// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   Copyright (C) International Business Machines  Corp., 2002, 2011
 *                 Etersoft, 2012
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *              Jeremy Allison (jra@samba.org) 2006
 *              Pavel Shilovsky (pshilovsky@samba.org) 2012
 *
 */

#include <linux/fs.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/net.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <linux/mempool.h>
#include <linux/highmem.h>
#include <crypto/aead.h>
#include <crypto/sha2.h>
#include <crypto/utils.h>
#include "cifsglob.h"
#include "cifsproto.h"
#include "smb2proto.h"
#include "cifs_debug.h"
#include "../common/smb2status.h"
#include "smb2glob.h"

int
smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
{
        struct cifs_secmech *p = &server->secmech;

        return cifs_alloc_hash("cmac(aes)", &p->aes_cmac);
}

static
int smb3_get_sign_key(__u64 ses_id, struct TCP_Server_Info *server, u8 *key)
{
        struct cifs_chan *chan;
        struct TCP_Server_Info *pserver;
        struct cifs_ses *ses = NULL;
        int i;
        int rc = 0;
        bool is_binding = false;

        spin_lock(&cifs_tcp_ses_lock);

        /* If server is a channel, select the primary channel */
        pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;

        list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
                if (ses->Suid == ses_id)
                        goto found;
        }
        trace_smb3_ses_not_found(ses_id);
        cifs_server_dbg(FYI, "%s: Could not find session 0x%llx\n",
                        __func__, ses_id);
        rc = -ENOENT;
        goto out;

found:
        spin_lock(&ses->ses_lock);
        spin_lock(&ses->chan_lock);

        is_binding = (cifs_chan_needs_reconnect(ses, server) &&
                      ses->ses_status == SES_GOOD);
        if (is_binding) {
                /*
                 * If we are in the process of binding a new channel
                 * to an existing session, use the master connection
                 * session key
                 */
                memcpy(key, ses->smb3signingkey, SMB3_SIGN_KEY_SIZE);
                spin_unlock(&ses->chan_lock);
                spin_unlock(&ses->ses_lock);
                goto out;
        }

        /*
         * Otherwise, use the channel key.
         */

        for (i = 0; i < ses->chan_count; i++) {
                chan = ses->chans + i;
                if (chan->server == server) {
                        memcpy(key, chan->signkey, SMB3_SIGN_KEY_SIZE);
                        spin_unlock(&ses->chan_lock);
                        spin_unlock(&ses->ses_lock);
                        goto out;
                }
        }
        spin_unlock(&ses->chan_lock);
        spin_unlock(&ses->ses_lock);

        cifs_dbg(VFS,
                 "%s: Could not find channel signing key for session 0x%llx\n",
                 __func__, ses_id);
        rc = -ENOENT;

out:
        spin_unlock(&cifs_tcp_ses_lock);
        return rc;
}

static struct cifs_ses *
smb2_find_smb_ses_unlocked(struct TCP_Server_Info *server, __u64 ses_id)
{
        struct TCP_Server_Info *pserver;
        struct cifs_ses *ses;

        /* If server is a channel, select the primary channel */
        pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;

        list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
                if (ses->Suid != ses_id)
                        continue;

                spin_lock(&ses->ses_lock);
                if (ses->ses_status == SES_EXITING) {
                        spin_unlock(&ses->ses_lock);
                        continue;
                }
                cifs_smb_ses_inc_refcount(ses);
                spin_unlock(&ses->ses_lock);
                return ses;
        }

        return NULL;
}

static int smb2_get_sign_key(struct TCP_Server_Info *server,
                             __u64 ses_id, u8 *key)
{
        struct cifs_ses *ses;
        int rc = -ENOENT;

        if (SERVER_IS_CHAN(server))
                server = server->primary_server;

        spin_lock(&cifs_tcp_ses_lock);
        list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
                if (ses->Suid != ses_id)
                        continue;

                rc = 0;
                spin_lock(&ses->ses_lock);
                switch (ses->ses_status) {
                case SES_EXITING: /* SMB2_LOGOFF */
                case SES_GOOD:
                        if (likely(ses->auth_key.response)) {
                                memcpy(key, ses->auth_key.response,
                                       SMB2_NTLMV2_SESSKEY_SIZE);
                        } else {
                                rc = smb_EIO(smb_eio_trace_no_auth_key);
                        }
                        break;
                default:
                        rc = -EAGAIN;
                        break;
                }
                spin_unlock(&ses->ses_lock);
                break;
        }
        spin_unlock(&cifs_tcp_ses_lock);
        return rc;
}

