[S390] zcrypt: add support for large random numbers
This patch allows user space applications to access large amounts of truly random data. The random data source is the build-in hardware random number generator on the CEX2C cards. Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>hifive-unleashed-5.1
Ralph Wuerthner
Heiko Carstens
parent
893f112866
commit
2f7c8bd6dc
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@ -64,6 +64,7 @@ config ZCRYPT
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tristate "Support for PCI-attached cryptographic adapters"
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depends on S390
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select ZCRYPT_MONOLITHIC if ZCRYPT="y"
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select HW_RANDOM
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help
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Select this option if you want to use a PCI-attached cryptographic
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adapter like:
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@ -36,6 +36,7 @@
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#include <linux/compat.h>
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#include <asm/atomic.h>
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#include <asm/uaccess.h>
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#include <linux/hw_random.h>
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#include "zcrypt_api.h"
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@ -52,6 +53,9 @@ static LIST_HEAD(zcrypt_device_list);
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static int zcrypt_device_count = 0;
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static atomic_t zcrypt_open_count = ATOMIC_INIT(0);
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static int zcrypt_rng_device_add(void);
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static void zcrypt_rng_device_remove(void);
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/**
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* Device attributes common for all crypto devices.
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*/
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@ -216,6 +220,22 @@ int zcrypt_device_register(struct zcrypt_device *zdev)
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__zcrypt_increase_preference(zdev);
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zcrypt_device_count++;
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spin_unlock_bh(&zcrypt_device_lock);
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if (zdev->ops->rng) {
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rc = zcrypt_rng_device_add();
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if (rc)
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goto out_unregister;
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}
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return 0;
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out_unregister:
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spin_lock_bh(&zcrypt_device_lock);
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zcrypt_device_count--;
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list_del_init(&zdev->list);
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spin_unlock_bh(&zcrypt_device_lock);
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sysfs_remove_group(&zdev->ap_dev->device.kobj,
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&zcrypt_device_attr_group);
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put_device(&zdev->ap_dev->device);
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zcrypt_device_put(zdev);
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out:
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return rc;
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}
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@ -226,6 +246,8 @@ EXPORT_SYMBOL(zcrypt_device_register);
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*/
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void zcrypt_device_unregister(struct zcrypt_device *zdev)
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{
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if (zdev->ops->rng)
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zcrypt_rng_device_remove();
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spin_lock_bh(&zcrypt_device_lock);
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zcrypt_device_count--;
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list_del_init(&zdev->list);
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@ -427,6 +449,37 @@ static long zcrypt_send_cprb(struct ica_xcRB *xcRB)
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return -ENODEV;
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}
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static long zcrypt_rng(char *buffer)
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{
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struct zcrypt_device *zdev;
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int rc;
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spin_lock_bh(&zcrypt_device_lock);
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list_for_each_entry(zdev, &zcrypt_device_list, list) {
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if (!zdev->online || !zdev->ops->rng)
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continue;
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zcrypt_device_get(zdev);
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get_device(&zdev->ap_dev->device);
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zdev->request_count++;
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__zcrypt_decrease_preference(zdev);
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if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
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spin_unlock_bh(&zcrypt_device_lock);
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rc = zdev->ops->rng(zdev, buffer);
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spin_lock_bh(&zcrypt_device_lock);
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module_put(zdev->ap_dev->drv->driver.owner);
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} else
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rc = -EAGAIN;
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zdev->request_count--;
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__zcrypt_increase_preference(zdev);
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put_device(&zdev->ap_dev->device);
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zcrypt_device_put(zdev);
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spin_unlock_bh(&zcrypt_device_lock);
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return rc;
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}
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spin_unlock_bh(&zcrypt_device_lock);
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return -ENODEV;
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}
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static void zcrypt_status_mask(char status[AP_DEVICES])
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{
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struct zcrypt_device *zdev;
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@ -1041,6 +1094,73 @@ out:
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return count;
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}
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static int zcrypt_rng_device_count;
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static u32 *zcrypt_rng_buffer;
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static int zcrypt_rng_buffer_index;
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static DEFINE_MUTEX(zcrypt_rng_mutex);
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static int zcrypt_rng_data_read(struct hwrng *rng, u32 *data)
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{
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int rc;
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/**
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* We don't need locking here because the RNG API guarantees serialized
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* read method calls.
