perform size checks on memcpy/memmove/memset

Signed-off-by: Tavi <tavi@divested.dev>
Co-authored-by: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>

Android.bp

@@ -28,6 +28,7 @@ common_cflags = [
     "-DN_ARENA=1",
     "-DCONFIG_STATS=true",
     "-DCONFIG_SELF_INIT=false",
+    "-DCONFIG_BLOCK_OPS_CHECK_SIZE=false",
 ]
 
 cc_defaults {

CREDITS

@@ -23,6 +23,30 @@ h_malloc.c open-addressed hash table (regions_grow, regions_insert, regions_find
     ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
+memcpy.c, memccpy.c, memmove.c, memset.c, wmemset.c:
+    Copyright © 2005-2020 Rich Felker, et al.
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+    Contributor list: https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+
 libdivide:
 
     Copyright (C) 2010 - 2019 ridiculous_fish, <libdivide@ridiculousfish.com>

Makefile

@@ -40,6 +40,10 @@ CXXFLAGS := $(CXXFLAGS) -std=c++17 -fsized-deallocation $(SHARED_FLAGS)
 LDFLAGS := $(LDFLAGS) -Wl,-O1,--as-needed,-z,defs,-z,relro,-z,now,-z,nodlopen,-z,text
 
 SOURCES := chacha.c h_malloc.c memory.c pages.c random.c util.c
+ifeq ($(CONFIG_BLOCK_OPS_CHECK_SIZE),true)
+    SOURCES += memcpy.c memccpy.c memmove.c memset.c wmemset.c
+    BOSC_EXTRAS := musl.h
+endif
 OBJECTS := $(SOURCES:.c=.o)
 
 ifeq ($(CONFIG_CXX_ALLOCATOR),true)
@@ -89,6 +93,10 @@ ifeq (,$(filter $(CONFIG_SELF_INIT),true false))
     $(error CONFIG_SELF_INIT must be true or false)
 endif
 
+ifeq (,$(filter $(CONFIG_BLOCK_OPS_CHECK_SIZE),true false))
+    $(error CONFIG_BLOCK_OPS_CHECK_SIZE must be true or false)
+endif
+
 CPPFLAGS += \
     -DCONFIG_SEAL_METADATA=$(CONFIG_SEAL_METADATA) \
     -DZERO_ON_FREE=$(CONFIG_ZERO_ON_FREE) \
@@ -108,7 +116,8 @@ CPPFLAGS += \
     -DCONFIG_CLASS_REGION_SIZE=$(CONFIG_CLASS_REGION_SIZE) \
     -DN_ARENA=$(CONFIG_N_ARENA) \
     -DCONFIG_STATS=$(CONFIG_STATS) \
-    -DCONFIG_SELF_INIT=$(CONFIG_SELF_INIT)
+    -DCONFIG_SELF_INIT=$(CONFIG_SELF_INIT) \
+    -DCONFIG_BLOCK_OPS_CHECK_SIZE=$(CONFIG_BLOCK_OPS_CHECK_SIZE)
 
 $(OUT)/libhardened_malloc$(SUFFIX).so: $(OBJECTS) | $(OUT)
 	$(CC) $(CFLAGS) $(LDFLAGS) -shared $^ $(LDLIBS) -o $@
@@ -118,7 +127,7 @@ $(OUT):
 
 $(OUT)/chacha.o: chacha.c chacha.h util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
-$(OUT)/h_malloc.o: h_malloc.c include/h_malloc.h mutex.h memory.h pages.h random.h util.h $(CONFIG_FILE) | $(OUT)
+$(OUT)/h_malloc.o: h_malloc.c include/h_malloc.h mutex.h memory.h $(BOSC_EXTRAS) pages.h random.h util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
 $(OUT)/memory.o: memory.c memory.h util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
@@ -126,11 +135,22 @@ $(OUT)/new.o: new.cc include/h_malloc.h util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.cc) $(OUTPUT_OPTION) $<
 $(OUT)/pages.o: pages.c pages.h memory.h util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
-$(OUT)/random.o: random.c random.h chacha.h util.h $(CONFIG_FILE) | $(OUT)
+$(OUT)/random.o: random.c random.h chacha.h $(BOSC_EXTRAS) util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
 $(OUT)/util.o: util.c util.h $(CONFIG_FILE) | $(OUT)
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
 
