Книга: Microsoft Windows Embedded CE 6.0 Exam Preparation Kit

Lesson Summary

Lesson Summary

Windows Embedded CE 6.0 facilitates inter-process communication between applications and device drivers through kernel features and marshaling helper functions that hide most of the complexities from driver developers. For parameter pointers, the kernel performs all checks and pointer marshaling automatically. Only embedded pointers require extra care because the kernel cannot evaluate the content of application buffers passed to a driver. Validating and marshaling an embedded pointer in a synchronous access scenario involves a straightforward call to CeOpenCallerBuffer. Asynchronous access scenarios, however, require an additional call to CeAllocAsynchronousBuffer to marshal the pointer one more time. To ensure that your driver does not introduce system vulnerabilities, make sure you handle buffers correctly, create a secure copy of the buffer content so that callers cannot manipulate the values, and do not use pointers or buffer size values in the caller's buffer after they have been marshaled. Never store marshaled pointers or other variables required for driver processing in the caller's buffer.

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