[S390] drivers/s390/crypto: Move dereference to after IS_ERR test

[linux-2.6/verdex.git] / drivers / s390 / crypto / zcrypt_pcicc.c

/*
 *  linux/drivers/s390/crypto/zcrypt_pcicc.c
 *
 *  zcrypt 2.1.0
 *
 *  Copyright (C)  2001, 2006 IBM Corporation
 *  Author(s): Robert Burroughs
 *             Eric Rossman (edrossma@us.ibm.com)
 *
 *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
 *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
 *                                Ralph Wuerthner <rwuerthn@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>

#include "ap_bus.h"
#include "zcrypt_api.h"
#include "zcrypt_error.h"
#include "zcrypt_pcicc.h"
#include "zcrypt_cca_key.h"

#define PCICC_MIN_MOD_SIZE       64     /*  512 bits */
#define PCICC_MAX_MOD_SIZE_OLD  128     /* 1024 bits */
#define PCICC_MAX_MOD_SIZE      256     /* 2048 bits */

/*
 * PCICC cards need a speed rating of 0. This keeps them at the end of
 * the zcrypt device list (see zcrypt_api.c). PCICC cards are only
 * used if no other cards are present because they are slow and can only
 * cope with PKCS12 padded requests. The logic is queer. PKCS11 padded
 * requests are rejected. The modexpo function encrypts PKCS12 padded data
 * and decrypts any non-PKCS12 padded data (except PKCS11) in the assumption
 * that it's encrypted PKCS12 data. The modexpo_crt function always decrypts
 * the data in the assumption that its PKCS12 encrypted data.
 */
#define PCICC_SPEED_RATING      0

#define PCICC_MAX_MESSAGE_SIZE 0x710    /* max size type6 v1 crt message */
#define PCICC_MAX_RESPONSE_SIZE 0x710   /* max size type86 v1 reply      */

#define PCICC_CLEANUP_TIME      (15*HZ)

static struct ap_device_id zcrypt_pcicc_ids[] = {
        { AP_DEVICE(AP_DEVICE_TYPE_PCICC) },
        { /* end of list */ },
};

#ifndef CONFIG_ZCRYPT_MONOLITHIC
MODULE_DEVICE_TABLE(ap, zcrypt_pcicc_ids);
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("PCICC Cryptographic Coprocessor device driver, "
                   "Copyright 2001, 2006 IBM Corporation");
MODULE_LICENSE("GPL");
#endif

static int zcrypt_pcicc_probe(struct ap_device *ap_dev);
static void zcrypt_pcicc_remove(struct ap_device *ap_dev);
static void zcrypt_pcicc_receive(struct ap_device *, struct ap_message *,
                                 struct ap_message *);

static struct ap_driver zcrypt_pcicc_driver = {
        .probe = zcrypt_pcicc_probe,
        .remove = zcrypt_pcicc_remove,
        .receive = zcrypt_pcicc_receive,
        .ids = zcrypt_pcicc_ids,
        .request_timeout = PCICC_CLEANUP_TIME,
};

/**
 * The following is used to initialize the CPRB passed to the PCICC card
 * in a type6 message. The 3 fields that must be filled in at execution
 * time are  req_parml, rpl_parml and usage_domain. Note that all three
 * fields are *little*-endian. Actually, everything about this interface
 * is ascii/little-endian, since the device has 'Intel inside'.
 *
 * The CPRB is followed immediately by the parm block.
 * The parm block contains:
 * - function code ('PD' 0x5044 or 'PK' 0x504B)
 * - rule block (0x0A00 'PKCS-1.2' or 0x0A00 'ZERO-PAD')
 * - VUD block
 */
static struct CPRB static_cprb = {
        .cprb_len       = __constant_cpu_to_le16(0x0070),
        .cprb_ver_id    =  0x41,
        .func_id        = {0x54,0x32},
        .checkpoint_flag=  0x01,
        .svr_namel      = __constant_cpu_to_le16(0x0008),
        .svr_name       = {'I','C','S','F',' ',' ',' ',' '}
};

