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 <john.calixto@modsystems.com>
Reviewed-by: Andrei Warkentin <andreiw@motorola.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index e7efd6f..407836d 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -31,7 +31,11 @@
#include <linux/mutex.h>
#include <linux/scatterlist.h>
#include <linux/string_helpers.h>
+#include <linux/delay.h>
+#include <linux/capability.h>
+#include <linux/compat.h>
+#include <linux/mmc/ioctl.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
@@ -218,11 +222,208 @@
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 {