提交 2f7c8bd6 编写于 作者: R Ralph Wuerthner 提交者: Heiko Carstens

[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: NRalph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
上级 893f1128
......@@ -64,6 +64,7 @@ config ZCRYPT
tristate "Support for PCI-attached cryptographic adapters"
depends on S390
select ZCRYPT_MONOLITHIC if ZCRYPT="y"
select HW_RANDOM
help
Select this option if you want to use a PCI-attached cryptographic
adapter like:
......
......@@ -36,6 +36,7 @@
#include <linux/compat.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
#include <linux/hw_random.h>
#include "zcrypt_api.h"
......@@ -52,6 +53,9 @@ static LIST_HEAD(zcrypt_device_list);
static int zcrypt_device_count = 0;
static atomic_t zcrypt_open_count = ATOMIC_INIT(0);
static int zcrypt_rng_device_add(void);
static void zcrypt_rng_device_remove(void);
/**
* Device attributes common for all crypto devices.
*/
......@@ -216,6 +220,22 @@ int zcrypt_device_register(struct zcrypt_device *zdev)
__zcrypt_increase_preference(zdev);
zcrypt_device_count++;
spin_unlock_bh(&zcrypt_device_lock);
if (zdev->ops->rng) {
rc = zcrypt_rng_device_add();
if (rc)
goto out_unregister;
}
return 0;
out_unregister:
spin_lock_bh(&zcrypt_device_lock);
zcrypt_device_count--;
list_del_init(&zdev->list);
spin_unlock_bh(&zcrypt_device_lock);
sysfs_remove_group(&zdev->ap_dev->device.kobj,
&zcrypt_device_attr_group);
put_device(&zdev->ap_dev->device);
zcrypt_device_put(zdev);
out:
return rc;
}
......@@ -226,6 +246,8 @@ EXPORT_SYMBOL(zcrypt_device_register);
*/
void zcrypt_device_unregister(struct zcrypt_device *zdev)
{
if (zdev->ops->rng)
zcrypt_rng_device_remove();
spin_lock_bh(&zcrypt_device_lock);
zcrypt_device_count--;
list_del_init(&zdev->list);
......@@ -427,6 +449,37 @@ static long zcrypt_send_cprb(struct ica_xcRB *xcRB)
return -ENODEV;
}
static long zcrypt_rng(char *buffer)
{
struct zcrypt_device *zdev;
int rc;
spin_lock_bh(&zcrypt_device_lock);
list_for_each_entry(zdev, &zcrypt_device_list, list) {
if (!zdev->online || !zdev->ops->rng)
continue;
zcrypt_device_get(zdev);
get_device(&zdev->ap_dev->device);
zdev->request_count++;
__zcrypt_decrease_preference(zdev);
if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
spin_unlock_bh(&zcrypt_device_lock);
rc = zdev->ops->rng(zdev, buffer);
spin_lock_bh(&zcrypt_device_lock);
module_put(zdev->ap_dev->drv->driver.owner);
} else
rc = -EAGAIN;
zdev->request_count--;
__zcrypt_increase_preference(zdev);
put_device(&zdev->ap_dev->device);
zcrypt_device_put(zdev);
spin_unlock_bh(&zcrypt_device_lock);
return rc;
}
spin_unlock_bh(&zcrypt_device_lock);
return -ENODEV;
}
static void zcrypt_status_mask(char status[AP_DEVICES])
{
struct zcrypt_device *zdev;
......@@ -1041,6 +1094,73 @@ static int zcrypt_status_write(struct file *file, const char __user *buffer,
return count;
}
static int zcrypt_rng_device_count;
static u32 *zcrypt_rng_buffer;
static int zcrypt_rng_buffer_index;
static DEFINE_MUTEX(zcrypt_rng_mutex);
static int zcrypt_rng_data_read(struct hwrng *rng, u32 *data)
{
int rc;
/**
* We don't need locking here because the RNG API guarantees serialized
* read method calls.
