Use the kernel "KEYS" subsystem to get a password for a card based on
the card's CID. This code was based on a patch set submitted by
Anderson Briglia in 2006.
Signed-off-by: Al Cooper <alcooperx@xxxxxxxxx>
---
drivers/mmc/core/Kconfig | 8 ++++
drivers/mmc/core/core.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/core.h | 10 ++++-
3 files changed, 114 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
index 9ebee72..1d073cd 100644
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -11,3 +11,11 @@ config MMC_CLKGATE
support handling this in order for it to be of any use.
If unsure, say N.
+
+config MMC_LOCK
+ bool "MMC/SD password based card lock/unlock"
+ select KEYS
+ help
+ This will add the ability to lock/unlock SD and MMC cards.
+
+ If unsure, say N.
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 92e7671..f7d7ad9 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -29,6 +29,7 @@
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/of.h>
+#include <linux/key-type.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -2707,6 +2708,96 @@ void mmc_init_context_info(struct mmc_host *host)
init_waitqueue_head(&host->context_info.wait);
}
+#ifdef CONFIG_MMC_LOCK
+
+static int mmc_key_instantiate(struct key *key,
+ struct key_preparsed_payload *prep)
+{
+ char *payload;
+
+ if (prep->datalen <= 0 || prep->datalen > MMC_PASSWORD_MAX ||
+ !prep->data) {
+ pr_warn("Invalid data\n");
+ return -EINVAL;
+ }
+
+ payload = kmalloc(prep->datalen, GFP_KERNEL);
+ if (!payload)
+ return -ENOMEM;
+ memcpy(payload, prep->data, prep->datalen);
+ key->payload.data = payload;
+ key->datalen = prep->datalen;
+ return 0;
+}
+
+/*
+ * dispose of the data dangling from the corpse of a mmc key
+ */
+static void mmc_key_destroy(struct key *key)
+{
+ kfree(key->payload.data);
+}
+
+struct key_type key_type_mmc = {
+ .name = "mmc",
+ .instantiate = mmc_key_instantiate,
+ .destroy = mmc_key_destroy,
+};
+
+int mmc_get_password(struct mmc_card *card, struct mmc_password *password)
+{
+ struct key *mmc_key;
+ char key_desc[(sizeof(card->raw_cid) * 2) + 1];
+
+ /* Use the CID to uniquely identify the card */
+ snprintf(key_desc, sizeof(key_desc), "%08x%08x%08x%08x",
+ card->raw_cid[0], card->raw_cid[1],
+ card->raw_cid[2], card->raw_cid[3]);
+
+ mmc_key = request_key(&key_type_mmc, key_desc,
+ "password");
+ if (IS_ERR(mmc_key)) {
+ dev_warn(&card->dev, "Error, request_key %ld\n",
+ PTR_ERR(mmc_key));
+ return PTR_ERR(mmc_key);
+ }
+ dev_dbg(&card->dev, "Found matching key\n");
+ memcpy(&password->password, mmc_key->payload.data,
+ mmc_key->datalen);
+ password->length = mmc_key->datalen;
+ key_put(mmc_key);
+
+ return 0;
+}
+
+static inline int mmc_register_key_type(void)
+{
+ return register_key_type(&key_type_mmc);
+}
+
+static inline void mmc_unregister_key_type(void)
+{
+ unregister_key_type(&key_type_mmc);
+}
+
+#else /* CONFIG_MMC_LOCK */
+
+int mmc_get_password(struct mmc_card *card, struct mmc_password *password)
+{
+ return -ENOKEY;
+}
+
+static inline int mmc_register_key_type(void)
+{
+ return 0;
+}
+
+static inline void mmc_unregister_key_type(void)
+{
+}
+
+#endif /* CONFIG_MMC_LOCK */
+
static int __init mmc_init(void)
{
int ret;
@@ -2727,8 +2818,13 @@ static int __init mmc_init(void)
if (ret)
goto unregister_host_class;
+ ret = mmc_register_key_type();
+ if (ret)
+ goto unregister_sdio_bus;
return 0;
+unregister_sdio_bus:
+ sdio_unregister_bus();
unregister_host_class:
mmc_unregister_host_class();
unregister_bus:
@@ -2741,6 +2837,7 @@ destroy_workqueue:
static void __exit mmc_exit(void)
{
+ mmc_unregister_key_type();
sdio_unregister_bus();
mmc_unregister_host_class();
mmc_unregister_bus();
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index cfba3c0..b91bc3e 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -89,5 +89,13 @@ void mmc_init_context_info(struct mmc_host *host);
int mmc_execute_tuning(struct mmc_card *card);
-#endif
+/* Lock/Unlock functionality */
+#define MMC_PASSWORD_MAX 16
+struct mmc_password {
+ char password[MMC_PASSWORD_MAX];
+ int length;
+};
+int mmc_unlock_card(struct mmc_card *card);
+int mmc_get_password(struct mmc_card *card, struct mmc_password *password);
+#endif
--
1.9.0.138.g2de3478
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