+$(OUT)/memcpy.o: memcpy.c musl.h $(CONFIG_FILE) | $(OUT)
+	$(COMPILE.c) -Wno-cast-align $(OUTPUT_OPTION) $<
+$(OUT)/memccpy.o: memccpy.c musl.h $(CONFIG_FILE) | $(OUT)
+	$(COMPILE.c) -Wno-cast-align $(OUTPUT_OPTION) $<
+$(OUT)/memmove.o: memmove.c musl.h $(CONFIG_FILE) | $(OUT)
+	$(COMPILE.c) -Wno-cast-align $(OUTPUT_OPTION) $<
+$(OUT)/memset.o: memset.c musl.h $(CONFIG_FILE) | $(OUT)
+	$(COMPILE.c) -Wno-cast-align $(OUTPUT_OPTION) $<
+$(OUT)/wmemset.o: wmemset.c musl.h $(CONFIG_FILE) | $(OUT)
+	$(COMPILE.c) $(OUTPUT_OPTION) $<
+
 check: tidy
 
 tidy:

README.md

@@ -276,6 +276,9 @@ The following boolean configuration options are available:
   hardware, which may become drastically lower in the future. Whether or not
   this feature is enabled, the metadata is all contained within an isolated
   memory region with high entropy random guard regions around it.
+* `CONFIG_BLOCK_OPS_CHECK_SIZE`: `true` or `false` (default) to ensure length
+  parameter of the memcpy/memccpy/memmove/memset block operations and their
+  wide variants are within approximate bounds to minimize buffer overflows.
 
 The following integer configuration options are available:
 

config/default.mk

@@ -21,3 +21,4 @@ CONFIG_CLASS_REGION_SIZE := 34359738368 # 32GiB
 CONFIG_N_ARENA := 4
 CONFIG_STATS := false
 CONFIG_SELF_INIT := true
+CONFIG_BLOCK_OPS_CHECK_SIZE := false

config/light.mk

@@ -21,3 +21,4 @@ CONFIG_CLASS_REGION_SIZE := 34359738368 # 32GiB
 CONFIG_N_ARENA := 4
 CONFIG_STATS := false
 CONFIG_SELF_INIT := true
+CONFIG_BLOCK_OPS_CHECK_SIZE := false

h_malloc.c

@@ -20,6 +20,10 @@
 #include "random.h"
 #include "util.h"
 
+#if CONFIG_BLOCK_OPS_CHECK_SIZE && !defined(HAS_ARM_MTE)
+#include "musl.h"
+#endif
+
 #ifdef USE_PKEY
 #include <sys/mman.h>
 #endif
@@ -528,7 +532,7 @@ static void set_canary(UNUSED const struct slab_metadata *metadata, UNUSED void
     }
 #endif
 
-    memcpy((char *)p + size - canary_size, &metadata->canary_value, canary_size);
+    h_memcpy_internal((char *)p + size - canary_size, &metadata->canary_value, canary_size);
 #endif
 }
 
@@ -541,7 +545,7 @@ static void check_canary(UNUSED const struct slab_metadata *metadata, UNUSED con
 #endif
 
     u64 canary_value;
-    memcpy(&canary_value, (const char *)p + size - canary_size, canary_size);
+    h_memcpy_internal(&canary_value, (const char *)p + size - canary_size, canary_size);
 
 #ifdef HAS_ARM_MTE
     if (unlikely(canary_value == 0)) {
@@ -831,7 +835,7 @@ static inline void deallocate_small(void *p, const size_t *expected_size) {
 #endif
 
         if (ZERO_ON_FREE && !skip_zero) {
-            memset(p, 0, size - canary_size);
+            h_memset_internal(p, 0, size - canary_size);
         }
     }
 
@@ -1502,7 +1506,7 @@ EXPORT void *h_calloc(size_t nmemb, size_t size) {
     total_size = adjust_size_for_canary(total_size);
     void *p = alloc(total_size);
     if (!ZERO_ON_FREE && likely(p != NULL) && total_size && total_size <= max_slab_size_class) {
-        memset(p, 0, total_size - canary_size);
+        h_memset_internal(p, 0, total_size - canary_size);
     }
 #ifdef HAS_ARM_MTE
     // use an assert instead of adding a conditional to memset() above (freed memory is always
@@ -1624,7 +1628,7 @@ EXPORT void *h_realloc(void *old, size_t size) {
                 mutex_unlock(&ra->lock);
 
                 if (memory_remap_fixed(old, old_size, new, size)) {
-                    memcpy(new, old, copy_size);
+                    h_memcpy_internal(new, old, copy_size);
                     deallocate_pages(old, old_size, old_guard_size);
                 } else {
                     memory_unmap((char *)old - old_guard_size, old_guard_size);
@@ -1646,7 +1650,7 @@ EXPORT void *h_realloc(void *old, size_t size) {
     if (copy_size > 0 && copy_size <= max_slab_size_class) {
         copy_size -= canary_size;
     }
-    memcpy(new, old_orig, copy_size);
+    h_memcpy_internal(new, old_orig, copy_size);
     if (old_size <= max_slab_size_class) {
         deallocate_small(old, NULL);
     } else {
@@ -1874,6 +1878,104 @@ EXPORT size_t h_malloc_object_size_fast(const void *p) {
     return SIZE_MAX;
 }
 
