Windows 7 SD Card Corruption Flaw Patched
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4:21 PM - November 25, 2009 by Marcus Yam
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Live well now with your SD cards, NTFS and ADMA.
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Are you running Windows 7 and are you a user of SD cards formatted using NTFS? Furthermore, do you use Advanced Direct Memory Access (ADMA) to transfer data between the SD card and your computer? You may find that when you transfer data from the computer to the SD card, the data on the SD card may be corrupted.
Thankfully, Microsoft has come up with a fix for this flaw, which it released today. You can download this update from the Microsoft Windows Update Web site or from the Windows Download Center, but if you prefer to do things manually, click here for the patch itself.
Here's more info if you wish to know what caused the problem
During an ADMA transfer process, the Secure Digital Bus Driver (Sdbus.sys) converts the DMA data structure of the operating system to the ADMA data structure of the SD card. The DMA and the ADMA data structures are also known as the descriptor tables. The descriptor table contains a data length value and a buffer address. The data-length field is 16-bit, and has a maximum size of 64K (kilobytes). However, during the data conversion process, the Sdbus.sys driver does not check the buffer size in the descriptor table of the system. Therefore, the Sdbus.sys driver may set an incorrect data length in the SD descriptor table. For example, the Sdbus.sys driver may set the data length larger than 0xFFFF. Also, corrupted I/O occurs. This causes data corruption.