/**
 * Check the message for PKCS11 padding.
 */
static inline int is_PKCS11_padded(unsigned char *buffer, int length)
{
        int i;
        if ((buffer[0] != 0x00) || (buffer[1] != 0x01))
                return 0;
        for (i = 2; i < length; i++)
                if (buffer[i] != 0xFF)
                        break;
        if (i < 10 || i == length)
                return 0;
        if (buffer[i] != 0x00)
                return 0;
        return 1;
}

/**
 * Check the message for PKCS12 padding.
 */
static inline int is_PKCS12_padded(unsigned char *buffer, int length)
{
        int i;
        if ((buffer[0] != 0x00) || (buffer[1] != 0x02))
                return 0;
        for (i = 2; i < length; i++)
                if (buffer[i] == 0x00)
                        break;
        if ((i < 10) || (i == length))
                return 0;
        if (buffer[i] != 0x00)
                return 0;
        return 1;
}

/**
 * Convert a ICAMEX message to a type6 MEX message.
 *
 * @zdev: crypto device pointer
 * @zreq: crypto request pointer
 * @mex: pointer to user input data
 *
 * Returns 0 on success or -EFAULT.
 */
static int ICAMEX_msg_to_type6MEX_msg(struct zcrypt_device *zdev,
                                      struct ap_message *ap_msg,
                                      struct ica_rsa_modexpo *mex)
{
        static struct type6_hdr static_type6_hdr = {
                .type           =  0x06,
                .offset1        =  0x00000058,
                .agent_id       = {0x01,0x00,0x43,0x43,0x41,0x2D,0x41,0x50,
                                   0x50,0x4C,0x20,0x20,0x20,0x01,0x01,0x01},
                .function_code  = {'P','K'},
        };
        static struct function_and_rules_block static_pke_function_and_rules ={
                .function_code  = {'P','K'},
                .ulen           = __constant_cpu_to_le16(10),
                .only_rule      = {'P','K','C','S','-','1','.','2'}
        };
        struct {
                struct type6_hdr hdr;
                struct CPRB cprb;
                struct function_and_rules_block fr;
                unsigned short length;
                char text[0];
        } __attribute__((packed)) *msg = ap_msg->message;
        int vud_len, pad_len, size;

        /* VUD.ciphertext */
        if (copy_from_user(msg->text, mex->inputdata, mex->inputdatalength))
                return -EFAULT;

        if (is_PKCS11_padded(msg->text, mex->inputdatalength))
                return -EINVAL;

        /* static message header and f&r */
        msg->hdr = static_type6_hdr;
        msg->fr = static_pke_function_and_rules;

        if (is_PKCS12_padded(msg->text, mex->inputdatalength)) {
                /* strip the padding and adjust the data length */
                pad_len = strnlen(msg->text + 2, mex->inputdatalength - 2) + 3;
                if (pad_len <= 9 || pad_len >= mex->inputdatalength)
                        return -ENODEV;
                vud_len = mex->inputdatalength - pad_len;
                memmove(msg->text, msg->text + pad_len, vud_len);
                msg->length = cpu_to_le16(vud_len + 2);

                /* Set up key after the variable length text. */
                size = zcrypt_type6_mex_key_en(mex, msg->text + vud_len, 0);
                if (size < 0)
                        return size;
                size += sizeof(*msg) + vud_len; /* total size of msg */
        } else {
                vud_len = mex->inputdatalength;
                msg->length = cpu_to_le16(2 + vud_len);

                msg->hdr.function_code[1] = 'D';
                msg->fr.function_code[1] = 'D';

                /* Set up key after the variable length text. */
                size = zcrypt_type6_mex_key_de(mex, msg->text + vud_len, 0);
                if (size < 0)
                        return size;
                size += sizeof(*msg) + vud_len; /* total size of msg */
        }