*/
if (zcrypt_rng_buffer_index == 0) {
rc = zcrypt_rng((char *) zcrypt_rng_buffer);
if (rc < 0)
return -EIO;
zcrypt_rng_buffer_index = rc / sizeof *data;
}
*data = zcrypt_rng_buffer[--zcrypt_rng_buffer_index];
return sizeof *data;
}
static struct hwrng zcrypt_rng_dev = {
.name = "zcrypt",
.data_read = zcrypt_rng_data_read,
};
static int zcrypt_rng_device_add(void)
{
int rc = 0;
mutex_lock(&zcrypt_rng_mutex);
if (zcrypt_rng_device_count == 0) {
zcrypt_rng_buffer = (u32 *) get_zeroed_page(GFP_KERNEL);
if (!zcrypt_rng_buffer) {
rc = -ENOMEM;
goto out;
}
zcrypt_rng_buffer_index = 0;
rc = hwrng_register(&zcrypt_rng_dev);
if (rc)
goto out_free;
zcrypt_rng_device_count = 1;
} else
zcrypt_rng_device_count++;
mutex_unlock(&zcrypt_rng_mutex);
return 0;
out_free:
free_page((unsigned long) zcrypt_rng_buffer);
out:
mutex_unlock(&zcrypt_rng_mutex);
return rc;
}
static void zcrypt_rng_device_remove(void)
{
mutex_lock(&zcrypt_rng_mutex);
zcrypt_rng_device_count--;
if (zcrypt_rng_device_count == 0) {
hwrng_unregister(&zcrypt_rng_dev);
free_page((unsigned long) zcrypt_rng_buffer);
}
mutex_unlock(&zcrypt_rng_mutex);
}
/**
* The module initialization code.
*/
......
......@@ -100,6 +100,13 @@ struct ica_z90_status {
#define ZCRYPT_CEX2C 5
#define ZCRYPT_CEX2A 6
/**
* Large random numbers are pulled in 4096 byte chunks from the crypto cards
* and stored in a page. Be carefull when increasing this buffer due to size
* limitations for AP requests.
*/
#define ZCRYPT_RNG_BUFFER_SIZE 4096
struct zcrypt_device;
struct zcrypt_ops {
......@@ -107,6 +114,7 @@ struct zcrypt_ops {
long (*rsa_modexpo_crt)(struct zcrypt_device *,
struct ica_rsa_modexpo_crt *);
long (*send_cprb)(struct zcrypt_device *, struct ica_xcRB *);
long (*rng)(struct zcrypt_device *, char *);
};
struct zcrypt_device {
......
......@@ -355,6 +355,55 @@ static int XCRB_msg_to_type6CPRB_msgX(struct zcrypt_device *zdev,
return 0;
}
/**
* Prepare a type6 CPRB message for random number generation
*
* @ap_dev: AP device pointer
* @ap_msg: pointer to AP message
*/
static void rng_type6CPRB_msgX(struct ap_device *ap_dev,
struct ap_message *ap_msg,
unsigned random_number_length)
{
struct {
struct type6_hdr hdr;
struct CPRBX cprbx;
char function_code[2];
short int rule_length;
char rule[8];
short int verb_length;
short int key_length;
} __attribute__((packed)) *msg = ap_msg->message;
static struct type6_hdr static_type6_hdrX = {
.type = 0x06,
.offset1 = 0x00000058,
.agent_id = {'C', 'A'},
.function_code = {'R', 'L'},
.ToCardLen1 = sizeof *msg - sizeof(msg->hdr),
.FromCardLen1 = sizeof *msg - sizeof(msg->hdr),
};
static struct CPRBX static_cprbx = {
.cprb_len = 0x00dc,
.cprb_ver_id = 0x02,
.func_id = {0x54, 0x32},
.req_parml = sizeof *msg - sizeof(msg->hdr) -
sizeof(msg->cprbx),
.rpl_msgbl = sizeof *msg - sizeof(msg->hdr),
};
msg->hdr = static_type6_hdrX;
msg->hdr.FromCardLen2 = random_number_length,
msg->cprbx = static_cprbx;
msg->cprbx.rpl_datal = random_number_length,
msg->cprbx.domain = AP_QID_QUEUE(ap_dev->qid);
memcpy(msg->function_code, msg->hdr.function_code, 0x02);
msg->rule_length = 0x0a;
memcpy(msg->rule, "RANDOM ", 8);
msg->verb_length = 0x02;
msg->key_length = 0x02;
ap_msg->length = sizeof *msg;
}
/**
* Copy results from a type 86 ICA reply message back to user space.
