X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/80e2389990082500d76eb566d4946be3e786c3ef..d8f41ccd20de16f8ebe2ccc84d47bf1cb2b26bbb:/Security/libsecurity_filedb/lib/OverUnderflowCheck.h

diff --git a/Security/libsecurity_filedb/lib/OverUnderflowCheck.h b/Security/libsecurity_filedb/lib/OverUnderflowCheck.h
new file mode 100644
index 00000000..7224ac77
--- /dev/null
+++ b/Security/libsecurity_filedb/lib/OverUnderflowCheck.h
@@ -0,0 +1,85 @@
+#ifndef __OVERUNDERFLOWCHECK__
+#define __OVERUNDERFLOWCHECK__
+
+inline uint32 CheckUInt32Add(uint32 a, uint32 b)
+{
+	uint32 c = a + b;
+	if (c < a)	
+	{
+		CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+	}
+	
+	return c;
+}
+
+
+
+inline uint32 CheckUInt32Subtract(uint32 a, uint32 b)
+{
+	if (a < b)
+	{
+		CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+	}
+
+	return a - b;
+}
+
+
+
+inline uint32 CheckUInt32Multiply(uint32 a, uint32 b)
+{
+	uint32 c = a * b;
+	uint64 cc = ((uint64) a) * ((uint64) b);
+	if (c != cc)
+	{
+		CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+	}
+	
+	return c;
+}
+
+
+
+inline uint64 Check64BitAdd(uint64 a, uint64 b)
+{
+	uint64 c = a + b;
+	if (c < a)
+	{
+		CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+	}
+	
+	return c;
+}
+
+
+
+inline uint64 Check64BitSubtract(uint64 a, uint64 b)
+{
+	if (a < b)
+	{
+		CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+	}
+
+	return a - b;
+}
+
+
+	
+inline uint64 Check64BitMultiply(uint64 a, uint64 b)
+{
+	if (a != 0)
+	{
+		uint64 max = (uint64) -1;
+		uint64 limit = max / a;
+		if (b > limit)
+		{
+			CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+		}
+	}
+	
+	return a * b;
+}
+
+
+
+#endif