lsteamclient: Get memory for SteamClient interface within native steamclient.dll loader range.

CW-Bug-ID: #19605

For Mafia II.

lsteamclient/steamclient_main.c

@@ -9,6 +9,7 @@
 #include "winbase.h"
 #include "winnls.h"
 #include "winuser.h"
+#include "winternl.h"
 #include "wine/debug.h"
 #include "wine/list.h"
 #include "steam_defs.h"
@@ -232,6 +233,144 @@ void steamclient_free_stringlist(const char **out)
     }
 }
 
+static BYTE *alloc_start, *alloc_end;
+
+static BOOL allocated_from_steamclient_dll( void *ptr )
+{
+    return (BYTE *)ptr >= alloc_start && (BYTE *)ptr < alloc_end;
+}
+
+static void *get_mem_from_steamclient_dll(size_t size, unsigned int version)
+{
+    static BYTE * const error_ptr = (BYTE *)~(ULONG_PTR)0;
+    static const unsigned int magic = 0x53ba947a;
+    static struct
+    {
+        unsigned int version;
+        size_t size;
+        void *ptr;
+    }
+    allocated[32];
+    static unsigned int allocated_count;
+    static BYTE *alloc_base;
+    unsigned int i;
+
+    if (alloc_base == error_ptr)
+    {
+        /* Previously failed to locate the section. */
+        return NULL;
+    }
+
+    if (alloc_base && (IsBadReadPtr(alloc_start, sizeof(magic)) || *(unsigned int *)alloc_start != magic))
+    {
+        TRACE("steamclient.dll reloaded.\n");
+        alloc_base = alloc_start = alloc_end = NULL;
+        allocated_count = 0;
+    }
+
+    for (i = 0; i < allocated_count; ++i)
+    {
+        if (allocated[i].version == version)
+        {
+            if (allocated[i].size != size)
+            {
+                FIXME("Size does not match.\n");
+                return NULL;
+            }
+            return allocated[i].ptr;
+        }
+    }
+
+    if (allocated_count == ARRAY_SIZE(allocated))
+    {
+        FIXME("Too many interface versions.\n");
+        return NULL;
+    }
+
+    if (!alloc_base)
+    {
+        const IMAGE_SECTION_HEADER *sec;
+        const IMAGE_NT_HEADERS *nt;
+        HMODULE mod;
+
+        if (!(mod = GetModuleHandleW(L"steamclient.dll")))
+        {
+            /* That is steamclient64.dll for x64 but no known use cases on x64.*/
+            WARN("Module not found, err %u.\n", GetLastError());
+            alloc_base = error_ptr;
+            return NULL;
+        }
+        if (!(nt = RtlImageNtHeader(mod)))
+        {
+            FIXME("Got NULL NT image headers.\n");
+            alloc_base = error_ptr;
+            return NULL;
+        }
+        sec = (const IMAGE_SECTION_HEADER *)((const BYTE *)&nt->OptionalHeader + nt->FileHeader.SizeOfOptionalHeader);
+        for (i = 0; i < nt->FileHeader.NumberOfSections; i++)
+        {
+            if (!memcmp(sec[i].Name, ".data", 5))
+            {
+                alloc_start = alloc_base = (BYTE *)mod + sec[i].VirtualAddress;
+                alloc_end = alloc_base + sec[i].SizeOfRawData;
+                if (alloc_end - alloc_start < sizeof(magic))
+                {
+                    ERR(".data section is too small.\n");
+                    alloc_base = error_ptr;
+                    return NULL;
+                }
+                TRACE("Found .data section, start %p, end %p.\n", alloc_base, alloc_end);
+                *(unsigned int *)alloc_base = magic;
+                alloc_base += sizeof(unsigned int);
+                break;
+            }
+        }
+        if (i == nt->FileHeader.NumberOfSections)
+        {
+            FIXME(".data section not found.\n");
+            alloc_base = error_ptr;
+            return NULL;
+        }
+    }
+
+    if (alloc_end - alloc_base < size)
+    {
+        FIXME("Not enough section size left.\n");
+        return NULL;
+    }
+    allocated[allocated_count].version = version;
+    allocated[allocated_count].size = size;
+    allocated[allocated_count].ptr = alloc_base;
+    alloc_base += size;
+
+    return allocated[allocated_count++].ptr;
+}
+
+void *alloc_mem_for_iface(size_t size, const char *iface_version)
+{
+    const char steamclient_iface_name[] = "SteamClient";
+    unsigned int version;
+    void *ret;
+
+    /* Mafia II depends on SteamClient interface pointer to point inside
+     * native Windows steamclient.dll. */
+    if (strncmp(iface_version, steamclient_iface_name, ARRAY_SIZE(steamclient_iface_name) - 1))
+         goto fallback;
+
+    version = atoi(iface_version + ARRAY_SIZE(steamclient_iface_name) - 1);
+    if (!version)
+    {
+        FIXME("Could not get iface version from %s.\n", iface_version);
+        goto fallback;
+    }
+
+    if ((ret = get_mem_from_steamclient_dll(size, version)))
+        return ret;
+
+fallback:
+    return HeapAlloc(GetProcessHeap(), 0, size);
+}
+
 #ifdef __linux__
 static const uint32 vk_to_xkeysym[0xFF] = {
     0, /* 0x0  Undefined */
@@ -417,13 +556,16 @@ void *create_win_interface(const char *name, void *linux_side)
     {
         if (!strcmp(name, constructors[i].iface_version))
         {
+            ret = constructors[i].ctor(linux_side);
+            if (allocated_from_steamclient_dll(ret))
+                break;
+
             e = HeapAlloc(GetProcessHeap(), 0, sizeof(*e));
             e->name = constructors[i].iface_version;
             e->linux_side = linux_side;
-            e->interface = constructors[i].ctor(linux_side);
+            e->interface = ret;
             list_add_tail(&steamclient_interfaces, &e->entry);
 
-            ret = e->interface;
             break;
         }
     }