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*/
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if (zcrypt_rng_buffer_index == 0) {
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rc = zcrypt_rng((char *) zcrypt_rng_buffer);
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if (rc < 0)
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return -EIO;
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zcrypt_rng_buffer_index = rc / sizeof *data;
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}
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*data = zcrypt_rng_buffer[--zcrypt_rng_buffer_index];
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return sizeof *data;
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}
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static struct hwrng zcrypt_rng_dev = {
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.name = "zcrypt",
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.data_read = zcrypt_rng_data_read,
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};
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static int zcrypt_rng_device_add(void)
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{
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int rc = 0;
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mutex_lock(&zcrypt_rng_mutex);
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if (zcrypt_rng_device_count == 0) {
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zcrypt_rng_buffer = (u32 *) get_zeroed_page(GFP_KERNEL);
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if (!zcrypt_rng_buffer) {
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rc = -ENOMEM;
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goto out;
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}
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zcrypt_rng_buffer_index = 0;
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rc = hwrng_register(&zcrypt_rng_dev);
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if (rc)
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goto out_free;
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zcrypt_rng_device_count = 1;
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} else
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zcrypt_rng_device_count++;
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mutex_unlock(&zcrypt_rng_mutex);
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return 0;
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out_free:
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free_page((unsigned long) zcrypt_rng_buffer);
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out:
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mutex_unlock(&zcrypt_rng_mutex);
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return rc;
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}
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static void zcrypt_rng_device_remove(void)
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{
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mutex_lock(&zcrypt_rng_mutex);
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zcrypt_rng_device_count--;
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if (zcrypt_rng_device_count == 0) {
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hwrng_unregister(&zcrypt_rng_dev);
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free_page((unsigned long) zcrypt_rng_buffer);
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}
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mutex_unlock(&zcrypt_rng_mutex);
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}
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/**
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* The module initialization code.
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*/
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@ -100,6 +100,13 @@ struct ica_z90_status {
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#define ZCRYPT_CEX2C 5
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#define ZCRYPT_CEX2A 6
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/**
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* Large random numbers are pulled in 4096 byte chunks from the crypto cards
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* and stored in a page. Be carefull when increasing this buffer due to size
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* limitations for AP requests.
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*/
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#define ZCRYPT_RNG_BUFFER_SIZE 4096
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struct zcrypt_device;
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struct zcrypt_ops {
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@ -107,6 +114,7 @@ struct zcrypt_ops {
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long (*rsa_modexpo_crt)(struct zcrypt_device *,
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struct ica_rsa_modexpo_crt *);
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long (*send_cprb)(struct zcrypt_device *, struct ica_xcRB *);
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long (*rng)(struct zcrypt_device *, char *);
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};
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struct zcrypt_device {
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@ -355,6 +355,55 @@ static int XCRB_msg_to_type6CPRB_msgX(struct zcrypt_device *zdev,
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return 0;
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}
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/**
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* Prepare a type6 CPRB message for random number generation
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*
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* @ap_dev: AP device pointer
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* @ap_msg: pointer to AP message
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*/
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static void rng_type6CPRB_msgX(struct ap_device *ap_dev,
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struct ap_message *ap_msg,
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unsigned random_number_length)
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{
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struct {
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struct type6_hdr hdr;
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struct CPRBX cprbx;
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char function_code[2];
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short int rule_length;
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char rule[8];
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short int verb_length;
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short int key_length;
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} __attribute__((packed)) *msg = ap_msg->message;
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static struct type6_hdr static_type6_hdrX = {
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.type = 0x06,
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.offset1 = 0x00000058,
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.agent_id = {'C', 'A'},
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.function_code = {'R', 'L'},
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.ToCardLen1 = sizeof *msg - sizeof(msg->hdr),
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.FromCardLen1 = sizeof *msg - sizeof(msg->hdr),
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};
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static struct CPRBX static_cprbx = {
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.cprb_len = 0x00dc,
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.cprb_ver_id = 0x02,
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.func_id = {0x54, 0x32},
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.req_parml = sizeof *msg - sizeof(msg->hdr) -
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sizeof(msg->cprbx),
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.rpl_msgbl = sizeof *msg - sizeof(msg->hdr),
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};
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msg->hdr = static_type6_hdrX;
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msg->hdr.FromCardLen2 = random_number_length,
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msg->cprbx = static_cprbx;
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msg->cprbx.rpl_datal = random_number_length,
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msg->cprbx.domain = AP_QID_QUEUE(ap_dev->qid);
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memcpy(msg->function_code, msg->hdr.function_code, 0x02);
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msg->rule_length = 0x0a;
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memcpy(msg->rule, "RANDOM ", 8);
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msg->verb_length = 0x02;
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msg->key_length = 0x02;
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ap_msg->length = sizeof *msg;
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}
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/**
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* Copy results from a type 86 ICA reply message back to user space.
