Hi Al,
On 13 August 2013 17:21, Al Cooper <[email protected]> wrote:
> From: Al Cooper <[email protected]>
>
> 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.
>
> refs #SWLINUX-2545
>
> Signed-off-by: Al Cooper <[email protected]>
> ---
> drivers/mmc/core/Kconfig | 8 +++++
> drivers/mmc/core/core.c | 86
> ++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/mmc/core/core.h | 16 ++++++++-
> 3 files changed, 109 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
> index 269d072..b0ba79d 100644
> --- a/drivers/mmc/core/Kconfig
> +++ b/drivers/mmc/core/Kconfig
> @@ -26,3 +26,11 @@ 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 49a5bca..510927f 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -27,6 +27,7 @@
> #include <linux/fault-inject.h>
> #include <linux/random.h>
> #include <linux/slab.h>
> +#include <linux/key-type.h>
>
> #include <linux/mmc/card.h>
> #include <linux/mmc/host.h>
> @@ -2705,6 +2706,78 @@ void mmc_init_context_info(struct mmc_host *host)
> init_waitqueue_head(&host->context_info.wait);
> }
>
> +#ifdef CONFIG_MMC_LOCK
> +
> +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(&mmc_key_type, 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 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;
> +}
> +
> +static int mmc_key_match(const struct key *key, const void *description)
> +{
> + pr_debug("mmc_key_match: %s, %s\n",
> + key->description, (char *)description);
> + return strcmp(key->description, description) == 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 mmc_key_type = {
> + .name = "mmc",
> + .instantiate = mmc_key_instantiate,
> + .match = mmc_key_match,
> + .destroy = mmc_key_destroy,
> +};
> +#endif /* CONFIG_MMC_LOCK */
> +
> static int __init mmc_init(void)
> {
> int ret;
> @@ -2725,8 +2798,18 @@ static int __init mmc_init(void)
> if (ret)
> goto unregister_host_class;
>
> +#ifdef CONFIG_MMC_LOCK
> + ret = register_key_type(&mmc_key_type);
> + if (ret)
> + goto unregister_sdio_bus;
> +#endif /* CONFIG_MMC_LOCK */
> +
Please don't add "#ifdefs" around the code like this. Instead add
stubbed versions of the functions in case !CONFIG_MMC_LOCK.
> return 0;
>
> +#ifdef CONFIG_MMC_LOCK
dito
> +unregister_sdio_bus:
> + sdio_unregister_bus();
> +#endif /* CONFIG_MMC_LOCK */
> unregister_host_class:
> mmc_unregister_host_class();
> unregister_bus:
> @@ -2739,6 +2822,9 @@ destroy_workqueue:
>
> static void __exit mmc_exit(void)
> {
> +#ifdef CONFIG_MMC_LOCK
> + unregister_key_type(&mmc_key_type);
> +#endif /* CONFIG_MMC_LOCK */
dito
> 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 5345d15..dcf516d 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -81,5 +81,19 @@ void mmc_add_card_debugfs(struct mmc_card *card);
> void mmc_remove_card_debugfs(struct mmc_card *card);
>
> void mmc_init_context_info(struct mmc_host *host);
> -#endif
>
> +/* Lock/Unlock functionality */
> +int mmc_unlock_card(struct mmc_card *card);
> +
> +#ifdef CONFIG_MMC_LOCK
> +#define MMC_PASSWORD_MAX 16
> +struct mmc_password {
> + char password[MMC_PASSWORD_MAX];
> + int length;
> +};
> +extern struct key_type mmc_key_type;
> +
> +int mmc_get_password(struct mmc_card *card, struct mmc_password *password);
> +#endif /* CONFIG_MMC_LOCK */
> +
> +#endif
> --
> 1.8.1.3
>
>
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Kind regards
Ulf Hansson
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