cifsencrypt.c

Go to the documentation of this file.

/*
 *   fs/cifs/cifsencrypt.c
 *
 *   Copyright (C) International Business Machines  Corp., 2005,2006
 *   Author(s): Steve French ([email protected])
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library 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 Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/fs.h>
#include <linux/slab.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "cifsproto.h"
#include "ntlmssp.h"
#include <linux/ctype.h>
#include <linux/random.h>
#include <linux/highmem.h>

/*
 * Calculate and return the CIFS signature based on the mac key and SMB PDU.
 * The 16 byte signature must be allocated by the caller. Note we only use the
 * 1st eight bytes and that the smb header signature field on input contains
 * the sequence number before this function is called. Also, this function
 * should be called with the server->srv_mutex held.
 */
static int cifs_calc_signature(struct smb_rqst *rqst,
            struct TCP_Server_Info *server, char *signature)
{
    int i;
    int rc;
    struct kvec *iov = rqst->rq_iov;
    int n_vec = rqst->rq_nvec;

    if (iov == NULL || signature == NULL || server == NULL)
        return -EINVAL;

    if (!server->secmech.sdescmd5) {
        cERROR(1, "%s: Can't generate signature", __func__);
        return -1;
    }

    rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
    if (rc) {
        cERROR(1, "%s: Could not init md5", __func__);
        return rc;
    }

    rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
        server->session_key.response, server->session_key.len);
    if (rc) {
        cERROR(1, "%s: Could not update with response", __func__);
        return rc;
    }

    for (i = 0; i < n_vec; i++) {
        if (iov[i].iov_len == 0)
            continue;
        if (iov[i].iov_base == NULL) {
            cERROR(1, "null iovec entry");
            return -EIO;
        }
        /* The first entry includes a length field (which does not get
           signed that occupies the first 4 bytes before the header */
        if (i == 0) {
            if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
                break; /* nothing to sign or corrupt header */
            rc =
            crypto_shash_update(&server->secmech.sdescmd5->shash,
                iov[i].iov_base + 4, iov[i].iov_len - 4);
        } else {
            rc =
            crypto_shash_update(&server->secmech.sdescmd5->shash,
                iov[i].iov_base, iov[i].iov_len);
        }
        if (rc) {
            cERROR(1, "%s: Could not update with payload",
                            __func__);
            return rc;
        }
    }

    /* now hash over the rq_pages array */
    for (i = 0; i < rqst->rq_npages; i++) {
        struct kvec p_iov;

        cifs_rqst_page_to_kvec(rqst, i, &p_iov);
        crypto_shash_update(&server->secmech.sdescmd5->shash,
                    p_iov.iov_base, p_iov.iov_len);
        kunmap(rqst->rq_pages[i]);
    }

    rc = crypto_shash_final(&server->secmech.sdescmd5->shash, signature);
    if (rc)
        cERROR(1, "%s: Could not generate md5 hash", __func__);

    return rc;
}

/* must be called with server->srv_mutex held */
int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
           __u32 *pexpected_response_sequence_number)
{
    int rc = 0;
    char smb_signature[20];
    struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base;

    if ((cifs_pdu == NULL) || (server == NULL))
        return -EINVAL;

    if (!(cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) ||
        server->tcpStatus == CifsNeedNegotiate)
        return rc;

    if (!server->session_estab) {
        memcpy(cifs_pdu->Signature.SecuritySignature, "BSRSPYL", 8);
        return rc;
    }

    cifs_pdu->Signature.Sequence.SequenceNumber =
                cpu_to_le32(server->sequence_number);
    cifs_pdu->Signature.Sequence.Reserved = 0;