*
......@@ -509,6 +558,26 @@ static int convert_type86_xcrb(struct zcrypt_device *zdev,
return 0;
}
static int convert_type86_rng(struct zcrypt_device *zdev,
struct ap_message *reply,
char *buffer)
{
struct {
struct type86_hdr hdr;
struct type86_fmt2_ext fmt2;
struct CPRBX cprbx;
} __attribute__((packed)) *msg = reply->message;
char *data = reply->message;
if (msg->cprbx.ccp_rtcode != 0 || msg->cprbx.ccp_rscode != 0) {
PDEBUG("RNG response error on PCIXCC/CEX2C rc=%hu/rs=%hu\n",
rc, rs);
return -EINVAL;
}
memcpy(buffer, data + msg->fmt2.offset2, msg->fmt2.count2);
return msg->fmt2.count2;
}
static int convert_response_ica(struct zcrypt_device *zdev,
struct ap_message *reply,
char __user *outputdata,
......@@ -567,6 +636,31 @@ static int convert_response_xcrb(struct zcrypt_device *zdev,
}
}
static int convert_response_rng(struct zcrypt_device *zdev,
struct ap_message *reply,
char *data)
{
struct type86x_reply *msg = reply->message;
switch (msg->hdr.type) {
case TYPE82_RSP_CODE:
case TYPE88_RSP_CODE:
return -EINVAL;
case TYPE86_RSP_CODE:
if (msg->hdr.reply_code)
return -EINVAL;
if (msg->cprbx.cprb_ver_id == 0x02)
return convert_type86_rng(zdev, reply, data);
/* no break, incorrect cprb version is an unknown response */
default: /* Unknown response type, this should NEVER EVER happen */
PRINTK("Unrecognized Message Header: %08x%08x\n",
*(unsigned int *) reply->message,
*(unsigned int *) (reply->message+4));
zdev->online = 0;
return -EAGAIN; /* repeat the request on a different device. */
}
}
/**
* This function is called from the AP bus code after a crypto request
* "msg" has finished with the reply message "reply".
......@@ -735,6 +829,42 @@ static long zcrypt_pcixcc_send_cprb(struct zcrypt_device *zdev,
return rc;
}
/**
* The request distributor calls this function if it picked the PCIXCC/CEX2C
* device to generate random data.
* @zdev: pointer to zcrypt_device structure that identifies the
* PCIXCC/CEX2C device to the request distributor
* @buffer: pointer to a memory page to return random data
*/
static long zcrypt_pcixcc_rng(struct zcrypt_device *zdev,
char *buffer)
{
struct ap_message ap_msg;
struct response_type resp_type = {
.type = PCIXCC_RESPONSE_TYPE_XCRB,
};
int rc;
ap_msg.message = kmalloc(PCIXCC_MAX_XCRB_MESSAGE_SIZE, GFP_KERNEL);
if (!ap_msg.message)
return -ENOMEM;
ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
atomic_inc_return(&zcrypt_step);
ap_msg.private = &resp_type;
rng_type6CPRB_msgX(zdev->ap_dev, &ap_msg, ZCRYPT_RNG_BUFFER_SIZE);
init_completion(&resp_type.work);
ap_queue_message(zdev->ap_dev, &ap_msg);
rc = wait_for_completion_interruptible(&resp_type.work);
if (rc == 0)
rc = convert_response_rng(zdev, &ap_msg, buffer);
else
/* Signal pending. */
ap_cancel_message(zdev->ap_dev, &ap_msg);
kfree(ap_msg.message);
return rc;
}
/**
* The crypto operations for a PCIXCC/CEX2C card.