static struct cifs_tcon *
smb2_find_smb_sess_tcon_unlocked(struct cifs_ses *ses, __u32  tid)
{
        struct cifs_tcon *tcon;

        list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
                if (tcon->tid != tid)
                        continue;
                ++tcon->tc_count;
                trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                    netfs_trace_tcon_ref_get_find_sess_tcon);
                return tcon;
        }

        return NULL;
}

/*
 * Obtain tcon corresponding to the tid in the given
 * cifs_ses
 */

struct cifs_tcon *
smb2_find_smb_tcon(struct TCP_Server_Info *server, __u64 ses_id, __u32  tid)
{
        struct cifs_ses *ses;
        struct cifs_tcon *tcon;

        spin_lock(&cifs_tcp_ses_lock);
        ses = smb2_find_smb_ses_unlocked(server, ses_id);
        if (!ses) {
                spin_unlock(&cifs_tcp_ses_lock);
                return NULL;
        }
        tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
        spin_unlock(&cifs_tcp_ses_lock);
        /* tcon already has a ref to ses, so we don't need ses anymore */
        cifs_put_smb_ses(ses);

        return tcon;
}

static int
smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
                    bool allocate_crypto)
{
        int rc;
        unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
        struct kvec *iov = rqst->rq_iov;
        struct smb2_hdr *shdr = (struct smb2_hdr *)iov[0].iov_base;
        struct hmac_sha256_ctx hmac_ctx;
        struct smb_rqst drqst;
        __u64 sid = le64_to_cpu(shdr->SessionId);
        u8 key[SMB2_NTLMV2_SESSKEY_SIZE];

        rc = smb2_get_sign_key(server, sid, key);
        if (unlikely(rc)) {
                cifs_server_dbg(FYI, "%s: [sesid=0x%llx] couldn't find signing key: %d\n",
                                __func__, sid, rc);
                return rc;
        }

        memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
        memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);

        hmac_sha256_init_usingrawkey(&hmac_ctx, key, sizeof(key));

        /*
         * For SMB2+, __cifs_calc_signature() expects to sign only the actual
         * data, that is, iov[0] should not contain a rfc1002 length.
         *
         * Sign the rfc1002 length prior to passing the data (iov[1-N]) down to
         * __cifs_calc_signature().
         */
        drqst = *rqst;
        if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) {
                hmac_sha256_update(&hmac_ctx, iov[0].iov_base, iov[0].iov_len);
                drqst.rq_iov++;
                drqst.rq_nvec--;
        }

        rc = __cifs_calc_signature(
                &drqst, server, smb2_signature,
                &(struct cifs_calc_sig_ctx){ .hmac = &hmac_ctx });
        if (!rc)
                memcpy(shdr->Signature, smb2_signature, SMB2_SIGNATURE_SIZE);

        return rc;
}

static int generate_key(struct cifs_ses *ses, struct kvec label,
                        struct kvec context, __u8 *key, unsigned int key_size)
{
        unsigned char zero = 0x0;
        __u8 i[4] = {0, 0, 0, 1};
        __u8 L128[4] = {0, 0, 0, 128};
        __u8 L256[4] = {0, 0, 1, 0};
        int rc = 0;
        unsigned char prfhash[SMB2_HMACSHA256_SIZE];
        struct TCP_Server_Info *server = ses->server;
        struct hmac_sha256_ctx hmac_ctx;

        memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
        memset(key, 0x0, key_size);

        rc = smb3_crypto_shash_allocate(server);
        if (rc) {
                cifs_server_dbg(VFS, "%s: crypto alloc failed\n", __func__);
                return rc;
        }

        hmac_sha256_init_usingrawkey(&hmac_ctx, ses->auth_key.response,
                                     SMB2_NTLMV2_SESSKEY_SIZE);
        hmac_sha256_update(&hmac_ctx, i, 4);
        hmac_sha256_update(&hmac_ctx, label.iov_base, label.iov_len);
        hmac_sha256_update(&hmac_ctx, &zero, 1);
        hmac_sha256_update(&hmac_ctx, context.iov_base, context.iov_len);