    *pexpected_response_sequence_number = server->sequence_number++;
    server->sequence_number++;

    rc = cifs_calc_signature(rqst, server, smb_signature);
    if (rc)
        memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
    else
        memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);

    return rc;
}

int cifs_sign_smbv(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
           __u32 *pexpected_response_sequence)
{
    struct smb_rqst rqst = { .rq_iov = iov,
                 .rq_nvec = n_vec };

    return cifs_sign_rqst(&rqst, server, pexpected_response_sequence);
}

/* must be called with server->srv_mutex held */
int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
          __u32 *pexpected_response_sequence_number)
{
    struct kvec iov;

    iov.iov_base = cifs_pdu;
    iov.iov_len = be32_to_cpu(cifs_pdu->smb_buf_length) + 4;

    return cifs_sign_smbv(&iov, 1, server,
                  pexpected_response_sequence_number);
}

int cifs_verify_signature(struct smb_rqst *rqst,
              struct TCP_Server_Info *server,
              __u32 expected_sequence_number)
{
    unsigned int rc;
    char server_response_sig[8];
    char what_we_think_sig_should_be[20];
    struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base;

    if (cifs_pdu == NULL || server == NULL)
        return -EINVAL;

    if (!server->session_estab)
        return 0;

    if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
        struct smb_com_lock_req *pSMB =
            (struct smb_com_lock_req *)cifs_pdu;
        if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
            return 0;
    }

    /* BB what if signatures are supposed to be on for session but
       server does not send one? BB */

    /* Do not need to verify session setups with signature "BSRSPYL "  */
    if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0)
        cFYI(1, "dummy signature received for smb command 0x%x",
            cifs_pdu->Command);

    /* save off the origiginal signature so we can modify the smb and check
        its signature against what the server sent */
    memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8);

    cifs_pdu->Signature.Sequence.SequenceNumber =
                    cpu_to_le32(expected_sequence_number);
    cifs_pdu->Signature.Sequence.Reserved = 0;

    mutex_lock(&server->srv_mutex);
    rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be);
    mutex_unlock(&server->srv_mutex);

    if (rc)
        return rc;

/*  cifs_dump_mem("what we think it should be: ",
              what_we_think_sig_should_be, 16); */

    if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
        return -EACCES;
    else
        return 0;

}

/* first calculate 24 bytes ntlm response and then 16 byte session key */
int setup_ntlm_response(struct cifs_ses *ses, const struct nls_table *nls_cp)
{
    int rc = 0;
    unsigned int temp_len = CIFS_SESS_KEY_SIZE + CIFS_AUTH_RESP_SIZE;
    char temp_key[CIFS_SESS_KEY_SIZE];

    if (!ses)
        return -EINVAL;

    ses->auth_key.response = kmalloc(temp_len, GFP_KERNEL);
    if (!ses->auth_key.response) {
        cERROR(1, "NTLM can't allocate (%u bytes) memory", temp_len);
        return -ENOMEM;
    }
    ses->auth_key.len = temp_len;

    rc = SMBNTencrypt(ses->password, ses->server->cryptkey,
            ses->auth_key.response + CIFS_SESS_KEY_SIZE, nls_cp);
    if (rc) {
        cFYI(1, "%s Can't generate NTLM response, error: %d",
            __func__, rc);
        return rc;
    }

    rc = E_md4hash(ses->password, temp_key, nls_cp);
    if (rc) {
        cFYI(1, "%s Can't generate NT hash, error: %d", __func__, rc);
        return rc;
    }

    rc = mdfour(ses->auth_key.response, temp_key, CIFS_SESS_KEY_SIZE);
    if (rc)
        cFYI(1, "%s Can't generate NTLM session key, error: %d",
            __func__, rc);

    return rc;
}

#ifdef CONFIG_CIFS_WEAK_PW_HASH
int calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
            char *lnm_session_key)
{
    int i;
    int rc;
    char password_with_pad[CIFS_ENCPWD_SIZE];

    memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
    if (password)
        strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);

    if (!encrypt && global_secflags & CIFSSEC_MAY_PLNTXT) {
        memset(lnm_session_key, 0, CIFS_SESS_KEY_SIZE);
        memcpy(lnm_session_key, password_with_pad,
            CIFS_ENCPWD_SIZE);
        return 0;
    }

