From 6fa526429246ed1a8b25151e3714e78fd66b53ef Mon Sep 17 00:00:00 2001
From: Frank Barchard <fbarchard@google.com>
Date: Fri, 14 Aug 2026 16:59:19 -0700
Subject: [PATCH] ARGBToRGB565Dither fix for unaligned dither matrix

Copy dither4x4 (16 bytes) into an aligned local uint32_t dither4[4] array
using memcpy and index using dither4[y & 3] to avoid unaligned 32-bit
pointer dereference traps in fastbuild / UB sanitizers.

Bug: None
Test: LibYUVConvertTest.TestNoDither, LibYUVConvertTest.TestDither
Change-Id: I4447cd2924b16739a9bce2792d57a550dedeb345
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/8262354
Reviewed-by: richard winterton <rrwinterton@gmail.com>
Commit-Queue: Frank Barchard <fbarchard@google.com>
Reviewed-by: Wan-Teh Chang <wtc@google.com>
---
 README.chromium             | 2 +-
 include/libyuv/version.h    | 2 +-
 source/convert_argb.cc      | 7 ++++---
 source/convert_from_argb.cc | 7 ++++---
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/README.chromium b/README.chromium
index 8b6708f23..ce06ea2ce 100644
--- a/README.chromium
+++ b/README.chromium
@@ -1,6 +1,6 @@
 Name: libyuv
 URL: https://chromium.googlesource.com/libyuv/libyuv/
-Version: 1958
+Version: 1959
 Revision: DEPS
 License: BSD-3-Clause
 License File: LICENSE
diff --git a/include/libyuv/version.h b/include/libyuv/version.h
index cd1d85c71..8e6470095 100644
--- a/include/libyuv/version.h
+++ b/include/libyuv/version.h
@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1958
+#define LIBYUV_VERSION 1959
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_
diff --git a/source/convert_argb.cc b/source/convert_argb.cc
index f20083257..8dad827ea 100644
--- a/source/convert_argb.cc
+++ b/source/convert_argb.cc
@@ -12,6 +12,7 @@
 
 #include <assert.h>
 #include <limits.h>
+#include <string.h>  // For memcpy.
 
 #include "libyuv/convert_from_argb.h"
 #include "libyuv/cpu_id.h"
@@ -6314,6 +6315,7 @@ int I420ToRGB565Dither(const uint8_t* src_y,
                        int width,
                        int height) {
   int y;
+  uint32_t dither4[4];
   void (*I422ToARGBRow)(const uint8_t* y_buf, const uint8_t* u_buf,
                         const uint8_t* v_buf, uint8_t* rgb_buf,
                         const struct YuvConstants* yuvconstants, int width) =
@@ -6334,6 +6336,7 @@ int I420ToRGB565Dither(const uint8_t* src_y,
   if (!dither4x4) {
     dither4x4 = kDither565_4x4;
   }
+  memcpy(dither4, dither4x4, 16);
 #if defined(HAS_I422TOARGBROW_SSSE3)
   if (TestCpuFlag(kCpuHasSSSE3)) {
     I422ToARGBRow = I422ToARGBRow_Any_SSSE3;
@@ -6450,9 +6453,7 @@ int I420ToRGB565Dither(const uint8_t* src_y,
       return 1;
     for (y = 0; y < height; ++y) {
       I422ToARGBRow(src_y, src_u, src_v, row_argb, &kYuvI601Constants, width);
-      ARGBToRGB565DitherRow(row_argb, dst_rgb565,
-                            *(const uint32_t*)(dither4x4 + ((y & 3) << 2)),
-                            width);
+      ARGBToRGB565DitherRow(row_argb, dst_rgb565, dither4[y & 3], width);
       dst_rgb565 += dst_stride_rgb565;
       src_y += src_stride_y;
       if (y & 1) {
diff --git a/source/convert_from_argb.cc b/source/convert_from_argb.cc
index a633085a7..11e54fcf1 100644
--- a/source/convert_from_argb.cc
+++ b/source/convert_from_argb.cc
@@ -11,6 +11,7 @@
 #include "libyuv/convert_from_argb.h"
 
 #include <limits.h>
+#include <string.h>  // For memcpy.
 
 #include "libyuv/basic_types.h"
 #include "libyuv/cpu_id.h"
@@ -1582,6 +1583,7 @@ int ARGBToRGB565Dither(const uint8_t* src_argb,
                        int width,
                        int height) {
   int y;
+  uint32_t dither4[4];
   void (*ARGBToRGB565DitherRow)(const uint8_t* src_argb, uint8_t* dst_rgb,
                                 uint32_t dither4, int width) =
       ARGBToRGB565DitherRow_C;
@@ -1597,6 +1599,7 @@ int ARGBToRGB565Dither(const uint8_t* src_argb,
   if (!dither4x4) {
     dither4x4 = kDither565_4x4;
   }
+  memcpy(dither4, dither4x4, 16);
 
 #if defined(HAS_ARGBTORGB565DITHERROW_AVX2)
   if (TestCpuFlag(kCpuHasAVX2)) {
@@ -1637,9 +1640,7 @@ int ARGBToRGB565Dither(const uint8_t* src_argb,
 #endif
 
   for (y = 0; y < height; ++y) {
-    ARGBToRGB565DitherRow(src_argb, dst_rgb565,
-                          *(const uint32_t*)(dither4x4 + ((y & 3) << 2)),
-                          width);
+    ARGBToRGB565DitherRow(src_argb, dst_rgb565, dither4[y & 3], width);
     src_argb += src_stride_argb;
     dst_rgb565 += dst_stride_rgb565;
   }