+	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 (check_mul_overflow(n, size, &nbytes))
+		return ERR_PTR(-EOVERFLOW);
+
+	return vmemdup_user(src, nbytes);
+}
+
 /*
  * Include machine specific inline routines
  */

kernel/kexec.c

@@ -247,7 +247,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 		((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
 		return -EINVAL;
 
-	ksegments = memdup_user(segments, nr_segments * sizeof(ksegments[0]));
+	ksegments = memdup_array_user(segments, nr_segments, sizeof(ksegments[0]));
 	if (IS_ERR(ksegments))
 		return PTR_ERR(ksegments);
 

kernel/watch_queue.c

@@ -331,7 +331,7 @@ long watch_queue_set_filter(struct pipe_inode_info *pipe,
 	    filter.__reserved != 0)
 		return -EINVAL;
 
-	tf = memdup_user(_filter->filters, filter.nr_filters * sizeof(*tf));
+	tf = memdup_array_user(_filter->filters, filter.nr_filters, sizeof(*tf));
 	if (IS_ERR(tf))
 		return PTR_ERR(tf);