I'm working on secure deletion of data on various media. I recalled that the MMC and SD card specs contain a low-level command for erasing blocks, which could be used to erase a whole card if desired. And later MMC specs provide a secure block erase command that also erases ancillary unaddressable garbage blocks, etc. However, after a perusal of the relevant kernel code (as of the 2.6.35 shipped by Ubuntu), I see no support for invoking these commands from a user program. I saw some patches on the LKML from Adrian Hunter in June 2010 that added support for ioctl(BLKSECDISCARD). Are these in an upcoming mainline kernel? Has someone provided a clean userspace way to invoke it on an entire SD card or MMC card? (On ATA disks, access to the SECURITY ERASE command is via the hdparm user program, which invokes the SG_IO (SCSI Generic) driver. But SECURITY ERASE has odd edges, e.g. it requires that you set and then supply a password. It would be a shame if higher level programs, e.g. the Linux installer, had to run different "secure erase" commands depending on what medium is being erased.) John Gilmore PS: Does anyone know a way to do secure erase via a USB Mass Storage adapter? -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
