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pointer lifetime in WriteNewVolumeLabelToDev() Previously, in WriteNewVolumeLabelToDev() a copy of the pointer dcr->block was saved and then used as a parameter to EmptyBlock(). This pointer's lifetime ends in dev->SetLabelBlockSize() when the previously written device's block size was larger than the label block size. This patch removes the copy and uses dcr->block directly, so the updated pointer is used.
When running in valgrind the ioctl() call that consumes struct mtop is flagged as accessing uninitialized memory. This patch initializes every struct mtop.
franku
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When a device in the SD is configured with custom Maximum Block Size, autolabeling may cause a memory corruption. When writing to a volume with a larger blocksize than the label blocksize and then autolabels a new volume,
WriteNewVolumeLabel()would callEmptyBlock()with an invalid pointer leading to heap corruption.While pinpointing this problem, valgrind also flagged the use of uninitialized
struct mtopin generic_tape_device. While this was probably not a real issue, the struct mtop is now always initialized, so valgrind does not complain anymore.