* [patch 5/6] [RFC] Add MMC Password Protection (lock/unlock) support V6
@ 2006-11-17 13:12 Anderson Briglia
2006-11-17 16:13 ` Russell King
0 siblings, 1 reply; 2+ messages in thread
From: Anderson Briglia @ 2006-11-17 13:12 UTC (permalink / raw)
To: Linux-omap-open-source@linux.omap.com
Cc: linux-kernel, Pierre Ossman, ext David Brownell, Russell King,
Tony Lindgren, Aguiar Carlos (EXT-INdT/Manaus),
Biris Ilias (EXT-INdT/Manaus)
[-- Attachment #1: Type: text/plain, Size: 4804 bytes --]
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-omap-2.6.git/drivers/mmc/mmc_sysfs.c
===================================================================
--- linux-omap-2.6.git.orig/drivers/mmc/mmc_sysfs.c 2006-11-16 15:45:20.000000000 -0400
+++ linux-omap-2.6.git/drivers/mmc/mmc_sysfs.c 2006-11-16 15:54:44.000000000 -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 +66,114 @@ 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);
+ /* Lock to protect the mmc_lock_unlock data */
+ spinlock_t mmc_lock = SPIN_LOCK_UNLOCKED;
+
+ if (!mmc_card_lockable(card))
+ return -EINVAL;
+
+ if (mmc_card_locked(card) && !strncmp(data, "erase", 5)) {
+ /* forced erase only works while card is locked */
+ spin_lock(&mmc_lock);
+ mmc_lock_unlock(card, NULL, MMC_LOCK_MODE_ERASE);
+ spin_unlock(&mmc_lock);
+ 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", "remove");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = 0;
+
+ spin_lock(&mmc_lock);
+ err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_CLR_PWD);
+ spin_unlock(&mmc_lock);
+ if (!err)
+ return len;
+ } else
+ dev_dbg(&card->dev, "request_key returned error %ld\n", PTR_ERR(mmc_key));
+ } else if (!mmc_card_locked(card) && !strncmp(data, "change", 6)) {
+ /* change */
+ struct key *mmc_key = request_key(&mmc_key_type, "mmc:key", "change");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = 0;
+
+ spin_lock(&mmc_lock);
+ err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_SET_PWD);
+ spin_unlock(&mmc_lock);
+ if (!err)
+ return len;
+ } 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 = 0;
+
+ spin_lock(&mmc_lock);
+ mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_UNLOCK);
+ spin_unlock(&mmc_lock);
+ if (err) {
+ dev_dbg(&card->dev, "Wrong password\n");
+ }
+ else {
+ device_release_driver(dev);
+ device_attach(dev);
+ return len;
+ }
+ } 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)) {
+ /* assign */
+ struct key *mmc_key = request_key(&mmc_key_type, "mmc:key", "assign");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = 0;
+
+ spin_lock(&mmc_lock);
+ err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_SET_PWD);
+ spin_unlock(&mmc_lock);
+ 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)
{
@@ -234,6 +343,11 @@ 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 +362,9 @@ 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);
}
[-- Attachment #2: mmc_sysfs.diff --]
[-- Type: text/x-patch, Size: 4792 bytes --]
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-omap-2.6.git/drivers/mmc/mmc_sysfs.c
===================================================================
--- linux-omap-2.6.git.orig/drivers/mmc/mmc_sysfs.c 2006-11-16 15:45:20.000000000 -0400
+++ linux-omap-2.6.git/drivers/mmc/mmc_sysfs.c 2006-11-16 15:54:44.000000000 -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 +66,114 @@ 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);
+ /* Lock to protect the mmc_lock_unlock data */
+ spinlock_t mmc_lock = SPIN_LOCK_UNLOCKED;
+
+ if (!mmc_card_lockable(card))
+ return -EINVAL;
+
+ if (mmc_card_locked(card) && !strncmp(data, "erase", 5)) {
+ /* forced erase only works while card is locked */
+ spin_lock(&mmc_lock);
+ mmc_lock_unlock(card, NULL, MMC_LOCK_MODE_ERASE);
+ spin_unlock(&mmc_lock);
+ 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", "remove");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = 0;
+
+ spin_lock(&mmc_lock);
+ err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_CLR_PWD);
+ spin_unlock(&mmc_lock);
+ if (!err)
+ return len;
+ } else
+ dev_dbg(&card->dev, "request_key returned error %ld\n", PTR_ERR(mmc_key));
+ } else if (!mmc_card_locked(card) && !strncmp(data, "change", 6)) {
+ /* change */
+ struct key *mmc_key = request_key(&mmc_key_type, "mmc:key", "change");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = 0;
+
+ spin_lock(&mmc_lock);
+ err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_SET_PWD);
+ spin_unlock(&mmc_lock);
+ if (!err)
+ return len;
+ } 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 = 0;
+
+ spin_lock(&mmc_lock);
+ mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_UNLOCK);
+ spin_unlock(&mmc_lock);
+ if (err) {
+ dev_dbg(&card->dev, "Wrong password\n");
+ }
+ else {
+ device_release_driver(dev);
+ device_attach(dev);
+ return len;
+ }
+ } 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)) {
+ /* assign */
+ struct key *mmc_key = request_key(&mmc_key_type, "mmc:key", "assign");
+
+ if (!IS_ERR(mmc_key)) {
+ int err = 0;
+
+ spin_lock(&mmc_lock);
+ err = mmc_lock_unlock(card, mmc_key, MMC_LOCK_MODE_SET_PWD);
+ spin_unlock(&mmc_lock);
+ 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)
{
@@ -234,6 +343,11 @@ 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 +362,9 @@ 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);
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [patch 5/6] [RFC] Add MMC Password Protection (lock/unlock) support V6
2006-11-17 13:12 [patch 5/6] [RFC] Add MMC Password Protection (lock/unlock) support V6 Anderson Briglia
@ 2006-11-17 16:13 ` Russell King
0 siblings, 0 replies; 2+ messages in thread
From: Russell King @ 2006-11-17 16:13 UTC (permalink / raw)
To: Anderson Briglia
Cc: Linux-omap-open-source@linux.omap.com, linux-kernel,
Pierre Ossman, ext David Brownell, Tony Lindgren,
Aguiar Carlos (EXT-INdT/Manaus), Biris Ilias (EXT-INdT/Manaus)
On Fri, Nov 17, 2006 at 09:12:39AM -0400, Anderson Briglia wrote:
> + if (mmc_card_locked(card) && !strncmp(data, "erase", 5)) {
> + /* forced erase only works while card is locked */
> + spin_lock(&mmc_lock);
> + mmc_lock_unlock(card, NULL, MMC_LOCK_MODE_ERASE);
> + spin_unlock(&mmc_lock);
mmc_lock_unlock can sleep; holding a spinlock while sleeping is illegal
and is a serious bug. Inappropriate locking? What's this lock trying
to achieve?
I don't see any requirement for locking here - mmc_lock_unlock() claims
the host, and if that succeeds, it has exclusive access via that host to
the card. No one else will be able to talk on the bus until
mmc_lock_unlock() releases it's claim on the host. So I suspect that
whatever locking you require is already in place.
Ditto for each other instances.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
^ permalink raw reply [flat|nested] 2+ messages in thread
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2006-11-17 13:12 [patch 5/6] [RFC] Add MMC Password Protection (lock/unlock) support V6 Anderson Briglia
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