+#if CONFIG_BLOCK_OPS_CHECK_SIZE && !defined(HAS_ARM_MTE)
+EXPORT void *memcpy(void *restrict dst, const void *restrict src, size_t len) {
+    if (unlikely(dst == src || len == 0)) {
+        return dst;
+    }
+    if (unlikely(dst < (src + len) && (dst + len) > src)) {
+        fatal_error("memcpy overlap");
+    }
+    if (unlikely(len > malloc_object_size(src))) {
+        fatal_error("memcpy read overflow");
+    }
+    if (unlikely(len > malloc_object_size(dst))) {
+        fatal_error("memcpy buffer overflow");
+    }
+    return musl_memcpy(dst, src, len);
+}
+
+EXPORT void *memccpy(void *restrict dst, const void *restrict src, int value, size_t len) {
+    if (unlikely(dst == src || len == 0)) {
+        return dst;
+    }
+    if (unlikely(dst < (src + len) && (dst + len) > src)) {
+        fatal_error("memccpy overlap");
+    }
+    if (unlikely(len > malloc_object_size(src))) {
+        fatal_error("memccpy read overflow");
+    }
+    if (unlikely(len > malloc_object_size(dst))) {
+        fatal_error("memccpy buffer overflow");
+    }
+    return musl_memccpy(dst, src, value, len);
+}
+
+EXPORT void *memmove(void *dst, const void *src, size_t len) {
+    if (unlikely(dst == src || len == 0)) {
+        return dst;
+    }
+    if (unlikely(len > malloc_object_size(src))) {
+        fatal_error("memmove read overflow");
+    }
+    if (unlikely(len > malloc_object_size(dst))) {
+        fatal_error("memmove buffer overflow");
+    }
+    return musl_memmove(dst, src, len);
+}
+
+EXPORT void *memset(void *dst, int value, size_t len) {
+    if (unlikely(len == 0)) {
+        return dst;
+    }
+    if (unlikely(len > malloc_object_size(dst))) {
+        fatal_error("memset buffer overflow");
+    }
+    return musl_memset(dst, value, len);
+}
+
+EXPORT wchar_t *wmemcpy(wchar_t *restrict dst, const wchar_t *restrict src, size_t len) {
+    if (unlikely(dst == src || len == 0)) {
+        return dst;
+    }
+    if (unlikely(dst < (src + len) && (dst + len) > src)) {
+        fatal_error("wmemcpy overlap");
+    }
+    size_t lenAdj = len * sizeof(wchar_t);
+    if (unlikely(lenAdj > malloc_object_size(src))) {
+        fatal_error("wmemcpy read overflow");
+    }
+    if (unlikely(lenAdj > malloc_object_size(dst))) {
+        fatal_error("wmemcpy buffer overflow");
+    }
+    return (wchar_t *)musl_memcpy((char *)dst, (const char *)src, lenAdj);
+}
+
+EXPORT wchar_t *wmemmove(wchar_t *dst, const wchar_t *src, size_t len) {
+    if (unlikely(dst == src || len == 0)) {
+        return dst;
+    }
+    size_t lenAdj = len * sizeof(wchar_t);
+    if (unlikely(lenAdj > malloc_object_size(src))) {
+        fatal_error("wmemmove read overflow");
+    }
+    if (unlikely(lenAdj > malloc_object_size(dst))) {
+        fatal_error("wmemmove buffer overflow");
+    }
+    return (wchar_t *)musl_memmove((char *)dst, (const char *)src, lenAdj);
+}
+
+EXPORT wchar_t *wmemset(wchar_t *dst, wchar_t value, size_t len) {
+    if (unlikely(len == 0)) {
+        return dst;
+    }
+    if (unlikely((len * sizeof(wchar_t)) > malloc_object_size(dst))) {
+        fatal_error("wmemset buffer overflow");
+    }
+    return musl_wmemset(dst, value, len);
+}
+#endif /* CONFIG_BLOCK_OPS_CHECK_SIZE && !defined(HAS_ARM_MTE) */
+
 EXPORT int h_mallopt(UNUSED int param, UNUSED int value) {
 #ifdef __ANDROID__
     if (param == M_PURGE) {

include/h_malloc.h

@@ -55,6 +55,23 @@ __attribute__((malloc)) __attribute__((alloc_size(2))) __attribute__((alloc_alig
 void *h_aligned_alloc(size_t alignment, size_t size);
 void h_free(void *ptr);
 