        /* message header, cprb and f&r */
        msg->hdr.ToCardLen1 = (size - sizeof(msg->hdr) + 3) & -4;
        msg->hdr.FromCardLen1 = PCICC_MAX_RESPONSE_SIZE - sizeof(msg->hdr);

        msg->cprb = static_cprb;
        msg->cprb.usage_domain[0]= AP_QID_QUEUE(zdev->ap_dev->qid);
        msg->cprb.req_parml = cpu_to_le16(size - sizeof(msg->hdr) -
                                           sizeof(msg->cprb));
        msg->cprb.rpl_parml = cpu_to_le16(msg->hdr.FromCardLen1);

        ap_msg->length = (size + 3) & -4;
        return 0;
}

/**
 * Convert a ICACRT message to a type6 CRT message.
 *
 * @zdev: crypto device pointer
 * @zreq: crypto request pointer
 * @crt: pointer to user input data
 *
 * Returns 0 on success or -EFAULT.
 */
static int ICACRT_msg_to_type6CRT_msg(struct zcrypt_device *zdev,
                                      struct ap_message *ap_msg,
                                      struct ica_rsa_modexpo_crt *crt)
{
        static struct type6_hdr static_type6_hdr = {
                .type           =  0x06,
                .offset1        =  0x00000058,
                .agent_id       = {0x01,0x00,0x43,0x43,0x41,0x2D,0x41,0x50,
                                   0x50,0x4C,0x20,0x20,0x20,0x01,0x01,0x01},
                .function_code  = {'P','D'},
        };
        static struct function_and_rules_block static_pkd_function_and_rules ={
                .function_code  = {'P','D'},
                .ulen           = __constant_cpu_to_le16(10),
                .only_rule      = {'P','K','C','S','-','1','.','2'}
        };
        struct {
                struct type6_hdr hdr;
                struct CPRB cprb;
                struct function_and_rules_block fr;
                unsigned short length;
                char text[0];
        } __attribute__((packed)) *msg = ap_msg->message;
        int size;

        /* VUD.ciphertext */
        msg->length = cpu_to_le16(2 + crt->inputdatalength);
        if (copy_from_user(msg->text, crt->inputdata, crt->inputdatalength))
                return -EFAULT;

        if (is_PKCS11_padded(msg->text, crt->inputdatalength))
                return -EINVAL;

        /* Set up key after the variable length text. */
        size = zcrypt_type6_crt_key(crt, msg->text + crt->inputdatalength, 0);
        if (size < 0)
                return size;
        size += sizeof(*msg) + crt->inputdatalength;    /* total size of msg */

        /* message header, cprb and f&r */
        msg->hdr = static_type6_hdr;
        msg->hdr.ToCardLen1 = (size -  sizeof(msg->hdr) + 3) & -4;
        msg->hdr.FromCardLen1 = PCICC_MAX_RESPONSE_SIZE - sizeof(msg->hdr);

        msg->cprb = static_cprb;
        msg->cprb.usage_domain[0] = AP_QID_QUEUE(zdev->ap_dev->qid);
        msg->cprb.req_parml = msg->cprb.rpl_parml =
                cpu_to_le16(size - sizeof(msg->hdr) - sizeof(msg->cprb));

        msg->fr = static_pkd_function_and_rules;

        ap_msg->length = (size + 3) & -4;
        return 0;
}

/**
 * Copy results from a type 86 reply message back to user space.
 *
 * @zdev: crypto device pointer
 * @reply: reply AP message.
 * @data: pointer to user output data
 * @length: size of user output data
 *
 * Returns 0 on success or -EINVAL, -EFAULT, -EAGAIN in case of an error.
 */
struct type86_reply {
        struct type86_hdr hdr;
        struct type86_fmt2_ext fmt2;
        struct CPRB cprb;
        unsigned char pad[4];   /* 4 byte function code/rules block ? */
        unsigned short length;
        char text[0];
} __attribute__((packed));