    /* calculate old style session key */
    /* calling toupper is less broken than repeatedly
    calling nls_toupper would be since that will never
    work for UTF8, but neither handles multibyte code pages
    but the only alternative would be converting to UCS-16 (Unicode)
    (using a routine something like UniStrupr) then
    uppercasing and then converting back from Unicode - which
    would only worth doing it if we knew it were utf8. Basically
    utf8 and other multibyte codepages each need their own strupper
    function since a byte at a time will ont work. */

    for (i = 0; i < CIFS_ENCPWD_SIZE; i++)
        password_with_pad[i] = toupper(password_with_pad[i]);

    rc = SMBencrypt(password_with_pad, cryptkey, lnm_session_key);

    return rc;
}
#endif /* CIFS_WEAK_PW_HASH */

/* Build a proper attribute value/target info pairs blob.
 * Fill in netbios and dns domain name and workstation name
 * and client time (total five av pairs and + one end of fields indicator.
 * Allocate domain name which gets freed when session struct is deallocated.
 */
static int
build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
{
    unsigned int dlen;
    unsigned int size = 2 * sizeof(struct ntlmssp2_name);
    char *defdmname = "WORKGROUP";
    unsigned char *blobptr;
    struct ntlmssp2_name *attrptr;

    if (!ses->domainName) {
        ses->domainName = kstrdup(defdmname, GFP_KERNEL);
        if (!ses->domainName)
            return -ENOMEM;
    }

    dlen = strlen(ses->domainName);

    /*
     * The length of this blob is two times the size of a
     * structure (av pair) which holds name/size
     * ( for NTLMSSP_AV_NB_DOMAIN_NAME followed by NTLMSSP_AV_EOL ) +
     * unicode length of a netbios domain name
     */
    ses->auth_key.len = size + 2 * dlen;
    ses->auth_key.response = kzalloc(ses->auth_key.len, GFP_KERNEL);
    if (!ses->auth_key.response) {
        ses->auth_key.len = 0;
        cERROR(1, "Challenge target info allocation failure");
        return -ENOMEM;
    }

    blobptr = ses->auth_key.response;
    attrptr = (struct ntlmssp2_name *) blobptr;

    /*
     * As defined in MS-NTLM 3.3.2, just this av pair field
     * is sufficient as part of the temp
     */
    attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_DOMAIN_NAME);
    attrptr->length = cpu_to_le16(2 * dlen);
    blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
    cifs_strtoUTF16((__le16 *)blobptr, ses->domainName, dlen, nls_cp);

    return 0;
}

/* Server has provided av pairs/target info in the type 2 challenge
 * packet and we have plucked it and stored within smb session.
 * We parse that blob here to find netbios domain name to be used
 * as part of ntlmv2 authentication (in Target String), if not already
 * specified on the command line.
 * If this function returns without any error but without fetching
 * domain name, authentication may fail against some server but
 * may not fail against other (those who are not very particular
 * about target string i.e. for some, just user name might suffice.
 */
static int
find_domain_name(struct cifs_ses *ses, const struct nls_table *nls_cp)
{
    unsigned int attrsize;
    unsigned int type;
    unsigned int onesize = sizeof(struct ntlmssp2_name);
    unsigned char *blobptr;
    unsigned char *blobend;
    struct ntlmssp2_name *attrptr;

    if (!ses->auth_key.len || !ses->auth_key.response)
        return 0;

    blobptr = ses->auth_key.response;
    blobend = blobptr + ses->auth_key.len;

    while (blobptr + onesize < blobend) {
        attrptr = (struct ntlmssp2_name *) blobptr;
        type = le16_to_cpu(attrptr->type);
        if (type == NTLMSSP_AV_EOL)
            break;
        blobptr += 2; /* advance attr type */
        attrsize = le16_to_cpu(attrptr->length);
        blobptr += 2; /* advance attr size */
        if (blobptr + attrsize > blobend)
            break;
        if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
            if (!attrsize)
                break;
            if (!ses->domainName) {
                ses->domainName =
                    kmalloc(attrsize + 1, GFP_KERNEL);
                if (!ses->domainName)
                        return -ENOMEM;
                cifs_from_utf16(ses->domainName,
                    (__le16 *)blobptr, attrsize, attrsize,
                    nls_cp, false);
                break;
            }
        }
        blobptr += attrsize; /* advance attr  value */
    }

    return 0;
}

static int calc_ntlmv2_hash(struct cifs_ses *ses, char *ntlmv2_hash,
                const struct nls_table *nls_cp)
{
    int rc = 0;
    int len;
    char nt_hash[CIFS_NTHASH_SIZE];
    wchar_t *user;
    wchar_t *domain;
    wchar_t *server;

    if (!ses->server->secmech.sdeschmacmd5) {
        cERROR(1, "calc_ntlmv2_hash: can't generate ntlmv2 hash");
        return -1;
    }

