From 20a572532bd9747c1ea02f3d45a0037242c3ed3c Mon Sep 17 00:00:00 2001
From: Alex Kotov <kotovalexarian@gmail.com>
Date: Sat, 28 Nov 2020 07:41:07 +0500
Subject: [PATCH] Multiboot 2 tags are aligned

---
 src/multiboot2/is_valid.c          |  3 +--
 src/multiboot2/print.c             |  3 +--
 tests/test_multiboot2_validation.c | 12 ++++++++----
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/multiboot2/is_valid.c b/src/multiboot2/is_valid.c
index 985a0a0..88700d7 100644
--- a/src/multiboot2/is_valid.c
+++ b/src/multiboot2/is_valid.c
@@ -24,8 +24,7 @@ unsigned char KernAux_Multiboot2_is_valid(
         }
 
         tag_base = (struct KernAux_Multiboot2_TagBase*)(
-            (void*)tag_base +
-            tag_base->size
+            (void*)tag_base + ((tag_base->size + 7) & ~7)
         );
     }
 
diff --git a/src/multiboot2/print.c b/src/multiboot2/print.c
index 1c6ef32..965b00e 100644
--- a/src/multiboot2/print.c
+++ b/src/multiboot2/print.c
@@ -80,8 +80,7 @@ void KernAux_Multiboot2_print(
         KernAux_Multiboot2_TagBase_print(tag_base, print);
 
         tag_base = (struct KernAux_Multiboot2_TagBase*)(
-            (void*)tag_base +
-            tag_base->size
+            (void*)tag_base + ((tag_base->size + 7) & ~7)
         );
     }
 }
diff --git a/tests/test_multiboot2_validation.c b/tests/test_multiboot2_validation.c
index 9554e7d..e329a16 100644
--- a/tests/test_multiboot2_validation.c
+++ b/tests/test_multiboot2_validation.c
@@ -516,10 +516,11 @@ static const struct {
     struct KernAux_Multiboot2 multiboot2;
     struct KernAux_Multiboot2_Tag_BasicMemoryInfo tag_basic_memory_info;
     struct KernAux_Multiboot2_Tag_BIOSBootDevice tag_bios_boot_device;
+    unsigned char _align1[4];
     struct KernAux_Multiboot2_Tag_None tag_none;
 } multiboot2_with_more_additional_tags_valid = {
     .multiboot2 = {
-        .total_size = 8 + 16 + 20 + 8,
+        .total_size = 8 + 16 + (20 + 4) + 8,
         .reserved1 = 0,
     },
     .tag_basic_memory_info = {
@@ -591,10 +592,11 @@ static const struct {
     struct KernAux_Multiboot2_Tag_BasicMemoryInfo tag_basic_memory_info;
     struct KernAux_Multiboot2_Tag_None tag_none1;
     struct KernAux_Multiboot2_Tag_BIOSBootDevice tag_bios_boot_device;
+    unsigned char _align1[4];
     struct KernAux_Multiboot2_Tag_None tag_none2;
 } multiboot2_with_early_none_tag_invalid = {
     .multiboot2 = {
-        .total_size = 8 + 16 + 8 + 20 + 8,
+        .total_size = 8 + 16 + 8 + (20 + 4) + 8,
         .reserved1 = 0,
     },
     .tag_basic_memory_info = {
@@ -632,10 +634,11 @@ static const struct {
     struct KernAux_Multiboot2 multiboot2;
     struct KernAux_Multiboot2_Tag_BasicMemoryInfo tag_basic_memory_info;
     struct KernAux_Multiboot2_Tag_BIOSBootDevice tag_bios_boot_device;
+    unsigned char _align1[4];
     struct KernAux_Multiboot2_Tag_None tag_none;
 } multiboot2_with_more_additional_tags_invalid_size_too_big = {
     .multiboot2 = {
-        .total_size = 8 + 16 + 20 + 8 + 1,
+        .total_size = 8 + 16 + (20 + 4) + 8 + 1,
         .reserved1 = 0,
     },
     .tag_basic_memory_info = {
@@ -667,10 +670,11 @@ static const struct {
     struct KernAux_Multiboot2 multiboot2;
     struct KernAux_Multiboot2_Tag_BasicMemoryInfo tag_basic_memory_info;
     struct KernAux_Multiboot2_Tag_BIOSBootDevice tag_bios_boot_device;
+    unsigned char _align1[4];
     struct KernAux_Multiboot2_Tag_None tag_none;
 } multiboot2_with_more_additional_tags_invalid_size_too_small = {
     .multiboot2 = {
-        .total_size = 8 + 16 + 20 + 8 - 1,
+        .total_size = 8 + 16 + (20 + 4) + 8 - 1,
         .reserved1 = 0,
     },
     .tag_basic_memory_info = {