        if ((server->cipher_type == SMB2_ENCRYPTION_AES256_CCM) ||
                (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM)) {
                hmac_sha256_update(&hmac_ctx, L256, 4);
        } else {
                hmac_sha256_update(&hmac_ctx, L128, 4);
        }
        hmac_sha256_final(&hmac_ctx, prfhash);

        memcpy(key, prfhash, key_size);
        return 0;
}

struct derivation {
        struct kvec label;
        struct kvec context;
};

struct derivation_triplet {
        struct derivation signing;
        struct derivation encryption;
        struct derivation decryption;
};

static int
generate_smb3signingkey(struct cifs_ses *ses,
                        struct TCP_Server_Info *server,
                        const struct derivation_triplet *ptriplet)
{
        int rc;
        bool is_binding = false;
        int chan_index = 0;

        spin_lock(&ses->ses_lock);
        spin_lock(&ses->chan_lock);
        is_binding = (cifs_chan_needs_reconnect(ses, server) &&
                      ses->ses_status == SES_GOOD);

        chan_index = cifs_ses_get_chan_index(ses, server);
        if (chan_index == CIFS_INVAL_CHAN_INDEX) {
                spin_unlock(&ses->chan_lock);
                spin_unlock(&ses->ses_lock);

                return -EINVAL;
        }

        spin_unlock(&ses->chan_lock);
        spin_unlock(&ses->ses_lock);

        /*
         * All channels use the same encryption/decryption keys but
         * they have their own signing key.
         *
         * When we generate the keys, check if it is for a new channel
         * (binding) in which case we only need to generate a signing
         * key and store it in the channel as to not overwrite the
         * master connection signing key stored in the session
         */

        if (is_binding) {
                rc = generate_key(ses, ptriplet->signing.label,
                                  ptriplet->signing.context,
                                  ses->chans[chan_index].signkey,
                                  SMB3_SIGN_KEY_SIZE);
                if (rc)
                        return rc;
        } else {
                rc = generate_key(ses, ptriplet->signing.label,
                                  ptriplet->signing.context,
                                  ses->smb3signingkey,
                                  SMB3_SIGN_KEY_SIZE);
                if (rc)
                        return rc;

                /* safe to access primary channel, since it will never go away */
                spin_lock(&ses->chan_lock);
                memcpy(ses->chans[chan_index].signkey, ses->smb3signingkey,
                       SMB3_SIGN_KEY_SIZE);
                spin_unlock(&ses->chan_lock);

                rc = generate_key(ses, ptriplet->encryption.label,
                                  ptriplet->encryption.context,
                                  ses->smb3encryptionkey,
                                  SMB3_ENC_DEC_KEY_SIZE);
                if (rc)
                        return rc;
                rc = generate_key(ses, ptriplet->decryption.label,
                                  ptriplet->decryption.context,
                                  ses->smb3decryptionkey,
                                  SMB3_ENC_DEC_KEY_SIZE);
                if (rc)
                        return rc;
        }

#ifdef CONFIG_CIFS_DEBUG_DUMP_KEYS
        cifs_dbg(VFS, "%s: dumping generated AES session keys\n", __func__);
        /*
         * The session id is opaque in terms of endianness, so we can't
         * print it as a long long. we dump it as we got it on the wire
         */
        cifs_dbg(VFS, "Session Id    %*ph\n", (int)sizeof(ses->Suid),
                        &ses->Suid);
        cifs_dbg(VFS, "Cipher type   %d\n", server->cipher_type);
        cifs_dbg(VFS, "Session Key   %*ph\n",
                 SMB2_NTLMV2_SESSKEY_SIZE, ses->auth_key.response);
        cifs_dbg(VFS, "Signing Key   %*ph\n",
                 SMB3_SIGN_KEY_SIZE, ses->smb3signingkey);
        if ((server->cipher_type == SMB2_ENCRYPTION_AES256_CCM) ||
                (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM)) {
                cifs_dbg(VFS, "ServerIn Key  %*ph\n",
                                SMB3_GCM256_CRYPTKEY_SIZE, ses->smb3encryptionkey);
                cifs_dbg(VFS, "ServerOut Key %*ph\n",
                                SMB3_GCM256_CRYPTKEY_SIZE, ses->smb3decryptionkey);
        } else {
                cifs_dbg(VFS, "ServerIn Key  %*ph\n",
                                SMB3_GCM128_CRYPTKEY_SIZE, ses->smb3encryptionkey);
                cifs_dbg(VFS, "ServerOut Key %*ph\n",
                                SMB3_GCM128_CRYPTKEY_SIZE, ses->smb3decryptionkey);
        }
#endif
        return rc;
}

int
generate_smb30signingkey(struct cifs_ses *ses,
                         struct TCP_Server_Info *server)