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*
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@ -509,6 +558,26 @@ static int convert_type86_xcrb(struct zcrypt_device *zdev,
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return 0;
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}
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static int convert_type86_rng(struct zcrypt_device *zdev,
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struct ap_message *reply,
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char *buffer)
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{
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struct {
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struct type86_hdr hdr;
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struct type86_fmt2_ext fmt2;
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struct CPRBX cprbx;
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} __attribute__((packed)) *msg = reply->message;
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char *data = reply->message;
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if (msg->cprbx.ccp_rtcode != 0 || msg->cprbx.ccp_rscode != 0) {
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PDEBUG("RNG response error on PCIXCC/CEX2C rc=%hu/rs=%hu\n",
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rc, rs);
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return -EINVAL;
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}
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memcpy(buffer, data + msg->fmt2.offset2, msg->fmt2.count2);
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return msg->fmt2.count2;
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}
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static int convert_response_ica(struct zcrypt_device *zdev,
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struct ap_message *reply,
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char __user *outputdata,
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@ -567,6 +636,31 @@ static int convert_response_xcrb(struct zcrypt_device *zdev,
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}
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}
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static int convert_response_rng(struct zcrypt_device *zdev,
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struct ap_message *reply,
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char *data)
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{
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struct type86x_reply *msg = reply->message;
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switch (msg->hdr.type) {
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case TYPE82_RSP_CODE:
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case TYPE88_RSP_CODE:
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return -EINVAL;
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case TYPE86_RSP_CODE:
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if (msg->hdr.reply_code)
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return -EINVAL;
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if (msg->cprbx.cprb_ver_id == 0x02)
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return convert_type86_rng(zdev, reply, data);
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/* no break, incorrect cprb version is an unknown response */
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default: /* Unknown response type, this should NEVER EVER happen */
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PRINTK("Unrecognized Message Header: %08x%08x\n",
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*(unsigned int *) reply->message,
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*(unsigned int *) (reply->message+4));
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zdev->online = 0;
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return -EAGAIN; /* repeat the request on a different device. */
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}
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}
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/**
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* This function is called from the AP bus code after a crypto request
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* "msg" has finished with the reply message "reply".
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@ -735,6 +829,42 @@ out_free:
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return rc;
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}
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/**
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* The request distributor calls this function if it picked the PCIXCC/CEX2C
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* device to generate random data.
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* @zdev: pointer to zcrypt_device structure that identifies the
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* PCIXCC/CEX2C device to the request distributor
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* @buffer: pointer to a memory page to return random data
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*/
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static long zcrypt_pcixcc_rng(struct zcrypt_device *zdev,
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char *buffer)
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{
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struct ap_message ap_msg;
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struct response_type resp_type = {
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.type = PCIXCC_RESPONSE_TYPE_XCRB,
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};
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int rc;
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ap_msg.message = kmalloc(PCIXCC_MAX_XCRB_MESSAGE_SIZE, GFP_KERNEL);
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if (!ap_msg.message)
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return -ENOMEM;
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ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
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atomic_inc_return(&zcrypt_step);
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ap_msg.private = &resp_type;
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rng_type6CPRB_msgX(zdev->ap_dev, &ap_msg, ZCRYPT_RNG_BUFFER_SIZE);
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init_completion(&resp_type.work);
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ap_queue_message(zdev->ap_dev, &ap_msg);
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rc = wait_for_completion_interruptible(&resp_type.work);
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if (rc == 0)
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rc = convert_response_rng(zdev, &ap_msg, buffer);
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else
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/* Signal pending. */
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ap_cancel_message(zdev->ap_dev, &ap_msg);
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kfree(ap_msg.message);
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return rc;
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}
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/**
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* The crypto operations for a PCIXCC/CEX2C card.