    /* calculate md4 hash of password */
    E_md4hash(ses->password, nt_hash, nls_cp);

    rc = crypto_shash_setkey(ses->server->secmech.hmacmd5, nt_hash,
                CIFS_NTHASH_SIZE);
    if (rc) {
        cERROR(1, "%s: Could not set NT Hash as a key", __func__);
        return rc;
    }

    rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
    if (rc) {
        cERROR(1, "calc_ntlmv2_hash: could not init hmacmd5");
        return rc;
    }

    /* convert ses->user_name to unicode and uppercase */
    len = ses->user_name ? strlen(ses->user_name) : 0;
    user = kmalloc(2 + (len * 2), GFP_KERNEL);
    if (user == NULL) {
        cERROR(1, "calc_ntlmv2_hash: user mem alloc failure");
        rc = -ENOMEM;
        return rc;
    }

    if (len) {
        len = cifs_strtoUTF16((__le16 *)user, ses->user_name, len, nls_cp);
        UniStrupr(user);
    } else {
        memset(user, '\0', 2);
    }

    rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
                (char *)user, 2 * len);
    kfree(user);
    if (rc) {
        cERROR(1, "%s: Could not update with user", __func__);
        return rc;
    }

    /* convert ses->domainName to unicode and uppercase */
    if (ses->domainName) {
        len = strlen(ses->domainName);

        domain = kmalloc(2 + (len * 2), GFP_KERNEL);
        if (domain == NULL) {
            cERROR(1, "calc_ntlmv2_hash: domain mem alloc failure");
            rc = -ENOMEM;
            return rc;
        }
        len = cifs_strtoUTF16((__le16 *)domain, ses->domainName, len,
                      nls_cp);
        rc =
        crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
                    (char *)domain, 2 * len);
        kfree(domain);
        if (rc) {
            cERROR(1, "%s: Could not update with domain",
                                __func__);
            return rc;
        }
    } else if (ses->serverName) {
        len = strlen(ses->serverName);

        server = kmalloc(2 + (len * 2), GFP_KERNEL);
        if (server == NULL) {
            cERROR(1, "calc_ntlmv2_hash: server mem alloc failure");
            rc = -ENOMEM;
            return rc;
        }
        len = cifs_strtoUTF16((__le16 *)server, ses->serverName, len,
                    nls_cp);
        rc =
        crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
                    (char *)server, 2 * len);
        kfree(server);
        if (rc) {
            cERROR(1, "%s: Could not update with server",
                                __func__);
            return rc;
        }
    }

    rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
                    ntlmv2_hash);
    if (rc)
        cERROR(1, "%s: Could not generate md5 hash", __func__);

    return rc;
}

static int
CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
{
    int rc;
    unsigned int offset = CIFS_SESS_KEY_SIZE + 8;

    if (!ses->server->secmech.sdeschmacmd5) {
        cERROR(1, "calc_ntlmv2_hash: can't generate ntlmv2 hash");
        return -1;
    }

    rc = crypto_shash_setkey(ses->server->secmech.hmacmd5,
                ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
    if (rc) {
        cERROR(1, "%s: Could not set NTLMV2 Hash as a key", __func__);
        return rc;
    }

    rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
    if (rc) {
        cERROR(1, "CalcNTLMv2_response: could not init hmacmd5");
        return rc;
    }

    if (ses->server->secType == RawNTLMSSP)
        memcpy(ses->auth_key.response + offset,
            ses->ntlmssp->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
    else
        memcpy(ses->auth_key.response + offset,
            ses->server->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
    rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
        ses->auth_key.response + offset, ses->auth_key.len - offset);
    if (rc) {
        cERROR(1, "%s: Could not update with response", __func__);
        return rc;
    }

    rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
        ses->auth_key.response + CIFS_SESS_KEY_SIZE);
    if (rc)
        cERROR(1, "%s: Could not generate md5 hash", __func__);

    return rc;
}


int
setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
{
    int rc;
    int baselen;
    unsigned int tilen;
    struct ntlmv2_resp *buf;
    char ntlmv2_hash[16];
    unsigned char *tiblob = NULL; /* target info blob */

