1 files changed, 45 insertions, 2 deletions

diff --git a/include/linux/string.h b/include/linux/string.h
index 3c920b6d609b..ce137830a0b9 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -6,7 +6,9 @@
 #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>
 
@@ -15,6 +17,44 @@ 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
  */
@@ -278,10 +318,12 @@ void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
  */
 #define strtomem_pad(dest, src, pad)	do {				\
 	const size_t _dest_len = __builtin_object_size(dest, 1);	\
+	const size_t _src_len = __builtin_object_size(src, 1);		\
 									\
 	BUILD_BUG_ON(!__builtin_constant_p(_dest_len) ||		\
 		     _dest_len == (size_t)-1);				\
-	memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
+	memcpy_and_pad(dest, _dest_len, src,				\
+		       strnlen(src, min(_src_len, _dest_len)), pad);	\
 } while (0)
 
 /**
@@ -299,10 +341,11 @@ void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
  */
 #define strtomem(dest, src)	do {					\
 	const size_t _dest_len = __builtin_object_size(dest, 1);	\
+	const size_t _src_len = __builtin_object_size(src, 1);		\
 									\
 	BUILD_BUG_ON(!__builtin_constant_p(_dest_len) ||		\
 		     _dest_len == (size_t)-1);				\
-	memcpy(dest, src, min(_dest_len, strnlen(src, _dest_len)));	\
+	memcpy(dest, src, strnlen(src, min(_src_len, _dest_len)));	\
 } while (0)
 
 /**