{
        struct derivation_triplet triplet;
        struct derivation *d;

        d = &triplet.signing;
        d->label.iov_base = "SMB2AESCMAC";
        d->label.iov_len = 12;
        d->context.iov_base = "SmbSign";
        d->context.iov_len = 8;

        d = &triplet.encryption;
        d->label.iov_base = "SMB2AESCCM";
        d->label.iov_len = 11;
        d->context.iov_base = "ServerIn ";
        d->context.iov_len = 10;

        d = &triplet.decryption;
        d->label.iov_base = "SMB2AESCCM";
        d->label.iov_len = 11;
        d->context.iov_base = "ServerOut";
        d->context.iov_len = 10;

        return generate_smb3signingkey(ses, server, &triplet);
}

int
generate_smb311signingkey(struct cifs_ses *ses,
                          struct TCP_Server_Info *server)

{
        struct derivation_triplet triplet;
        struct derivation *d;

        d = &triplet.signing;
        d->label.iov_base = "SMBSigningKey";
        d->label.iov_len = 14;
        d->context.iov_base = ses->preauth_sha_hash;
        d->context.iov_len = 64;

        d = &triplet.encryption;
        d->label.iov_base = "SMBC2SCipherKey";
        d->label.iov_len = 16;
        d->context.iov_base = ses->preauth_sha_hash;
        d->context.iov_len = 64;

        d = &triplet.decryption;
        d->label.iov_base = "SMBS2CCipherKey";
        d->label.iov_len = 16;
        d->context.iov_base = ses->preauth_sha_hash;
        d->context.iov_len = 64;

        return generate_smb3signingkey(ses, server, &triplet);
}

static int
smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
                    bool allocate_crypto)
{
        int rc;
        unsigned char smb3_signature[SMB2_CMACAES_SIZE];
        struct kvec *iov = rqst->rq_iov;
        struct smb2_hdr *shdr = (struct smb2_hdr *)iov[0].iov_base;
        struct shash_desc *shash = NULL;
        struct smb_rqst drqst;
        u8 key[SMB3_SIGN_KEY_SIZE];

        if (server->vals->protocol_id <= SMB21_PROT_ID)
                return smb2_calc_signature(rqst, server, allocate_crypto);

        rc = smb3_get_sign_key(le64_to_cpu(shdr->SessionId), server, key);
        if (unlikely(rc)) {
                cifs_server_dbg(FYI, "%s: Could not get signing key\n", __func__);
                return rc;
        }

        if (allocate_crypto) {
                rc = cifs_alloc_hash("cmac(aes)", &shash);
                if (rc)
                        return rc;
        } else {
                shash = server->secmech.aes_cmac;
        }

        memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
        memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);

        rc = crypto_shash_setkey(shash->tfm, key, SMB2_CMACAES_SIZE);
        if (rc) {
                cifs_server_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
                goto out;
        }

        /*
         * we already allocate aes_cmac when we init smb3 signing key,
         * so unlike smb2 case we do not have to check here if secmech are
         * initialized
         */
        rc = crypto_shash_init(shash);
        if (rc) {
                cifs_server_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
                goto out;
        }

        /*
         * For SMB2+, __cifs_calc_signature() expects to sign only the actual
         * data, that is, iov[0] should not contain a rfc1002 length.
         *
         * Sign the rfc1002 length prior to passing the data (iov[1-N]) down to
         * __cifs_calc_signature().
         */
        drqst = *rqst;
        if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) {
                rc = crypto_shash_update(shash, iov[0].iov_base,
                                         iov[0].iov_len);
                if (rc) {
                        cifs_server_dbg(VFS, "%s: Could not update with payload\n",
                                 __func__);
                        goto out;
                }
                drqst.rq_iov++;
                drqst.rq_nvec--;
        }

        rc = __cifs_calc_signature(
                &drqst, server, smb3_signature,
                &(struct cifs_calc_sig_ctx){ .shash = shash });
        if (!rc)
                memcpy(shdr->Signature, smb3_signature, SMB2_SIGNATURE_SIZE);

out:
        if (allocate_crypto)
                cifs_free_hash(&shash);
        return rc;
}

