[PATCH v2 1/1] rpcrt4: Pointer arithmetic fixes (-Wtautological-compare).

[William Horvath]

From: William Horvath

---
 dlls/rpcrt4/ndr_marshall.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/dlls/rpcrt4/ndr_marshall.c b/dlls/rpcrt4/ndr_marshall.c
index c68eb0ee57e..f0249cba953 100644
--- a/dlls/rpcrt4/ndr_marshall.c
+++ b/dlls/rpcrt4/ndr_marshall.c
@@ -711,9 +711,8 @@ static inline ULONG safe_multiply(ULONG a, ULONG b)

static inline void safe_buffer_increment(MIDL_STUB_MESSAGE *pStubMsg, ULONG size)
 {
-    if ((pStubMsg->Buffer + size < pStubMsg->Buffer) || /* integer overflow of pStubMsg->Buffer */
-        (pStubMsg->Buffer + size > (unsigned char *)pStubMsg->RpcMsg->Buffer + pStubMsg->BufferLength))
-        RpcRaiseException(RPC_X_BAD_STUB_DATA);
+    if (size > (SIZE_T)(((unsigned char *)pStubMsg->RpcMsg->Buffer + pStubMsg->BufferLength) - pStubMsg->Buffer))
+        RpcRaiseException(RPC_X_BAD_STUB_DATA); /* integer overflow of pStubMsg->BufferSize */
     pStubMsg->Buffer += size;
 }

@@ -732,8 +731,7 @@ static inline void safe_buffer_length_increment(MIDL_STUB_MESSAGE *pStubMsg, ULO
  * to do so */
 static inline void safe_copy_from_buffer(MIDL_STUB_MESSAGE *pStubMsg, void *p, ULONG size)
 {
-    if ((pStubMsg->Buffer + size < pStubMsg->Buffer) || /* integer overflow of pStubMsg->Buffer */
-        (pStubMsg->Buffer + size > pStubMsg->BufferEnd))
+    if (size > (SIZE_T)(pStubMsg->BufferEnd - pStubMsg->Buffer)) /* integer overflow of pStubMsg->Buffer */
     {
         ERR("buffer overflow - Buffer = %p, BufferEnd = %p, size = %lu\n",
             pStubMsg->Buffer, pStubMsg->BufferEnd, size);
@@ -748,8 +746,7 @@ static inline void safe_copy_from_buffer(MIDL_STUB_MESSAGE *pStubMsg, void *p, U
 /* copies data to the buffer, checking that there is enough space to do so */
 static inline void safe_copy_to_buffer(MIDL_STUB_MESSAGE *pStubMsg, const void *p, ULONG size)
 {
-    if ((pStubMsg->Buffer + size < pStubMsg->Buffer) || /* integer overflow of pStubMsg->Buffer */
-        (pStubMsg->Buffer + size > (unsigned char *)pStubMsg->RpcMsg->Buffer + pStubMsg->BufferLength))
+    if (size > (SIZE_T)(((unsigned char *)pStubMsg->RpcMsg->Buffer + pStubMsg->BufferLength) - pStubMsg->Buffer)) /* integer overflow of pStubMsg->Buffer */
     {
         ERR("buffer overflow - Buffer = %p, BufferEnd = %p, size = %lu\n",
             pStubMsg->Buffer, (unsigned char *)pStubMsg->RpcMsg->Buffer + pStubMsg->BufferLength,
@@ -767,8 +764,7 @@ static void validate_string_data(MIDL_STUB_MESSAGE *pStubMsg, ULONG bufsize, ULO
     ULONG i;

/* verify the buffer is safe to access */
-    if ((pStubMsg->Buffer + bufsize < pStubMsg->Buffer) ||
-        (pStubMsg->Buffer + bufsize > pStubMsg->BufferEnd))
+    if (bufsize > (SIZE_T)(pStubMsg->BufferEnd - pStubMsg->Buffer))
     {
         ERR("bufsize 0x%lx exceeded buffer end %p of buffer %p\n", bufsize,
             pStubMsg->BufferEnd, pStubMsg->Buffer);