+#if CONFIG_BLOCK_OPS_CHECK_SIZE && !defined(HAS_ARM_MTE)
+void *memcpy(void *dst, const void *src, size_t len);
+void *memccpy(void *dst, const void *src, int value, size_t len);
+void *memmove(void *dst, const void *src, size_t len);
+void *memset(void *dst, int value, size_t len);
+wchar_t *wmemcpy(wchar_t *dst, const wchar_t *src, size_t len);
+wchar_t *wmemmove(wchar_t *dst, const wchar_t *src, size_t len);
+wchar_t *wmemset(wchar_t *dst, wchar_t value, size_t len);
+#define h_memcpy_internal musl_memcpy
+#define h_memmove_internal musl_memmove
+#define h_memset_internal musl_memset
+#else
+#define h_memcpy_internal memcpy
+#define h_memmove_internal memmove
+#define h_memset_internal memset
+#endif
+
 // POSIX
 int h_posix_memalign(void **memptr, size_t alignment, size_t size);
 

memccpy.c

@@ -0,0 +1,38 @@
+#include "musl.h"
+
+/* Copied from musl libc version 1.2.5 licensed under the MIT license */
+
+#include <string.h>
+#include <stdint.h>
+#include <limits.h>
+
+#define ALIGN (sizeof(size_t)-1)
+#define ONES ((size_t)-1/UCHAR_MAX)
+#define HIGHS (ONES * (UCHAR_MAX/2+1))
+#define HASZERO(x) (((x)-ONES) & ~(x) & HIGHS)
+
+void *musl_memccpy(void *restrict dest, const void *restrict src, int c, size_t n)
+{
+	unsigned char *d = dest;
+	const unsigned char *s = src;
+
+	c = (unsigned char)c;
+#ifdef __GNUC__
+	typedef size_t __attribute__((__may_alias__)) word;
+	word *wd;
+	const word *ws;
+	if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) {
+		for (; ((uintptr_t)s & ALIGN) && n && (*d=*s)!=c; n--, s++, d++);
+		if ((uintptr_t)s & ALIGN) goto tail;
+		size_t k = ONES * c;
+		wd=(void *)d; ws=(const void *)s;
+		for (; n>=sizeof(size_t) && !HASZERO(*ws^k);
+		       n-=sizeof(size_t), ws++, wd++) *wd = *ws;
+		d=(void *)wd; s=(const void *)ws;
+	}
+#endif
+	for (; n && (*d=*s)!=c; n--, s++, d++);
+tail:
+	if (n) return d+1;
+	return 0;
+}