/* must be called with server->srv_mutex held */
static int
smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
{
        struct smb2_hdr *shdr;
        struct smb2_sess_setup_req *ssr;
        bool is_binding;
        bool is_signed;

        shdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
        ssr = (struct smb2_sess_setup_req *)shdr;

        is_binding = shdr->Command == SMB2_SESSION_SETUP &&
                (ssr->Flags & SMB2_SESSION_REQ_FLAG_BINDING);
        is_signed = shdr->Flags & SMB2_FLAGS_SIGNED;

        if (!is_signed)
                return 0;
        spin_lock(&server->srv_lock);
        if (server->ops->need_neg &&
            server->ops->need_neg(server)) {
                spin_unlock(&server->srv_lock);
                return 0;
        }
        spin_unlock(&server->srv_lock);
        if (!is_binding && !server->session_estab) {
                strscpy(shdr->Signature, "BSRSPYL");
                return 0;
        }

        return smb3_calc_signature(rqst, server, false);
}

int
smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
{
        unsigned int rc;
        char server_response_sig[SMB2_SIGNATURE_SIZE];
        struct smb2_hdr *shdr =
                        (struct smb2_hdr *)rqst->rq_iov[0].iov_base;

        if ((shdr->Command == SMB2_NEGOTIATE) ||
            (shdr->Command == SMB2_SESSION_SETUP) ||
            (shdr->Command == SMB2_OPLOCK_BREAK) ||
            server->ignore_signature ||
            (!server->session_estab))
                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(shdr->Signature, "BSRSPYL ", 8) == 0)
                cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
                         shdr->Command);

        /*
         * Save off the original signature so we can modify the smb and check
         * our calculated signature against what the server sent.
         */
        memcpy(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE);

        memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);

        rc = smb3_calc_signature(rqst, server, true);

        if (rc)
                return rc;

        if (crypto_memneq(server_response_sig, shdr->Signature,
                          SMB2_SIGNATURE_SIZE)) {
                cifs_dbg(VFS, "sign fail cmd 0x%x message id 0x%llx\n",
                        shdr->Command, shdr->MessageId);
                return -EACCES;
        } else
                return 0;
}

/*
 * Set message id for the request. Should be called after wait_for_free_request
 * and when srv_mutex is held.
 */
static inline void
smb2_seq_num_into_buf(struct TCP_Server_Info *server,
                      struct smb2_hdr *shdr)
{
        unsigned int i, num = le16_to_cpu(shdr->CreditCharge);

        shdr->MessageId = get_next_mid64(server);
        /* skip message numbers according to CreditCharge field */
        for (i = 1; i < num; i++)
                get_next_mid(server);
}

static struct mid_q_entry *
smb2_mid_entry_alloc(const struct smb2_hdr *shdr,
                     struct TCP_Server_Info *server)
{
        struct mid_q_entry *temp;
        unsigned int credits = le16_to_cpu(shdr->CreditCharge);

        if (server == NULL) {
                cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
                return NULL;
        }

        temp = mempool_alloc(&cifs_mid_pool, GFP_NOFS);
        memset(temp, 0, sizeof(struct mid_q_entry));
        refcount_set(&temp->refcount, 1);
        spin_lock_init(&temp->mid_lock);
        temp->mid = le64_to_cpu(shdr->MessageId);
        temp->credits = credits > 0 ? credits : 1;
        temp->pid = current->pid;
        temp->command = shdr->Command; /* Always LE */
        temp->when_alloc = jiffies;

        /*
         * The default is for the mid to be synchronous, so the
         * default callback just wakes up the current task.
         */
        get_task_struct(current);
        temp->creator = current;
        temp->callback = cifs_wake_up_task;
        temp->callback_data = current;

        atomic_inc(&mid_count);
        temp->mid_state = MID_REQUEST_ALLOCATED;
        trace_smb3_cmd_enter(le32_to_cpu(shdr->Id.SyncId.TreeId),
                             le64_to_cpu(shdr->SessionId),
                             le16_to_cpu(shdr->Command), temp->mid);
        return temp;
}

