Commit cb87ea28 authored by John Calixto's avatar John Calixto Committed by Chris Ball

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: default avatarJohn Calixto <john.calixto@modsystems.com>
Reviewed-by: default avatarAndrei Warkentin <andreiw@motorola.com>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 641c3187
......@@ -304,6 +304,7 @@ Code Seq#(hex) Include File Comments
0xB0 all RATIO devices in development:
<mailto:vgo@ratio.de>
0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca>
0xB3 00 linux/mmc/ioctl.h
0xC0 00-0F linux/usb/iowarrior.h
0xCB 00-1F CBM serial IEC bus in development:
<mailto:michael.klein@puffin.lb.shuttle.de>
......
......@@ -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 @@ 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 {
......
......@@ -21,7 +21,7 @@
#include "core.h"
#include "sd_ops.h"
static int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
{
int err;
struct mmc_command cmd = {0};
......@@ -49,6 +49,7 @@ static int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
return 0;
}
EXPORT_SYMBOL_GPL(mmc_app_cmd);
/**
* mmc_wait_for_app_cmd - start an application command and wait for
......
......@@ -4,6 +4,7 @@ header-y += caif/
header-y += dvb/
header-y += hdlc/
header-y += isdn/
header-y += mmc/
header-y += nfsd/
header-y += raid/
header-y += spi/
......
header-y += ioctl.h
......@@ -133,6 +133,7 @@ struct mmc_card;
extern void mmc_wait_for_req(struct mmc_host *, struct mmc_request *);
extern int mmc_wait_for_cmd(struct mmc_host *, struct mmc_command *, int);
extern int mmc_app_cmd(struct mmc_host *, struct mmc_card *);
extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
struct mmc_command *, int);
extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
......
#ifndef LINUX_MMC_IOCTL_H
#define LINUX_MMC_IOCTL_H
struct mmc_ioc_cmd {
/* Implies direction of data. true = write, false = read */
int write_flag;
/* Application-specific command. true = precede with CMD55 */
int is_acmd;
__u32 opcode;
__u32 arg;
__u32 response[4]; /* CMD response */
unsigned int flags;
unsigned int blksz;
unsigned int blocks;
/*
* Sleep at least postsleep_min_us useconds, and at most
* postsleep_max_us useconds *after* issuing command. Needed for
* some read commands for which cards have no other way of indicating
* they're ready for the next command (i.e. there is no equivalent of
* a "busy" indicator for read operations).
*/
unsigned int postsleep_min_us;
unsigned int postsleep_max_us;
/*
* Override driver-computed timeouts. Note the difference in units!
*/
unsigned int data_timeout_ns;
unsigned int cmd_timeout_ms;
/*
* For 64-bit machines, the next member, ``__u64 data_ptr``, wants to
* be 8-byte aligned. Make sure this struct is the same size when
* built for 32-bit.
*/
__u32 __pad;
/* DAT buffer */
__u64 data_ptr;
};
#define mmc_ioc_cmd_set_data(ic, ptr) ic.data_ptr = (__u64)(unsigned long) ptr
#define MMC_IOC_CMD _IOWR(MMC_BLOCK_MAJOR, 0, struct mmc_ioc_cmd)
/*
* Since this ioctl is only meant to enhance (and not replace) normal access
* to the mmc bus device, an upper data transfer limit of MMC_IOC_MAX_BYTES
* is enforced per ioctl call. For larger data transfers, use the normal
* block device operations.
*/
#define MMC_IOC_MAX_BYTES (512L * 256)
#endif /* LINUX_MMC_IOCTL_H */
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