memcpy.c

@@ -0,0 +1,132 @@
+#include "musl.h"
+
+/*
+ * Copied from musl libc version 1.2.5 licensed under the MIT license
+ *
+ * Christian Göttsche: Added const qualifiers to retain const correctness.
+ */
+
+#include <string.h>
+#include <stdint.h>
+#include <endian.h>
+
+void *musl_memcpy(void *restrict dest, const void *restrict src, size_t n)
+{
+	unsigned char *d = dest;
+	const unsigned char *s = src;
+
+#ifdef __GNUC__
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define LS >>
+#define RS <<
+#else
+#define LS <<
+#define RS >>
+#endif
+
+	typedef uint32_t __attribute__((__may_alias__)) u32;
+	uint32_t w, x;
+
+	for (; (uintptr_t)s % 4 && n; n--) *d++ = *s++;
+
+	if ((uintptr_t)d % 4 == 0) {
+		for (; n>=16; s+=16, d+=16, n-=16) {
+			*(u32 *)(d+0) = *(const u32 *)(s+0);
+			*(u32 *)(d+4) = *(const u32 *)(s+4);
+			*(u32 *)(d+8) = *(const u32 *)(s+8);
+			*(u32 *)(d+12) = *(const u32 *)(s+12);
+		}
+		if (n&8) {
+			*(u32 *)(d+0) = *(const u32 *)(s+0);
+			*(u32 *)(d+4) = *(const u32 *)(s+4);
+			d += 8; s += 8;
+		}
+		if (n&4) {
+			*(u32 *)(d+0) = *(const u32 *)(s+0);
+			d += 4; s += 4;
+		}
+		if (n&2) {
+			*d++ = *s++; *d++ = *s++;
+		}
+		if (n&1) {
+			*d = *s;
+		}
+		return dest;
+	}
+
+	if (n >= 32) switch ((uintptr_t)d % 4) {
+	case 1:
+		w = *(const u32 *)s;
+		*d++ = *s++;
+		*d++ = *s++;
+		*d++ = *s++;
+		n -= 3;
+		for (; n>=17; s+=16, d+=16, n-=16) {
+			x = *(const u32 *)(s+1);
+			*(u32 *)(d+0) = (w LS 24) | (x RS 8);
+			w = *(const u32 *)(s+5);
+			*(u32 *)(d+4) = (x LS 24) | (w RS 8);
+			x = *(const u32 *)(s+9);
+			*(u32 *)(d+8) = (w LS 24) | (x RS 8);
+			w = *(const u32 *)(s+13);
+			*(u32 *)(d+12) = (x LS 24) | (w RS 8);
+		}
+		break;
+	case 2:
+		w = *(const u32 *)s;
+		*d++ = *s++;
+		*d++ = *s++;
+		n -= 2;
+		for (; n>=18; s+=16, d+=16, n-=16) {
+			x = *(const u32 *)(s+2);
+			*(u32 *)(d+0) = (w LS 16) | (x RS 16);
+			w = *(const u32 *)(s+6);
+			*(u32 *)(d+4) = (x LS 16) | (w RS 16);
+			x = *(const u32 *)(s+10);
+			*(u32 *)(d+8) = (w LS 16) | (x RS 16);
+			w = *(const u32 *)(s+14);
+			*(u32 *)(d+12) = (x LS 16) | (w RS 16);
+		}
+		break;
+	case 3:
+		w = *(const u32 *)s;
+		*d++ = *s++;
+		n -= 1;
+		for (; n>=19; s+=16, d+=16, n-=16) {
+			x = *(const u32 *)(s+3);
+			*(u32 *)(d+0) = (w LS 8) | (x RS 24);
+			w = *(const u32 *)(s+7);
+			*(u32 *)(d+4) = (x LS 8) | (w RS 24);
+			x = *(const u32 *)(s+11);
+			*(u32 *)(d+8) = (w LS 8) | (x RS 24);
+			w = *(const u32 *)(s+15);
+			*(u32 *)(d+12) = (x LS 8) | (w RS 24);
+		}
+		break;
+	}
+	if (n&16) {
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+	}
+	if (n&8) {
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+	}
+	if (n&4) {
+		*d++ = *s++; *d++ = *s++; *d++ = *s++; *d++ = *s++;
+	}
+	if (n&2) {
+		*d++ = *s++; *d++ = *s++;
+	}
+	if (n&1) {
+		*d = *s;
+	}
+	return dest;
+#endif
+
+	for (; n; n--) *d++ = *s++;
+	return dest;
+}

memmove.c

@@ -0,0 +1,50 @@
+#include "musl.h"
+
+/*
+ * Copied from musl libc version 1.2.5 licensed under the MIT license
+ *
+ * Christian Göttsche: Added const qualifiers to retain const correctness.
+ */
+
+#include <string.h>
+#include <stdint.h>
+
+#ifdef __GNUC__
+typedef __attribute__((__may_alias__)) size_t WT;
+#define WS (sizeof(WT))
+#endif
+
+void *musl_memmove(void *dest, const void *src, size_t n)
+{
+	char *d = dest;
+	const char *s = src;
+
+	if (d==s) return d;
+	if ((uintptr_t)s-(uintptr_t)d-n <= -2*n) return musl_memcpy(d, s, n);
+
+	if (d<s) {
+#ifdef __GNUC__
+		if ((uintptr_t)s % WS == (uintptr_t)d % WS) {
+			while ((uintptr_t)d % WS) {
+				if (!n--) return dest;
+				*d++ = *s++;
+			}
+			for (; n>=WS; n-=WS, d+=WS, s+=WS) *(WT *)d = *(const WT *)s;
+		}
+#endif
+		for (; n; n--) *d++ = *s++;
+	} else {
+#ifdef __GNUC__
+		if ((uintptr_t)s % WS == (uintptr_t)d % WS) {
+			while ((uintptr_t)(d+n) % WS) {
+				if (!n--) return dest;
+				d[n] = s[n];
+			}
+			while (n>=WS) n-=WS, *(WT *)(d+n) = *(const WT *)(s+n);
+		}
+#endif
+		while (n) n--, d[n] = s[n];
+	}
+
+	return dest;
+}

