Implement MMC password reset and forced erase support. It uses the sysfs
mechanism to send commands to the MMC subsystem. Usage:
Forced erase:
echo erase > /sys/bus/mmc/devices/mmc0\:0001/lockable
Remove password:
echo remove > /sys/bus/mmc/devices/mmc0\:0001/lockable
Signed-off-by: Anderson Briglia <[email protected]>
Signed-off-by: Anderson Lizardo <[email protected]>
Signed-off-by: Carlos Eduardo Aguiar <[email protected]>
Index: linux-2.6.15-rc4/drivers/mmc/mmc_sysfs.c
===================================================================
--- linux-2.6.15-rc4.orig/drivers/mmc/mmc_sysfs.c 2006-01-09 10:35:09.000000000 -0400
+++ linux-2.6.15-rc4/drivers/mmc/mmc_sysfs.c 2006-01-09 12:19:05.000000000 -0400
@@ -16,6 +16,7 @@
#include <linux/device.h>
#include <linux/idr.h>
#include <linux/key.h>
+#include <linux/err.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -26,6 +27,10 @@
#define KEY_OP_INSTANTIATE 1
#define KEY_OP_UPDATE 2
+#ifdef CONFIG_MMC_DEBUG
+#define DEBUG /* for dev_dbg(), pr_debug(), etc */
+#endif
+
#define dev_to_mmc_card(d) container_of(d, struct mmc_card, dev)
#define to_mmc_driver(d) container_of(d, struct mmc_driver, drv)
#define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev)
@@ -67,6 +72,58 @@ static struct device_attribute mmc_dev_a
static struct device_attribute mmc_dev_attr_scr = MMC_ATTR_RO(scr);
+#ifdef CONFIG_MMC_PASSWORDS
+
+static ssize_t
+mmc_lockable_show(struct device *dev, struct device_attribute *att, char *buf)
+{
+ struct mmc_card *card = dev_to_mmc_card(dev);
+
+ if (!mmc_card_lockable(card))
+ return sprintf(buf, "unlockable\n");
+ else
+ return sprintf(buf, "lockable, %slocked\n", mmc_card_locked(card) ?
+ "" : "un");
+}
+
+/*
+ * implement MMC password reset ("remove password") and forced erase ("forgot
+ * password").
+ */
+static ssize_t
+mmc_lockable_store(struct device *dev, struct device_attribute *att,
+ const char *data, size_t len)
+{
+ struct mmc_card *card = dev_to_mmc_card(dev);
+
+ if (!mmc_card_lockable(card))
+ return -EINVAL;
+
+ if (mmc_card_locked(card) && !strncmp(data, "erase", 5)) {
+ /* forced erase only works while card is locked */
+ mmc_lock_unlock(card, NULL, MMC_LOCK_MODE_ERASE);
+ return len;
+ } else if (!mmc_card_locked(card) && !strncmp(data, "remove", 6)) {
+ /* remove password only works while card is unlocked */
+ struct key *mmc_key = request_key(&mmc_key_type, "mmc:key", NULL);
+
+ if (!IS_ERR(mmc_key)) {
+ int err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_CLR_PWD);
+ if (!err)
+ return len;
+ } else
+ dev_dbg(&card->dev, "request_key returned error %ld\n", PTR_ERR(mmc_key));
+ }
+
+ return -EINVAL;
+}
+
+static struct device_attribute mmc_dev_attr_lockable =
+ __ATTR(lockable, S_IWUSR | S_IRUGO,
+ mmc_lockable_show, mmc_lockable_store);
+
+#endif
+
static void mmc_release_card(struct device *dev)
{
@@ -238,6 +295,11 @@ int mmc_register_card(struct mmc_card *c
if (ret)
device_del(&card->dev);
}
+#ifdef CONFIG_MMC_PASSWORDS
+ ret = device_create_file(&card->dev, &mmc_dev_attr_lockable);
+ if (ret)
+ device_del(&card->dev);
+#endif
}
return ret;
}
@@ -251,7 +313,9 @@ void mmc_remove_card(struct mmc_card *ca
if (mmc_card_present(card)) {
if (mmc_card_sd(card))
device_remove_file(&card->dev, &mmc_dev_attr_scr);
-
+#ifdef CONFIG_MMC_PASSWORDS
+ device_remove_file(&card->dev, &mmc_dev_attr_lockable);
+#endif
device_del(&card->dev);
}
@@ -305,19 +369,25 @@ static int manage_key(struct key *key, c
zap = NULL;
ret = -EINVAL;
- if (datalen <= 0 || datalen > MMC_KEYLEN_MAXBYTES || !data)
+ if (datalen <= 0 || datalen > MMC_KEYLEN_MAXBYTES || !data){
+ dev_dbg(&card->dev, "Invalid data\n");
goto error;
+ }
if (operation == KEY_OP_INSTANTIATE) { /* KEY_OP_INSTANTIATE */
ret = key_payload_reserve(key, datalen);
- if (ret < 0)
- goto error;
+ if (ret < 0){
+ dev_dbg(&card->dev, "ret = %d", ret);
+ goto error;
+ }
}
ret = -ENOMEM;
mpayload = kmalloc(sizeof(*mpayload) + datalen, GFP_KERNEL);
- if (!mpayload)
+ if (!mpayload){
+ dev_dbg(&card->dev, "Unable to allocate mpayload structure\n");
goto error;
+ }
mpayload->datalen = datalen;
memcpy(mpayload->data, data, datalen);
@@ -341,8 +411,10 @@ static int manage_key(struct key *key, c
ret = -EINVAL;
dev = bus_find_device(&mmc_bus_type, NULL, NULL, mmc_match_lockable);
- if (!dev)
+ if (!dev){
+ dev_dbg(&card->dev, "Unable to locate device\n");
goto error;
+ }
card = dev_to_mmc_card(dev);
if (operation == KEY_OP_INSTANTIATE) { /* KEY_OP_INSTANTIATE */
@@ -359,8 +431,10 @@ static int manage_key(struct key *key, c
ret = mmc_lock_unlock(card, key, MMC_LOCK_MODE_SET_PWD);
}
- if (ret)
+ if (ret){
ret = -EKEYREJECTED;
+ dev_dbg(&card->dev, "Key was rejected\n");
+ }
if (operation == KEY_OP_UPDATE) /* KEY_OP_UPDATE */
call_rcu(&zap->rcu, mmc_key_update_rcu_disposal);
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