DPM: fix misaligned memory access

Signed-off-by: bones_was_here <bones_was_here@xonotic.au>

diff --git a/model_alias.c b/model_alias.c
index fc9c93138d000536502b5de5148543fa7674737f..4c87c32ef742049f94bee42cae1f2d49649cf667 100644 (file)
--- a/model_alias.c
+++ b/model_alias.c
@@ -2255,33 +2255,44 @@ void Mod_DARKPLACESMODEL_Load(model_t *mod, void *buffer, void *bufferend)
        loadmodel->submodelsurfaces_end = loadmodel->num_surfaces = pheader->num_meshs;
        loadmodel->num_textures = loadmodel->num_surfaces * loadmodel->numskins;
        loadmodel->num_texturesperskin = loadmodel->num_surfaces;
-       // do most allocations as one merged chunk
-       data = (unsigned char *)Mem_Alloc(loadmodel->mempool, loadmodel->num_surfaces * sizeof(msurface_t) + loadmodel->num_surfaces * sizeof(int) + loadmodel->num_surfaces * loadmodel->numskins * sizeof(texture_t) + meshtriangles * sizeof(int[3]) + (meshvertices <= 65536 ? meshtriangles * sizeof(unsigned short[3]) : 0) + meshvertices * (sizeof(float[14]) + sizeof(unsigned short) + sizeof(unsigned char[2][4])) + loadmodel->num_poses * loadmodel->num_bones * sizeof(short[7]) + loadmodel->num_bones * sizeof(float[12]) + loadmodel->numskins * sizeof(animscene_t) + loadmodel->num_bones * sizeof(aliasbone_t) + loadmodel->numframes * sizeof(animscene_t));
-       loadmodel->data_surfaces = (msurface_t *)data;data += loadmodel->num_surfaces * sizeof(msurface_t);
-       loadmodel->modelsurfaces_sorted = (int *)data;data += loadmodel->num_surfaces * sizeof(int);
-       loadmodel->data_textures = (texture_t *)data;data += loadmodel->num_surfaces * loadmodel->numskins * sizeof(texture_t);
        loadmodel->surfmesh.num_vertices = meshvertices;
        loadmodel->surfmesh.num_triangles = meshtriangles;
-       loadmodel->surfmesh.data_element3i = (int *)data;data += meshtriangles * sizeof(int[3]);
-       loadmodel->surfmesh.data_vertex3f = (float *)data;data += meshvertices * sizeof(float[3]);
-       loadmodel->surfmesh.data_svector3f = (float *)data;data += meshvertices * sizeof(float[3]);
-       loadmodel->surfmesh.data_tvector3f = (float *)data;data += meshvertices * sizeof(float[3]);
-       loadmodel->surfmesh.data_normal3f = (float *)data;data += meshvertices * sizeof(float[3]);
-       loadmodel->surfmesh.data_texcoordtexture2f = (float *)data;data += meshvertices * sizeof(float[2]);
-       loadmodel->surfmesh.data_skeletalindex4ub = (unsigned char *)data;data += meshvertices * sizeof(unsigned char[4]);
-       loadmodel->surfmesh.data_skeletalweight4ub = (unsigned char *)data;data += meshvertices * sizeof(unsigned char[4]);
-       loadmodel->data_baseboneposeinverse = (float *)data;data += loadmodel->num_bones * sizeof(float[12]);
-       loadmodel->skinscenes = (animscene_t *)data;data += loadmodel->numskins * sizeof(animscene_t);
-       loadmodel->data_bones = (aliasbone_t *)data;data += loadmodel->num_bones * sizeof(aliasbone_t);
-       loadmodel->animscenes = (animscene_t *)data;data += loadmodel->numframes * sizeof(animscene_t);
        loadmodel->surfmesh.num_blends = 0;
-       loadmodel->surfmesh.blends = (unsigned short *)data;data += meshvertices * sizeof(unsigned short);
+
+       // do most allocations as one merged chunk
+       // This is only robust for C standard types!
+       data = (unsigned char *)Mem_Alloc(loadmodel->mempool,
+               loadmodel->num_surfaces * sizeof(int)
+               + meshtriangles * sizeof(int[3])
+               + (meshvertices <= 65536 ? meshtriangles * sizeof(unsigned short[3]) : 0)
+               + meshvertices * (sizeof(float[14]) + sizeof(unsigned short) + sizeof(unsigned char[2][4]))
+               + loadmodel->num_poses * loadmodel->num_bones * sizeof(short[7])
+               + loadmodel->num_bones * sizeof(float[12]));
+       // Pointers must be taken in descending order of alignment requirement!