memset.c

@@ -0,0 +1,94 @@
+#include "musl.h"
+
+/* Copied from musl libc version 1.2.5 licensed under the MIT license */
+
+#include <string.h>
+#include <stdint.h>
+
+void *musl_memset(void *dest, int c, size_t n)
+{
+	unsigned char *s = dest;
+	size_t k;
+
+	/* Fill head and tail with minimal branching. Each
+	 * conditional ensures that all the subsequently used
+	 * offsets are well-defined and in the dest region. */
+
+	if (!n) return dest;
+	s[0] = c;
+	s[n-1] = c;
+	if (n <= 2) return dest;
+	s[1] = c;
+	s[2] = c;
+	s[n-2] = c;
+	s[n-3] = c;
+	if (n <= 6) return dest;
+	s[3] = c;
+	s[n-4] = c;
+	if (n <= 8) return dest;
+
+	/* Advance pointer to align it at a 4-byte boundary,
+	 * and truncate n to a multiple of 4. The previous code
+	 * already took care of any head/tail that get cut off
+	 * by the alignment. */
+
+	k = -(uintptr_t)s & 3;
+	s += k;
+	n -= k;
+	n &= -4;
+
+#ifdef __GNUC__
+	typedef uint32_t __attribute__((__may_alias__)) u32;
+	typedef uint64_t __attribute__((__may_alias__)) u64;
+
+	u32 c32 = ((u32)-1)/255 * (unsigned char)c;
+
+	/* In preparation to copy 32 bytes at a time, aligned on
+	 * an 8-byte bounary, fill head/tail up to 28 bytes each.
+	 * As in the initial byte-based head/tail fill, each
+	 * conditional below ensures that the subsequent offsets
+	 * are valid (e.g. !(n<=24) implies n>=28). */
+
+	*(u32 *)(s+0) = c32;
+	*(u32 *)(s+n-4) = c32;
+	if (n <= 8) return dest;
+	*(u32 *)(s+4) = c32;
+	*(u32 *)(s+8) = c32;
+	*(u32 *)(s+n-12) = c32;
+	*(u32 *)(s+n-8) = c32;
+	if (n <= 24) return dest;
+	*(u32 *)(s+12) = c32;
+	*(u32 *)(s+16) = c32;
+	*(u32 *)(s+20) = c32;
+	*(u32 *)(s+24) = c32;
+	*(u32 *)(s+n-28) = c32;
+	*(u32 *)(s+n-24) = c32;
+	*(u32 *)(s+n-20) = c32;
+	*(u32 *)(s+n-16) = c32;
+
+	/* Align to a multiple of 8 so we can fill 64 bits at a time,
+	 * and avoid writing the same bytes twice as much as is
+	 * practical without introducing additional branching. */
+
+	k = 24 + ((uintptr_t)s & 4);
+	s += k;
+	n -= k;
+
+	/* If this loop is reached, 28 tail bytes have already been
+	 * filled, so any remainder when n drops below 32 can be
+	 * safely ignored. */
+
+	u64 c64 = c32 | ((u64)c32 << 32);
+	for (; n >= 32; n-=32, s+=32) {
+		*(u64 *)(s+0) = c64;
+		*(u64 *)(s+8) = c64;
+		*(u64 *)(s+16) = c64;
+		*(u64 *)(s+24) = c64;
+	}
+#else
+	/* Pure C fallback with no aliasing violations. */
+	for (; n; n--, s++) *s = c;
+#endif
+
+	return dest;
+}

musl.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <stddef.h>
+
+void *musl_memcpy(void *dst, const void *src, size_t len);
+void *musl_memccpy(void *restrict dest, const void *restrict src, int c, size_t n);
+void *musl_memmove(void *dst, const void *src, size_t len);
+void *musl_memset(void *dst, int value, size_t len);
+wchar_t *musl_wmemset(wchar_t *dst, wchar_t value, size_t len);

random.c

@@ -5,6 +5,10 @@
 #include "random.h"
 #include "util.h"
 
+#if CONFIG_BLOCK_OPS_CHECK_SIZE && !defined(HAS_ARM_MTE)
+#include "musl.h"
+#endif
+
 #include <sys/random.h>
 
 static void get_random_seed(void *buf, size_t size) {
@@ -65,7 +69,7 @@ void get_random_bytes(struct random_state *state, void *buf, size_t size) {
 
         size_t remaining = RANDOM_CACHE_SIZE - state->index;
         size_t copy_size = min(size, remaining);
-        memcpy(buf, state->cache + state->index, copy_size);
+        h_memcpy_internal(buf, state->cache + state->index, copy_size);
         state->index += copy_size;
 
         buf = (char *)buf + copy_size;
@@ -79,7 +83,7 @@ u16 get_random_u16(struct random_state *state) {
     if (remaining < sizeof(value)) {
         refill(state);
     }
-    memcpy(&value, state->cache + state->index, sizeof(value));
+    h_memcpy_internal(&value, state->cache + state->index, sizeof(value));
     state->index += sizeof(value);
     return value;
 }
@@ -106,7 +110,7 @@ u64 get_random_u64(struct random_state *state) {
     if (remaining < sizeof(value)) {
         refill(state);
     }
-    memcpy(&value, state->cache + state->index, sizeof(value));
+    h_memcpy_internal(&value, state->cache + state->index, sizeof(value));
     state->index += sizeof(value);
     return value;
 }

random.h

@@ -22,4 +22,10 @@ u16 get_random_u16_uniform(struct random_state *state, u16 bound);
 u64 get_random_u64(struct random_state *state);
 u64 get_random_u64_uniform(struct random_state *state, u64 bound);
 
