blob: 2e6f4034403767ca621c65fa394337a0416007af [file] [log] [blame]
// SPDX-License-Identifier: LGPL-2.1
/*
* fs/cifs/cifsencrypt.c
*
* Encryption and hashing operations relating to NTLM, NTLMv2. See MS-NLMP
* for more detailed information
*
* Copyright (C) International Business Machines Corp., 2005,2013
* Author(s): Steve French (sfrench@us.ibm.com)
*
*/
#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>
#include <linux/fips.h>
#include "../smbfs_common/arc4.h"
#include <crypto/aead.h>
int __cifs_calc_signature(struct smb_rqst *rqst,
struct TCP_Server_Info *server, char *signature,
struct shash_desc *shash)
{
int i;
int rc;
struct kvec *iov = rqst->rq_iov;
int n_vec = rqst->rq_nvec;
int is_smb2 = server->vals->header_preamble_size == 0;
/* iov[0] is actual data and not the rfc1002 length for SMB2+ */
if (is_smb2) {
if (iov[0].iov_len <= 4)
return -EIO;
i = 0;
} else {
if (n_vec < 2 || iov[0].iov_len != 4)
return -EIO;
i = 1; /* skip rfc1002 length */
}
for (; i < n_vec; i++) {
if (iov[i].iov_len == 0)
continue;
if (iov[i].iov_base == NULL) {
cifs_dbg(VFS, "null iovec entry\n");
return -EIO;
}
rc = crypto_shash_update(shash,
iov[i].iov_base, iov[i].iov_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with payload\n",
__func__);
return rc;
}
}
/* now hash over the rq_pages array */
for (i = 0; i < rqst->rq_npages; i++) {
void *kaddr;
unsigned int len, offset;
rqst_page_get_length(rqst, i, &len, &offset);
kaddr = (char *) kmap(rqst->rq_pages[i]) + offset;
rc = crypto_shash_update(shash, kaddr, len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with payload\n",
__func__);
kunmap(rqst->rq_pages[i]);
return rc;
}
kunmap(rqst->rq_pages[i]);
}
rc = crypto_shash_final(shash, signature);
if (rc)
cifs_dbg(VFS, "%s: Could not generate hash\n", __func__);
return rc;
}
/*
* 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 rc;
if (!rqst->rq_iov || !signature || !server)
return -EINVAL;
rc = cifs_alloc_hash("md5", &server->secmech.md5,
&server->secmech.sdescmd5);
if (rc)
return -1;
rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
return rc;
}
rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
server->session_key.response, server->session_key.len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
return rc;
}
return __cifs_calc_signature(rqst, server, signature,
&server->secmech.sdescmd5->shash);
}
/* 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 (rqst->rq_iov[0].iov_len != 4 ||
rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
return -EIO;
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[2];
iov[0].iov_base = cifs_pdu;
iov[0].iov_len = 4;
iov[1].iov_base = (char *)cifs_pdu + 4;
iov[1].iov_len = be32_to_cpu(cifs_pdu->smb_buf_length);
return cifs_sign_smbv(iov, 2, 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 (rqst->rq_iov[0].iov_len != 4 ||
rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
return -EIO;
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)
cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
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;
}
/* 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;
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 || attrsize >= CIFS_MAX_DOMAINNAME_LEN)
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, NO_MAP_UNI_RSVD);
break;
}
}
blobptr += attrsize; /* advance attr value */
}
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 the server given timestamp
* as part of ntlmv2 authentication (or local current time as
* default in case of failure)
*/
static __le64
find_timestamp(struct cifs_ses *ses)
{
unsigned int attrsize;
unsigned int type;
unsigned int onesize = sizeof(struct ntlmssp2_name);
unsigned char *blobptr;
unsigned char *blobend;
struct ntlmssp2_name *attrptr;
