misc: add system version hook

hooklib/reg.c

@@ -43,6 +43,11 @@ static LSTATUS reg_hook_query_val_locked(
         void *bytes,
         uint32_t *nbytes);
 
+static LSTATUS reg_hook_open_locked_a(
+        HKEY parent,
+        const char *name,
+        HKEY *out);
+
 /* API hooks */
 
 static LSTATUS WINAPI hook_RegOpenKeyExW(
@@ -52,6 +57,13 @@ static LSTATUS WINAPI hook_RegOpenKeyExW(
         uint32_t access,
         HKEY *out);
 
+static LSTATUS WINAPI hook_RegOpenKeyExA(
+        HKEY parent,
+        const char *name,
+        uint32_t flags,
+        uint32_t access,
+        HKEY *out);
+
 static LSTATUS WINAPI hook_RegCreateKeyExW(
         HKEY parent,
         const wchar_t *name,
@@ -108,6 +120,13 @@ static LSTATUS (WINAPI *next_RegOpenKeyExW)(
         uint32_t access,
         HKEY *out);
 
+static LSTATUS (WINAPI *next_RegOpenKeyExA)(
+        HKEY parent,
+        const char *name,
+        uint32_t flags,
+        uint32_t access,
+        HKEY *out);
+
 static LSTATUS (WINAPI *next_RegCreateKeyExW)(
         HKEY parent,
         const wchar_t *name,
@@ -160,6 +179,10 @@ static const struct hook_symbol reg_hook_syms[] = {
         .name   = "RegOpenKeyExW",
         .patch  = hook_RegOpenKeyExW,
         .link   = (void **) &next_RegOpenKeyExW,
+    },{
+        .name   = "RegOpenKeyExA",
+        .patch  = hook_RegOpenKeyExA,
+        .link   = (void **) &next_RegOpenKeyExA,
     }, {
         .name   = "RegCreateKeyExW",
         .patch  = hook_RegCreateKeyExW,
@@ -369,6 +392,70 @@ static LSTATUS reg_hook_open_locked(
     return err;
 }
 
+static LSTATUS reg_hook_open_locked_a(
+        HKEY parent,
+        const char *name,
+        HKEY *out)
+{
+    struct reg_hook_key *key;
+    LSTATUS err;
+    size_t i;
+    wchar_t *name_w;
+    size_t name_c;
+
+    *out = NULL;
+
+    mbstowcs_s(&name_c, NULL, 0, name, 0);
+    name_w = malloc(name_c * sizeof(wchar_t));
+
+    if (name_w == NULL) {
+        return ERROR_OUTOFMEMORY;
+    }
+
+    mbstowcs_s(NULL, name_w, name_c, name, name_c - 1);
+
+    for (i = 0 ; i < reg_hook_nkeys ; i++) {
+        /* Assume reg keys are referenced from a root key and not from some
+           intermediary key */
+        key = &reg_hook_keys[i];
+
+        if (key->root == parent && wstr_ieq(key->name, name_w)) {
+            break;
+        }
+    }
+
+    /* (Bail out if we didn't find anything; this causes the open/create call
+       to be passed onward down the hook chain) */
+
+    if (i >= reg_hook_nkeys) {
+        return ERROR_SUCCESS;
+    }
+
+    /* Assume only one handle will be open at a time */
+
+    if (key->handle != NULL) {
+        return ERROR_SHARING_VIOLATION;
+    }
+
+    /* Open a unique HKEY handle that we can use to identify accesses to
+       this virtual registry key. We open a read-only handle to an arbitrary
+       registry key that we can reliably assume exists and isn't one of the
+       hardcoded root handles. HKLM\SOFTWARE will suffice for this purpose. */
+
+    err = next_RegOpenKeyExA(
+            HKEY_LOCAL_MACHINE,
+            "SOFTWARE",
+            0,
+            KEY_READ,
+            out);
+
+    if (err == ERROR_SUCCESS) {
+        key->handle = *out;
+    }
+
+    return err;
+}
+
 static LSTATUS WINAPI hook_RegOpenKeyExW(
         HKEY parent,
         const wchar_t *name,
@@ -397,6 +484,34 @@ static LSTATUS WINAPI hook_RegOpenKeyExW(
     return err;
 }
 
+static LSTATUS WINAPI hook_RegOpenKeyExA(
+        HKEY parent,
+        const char *name,
+        uint32_t flags,
+        uint32_t access,
+        HKEY *out)
+{
+    LSTATUS err;
+
+    if (out == NULL) {
+        return ERROR_INVALID_PARAMETER;
+    }
+    
+    EnterCriticalSection(&reg_hook_lock);
+    err = reg_hook_open_locked_a(parent, name, out);
+    LeaveCriticalSection(&reg_hook_lock);
+    
+
+    if (err == ERROR_SUCCESS) {
+        if (*out != NULL) {
+            //dprintf("Registry: Opened virtual key %s\n", name);
+        } else {
+            err = next_RegOpenKeyExA(parent, name, flags, access, out);
+        }
+    }
+
+    return err;
+}
 static LSTATUS WINAPI hook_RegCreateKeyExW(
         HKEY parent,
         const wchar_t *name,