static int
smb2_get_mid_entry(struct cifs_ses *ses, struct TCP_Server_Info *server,
                   struct smb2_hdr *shdr, struct mid_q_entry **mid)
{
        switch (READ_ONCE(server->tcpStatus)) {
        case CifsExiting:
                return -ENOENT;
        case CifsNeedReconnect:
                cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
                return -EAGAIN;
        case CifsNeedNegotiate:
                if (shdr->Command != SMB2_NEGOTIATE)
                        return -EAGAIN;
                break;
        default:
                break;
        }

        switch (READ_ONCE(ses->ses_status)) {
        case SES_NEW:
                if (shdr->Command != SMB2_SESSION_SETUP &&
                    shdr->Command != SMB2_NEGOTIATE)
                        return -EAGAIN;
                        /* else ok - we are setting up session */
                break;
        case SES_EXITING:
                if (shdr->Command != SMB2_LOGOFF)
                        return -EAGAIN;
                /* else ok - we are shutting down the session */
                break;
        default:
                break;
        }

        *mid = smb2_mid_entry_alloc(shdr, server);
        if (*mid == NULL)
                return -ENOMEM;
        spin_lock(&server->mid_queue_lock);
        list_add_tail(&(*mid)->qhead, &server->pending_mid_q);
        spin_unlock(&server->mid_queue_lock);

        return 0;
}

int
smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
                   bool log_error)
{
        unsigned int len = mid->resp_buf_size;
        struct kvec iov[1];
        struct smb_rqst rqst = { .rq_iov = iov,
                                 .rq_nvec = 1 };

        iov[0].iov_base = (char *)mid->resp_buf;
        iov[0].iov_len = len;

        dump_smb(mid->resp_buf, min_t(u32, 80, len));
        /* convert the length into a more usable form */
        if (len > 24 && server->sign && !mid->decrypted) {
                int rc;

                rc = smb2_verify_signature(&rqst, server);
                if (rc)
                        cifs_server_dbg(VFS, "SMB signature verification returned error = %d\n",
                                 rc);
        }

        return map_smb2_to_linux_error(mid->resp_buf, log_error);
}

struct mid_q_entry *
smb2_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *server,
                   struct smb_rqst *rqst)
{
        int rc;
        struct smb2_hdr *shdr =
                        (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
        struct mid_q_entry *mid;

        smb2_seq_num_into_buf(server, shdr);

        rc = smb2_get_mid_entry(ses, server, shdr, &mid);
        if (rc) {
                revert_current_mid_from_hdr(server, shdr);
                return ERR_PTR(rc);
        }

        rc = smb2_sign_rqst(rqst, server);
        if (rc) {
                revert_current_mid_from_hdr(server, shdr);
                delete_mid(server, mid);
                return ERR_PTR(rc);
        }

        return mid;
}

struct mid_q_entry *
smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
        int rc;
        struct smb2_hdr *shdr =
                        (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
        struct mid_q_entry *mid;

        spin_lock(&server->srv_lock);
        if (server->tcpStatus == CifsNeedNegotiate &&
           shdr->Command != SMB2_NEGOTIATE) {
                spin_unlock(&server->srv_lock);
                return ERR_PTR(-EAGAIN);
        }
        spin_unlock(&server->srv_lock);

        smb2_seq_num_into_buf(server, shdr);

        mid = smb2_mid_entry_alloc(shdr, server);
        if (mid == NULL) {
                revert_current_mid_from_hdr(server, shdr);
                return ERR_PTR(-ENOMEM);
        }

        rc = smb2_sign_rqst(rqst, server);
        if (rc) {
                revert_current_mid_from_hdr(server, shdr);
                release_mid(server, mid);
                return ERR_PTR(rc);
        }

        return mid;
}

int
smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
{
        struct crypto_aead *tfm;

        if (!server->secmech.enc) {
                if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) ||
                    (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM))
                        tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
                else
                        tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
                if (IS_ERR(tfm)) {
                        cifs_server_dbg(VFS, "%s: Failed alloc encrypt aead\n",
                                 __func__);
                        return PTR_ERR(tfm);
                }
                server->secmech.enc = tfm;
        }

        if (!server->secmech.dec) {
                if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) ||
                    (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM))
                        tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
                else
                        tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
                if (IS_ERR(tfm)) {
                        crypto_free_aead(server->secmech.enc);
                        server->secmech.enc = NULL;
                        cifs_server_dbg(VFS, "%s: Failed to alloc decrypt aead\n",
                                 __func__);
                        return PTR_ERR(tfm);
                }
                server->secmech.dec = tfm;
        }

        return 0;
}