Changeset 73703 in vbox

Timestamp:

Aug 16, 2018 9:27:22 AM (6 years ago)

Author:

vboxsync

Message:

IPRT/r3/memsafer: Switched to individual scrambling words for each allocation.

File:

• trunk/src/VBox/Runtime/r3/memsafer-r3.cpp (modified) (7 diffs)

trunk/src/VBox/Runtime/r3/memsafer-r3.cpp

@@ -87 +87 @@
     /** The allocator used for this node. */
     RTMEMSAFERALLOCATOR     enmAllocator;
+    /** XOR scrambler value for memory. */
+    uintptr_t               uScramblerXor;
 } RTMEMSAFERNODE;
 /** Pointer to an allocation tracking node. */
@@ -101 +103 @@
 /** Tree of allocation nodes. */
 static AVLPVTREE    g_pMemSaferTree;
-/** XOR scrambler value for memory. */
-static uintptr_t    g_uMemSaferScramblerXor;
 /** XOR scrambler value pointers. */
 static uintptr_t    g_uMemSaferPtrScramblerXor;
@@ -116 +116 @@
     RT_NOREF_PV(pvUserIgnore);
 
-    g_uMemSaferScramblerXor = (uintptr_t)RTRandU64();
     g_uMemSaferPtrScramblerXor = (uintptr_t)RTRandU64();
     g_cMemSaferPtrScramblerRotate = RTRandU32Ex(0, ARCH_BITS - 1);
@@ -203 +202 @@
 RTDECL(int) RTMemSaferScramble(void *pv, size_t cb)
 {
-#ifdef RT_STRICT
     PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pv);
     AssertReturn(pThis, VERR_INVALID_POINTER);
     AssertMsgReturn(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser), VERR_INVALID_PARAMETER);
-#endif
+
+    /* First time we get a new xor value. */
+    if (!pThis->uScramblerXor)
+        pThis->uScramblerXor = (uintptr_t)RTRandU64();
 
     /* Note! This isn't supposed to be safe, just less obvious. */
@@ -214 +215 @@
     while (cb > 0)
     {
-        *pu ^= g_uMemSaferScramblerXor;
+        *pu ^= pThis->uScramblerXor;
         pu++;
         cb -= sizeof(*pu);
@@ -226 +227 @@
 RTDECL(int) RTMemSaferUnscramble(void *pv, size_t cb)
 {
-#ifdef RT_STRICT
     PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pv);
     AssertReturn(pThis, VERR_INVALID_POINTER);
     AssertMsgReturn(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser), VERR_INVALID_PARAMETER);
-#endif
 
     /* Note! This isn't supposed to be safe, just less obvious. */
@@ -237 +236 @@
     while (cb > 0)
     {
-        *pu ^= g_uMemSaferScramblerXor;
+        *pu ^= pThis->uScramblerXor;
         pu++;
         cb -= sizeof(*pu);