*/
......@@ -744,6 +874,13 @@ static struct zcrypt_ops zcrypt_pcixcc_ops = {
.send_cprb = zcrypt_pcixcc_send_cprb,
};
static struct zcrypt_ops zcrypt_pcixcc_with_rng_ops = {
.rsa_modexpo = zcrypt_pcixcc_modexpo,
.rsa_modexpo_crt = zcrypt_pcixcc_modexpo_crt,
.send_cprb = zcrypt_pcixcc_send_cprb,
.rng = zcrypt_pcixcc_rng,
};
/**
* Micro-code detection function. Its sends a message to a pcixcc card
* to find out the microcode level.
......@@ -858,6 +995,58 @@ static int zcrypt_pcixcc_mcl(struct ap_device *ap_dev)
return rc;
}
/**
* Large random number detection function. Its sends a message to a pcixcc
* card to find out if large random numbers are supported.
* @ap_dev: pointer to the AP device.
*
* Returns 1 if large random numbers are supported, 0 if not and < 0 on error.
*/
static int zcrypt_pcixcc_rng_supported(struct ap_device *ap_dev)
{
struct ap_message ap_msg;
unsigned long long psmid;
struct {
struct type86_hdr hdr;
struct type86_fmt2_ext fmt2;
struct CPRBX cprbx;
} __attribute__((packed)) *reply;
int rc, i;
ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
if (!ap_msg.message)
return -ENOMEM;
rng_type6CPRB_msgX(ap_dev, &ap_msg, 4);
rc = ap_send(ap_dev->qid, 0x0102030405060708ULL, ap_msg.message,
ap_msg.length);
if (rc)
goto out_free;
/* Wait for the test message to complete. */
for (i = 0; i < 2 * HZ; i++) {
msleep(1000 / HZ);
rc = ap_recv(ap_dev->qid, &psmid, ap_msg.message, 4096);
if (rc == 0 && psmid == 0x0102030405060708ULL)
break;
}
if (i >= 2 * HZ) {
/* Got no answer. */
rc = -ENODEV;
goto out_free;
}
reply = ap_msg.message;
if (reply->cprbx.ccp_rtcode == 0 && reply->cprbx.ccp_rscode == 0)
rc = 1;
else
rc = 0;
out_free:
free_page((unsigned long) ap_msg.message);
return rc;
}
/**
* Probe function for PCIXCC/CEX2C cards. It always accepts the AP device
* since the bus_match already checked the hardware type. The PCIXCC
......@@ -874,7 +1063,6 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
if (!zdev)
return -ENOMEM;
zdev->ap_dev = ap_dev;
zdev->ops = &zcrypt_pcixcc_ops;
zdev->online = 1;
if (ap_dev->device_type == AP_DEVICE_TYPE_PCIXCC) {
rc = zcrypt_pcixcc_mcl(ap_dev);
......@@ -901,6 +1089,15 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
zdev->min_mod_size = PCIXCC_MIN_MOD_SIZE;
zdev->max_mod_size = PCIXCC_MAX_MOD_SIZE;
}
rc = zcrypt_pcixcc_rng_supported(ap_dev);
if (rc < 0) {
zcrypt_device_free(zdev);
return rc;
}
if (rc)
zdev->ops = &zcrypt_pcixcc_with_rng_ops;
else
zdev->ops = &zcrypt_pcixcc_ops;
ap_dev->reply = &zdev->reply;
ap_dev->private = zdev;
rc = zcrypt_device_register(zdev);
......
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