struct timespec64 ts;
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_TIMESTAMP) {
if (attrsize == sizeof(u64))
return *((__le64 *)blobptr);
}
blobptr += attrsize; /* advance attr value */
}
ktime_get_real_ts64(&ts);
return cpu_to_le64(cifs_UnixTimeToNT(ts));
}
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];
__le16 *user;
wchar_t *domain;
wchar_t *server;
if (!ses->server->secmech.sdeschmacmd5) {
cifs_dbg(VFS, "%s: can't generate ntlmv2 hash\n", __func__);
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) {
cifs_dbg(VFS, "%s: Could not set NT Hash as a key\n", __func__);
return rc;
}
rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init hmacmd5\n", __func__);
return rc;
}
/* convert ses->user_name to unicode */
len = ses->user_name ? strlen(ses->user_name) : 0;
user = kmalloc(2 + (len * 2), GFP_KERNEL);
if (user == NULL) {
rc = -ENOMEM;
return rc;
}
if (len) {
len = cifs_strtoUTF16(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) {
cifs_dbg(VFS, "%s: Could not update with user\n", __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) {
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) {
cifs_dbg(VFS, "%s: Could not update with domain\n",
__func__);
return rc;
}
} else {
/* We use ses->ip_addr if no domain name available */
len = strlen(ses->ip_addr);
server = kmalloc(2 + (len * 2), GFP_KERNEL);
if (server == NULL) {
rc = -ENOMEM;
return rc;
}
len = cifs_strtoUTF16((__le16 *)server, ses->ip_addr, len,
nls_cp);
rc =
crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
(char *)server, 2 * len);
kfree(server);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with server\n",
__func__);
return rc;
}
}
rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
ntlmv2_hash);
if (rc)
cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
return rc;
}
static int
CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
{
int rc;
struct ntlmv2_resp *ntlmv2 = (struct ntlmv2_resp *)
(ses->auth_key.response + CIFS_SESS_KEY_SIZE);
unsigned int hash_len;
/* The MD5 hash starts at challenge_key.key */
hash_len = ses->auth_key.len - (CIFS_SESS_KEY_SIZE +
offsetof(struct ntlmv2_resp, challenge.key[0]));
if (!ses->server->secmech.sdeschmacmd5) {
cifs_dbg(VFS, "%s: can't generate ntlmv2 hash\n", __func__);
return -1;
}
rc = crypto_shash_setkey(ses->server->secmech.hmacmd5,
ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not set NTLMV2 Hash as a key\n",
__func__);
return rc;
}
rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init hmacmd5\n", __func__);
return rc;
}
if (ses->server->negflavor == CIFS_NEGFLAVOR_EXTENDED)
memcpy(ntlmv2->challenge.key,
ses->ntlmssp->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
else
memcpy(ntlmv2->challenge.key,
ses->server->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
ntlmv2->challenge.key, hash_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
return rc;
}
/* Note that the MD5 digest over writes anon.challenge_key.key */
rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
ntlmv2->ntlmv2_hash);
if (rc)
cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __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 *ntlmv2;
char ntlmv2_hash[16];
unsigned char *tiblob = NULL; /* target info blob */
__le64 rsp_timestamp;
if (nls_cp == NULL) {
cifs_dbg(VFS, "%s called with nls_cp==NULL\n", __func__);
return -EINVAL;
}
if (ses->server->negflavor == CIFS_NEGFLAVOR_EXTENDED) {
if (!ses->domainName) {
if (ses->domainAuto) {
rc = find_domain_name(ses, nls_cp);
if (rc) {
cifs_dbg(VFS, "error %d finding domain name\n",
rc);
goto setup_ntlmv2_rsp_ret;
}
} else {
ses->domainName = kstrdup("", GFP_KERNEL);
}
}
} else {
rc = build_avpair_blob(ses, nls_cp);
if (rc) {
cifs_dbg(VFS, "error %d building av pair blob\n", rc);