static int convert_type86(struct zcrypt_device *zdev,
                          struct ap_message *reply,
                          char __user *outputdata,
                          unsigned int outputdatalength)
{
        static unsigned char static_pad[] = {
                0x00,0x02,
                0x1B,0x7B,0x5D,0xB5,0x75,0x01,0x3D,0xFD,
                0x8D,0xD1,0xC7,0x03,0x2D,0x09,0x23,0x57,
                0x89,0x49,0xB9,0x3F,0xBB,0x99,0x41,0x5B,
                0x75,0x21,0x7B,0x9D,0x3B,0x6B,0x51,0x39,
                0xBB,0x0D,0x35,0xB9,0x89,0x0F,0x93,0xA5,
                0x0B,0x47,0xF1,0xD3,0xBB,0xCB,0xF1,0x9D,
                0x23,0x73,0x71,0xFF,0xF3,0xF5,0x45,0xFB,
                0x61,0x29,0x23,0xFD,0xF1,0x29,0x3F,0x7F,
                0x17,0xB7,0x1B,0xA9,0x19,0xBD,0x57,0xA9,
                0xD7,0x95,0xA3,0xCB,0xED,0x1D,0xDB,0x45,
                0x7D,0x11,0xD1,0x51,0x1B,0xED,0x71,0xE9,
                0xB1,0xD1,0xAB,0xAB,0x21,0x2B,0x1B,0x9F,
                0x3B,0x9F,0xF7,0xF7,0xBD,0x63,0xEB,0xAD,
                0xDF,0xB3,0x6F,0x5B,0xDB,0x8D,0xA9,0x5D,
                0xE3,0x7D,0x77,0x49,0x47,0xF5,0xA7,0xFD,
                0xAB,0x2F,0x27,0x35,0x77,0xD3,0x49,0xC9,
                0x09,0xEB,0xB1,0xF9,0xBF,0x4B,0xCB,0x2B,
                0xEB,0xEB,0x05,0xFF,0x7D,0xC7,0x91,0x8B,
                0x09,0x83,0xB9,0xB9,0x69,0x33,0x39,0x6B,
                0x79,0x75,0x19,0xBF,0xBB,0x07,0x1D,0xBD,
                0x29,0xBF,0x39,0x95,0x93,0x1D,0x35,0xC7,
                0xC9,0x4D,0xE5,0x97,0x0B,0x43,0x9B,0xF1,
                0x16,0x93,0x03,0x1F,0xA5,0xFB,0xDB,0xF3,
                0x27,0x4F,0x27,0x61,0x05,0x1F,0xB9,0x23,
                0x2F,0xC3,0x81,0xA9,0x23,0x71,0x55,0x55,
                0xEB,0xED,0x41,0xE5,0xF3,0x11,0xF1,0x43,
                0x69,0x03,0xBD,0x0B,0x37,0x0F,0x51,0x8F,
                0x0B,0xB5,0x89,0x5B,0x67,0xA9,0xD9,0x4F,
                0x01,0xF9,0x21,0x77,0x37,0x73,0x79,0xC5,
                0x7F,0x51,0xC1,0xCF,0x97,0xA1,0x75,0xAD,
                0x35,0x9D,0xD3,0xD3,0xA7,0x9D,0x5D,0x41,
                0x6F,0x65,0x1B,0xCF,0xA9,0x87,0x91,0x09
        };
        struct type86_reply *msg = reply->message;
        unsigned short service_rc, service_rs;
        unsigned int reply_len, pad_len;
        char *data;