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*/
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@ -744,6 +874,13 @@ static struct zcrypt_ops zcrypt_pcixcc_ops = {
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.send_cprb = zcrypt_pcixcc_send_cprb,
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};
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static struct zcrypt_ops zcrypt_pcixcc_with_rng_ops = {
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.rsa_modexpo = zcrypt_pcixcc_modexpo,
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.rsa_modexpo_crt = zcrypt_pcixcc_modexpo_crt,
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.send_cprb = zcrypt_pcixcc_send_cprb,
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.rng = zcrypt_pcixcc_rng,
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};
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/**
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* Micro-code detection function. Its sends a message to a pcixcc card
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* to find out the microcode level.
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@ -858,6 +995,58 @@ out_free:
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return rc;
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}
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/**
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* Large random number detection function. Its sends a message to a pcixcc
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* card to find out if large random numbers are supported.
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* @ap_dev: pointer to the AP device.
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*
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* Returns 1 if large random numbers are supported, 0 if not and < 0 on error.
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*/
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static int zcrypt_pcixcc_rng_supported(struct ap_device *ap_dev)
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{
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struct ap_message ap_msg;
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unsigned long long psmid;
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struct {
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struct type86_hdr hdr;
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struct type86_fmt2_ext fmt2;
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struct CPRBX cprbx;
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} __attribute__((packed)) *reply;
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int rc, i;
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ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
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if (!ap_msg.message)
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return -ENOMEM;
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rng_type6CPRB_msgX(ap_dev, &ap_msg, 4);
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rc = ap_send(ap_dev->qid, 0x0102030405060708ULL, ap_msg.message,
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ap_msg.length);
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if (rc)
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goto out_free;
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/* Wait for the test message to complete. */
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for (i = 0; i < 2 * HZ; i++) {
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msleep(1000 / HZ);
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rc = ap_recv(ap_dev->qid, &psmid, ap_msg.message, 4096);
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if (rc == 0 && psmid == 0x0102030405060708ULL)
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break;
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}
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if (i >= 2 * HZ) {
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/* Got no answer. */
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rc = -ENODEV;
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goto out_free;
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}
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reply = ap_msg.message;
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if (reply->cprbx.ccp_rtcode == 0 && reply->cprbx.ccp_rscode == 0)
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rc = 1;
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else
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rc = 0;
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out_free:
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free_page((unsigned long) ap_msg.message);
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return rc;
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}
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/**
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* Probe function for PCIXCC/CEX2C cards. It always accepts the AP device
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* since the bus_match already checked the hardware type. The PCIXCC
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@ -874,7 +1063,6 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
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if (!zdev)
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return -ENOMEM;
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zdev->ap_dev = ap_dev;
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zdev->ops = &zcrypt_pcixcc_ops;
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zdev->online = 1;
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if (ap_dev->device_type == AP_DEVICE_TYPE_PCIXCC) {
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rc = zcrypt_pcixcc_mcl(ap_dev);
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@ -901,6 +1089,15 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
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zdev->min_mod_size = PCIXCC_MIN_MOD_SIZE;
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zdev->max_mod_size = PCIXCC_MAX_MOD_SIZE;
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}
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rc = zcrypt_pcixcc_rng_supported(ap_dev);
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if (rc < 0) {
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zcrypt_device_free(zdev);
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return rc;
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}
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if (rc)
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zdev->ops = &zcrypt_pcixcc_with_rng_ops;
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||||
else
|
||||
zdev->ops = &zcrypt_pcixcc_ops;
|
||||
ap_dev->reply = &zdev->reply;
|
||||
ap_dev->private = zdev;
|
||||
rc = zcrypt_device_register(zdev);
|
||||
|
|
|
|||
Loading…
Reference in New Issue