+#if CONFIG_BLOCK_OPS_CHECK_SIZE && !defined(HAS_ARM_MTE)
+#define h_memcpy_internal musl_memcpy
+#else
+#define h_memcpy_internal memcpy
+#endif
+
 #endif

test/.gitignore

@@ -41,4 +41,30 @@ overflow_small_8_byte
 uninitialized_read_large
 uninitialized_read_small
 realloc_init
+memcpy_buffer_overflow
+memcpy_read_overflow
+memcpy_valid_same
+memcpy_valid_mismatched
+memccpy_buffer_overflow
+memccpy_read_overflow
+memccpy_valid_same
+memccpy_valid_mismatched
+memmove_buffer_overflow
+memmove_read_overflow
+memmove_valid_same
+memmove_valid_mismatched
+memset_buffer_overflow
+memset_valid_same
+memset_valid_mismatched
+wmemcpy_buffer_overflow
+wmemcpy_read_overflow
+wmemcpy_valid_same
+wmemcpy_valid_mismatched
+wmemmove_buffer_overflow
+wmemmove_read_overflow
+wmemmove_valid_same
+wmemmove_valid_mismatched
+wmemset_buffer_overflow
+wmemset_valid_same
+wmemset_valid_mismatched
 __pycache__/

test/Makefile

@@ -67,7 +67,33 @@ EXECUTABLES := \
     invalid_malloc_object_size_small \
     invalid_malloc_object_size_small_quarantine \
     impossibly_large_malloc \
-    realloc_init
+    realloc_init \
+    memcpy_buffer_overflow \
+    memcpy_read_overflow \
+    memcpy_valid_same \
+    memcpy_valid_mismatched \
+    memccpy_buffer_overflow \
+    memccpy_read_overflow \
+    memccpy_valid_same \
+    memccpy_valid_mismatched \
+    memmove_buffer_overflow \
+    memmove_read_overflow \
+    memmove_valid_same \
+    memmove_valid_mismatched \
+    memset_buffer_overflow \
+    memset_valid_same \
+    memset_valid_mismatched \
+    wmemcpy_buffer_overflow \
+    wmemcpy_read_overflow \
+    wmemcpy_valid_same \
+    wmemcpy_valid_mismatched \
+    wmemmove_buffer_overflow \
+    wmemmove_read_overflow \
+    wmemmove_valid_same \
+    wmemmove_valid_mismatched \
+    wmemset_buffer_overflow \
+    wmemset_valid_same \
+    wmemset_valid_mismatched
 
 all: $(EXECUTABLES)
 

test/memccpy_buffer_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(16);
+    char *secondbuffer = malloc(32);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 32);
+    memccpy(firstbuffer, secondbuffer, 'b', 32);
+    return 1;
+}

test/memccpy_read_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(32);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memccpy(firstbuffer, secondbuffer, 'b', 32);
+    return 1;
+}

test/memccpy_valid_mismatched.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(32);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memccpy(firstbuffer, secondbuffer, 'b', 16);
+    return 0;
+}

test/memccpy_valid_same.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(16);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memccpy(firstbuffer, secondbuffer, 'b', 16);
+    return 0;
+}

test/memcpy_buffer_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(16);
+    char *secondbuffer = malloc(32);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 32);
+    memcpy(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/memcpy_read_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(32);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memcpy(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/memcpy_valid_mismatched.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(32);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memcpy(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/memcpy_valid_same.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(16);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memcpy(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/memmove_buffer_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(16);
+    char *secondbuffer = malloc(32);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 32);
+    memmove(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/memmove_read_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(32);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memmove(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/memmove_valid_mismatched.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(32);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memmove(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/memmove_valid_same.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *firstbuffer = malloc(16);
+    char *secondbuffer = malloc(16);
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    memset(secondbuffer, 'a', 16);
+    memmove(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/memset_buffer_overflow.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *buffer = malloc(16);
+    if (!buffer) {
+        return 1;
+    }
+    memset(buffer, 'a', 32);
+    return 1;
+}

test/memset_valid_mismatched.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *buffer = malloc(32);
+    if (!buffer) {
+        return 1;
+    }
+    memset(buffer, 'a', 16);
+    return 0;
+}

test/memset_valid_same.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    char *buffer = malloc(16);
+    if (!buffer) {
+        return 1;
+    }
+    memset(buffer, 'a', 16);
+    return 0;
+}

test/test_smc.py

@@ -238,5 +238,160 @@ class TestSimpleMemoryCorruption(unittest.TestCase):
             "realloc_init")
         self.assertEqual(returncode, 0)
 
