From 38dbeec767ad10021020e3833b1dbc3d04442f85 Mon Sep 17 00:00:00 2001
From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Fri, 27 Jan 2023 16:31:28 +0200
Subject: [PATCH] lib: Add memcpy() macro that assert-crashes if either
 parameter is NULL

---
 src/lib/buffer.c            | 4 ++++
 src/lib/lib.h               | 8 ++++++++
 src/lib/printf-format-fix.c | 4 ++++
 src/lib/strfuncs.c          | 4 ++++
 4 files changed, 20 insertions(+)

diff --git a/src/lib/buffer.c b/src/lib/buffer.c
index a6d8fef03e..74f4c03b7f 100644
--- a/src/lib/buffer.c
+++ b/src/lib/buffer.c
@@ -6,6 +6,10 @@
 #include "safe-memset.h"
 #include "buffer.h"
 
+/* Disable our memcpy() safety wrapper. This file is very performance sensitive
+   and it's been checked to work correctly with memcpy(). */
+#undef memcpy
+
 struct real_buffer {
 	union {
 		struct buffer buf;
diff --git a/src/lib/lib.h b/src/lib/lib.h
index 2b1ecde41d..16dc71f589 100644
--- a/src/lib/lib.h
+++ b/src/lib/lib.h
@@ -66,6 +66,14 @@ typedef void lib_atexit_callback_t(void);
 #define static_assert_array_size(arr, count) \
 	static_assert(N_ELEMENTS(arr) == (count), "array/enum size mismatch")
 
+/* Using memcpy() with NULL pointers is undefined behavior. Make sure we don't
+   do that. */
+static inline void *i_memcpy(void *dest, const void *src, size_t n) {
+	i_assert(dest != NULL && src != NULL);
+	return memcpy(dest, src, n);
+}
+#define memcpy(dest, src, n) i_memcpy(dest, src, n)
+
 /* /dev/null opened as O_WRONLY. Opened at lib_init(), so it can be accessed
    also inside chroots. */
 extern int dev_null_fd;
diff --git a/src/lib/printf-format-fix.c b/src/lib/printf-format-fix.c
index f72253fef4..d68e4f6159 100644
--- a/src/lib/printf-format-fix.c
+++ b/src/lib/printf-format-fix.c
@@ -3,6 +3,10 @@
 #include "lib.h"
 #include "printf-format-fix.h"
 
+/* Disable our memcpy() safety wrapper. This file is very performance sensitive
+   and it's been checked to work correctly with memcpy(). */
+#undef memcpy
+
 static const char *
 fix_format_real(const char *fmt, const char *p, size_t *len_r)
 {
diff --git a/src/lib/strfuncs.c b/src/lib/strfuncs.c
index 8aeecc10a8..4a4e1d1f59 100644
--- a/src/lib/strfuncs.c
+++ b/src/lib/strfuncs.c
@@ -12,6 +12,10 @@
 #include <limits.h>
 #include <ctype.h>
 
+/* Disable our memcpy() safety wrapper. This file is very performance sensitive
+   and it's been checked to work correctly with memcpy(). */
+#undef memcpy
+
 #define STRCONCAT_BUFSIZE 512
 
 enum _str_trim_sides {
-- 
2.47.3