        service_rc = le16_to_cpu(msg->cprb.ccp_rtcode);
        if (unlikely(service_rc != 0)) {
                service_rs = le16_to_cpu(msg->cprb.ccp_rscode);
                if (service_rc == 8 && service_rs == 66)
                        return -EINVAL;
                if (service_rc == 8 && service_rs == 65)
                        return -EINVAL;
                if (service_rc == 8 && service_rs == 770) {
                        zdev->max_mod_size = PCICC_MAX_MOD_SIZE_OLD;
                        return -EAGAIN;
                }
                if (service_rc == 8 && service_rs == 783) {
                        zdev->max_mod_size = PCICC_MAX_MOD_SIZE_OLD;
                        return -EAGAIN;
                }
                zdev->online = 0;
                return -EAGAIN; /* repeat the request on a different device. */
        }
        data = msg->text;
        reply_len = le16_to_cpu(msg->length) - 2;
        if (reply_len > outputdatalength)
                return -EINVAL;
        /*
         * For all encipher requests, the length of the ciphertext (reply_len)
         * will always equal the modulus length. For MEX decipher requests
         * the output needs to get padded. Minimum pad size is 10.
         *
         * Currently, the cases where padding will be added is for:
         * - PCIXCC_MCL2 using a CRT form token (since PKD didn't support
         *   ZERO-PAD and CRT is only supported for PKD requests)
         * - PCICC, always
         */
        pad_len = outputdatalength - reply_len;
        if (pad_len > 0) {
                if (pad_len < 10)
                        return -EINVAL;
                /* 'restore' padding left in the PCICC/PCIXCC card. */
                if (copy_to_user(outputdata, static_pad, pad_len - 1))
                        return -EFAULT;
                if (put_user(0, outputdata + pad_len - 1))
                        return -EFAULT;
        }
        /* Copy the crypto response to user space. */
        if (copy_to_user(outputdata + pad_len, data, reply_len))
                return -EFAULT;
        return 0;
}

static int convert_response(struct zcrypt_device *zdev,
                            struct ap_message *reply,
                            char __user *outputdata,
                            unsigned int outputdatalength)
{
        struct type86_reply *msg = reply->message;

        /* Response type byte is the second byte in the response. */
        switch (msg->hdr.type) {
        case TYPE82_RSP_CODE:
        case TYPE88_RSP_CODE:
                return convert_error(zdev, reply);
        case TYPE86_RSP_CODE:
                if (msg->hdr.reply_code)
                        return convert_error(zdev, reply);
                if (msg->cprb.cprb_ver_id == 0x01)
                        return convert_type86(zdev, reply,
                                              outputdata, outputdatalength);
                /* no break, incorrect cprb version is an unknown response */
        default: /* Unknown response type, this should NEVER EVER happen */
                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".
 * It is called from tasklet context.
 * @ap_dev: pointer to the AP device
 * @msg: pointer to the AP message
 * @reply: pointer to the AP reply message
 */
static void zcrypt_pcicc_receive(struct ap_device *ap_dev,
                                 struct ap_message *msg,
                                 struct ap_message *reply)
{
        static struct error_hdr error_reply = {
                .type = TYPE82_RSP_CODE,
                .reply_code = REP82_ERROR_MACHINE_FAILURE,
        };
        struct type86_reply *t86r;
        int length;

        /* Copy the reply message to the request message buffer. */
        if (IS_ERR(reply)) {
                memcpy(msg->message, &error_reply, sizeof(error_reply));
                goto out;
        }
        t86r = reply->message;
        if (t86r->hdr.type == TYPE86_RSP_CODE &&
                 t86r->cprb.cprb_ver_id == 0x01) {
                length = sizeof(struct type86_reply) + t86r->length - 2;
                length = min(PCICC_MAX_RESPONSE_SIZE, length);
                memcpy(msg->message, reply->message, length);
        } else
                memcpy(msg->message, reply->message, sizeof error_reply);
out:
        complete((struct completion *) msg->private);
}

static atomic_t zcrypt_step = ATOMIC_INIT(0);

/**
 * The request distributor calls this function if it picked the PCICC
 * device to handle a modexpo request.
 * @zdev: pointer to zcrypt_device structure that identifies the
 *        PCICC device to the request distributor
 * @mex: pointer to the modexpo request buffer
 */
static long zcrypt_pcicc_modexpo(struct zcrypt_device *zdev,
                                 struct ica_rsa_modexpo *mex)
{
        struct ap_message ap_msg;
        struct completion work;
        int rc;

        ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
        if (!ap_msg.message)
                return -ENOMEM;
        ap_msg.length = PAGE_SIZE;
        ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
                                atomic_inc_return(&zcrypt_step);
        ap_msg.private = &work;
        rc = ICAMEX_msg_to_type6MEX_msg(zdev, &ap_msg, mex);
        if (rc)
                goto out_free;
        init_completion(&work);
        ap_queue_message(zdev->ap_dev, &ap_msg);
        rc = wait_for_completion_interruptible(&work);
        if (rc == 0)
                rc = convert_response(zdev, &ap_msg, mex->outputdata,
                                      mex->outputdatalength);
        else
                /* Signal pending. */
                ap_cancel_message(zdev->ap_dev, &ap_msg);
out_free:
        free_page((unsigned long) ap_msg.message);
        return rc;
}

/**
 * The request distributor calls this function if it picked the PCICC
 * device to handle a modexpo_crt request.
 * @zdev: pointer to zcrypt_device structure that identifies the
 *        PCICC device to the request distributor
 * @crt: pointer to the modexpoc_crt request buffer
 */
static long zcrypt_pcicc_modexpo_crt(struct zcrypt_device *zdev,
                                     struct ica_rsa_modexpo_crt *crt)
{
        struct ap_message ap_msg;
        struct completion work;
        int rc;

        ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
        if (!ap_msg.message)
                return -ENOMEM;
        ap_msg.length = PAGE_SIZE;
        ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
                                atomic_inc_return(&zcrypt_step);
        ap_msg.private = &work;
        rc = ICACRT_msg_to_type6CRT_msg(zdev, &ap_msg, crt);
        if (rc)
                goto out_free;
        init_completion(&work);
        ap_queue_message(zdev->ap_dev, &ap_msg);
        rc = wait_for_completion_interruptible(&work);
        if (rc == 0)
                rc = convert_response(zdev, &ap_msg, crt->outputdata,
                                      crt->outputdatalength);
        else
                /* Signal pending. */
                ap_cancel_message(zdev->ap_dev, &ap_msg);
out_free:
        free_page((unsigned long) ap_msg.message);
        return rc;
}

/**
 * The crypto operations for a PCICC card.
 */
static struct zcrypt_ops zcrypt_pcicc_ops = {
        .rsa_modexpo = zcrypt_pcicc_modexpo,
        .rsa_modexpo_crt = zcrypt_pcicc_modexpo_crt,
};

/**
 * Probe function for PCICC cards. It always accepts the AP device
 * since the bus_match already checked the hardware type.
 * @ap_dev: pointer to the AP device.
 */
static int zcrypt_pcicc_probe(struct ap_device *ap_dev)
{
        struct zcrypt_device *zdev;
        int rc;

        zdev = zcrypt_device_alloc(PCICC_MAX_RESPONSE_SIZE);
        if (!zdev)
                return -ENOMEM;
        zdev->ap_dev = ap_dev;
        zdev->ops = &zcrypt_pcicc_ops;
        zdev->online = 1;
        zdev->user_space_type = ZCRYPT_PCICC;
        zdev->type_string = "PCICC";
        zdev->min_mod_size = PCICC_MIN_MOD_SIZE;
        zdev->max_mod_size = PCICC_MAX_MOD_SIZE;
        zdev->speed_rating = PCICC_SPEED_RATING;
        ap_dev->reply = &zdev->reply;
        ap_dev->private = zdev;
        rc = zcrypt_device_register(zdev);
        if (rc)
                goto out_free;
        return 0;

 out_free:
        ap_dev->private = NULL;
        zcrypt_device_free(zdev);
        return rc;
}

/**
 * This is called to remove the extended PCICC driver information
 * if an AP device is removed.
 */
static void zcrypt_pcicc_remove(struct ap_device *ap_dev)
{
        struct zcrypt_device *zdev = ap_dev->private;

        zcrypt_device_unregister(zdev);
}

int __init zcrypt_pcicc_init(void)
{
        return ap_driver_register(&zcrypt_pcicc_driver, THIS_MODULE, "pcicc");
}

void zcrypt_pcicc_exit(void)
{
        ap_driver_unregister(&zcrypt_pcicc_driver);
}

#ifndef CONFIG_ZCRYPT_MONOLITHIC
module_init(zcrypt_pcicc_init);
module_exit(zcrypt_pcicc_exit);
#endif