+       loadmodel->surfmesh.data_vertex3f                  = (float *)data; data += meshvertices * sizeof(float[3]);
+       loadmodel->surfmesh.data_svector3f                 = (float *)data; data += meshvertices * sizeof(float[3]);
+       loadmodel->surfmesh.data_tvector3f                 = (float *)data; data += meshvertices * sizeof(float[3]);
+       loadmodel->surfmesh.data_normal3f                  = (float *)data; data += meshvertices * sizeof(float[3]);
+       loadmodel->surfmesh.data_texcoordtexture2f         = (float *)data; data += meshvertices * sizeof(float[2]);
+       loadmodel->data_baseboneposeinverse                = (float *)data; data += loadmodel->num_bones * sizeof(float[12]);
+       loadmodel->modelsurfaces_sorted                      = (int *)data; data += loadmodel->num_surfaces * sizeof(int);
+       loadmodel->surfmesh.data_element3i                   = (int *)data; data += meshtriangles * sizeof(int[3]);
+       loadmodel->surfmesh.blends                = (unsigned short *)data; data += meshvertices * sizeof(unsigned short);
        if (meshvertices <= 65536)
        {
-               loadmodel->surfmesh.data_element3s = (unsigned short *)data;data += meshtriangles * sizeof(unsigned short[3]);
+               loadmodel->surfmesh.data_element3s = (unsigned short *)data; data += meshtriangles * sizeof(unsigned short[3]);
        }
-       loadmodel->data_poses7s = (short *)data;data += loadmodel->num_poses * loadmodel->num_bones * sizeof(short[7]);
-       loadmodel->surfmesh.data_blendweights = (blendweights_t *)Mem_Alloc(loadmodel->mempool, meshvertices * sizeof(blendweights_t));
+       loadmodel->data_poses7s                            = (short *)data; data += loadmodel->num_poses * loadmodel->num_bones * sizeof(short[7]);
+       loadmodel->surfmesh.data_skeletalindex4ub  = (unsigned char *)data; data += meshvertices * sizeof(unsigned char[4]);
+       loadmodel->surfmesh.data_skeletalweight4ub = (unsigned char *)data; data += meshvertices * sizeof(unsigned char[4]);
+       // Struct alignment requirements could change so we can't assume them here
+       // otherwise a safe-looking commit could introduce undefined behaviour!
+       loadmodel->data_surfaces = Mem_AllocType(loadmodel->mempool, msurface_t, loadmodel->num_surfaces * sizeof(msurface_t));
+       loadmodel->data_textures = Mem_AllocType(loadmodel->mempool, texture_t, loadmodel->num_surfaces * loadmodel->numskins * sizeof(texture_t));
+       loadmodel->skinscenes = Mem_AllocType(loadmodel->mempool, animscene_t, loadmodel->numskins * sizeof(animscene_t));
+       loadmodel->data_bones = Mem_AllocType(loadmodel->mempool, aliasbone_t, loadmodel->num_bones * sizeof(aliasbone_t));
+       loadmodel->animscenes = Mem_AllocType(loadmodel->mempool, animscene_t, loadmodel->numframes * sizeof(animscene_t));
+       loadmodel->surfmesh.data_blendweights = Mem_AllocType(loadmodel->mempool, blendweights_t, meshvertices * sizeof(blendweights_t));
 
        for (i = 0;i < loadmodel->numskins;i++)
        {
@@ -2488,7 +2499,7 @@ void Mod_DARKPLACESMODEL_Load(model_t *mod, void *buffer, void *bufferend)
                Mod_ValidateElements(loadmodel->surfmesh.data_element3i + surface->num_firsttriangle * 3, loadmodel->surfmesh.data_element3s + surface->num_firsttriangle * 3, surface->num_triangles, surface->num_firstvertex, surface->num_vertices, __FILE__, __LINE__);
        }
        if (loadmodel->surfmesh.num_blends < meshvertices)
-               loadmodel->surfmesh.data_blendweights = (blendweights_t *)Mem_Realloc(loadmodel->mempool, loadmodel->surfmesh.data_blendweights, loadmodel->surfmesh.num_blends * sizeof(blendweights_t));
+               loadmodel->surfmesh.data_blendweights = Mem_ReallocType(loadmodel->mempool, loadmodel->surfmesh.data_blendweights, blendweights_t, loadmodel->surfmesh.num_blends * sizeof(blendweights_t));
        Z_Free(bonepose);
        Mod_FreeSkinFiles(skinfiles);
        Mod_MakeSortedSurfaces(loadmodel);