From cb87ea28ed9e75a41eb456bfcb547b4e6f10e750 Mon Sep 17 00:00:00 2001 From: John Calixto Date: Tue, 26 Apr 2011 18:56:29 -0400 Subject: mmc: core: Add mmc CMD+ACMD passthrough ioctl Allows appropriately-privileged applications to send CMD (normal) and ACMD (application-specific; preceded with CMD55) commands to cards/devices on the mmc bus. This is primarily useful for enabling the security functionality built in to every SD card. It can also be used as a generic passthrough (e.g. to enable virtual machines to control mmc bus devices directly). However, this use case has not been tested rigorously. Generic passthrough testing was only conducted for a few non-security opcodes to prove the feasibility of the passthrough. Since any opcode can be sent using this passthrough, it is very possible to render the card/device unusable. Applications that use this ioctl must have CAP_SYS_RAWIO. Security commands tested on TI PCIxx12 (SDHCI), Sigma Designs SMP8652 SoC, TI OMAP3621/OMAP3630 SoC, Samsung S5PC110 SoC, Qualcomm MSM7200A SoC. Signed-off-by: John Calixto Reviewed-by: Andrei Warkentin Reviewed-by: Arnd Bergmann Signed-off-by: Chris Ball --- drivers/mmc/card/block.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 201 insertions(+) (limited to 'drivers/mmc/card/block.c') diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index e7efd6faeaf9..407836d55712 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -31,7 +31,11 @@ #include #include #include +#include +#include +#include +#include #include #include #include @@ -218,11 +222,208 @@ mmc_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) return 0; } +struct mmc_blk_ioc_data { + struct mmc_ioc_cmd ic; + unsigned char *buf; + u64 buf_bytes; +}; + +static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user( + struct mmc_ioc_cmd __user *user) +{ + struct mmc_blk_ioc_data *idata; + int err; + + idata = kzalloc(sizeof(*idata), GFP_KERNEL); + if (!idata) { + err = -ENOMEM; + goto copy_err; + } + + if (copy_from_user(&idata->ic, user, sizeof(idata->ic))) { + err = -EFAULT; + goto copy_err; + } + + idata->buf_bytes = (u64) idata->ic.blksz * idata->ic.blocks; + if (idata->buf_bytes > MMC_IOC_MAX_BYTES) { + err = -EOVERFLOW; + goto copy_err; + } + + idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL); + if (!idata->buf) { + err = -ENOMEM; + goto copy_err; + } + + if (copy_from_user(idata->buf, (void __user *)(unsigned long) + idata->ic.data_ptr, idata->buf_bytes)) { + err = -EFAULT; + goto copy_err; + } + + return idata; + +copy_err: + kfree(idata->buf); + kfree(idata); + return ERR_PTR(err); + +} + +static int mmc_blk_ioctl_cmd(struct block_device *bdev, + struct mmc_ioc_cmd __user *ic_ptr) +{ + struct mmc_blk_ioc_data *idata; + struct mmc_blk_data *md; + struct mmc_card *card; + struct mmc_command cmd = {0}; + struct mmc_data data = {0}; + struct mmc_request mrq = {0}; + struct scatterlist sg; + int err; + + /* + * The caller must have CAP_SYS_RAWIO, and must be calling this on the + * whole block device, not on a partition. This prevents overspray + * between sibling partitions. + */ + if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains)) + return -EPERM; + + idata = mmc_blk_ioctl_copy_from_user(ic_ptr); + if (IS_ERR(idata)) + return PTR_ERR(idata); + + cmd.opcode = idata->ic.opcode; + cmd.arg = idata->ic.arg; + cmd.flags = idata->ic.flags; + + data.sg = &sg; + data.sg_len = 1; + data.blksz = idata->ic.blksz; + data.blocks = idata->ic.blocks; + + sg_init_one(data.sg, idata->buf, idata->buf_bytes); + + if (idata->ic.write_flag) + data.flags = MMC_DATA_WRITE; + else + data.flags = MMC_DATA_READ; + + mrq.cmd = &cmd; + mrq.data = &data; + + md = mmc_blk_get(bdev->bd_disk); + if (!md) { + err = -EINVAL; + goto cmd_done; + } + + card = md->queue.card; + if (IS_ERR(card)) { + err = PTR_ERR(card); + goto cmd_done; + } + + mmc_claim_host(card->host); + + if (idata->ic.is_acmd) { + err = mmc_app_cmd(card->host, card); + if (err) + goto cmd_rel_host; + } + + /* data.flags must already be set before doing this. */ + mmc_set_data_timeout(&data, card); + /* Allow overriding the timeout_ns for empirical tuning. */ + if (idata->ic.data_timeout_ns) + data.timeout_ns = idata->ic.data_timeout_ns; + + if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) { + /* + * Pretend this is a data transfer and rely on the host driver + * to compute timeout. When all host drivers support + * cmd.cmd_timeout for R1B, this can be changed to: + * + * mrq.data = NULL; + * cmd.cmd_timeout = idata->ic.cmd_timeout_ms; + */ + data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000; + } + + mmc_wait_for_req(card->host, &mrq); + + if (cmd.error) { + dev_err(mmc_dev(card->host), "%s: cmd error %d\n", + __func__, cmd.error); + err = cmd.error; + goto cmd_rel_host; + } + if (data.error) { + dev_err(mmc_dev(card->host), "%s: data error %d\n", + __func__, data.error); + err = data.error; + goto cmd_rel_host; + } + + /* + * According to the SD specs, some commands require a delay after + * issuing the command. + */ + if (idata->ic.postsleep_min_us) + usleep_range(idata->ic.postsleep_min_us, idata->ic.postsleep_max_us); + + if (copy_to_user(&(ic_ptr->response), cmd.resp, sizeof(cmd.resp))) { + err = -EFAULT; + goto cmd_rel_host; + } + + if (!idata->ic.write_flag) { + if (copy_to_user((void __user *)(unsigned long) idata->ic.data_ptr, + idata->buf, idata->buf_bytes)) { + err = -EFAULT; + goto cmd_rel_host; + } + } + +cmd_rel_host: + mmc_release_host(card->host); + +cmd_done: + mmc_blk_put(md); + kfree(idata->buf); + kfree(idata); + return err; +} + +static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + int ret = -EINVAL; + if (cmd == MMC_IOC_CMD) + ret = mmc_blk_ioctl_cmd(bdev, (struct mmc_ioc_cmd __user *)arg); + return ret; +} + +#ifdef CONFIG_COMPAT +static int mmc_blk_compat_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + return mmc_blk_ioctl(bdev, mode, cmd, (unsigned long) compat_ptr(arg)); +} +#endif + static const struct block_device_operations mmc_bdops = { .open = mmc_blk_open, .release = mmc_blk_release, .getgeo = mmc_blk_getgeo, .owner = THIS_MODULE, + .ioctl = mmc_blk_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = mmc_blk_compat_ioctl, +#endif }; struct mmc_blk_request { -- cgit v1.2.3