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Subject[PATCH 4/4] Add MMC Password Protection (lock/unlock) support V8: mmc_sysfs.diff




Implement MMC password force erase, remove password, change password,
unlock card and assign password operations. It uses the sysfs mechanism
to send commands to the MMC subsystem.

Signed-off-by: Carlos Eduardo Aguiar <carlos.aguiar <at> indt.org.br>
Signed-off-by: Anderson Lizardo <anderson.lizardo <at> indt.org.br>
Signed-off-by: Anderson Briglia <anderson.briglia <at> indt.org.br>

Index: linux-linus-2.6/drivers/mmc/mmc_sysfs.c
===================================================================
--- linux-linus-2.6.orig/drivers/mmc/mmc_sysfs.c 2006-12-04 15:26:05.000000000 -0400
+++ linux-linus-2.6/drivers/mmc/mmc_sysfs.c 2006-12-04 15:33:55.000000000 -0400
@@ -17,6 +17,7 @@
#include <linux/idr.h>
#include <linux/workqueue.h>
#include <linux/key.h>
+#include <linux/err.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -65,6 +66,100 @@ 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, "unsupported\n");
+ else
+ return sprintf(buf, "%slocked\n", mmc_card_locked(card) ?
+ "" : "un");
+}
+
+/*
+ * implement MMC password functions: force erase, remove password, change
+ * password, unlock card and assign 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);
+ int err = 0;
+
+ err = mmc_card_claim_host(card);
+ if (err != MMC_ERR_NONE)
+ return -EINVAL;
+
+ 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);
+ goto out;
+ } 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", "remove");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_CLR_PWD);
+ if (!err)
+ goto out;
+ } else
+ dev_dbg(&card->dev, "request_key returned error %ld\n", PTR_ERR(mmc_key));
+ } else if (!mmc_card_locked(card) && ((!strncmp(data, "assign", 6)) ||
+ (!strncmp(data, "change", 6)))) {
+
+ /* assign or change */
+ struct key *mmc_key;
+
+ if(!strncmp(data, "assign", 6))
+ mmc_key = request_key(&mmc_key_type, "mmc:key", "assign");
+ else
+ mmc_key = request_key(&mmc_key_type, "mmc:key", "change");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_SET_PWD);
+ if (!err)
+ goto out;
+ } else
+ dev_dbg(&card->dev, "request_key returned error %ld\n", PTR_ERR(mmc_key));
+ } else if (mmc_card_locked(card) && !strncmp(data, "unlock", 6)) {
+ /* unlock */
+ struct key *mmc_key = request_key(&mmc_key_type, "mmc:key", "unlock");
+ if (!IS_ERR(mmc_key)) {
+ int err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_UNLOCK);
+ if (err) {
+ dev_dbg(&card->dev, "Wrong password\n");
+ }
+ else {
+ mmc_card_release_host(card);
+ device_release_driver(dev);
+ device_attach(dev);
+ return len;
+ }
+ } else
+ dev_dbg(&card->dev, "request_key returned error %ld\n", PTR_ERR(mmc_key));
+ }
+
+ mmc_card_release_host(card);
+ return -EINVAL;
+out:
+ mmc_card_release_host(card);
+ return len;
+}
+
+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)
{
@@ -234,6 +329,11 @@ 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;
}
@@ -248,6 +348,9 @@ void mmc_remove_card(struct mmc_card *ca
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);
}
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