+    #def test_memcpy_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memcpy_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memcpy buffer overflow\n")
+
+    #def test_memcpy_read_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memcpy_read_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memcpy read overflow\n")
+
+    def test_memcpy_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memcpy_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_memcpy_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memcpy_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
+    #def test_memccpy_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memccpy_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memccpy buffer overflow\n")
+
+    #def test_memccpy_read_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memccpy_read_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memccpy read overflow\n")
+
+    def test_memccpy_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memccpy_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_memccpy_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memccpy_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
+
+    #def test_memmove_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memmove_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memmove buffer overflow\n")
+
+    #def test_memmove_read_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memmove_read_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memmove read overflow\n")
+
+    def test_memmove_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memmove_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_memmove_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memmove_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
+    #def test_memset_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "memset_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: memset buffer overflow\n")
+
+    #def test_wmemcpy_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "wmemcpy_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: wmemcpy buffer overflow\n")
+
+    #def test_wmemcpy_read_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "wmemcpy_read_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: wmemcpy read overflow\n")
+
+    def test_wmemcpy_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "wmemcpy_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_wmemcpy_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "wmemcpy_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
+    #def test_wmemmove_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "wmemmove_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: wmemmove buffer overflow\n")
+
+    #def test_wmemmove_read_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "wmemmove_read_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: wmemmove read overflow\n")
+
+    def test_wmemmove_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "wmemmove_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_wmemmove_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "wmemmove_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
+    #def test_wmemset_buffer_overflow(self):
+    #    _stdout, stderr, returncode = self.run_test(
+    #        "wmemset_buffer_overflow")
+    #    self.assertEqual(returncode, -6)
+    #    self.assertEqual(stderr.decode(
+    #        "utf-8"), "fatal allocator error: wmemset buffer overflow\n")
+
+    def test_wmemset_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "wmemset_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_wmemset_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "wmemset_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
+    def test_memset_valid_same(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memset_valid_same")
+        self.assertEqual(returncode, 0)
+
+    def test_memset_valid_mismatched(self):
+        _stdout, _stderr, returncode = self.run_test(
+            "memset_valid_mismatched")
+        self.assertEqual(returncode, 0)
+
 if __name__ == '__main__':
     unittest.main()

test/wmemcpy_buffer_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(16 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(32 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 32);
+    wmemcpy(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/wmemcpy_read_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(32 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(16 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 16);
+    wmemcpy(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/wmemcpy_valid_mismatched.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(32 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(16 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 16);
+    wmemcpy(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/wmemcpy_valid_same.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(16 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(16 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 16);
+    wmemcpy(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/wmemmove_buffer_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(16 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(32 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 32);
+    wmemmove(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/wmemmove_read_overflow.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(32 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(16 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 16);
+    wmemmove(firstbuffer, secondbuffer, 32);
+    return 1;
+}

test/wmemmove_valid_mismatched.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(32 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(16 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 16);
+    wmemmove(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/wmemmove_valid_same.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *firstbuffer = malloc(16 * sizeof(wchar_t));
+    wchar_t *secondbuffer = malloc(16 * sizeof(wchar_t));
+    if (!firstbuffer && !secondbuffer) {
+        return 1;
+    }
+    wmemset(secondbuffer, L'\U0001F642', 16);
+    wmemmove(firstbuffer, secondbuffer, 16);
+    return 0;
+}

test/wmemset_buffer_overflow.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *buffer = malloc(16 * sizeof(wchar_t));
+    if (!buffer) {
+        return 1;
+    }
+    wmemset(buffer, L'\U0001F642', 32);
+    return 1;
+}

test/wmemset_valid_mismatched.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *buffer = malloc(32 * sizeof(wchar_t));
+    if (!buffer) {
+        return 1;
+    }
+    wmemset(buffer, L'\U0001F642', 16);
+    return 0;
+}

test/wmemset_valid_same.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <wchar.h>
+
+#include "test_util.h"
+
+OPTNONE int main(void) {
+    wchar_t *buffer = malloc(16 * sizeof(wchar_t));
+    if (!buffer) {
+        return 1;
+    }
+    wmemset(buffer, L'\U0001F642', 16);
+    return 0;
+}

wmemset.c

@@ -0,0 +1,12 @@
+#include "musl.h"
+
+/* Copied from musl libc version 1.2.5 licensed under the MIT license */
+
+#include <wchar.h>
+
+wchar_t *musl_wmemset(wchar_t *d, wchar_t c, size_t n)
+{
+	wchar_t *ret = d;
+	while (n--) *d++ = c;
+	return ret;
+}