fortify: Detect struct member overflows in memmove()

As done for memcpy(), also update memmove() to use the same tightened
checks under CONFIG_FORTIFY_SOURCE.

Signed-off-by: Kees Cook <keescook@chromium.org>

5 files changed, 9 insertions, 15 deletions

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 743f13ea25c12..83ff4354970e5 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -34,10 +34,11 @@
  * try to define their own functions if these are not defined as macros.
  */
 #define memzero(s, n)	memset((s), 0, (n))
+#ifndef memmove
 #define memmove		memmove
-
 /* Functions used by the included decompressor code below. */
 void *memmove(void *dest, const void *src, size_t n);
+#endif
 
 /*
  * This is set up by the setup-routine at boot-time
diff --git a/arch/x86/lib/memcpy_32.c b/arch/x86/lib/memcpy_32.c
index e565d1c9019ee..f19b7fd07f042 100644
--- a/arch/x86/lib/memcpy_32.c
+++ b/arch/x86/lib/memcpy_32.c
@@ -4,6 +4,7 @@
 
 #undef memcpy
 #undef memset
+#undef memmove
 
 __visible void *memcpy(void *to, const void *from, size_t n)
 {
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index 950d38657b31a..3a96d386b0d4d 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -278,19 +278,11 @@ __FORTIFY_INLINE void *__fortify_memcpy(void *p, const void *q,
 	return __underlying_memcpy(p, q, size);
 }
 
-__FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
+#define memmove(p, q, s) __fortify_memmove(p, q, s)
+__FORTIFY_INLINE void *__fortify_memmove(void *p, const void *q,
+					__kernel_size_t size)
 {
-	size_t p_size = __builtin_object_size(p, 0);
-	size_t q_size = __builtin_object_size(q, 0);
-
-	if (__builtin_constant_p(size)) {
-		if (p_size < size)
-			__write_overflow();
-		if (q_size < size)
-			__read_overflow2();
-	}
-	if (p_size < size || q_size < size)
-		fortify_panic(__func__);
+	__fortify_memcpy_chk(p, q, size, "memmove");
 	return __underlying_memmove(p, q, size);
 }
 
diff --git a/lib/test_fortify/read_overflow2-memmove.c b/lib/test_fortify/read_overflow2_field-memmove.c
index bc905f9278990..6cc2724c8f62c 100644
--- a/lib/test_fortify/read_overflow2-memmove.c
+++ b/lib/test_fortify/read_overflow2_field-memmove.c
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #define TEST	\
-	memmove(large, small, sizeof(large))
+	memmove(large, instance.buf, sizeof(instance.buf) + 1)
 
 #include "test_fortify.h"
diff --git a/lib/test_fortify/write_overflow-memmove.c b/lib/test_fortify/write_overflow_field-memmove.c
index 6cbd2af678567..377fcf9bb2fdc 100644
--- a/lib/test_fortify/write_overflow-memmove.c
+++ b/lib/test_fortify/write_overflow_field-memmove.c
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #define TEST	\
-	memmove(small, large, sizeof(large))
+	memmove(instance.buf, large, sizeof(instance.buf) + 1)
 
 #include "test_fortify.h"