goto setup_ntlmv2_rsp_ret;
}
}
/* Must be within 5 minutes of the server (or in range +/-2h
* in case of Mac OS X), so simply carry over server timestamp
* (as Windows 7 does)
*/
rsp_timestamp = find_timestamp(ses);
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;
goto setup_ntlmv2_rsp_ret;
}
ses->auth_key.len += baselen;
ntlmv2 = (struct ntlmv2_resp *)
(ses->auth_key.response + CIFS_SESS_KEY_SIZE);
ntlmv2->blob_signature = cpu_to_le32(0x00000101);
ntlmv2->reserved = 0;
ntlmv2->time = rsp_timestamp;
get_random_bytes(&ntlmv2->client_chal, sizeof(ntlmv2->client_chal));
ntlmv2->reserved2 = 0;
memcpy(ses->auth_key.response + baselen, tiblob, tilen);
mutex_lock(&ses->server->srv_mutex);
rc = cifs_alloc_hash("hmac(md5)",
&ses->server->secmech.hmacmd5,
&ses->server->secmech.sdeschmacmd5);
if (rc) {
goto unlock;
}
/* calculate ntlmv2_hash */
rc = calc_ntlmv2_hash(ses, ntlmv2_hash, nls_cp);
if (rc) {
cifs_dbg(VFS, "Could not get v2 hash rc %d\n", rc);
goto unlock;
}
/* calculate first part of the client response (CR1) */
rc = CalcNTLMv2_response(ses, ntlmv2_hash);
if (rc) {
cifs_dbg(VFS, "Could not calculate CR1 rc: %d\n", rc);
goto unlock;
}
/* now calculate the session key for NTLMv2 */
rc = crypto_shash_setkey(ses->server->secmech.hmacmd5,
ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not set NTLMV2 Hash as a key\n",
__func__);
goto unlock;
}
rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init hmacmd5\n", __func__);
goto unlock;
}
rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
ntlmv2->ntlmv2_hash,
CIFS_HMAC_MD5_HASH_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
goto unlock;
}
rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
ses->auth_key.response);
if (rc)
cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
unlock:
mutex_unlock(&ses->server->srv_mutex);
setup_ntlmv2_rsp_ret:
kfree(tiblob);
return rc;
}
int
calc_seckey(struct cifs_ses *ses)
{
unsigned char sec_key[CIFS_SESS_KEY_SIZE]; /* a nonce */
struct arc4_ctx *ctx_arc4;
if (fips_enabled)
return -ENODEV;
get_random_bytes(sec_key, CIFS_SESS_KEY_SIZE);
ctx_arc4 = kmalloc(sizeof(*ctx_arc4), GFP_KERNEL);
if (!ctx_arc4) {
cifs_dbg(VFS, "Could not allocate arc4 context\n");
return -ENOMEM;
}
cifs_arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);
cifs_arc4_crypt(ctx_arc4, ses->ntlmssp->ciphertext, sec_key,
CIFS_CPHTXT_SIZE);
/* 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;
memzero_explicit(sec_key, CIFS_SESS_KEY_SIZE);
kfree_sensitive(ctx_arc4);
return 0;
}
void
cifs_crypto_secmech_release(struct TCP_Server_Info *server)
{
if (server->secmech.cmacaes) {
crypto_free_shash(server->secmech.cmacaes);
server->secmech.cmacaes = NULL;
}
if (server->secmech.hmacsha256) {
crypto_free_shash(server->secmech.hmacsha256);
server->secmech.hmacsha256 = NULL;
}
if (server->secmech.md5) {
crypto_free_shash(server->secmech.md5);
server->secmech.md5 = NULL;
}
if (server->secmech.sha512) {
crypto_free_shash(server->secmech.sha512);
server->secmech.sha512 = NULL;
}
if (server->secmech.hmacmd5) {
crypto_free_shash(server->secmech.hmacmd5);
server->secmech.hmacmd5 = NULL;
}
if (server->secmech.ccmaesencrypt) {
crypto_free_aead(server->secmech.ccmaesencrypt);
server->secmech.ccmaesencrypt = NULL;
}
if (server->secmech.ccmaesdecrypt) {
crypto_free_aead(server->secmech.ccmaesdecrypt);
server->secmech.ccmaesdecrypt = NULL;
}
kfree(server->secmech.sdesccmacaes);
server->secmech.sdesccmacaes = NULL;
kfree(server->secmech.sdeschmacsha256);
server->secmech.sdeschmacsha256 = NULL;
kfree(server->secmech.sdeschmacmd5);
server->secmech.sdeschmacmd5 = NULL;
kfree(server->secmech.sdescmd5);
server->secmech.sdescmd5 = NULL;
kfree(server->secmech.sdescsha512);
server->secmech.sdescsha512 = NULL;
}