    if (ses->server->secType == RawNTLMSSP) {
        if (!ses->domainName) {
            rc = find_domain_name(ses, nls_cp);
            if (rc) {
                cERROR(1, "error %d finding domain name", rc);
                goto setup_ntlmv2_rsp_ret;
            }
        }
    } else {
        rc = build_avpair_blob(ses, nls_cp);
        if (rc) {
            cERROR(1, "error %d building av pair blob", rc);
            goto setup_ntlmv2_rsp_ret;
        }
    }

    baselen = CIFS_SESS_KEY_SIZE + sizeof(struct ntlmv2_resp);
    tilen = ses->auth_key.len;
    tiblob = ses->auth_key.response;

    ses->auth_key.response = kmalloc(baselen + tilen, GFP_KERNEL);
    if (!ses->auth_key.response) {
        rc = ENOMEM;
        ses->auth_key.len = 0;
        cERROR(1, "%s: Can't allocate auth blob", __func__);
        goto setup_ntlmv2_rsp_ret;
    }
    ses->auth_key.len += baselen;

    buf = (struct ntlmv2_resp *)
            (ses->auth_key.response + CIFS_SESS_KEY_SIZE);
    buf->blob_signature = cpu_to_le32(0x00000101);
    buf->reserved = 0;
    buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
    get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
    buf->reserved2 = 0;

    memcpy(ses->auth_key.response + baselen, tiblob, tilen);

    /* calculate ntlmv2_hash */
    rc = calc_ntlmv2_hash(ses, ntlmv2_hash, nls_cp);
    if (rc) {
        cERROR(1, "could not get v2 hash rc %d", rc);
        goto setup_ntlmv2_rsp_ret;
    }

    /* calculate first part of the client response (CR1) */
    rc = CalcNTLMv2_response(ses, ntlmv2_hash);
    if (rc) {
        cERROR(1, "Could not calculate CR1  rc: %d", rc);
        goto setup_ntlmv2_rsp_ret;
    }

    /* now calculate the session key for NTLMv2 */
    rc = crypto_shash_setkey(ses->server->secmech.hmacmd5,
        ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
    if (rc) {
        cERROR(1, "%s: Could not set NTLMV2 Hash as a key", __func__);
        goto setup_ntlmv2_rsp_ret;
    }

    rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
    if (rc) {
        cERROR(1, "%s: Could not init hmacmd5", __func__);
        goto setup_ntlmv2_rsp_ret;
    }

    rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
        ses->auth_key.response + CIFS_SESS_KEY_SIZE,
        CIFS_HMAC_MD5_HASH_SIZE);
    if (rc) {
        cERROR(1, "%s: Could not update with response", __func__);
        goto setup_ntlmv2_rsp_ret;
    }

    rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
        ses->auth_key.response);
    if (rc)
        cERROR(1, "%s: Could not generate md5 hash", __func__);

setup_ntlmv2_rsp_ret:
    kfree(tiblob);

    return rc;
}

int
calc_seckey(struct cifs_ses *ses)
{
    int rc;
    struct crypto_blkcipher *tfm_arc4;
    struct scatterlist sgin, sgout;
    struct blkcipher_desc desc;
    unsigned char sec_key[CIFS_SESS_KEY_SIZE]; /* a nonce */

    get_random_bytes(sec_key, CIFS_SESS_KEY_SIZE);

    tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
    if (IS_ERR(tfm_arc4)) {
        rc = PTR_ERR(tfm_arc4);
        cERROR(1, "could not allocate crypto API arc4");
        return rc;
    }

    desc.tfm = tfm_arc4;

    rc = crypto_blkcipher_setkey(tfm_arc4, ses->auth_key.response,
                    CIFS_SESS_KEY_SIZE);
    if (rc) {
        cERROR(1, "%s: Could not set response as a key", __func__);
        return rc;
    }

    sg_init_one(&sgin, sec_key, CIFS_SESS_KEY_SIZE);
    sg_init_one(&sgout, ses->ntlmssp->ciphertext, CIFS_CPHTXT_SIZE);

    rc = crypto_blkcipher_encrypt(&desc, &sgout, &sgin, CIFS_CPHTXT_SIZE);
    if (rc) {
        cERROR(1, "could not encrypt session key rc: %d", rc);
        crypto_free_blkcipher(tfm_arc4);
        return rc;
    }

