Description: Ensure the _aligned_meminfo pointer itself is sufficiently aligned
Author: James Clarke <jrtc27@jrtc27.com>

--- a/winpr/libwinpr/crt/alignment.c
+++ b/winpr/libwinpr/crt/alignment.c
@@ -73,15 +73,20 @@ void* _aligned_offset_malloc(size_t size
 	if (alignment < sizeof(void*))
 		alignment = sizeof(void*);
 
-	/* malloc size + alignment to make sure we can align afterwards */
-	tmpptr = malloc(size + alignment + sizeof(struct _aligned_meminfo));
+	/* malloc size + alignment to make sure we can align afterwards.
+	 * Include an extra sizeof(void*) to ensure there's always space to align
+	 * ameminfo downwards, in case malloc doesn't align to sizeof(void*). This
+	 * could be dropped if there was a portable way to get alignof(struct
+	 * _aligned_meminfo), but instead we have to overestimate with
+	 * sizeof(void*). */
+	tmpptr = malloc(size + alignment + sizeof(struct _aligned_meminfo) + sizeof(void*));
 	if (!tmpptr)
 		return NULL;
 
 
-	memptr = (void *)((((size_t)((PBYTE)tmpptr + alignment + offset + sizeof(struct _aligned_meminfo)) & ~(alignment - 1)) - offset));
+	memptr = (void *)((((size_t)((PBYTE)tmpptr + alignment + offset + sizeof(struct _aligned_meminfo) + sizeof(void*)) & ~(alignment - 1)) - offset));
 
-	ameminfo = (struct _aligned_meminfo *) (((size_t)((PBYTE)memptr - sizeof(struct _aligned_meminfo))));
+	ameminfo = (struct _aligned_meminfo *) (((size_t)((PBYTE)memptr - sizeof(struct _aligned_meminfo))) & ~(sizeof(void*)-1));
 	ameminfo->base_addr = tmpptr;
 	ameminfo->size = size;
 
@@ -107,7 +112,7 @@ void* _aligned_offset_realloc(void* memb
 	if (!newmem)
 		return NULL;
 
-	ameminfo = (struct _aligned_meminfo *) (((size_t)((PBYTE)memblock - sizeof(struct _aligned_meminfo))));
+	ameminfo = (struct _aligned_meminfo *) (((size_t)((PBYTE)memblock - sizeof(struct _aligned_meminfo))) & ~(sizeof(void*)-1));
 	memcpy(newmem, memblock, ameminfo->size);
 	_aligned_free(memblock);
 	return newmem;
@@ -129,7 +134,7 @@ void _aligned_free(void* memblock)
 	if (!memblock)
 		return;
 
-	ameminfo = (struct _aligned_meminfo *) (((size_t)((PBYTE)memblock - sizeof(struct _aligned_meminfo))));
+	ameminfo = (struct _aligned_meminfo *) (((size_t)((PBYTE)memblock - sizeof(struct _aligned_meminfo))) & ~(sizeof(void*)-1));
 
 	free(ameminfo->base_addr);
 }