    /* make secondary_key/nonce as session key */
    memcpy(ses->auth_key.response, sec_key, CIFS_SESS_KEY_SIZE);
    /* and make len as that of session key only */
    ses->auth_key.len = CIFS_SESS_KEY_SIZE;

    crypto_free_blkcipher(tfm_arc4);

    return rc;
}

void
cifs_crypto_shash_release(struct TCP_Server_Info *server)
{
    if (server->secmech.hmacsha256)
        crypto_free_shash(server->secmech.hmacsha256);

    if (server->secmech.md5)
        crypto_free_shash(server->secmech.md5);

    if (server->secmech.hmacmd5)
        crypto_free_shash(server->secmech.hmacmd5);

    kfree(server->secmech.sdeschmacsha256);

    kfree(server->secmech.sdeschmacmd5);

    kfree(server->secmech.sdescmd5);
}

int
cifs_crypto_shash_allocate(struct TCP_Server_Info *server)
{
    int rc;
    unsigned int size;

    server->secmech.hmacmd5 = crypto_alloc_shash("hmac(md5)", 0, 0);
    if (IS_ERR(server->secmech.hmacmd5)) {
        cERROR(1, "could not allocate crypto hmacmd5");
        return PTR_ERR(server->secmech.hmacmd5);
    }

    server->secmech.md5 = crypto_alloc_shash("md5", 0, 0);
    if (IS_ERR(server->secmech.md5)) {
        cERROR(1, "could not allocate crypto md5");
        rc = PTR_ERR(server->secmech.md5);
        goto crypto_allocate_md5_fail;
    }

    server->secmech.hmacsha256 = crypto_alloc_shash("hmac(sha256)", 0, 0);
    if (IS_ERR(server->secmech.hmacsha256)) {
        cERROR(1, "could not allocate crypto hmacsha256\n");
        rc = PTR_ERR(server->secmech.hmacsha256);
        goto crypto_allocate_hmacsha256_fail;
    }

    size = sizeof(struct shash_desc) +
            crypto_shash_descsize(server->secmech.hmacmd5);
    server->secmech.sdeschmacmd5 = kmalloc(size, GFP_KERNEL);
    if (!server->secmech.sdeschmacmd5) {
        cERROR(1, "cifs_crypto_shash_allocate: can't alloc hmacmd5");
        rc = -ENOMEM;
        goto crypto_allocate_hmacmd5_sdesc_fail;
    }
    server->secmech.sdeschmacmd5->shash.tfm = server->secmech.hmacmd5;
    server->secmech.sdeschmacmd5->shash.flags = 0x0;

    size = sizeof(struct shash_desc) +
            crypto_shash_descsize(server->secmech.md5);
    server->secmech.sdescmd5 = kmalloc(size, GFP_KERNEL);
    if (!server->secmech.sdescmd5) {
        cERROR(1, "cifs_crypto_shash_allocate: can't alloc md5");
        rc = -ENOMEM;
        goto crypto_allocate_md5_sdesc_fail;
    }
    server->secmech.sdescmd5->shash.tfm = server->secmech.md5;
    server->secmech.sdescmd5->shash.flags = 0x0;

    size = sizeof(struct shash_desc) +
            crypto_shash_descsize(server->secmech.hmacsha256);
    server->secmech.sdeschmacsha256 = kmalloc(size, GFP_KERNEL);
    if (!server->secmech.sdeschmacsha256) {
        cERROR(1, "%s: Can't alloc hmacsha256\n", __func__);
        rc = -ENOMEM;
        goto crypto_allocate_hmacsha256_sdesc_fail;
    }
    server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;
    server->secmech.sdeschmacsha256->shash.flags = 0x0;

    return 0;

crypto_allocate_hmacsha256_sdesc_fail:
    kfree(server->secmech.sdescmd5);

crypto_allocate_md5_sdesc_fail:
    kfree(server->secmech.sdeschmacmd5);

crypto_allocate_hmacmd5_sdesc_fail:
    crypto_free_shash(server->secmech.hmacsha256);

crypto_allocate_hmacsha256_fail:
    crypto_free_shash(server->secmech.md5);

crypto_allocate_md5_fail:
    crypto_free_shash(server->secmech.hmacmd5);

    return rc;
}