// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   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 "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 <linux/iov_iter.h>
#include <crypto/aead.h>
#include <crypto/arc4.h>
#include <crypto/md5.h>
#include <crypto/sha2.h>

static int cifs_sig_update(struct cifs_calc_sig_ctx *ctx,
                           const u8 *data, size_t len)
{
        if (ctx->md5) {
                md5_update(ctx->md5, data, len);
                return 0;
        }
        if (ctx->hmac) {
                hmac_sha256_update(ctx->hmac, data, len);
                return 0;
        }
        return crypto_shash_update(ctx->shash, data, len);
}

static int cifs_sig_final(struct cifs_calc_sig_ctx *ctx, u8 *out)
{
        if (ctx->md5) {
                md5_final(ctx->md5, out);
                return 0;
        }
        if (ctx->hmac) {
                hmac_sha256_final(ctx->hmac, out);
                return 0;
        }
        return crypto_shash_final(ctx->shash, out);
}

static size_t cifs_sig_step(void *iter_base, size_t progress, size_t len,
                            void *priv, void *priv2)
{
        struct cifs_calc_sig_ctx *ctx = priv;
        int ret, *pret = priv2;

        ret = cifs_sig_update(ctx, iter_base, len);
        if (ret < 0) {
                *pret = ret;
                return len;
        }
        return 0;
}

/*
 * Pass the data from an iterator into a hash.
 */
static int cifs_sig_iter(const struct iov_iter *iter, size_t maxsize,
                         struct cifs_calc_sig_ctx *ctx)
{
        struct iov_iter tmp_iter = *iter;
        size_t did;
        int err;

        did = iterate_and_advance_kernel(&tmp_iter, maxsize, ctx, &err,
                                         cifs_sig_step);
        if (did != maxsize)
                return smb_EIO2(smb_eio_trace_sig_iter, did, maxsize);
        return 0;
}

int __cifs_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
                          char *signature, struct cifs_calc_sig_ctx *ctx)
{
        struct iov_iter iter;
        ssize_t rc;
        size_t size = 0;

        for (int i = 0; i < rqst->rq_nvec; i++)
                size += rqst->rq_iov[i].iov_len;

        iov_iter_kvec(&iter, ITER_SOURCE, rqst->rq_iov, rqst->rq_nvec, size);

        if (iov_iter_count(&iter) <= 4)
                return smb_EIO2(smb_eio_trace_sig_data_too_small,
                                iov_iter_count(&iter), 4);

        rc = cifs_sig_iter(&iter, iov_iter_count(&iter), ctx);
        if (rc < 0)
                return rc;

        rc = cifs_sig_iter(&rqst->rq_iter, iov_iter_count(&rqst->rq_iter), ctx);
        if (rc < 0)
                return rc;

        rc = cifs_sig_final(ctx, signature);
        if (rc)
                cifs_dbg(VFS, "%s: Could not generate hash\n", __func__);

        return rc;
}

/* 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
         */
        kfree_sensitive(ses->auth_key.response);
        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;
}

#define AV_TYPE(av)             (le16_to_cpu(av->type))
#define AV_LEN(av)              (le16_to_cpu(av->length))
#define AV_DATA_PTR(av) ((void *)av->data)

#define av_for_each_entry(ses, av) \
        for (av = NULL; (av = find_next_av(ses, av));)

static struct ntlmssp2_name *find_next_av(struct cifs_ses *ses,
                                          struct ntlmssp2_name *av)
{
        u16 len;
        u8 *end;

        end = (u8 *)ses->auth_key.response + ses->auth_key.len;
        if (!av) {
                if (unlikely(!ses->auth_key.response || !ses->auth_key.len))
                        return NULL;
                av = (void *)ses->auth_key.response;
        } else {
                av = (void *)((u8 *)av + sizeof(*av) + AV_LEN(av));
        }

        if ((u8 *)av + sizeof(*av) > end)
                return NULL;

        len = AV_LEN(av);
        if (AV_TYPE(av) == NTLMSSP_AV_EOL)
                return NULL;
        if ((u8 *)av + sizeof(*av) + len > end)
                return NULL;
        return av;
}

/*
 * Check if server has provided av pair of @type in the NTLMSSP
 * CHALLENGE_MESSAGE blob.
 */
static int find_av_name(struct cifs_ses *ses, u16 type, char **name, u16 maxlen)
{
        const struct nls_table *nlsc = ses->local_nls;
        struct ntlmssp2_name *av;
        u16 len, nlen;

        if (*name)
                return 0;

        av_for_each_entry(ses, av) {
                len = AV_LEN(av);
                if (AV_TYPE(av) != type || !len)
                        continue;
                if (!IS_ALIGNED(len, sizeof(__le16))) {
                        cifs_dbg(VFS | ONCE, "%s: bad length(%u) for type %u\n",
                                 __func__, len, type);
                        continue;
                }
                nlen = len / sizeof(__le16);
                if (nlen <= maxlen) {
                        ++nlen;
                        *name = kmalloc(nlen, GFP_KERNEL);
                        if (!*name)
                                return -ENOMEM;
                        cifs_from_utf16(*name, AV_DATA_PTR(av), nlen,
                                        len, nlsc, NO_MAP_UNI_RSVD);
                        break;
                }
        }
        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)
{
        struct ntlmssp2_name *av;
        struct timespec64 ts;

        av_for_each_entry(ses, av) {
                if (AV_TYPE(av) == NTLMSSP_AV_TIMESTAMP &&
                    AV_LEN(av) == sizeof(u64))
                        return *((__le64 *)AV_DATA_PTR(av));
        }
        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 len;
        char nt_hash[CIFS_NTHASH_SIZE];
        struct hmac_md5_ctx hmac_ctx;
        __le16 *user;
        wchar_t *domain;
        wchar_t *server;

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

        hmac_md5_init_usingrawkey(&hmac_ctx, nt_hash, CIFS_NTHASH_SIZE);

        /* 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)
                return -ENOMEM;

        if (len) {
                len = cifs_strtoUTF16(user, ses->user_name, len, nls_cp);
                UniStrupr(user);
        } else {
                *(u16 *)user = 0;
        }

        hmac_md5_update(&hmac_ctx, (const u8 *)user, 2 * len);
        kfree(user);

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

                domain = kmalloc(2 + (len * 2), GFP_KERNEL);
                if (domain == NULL)
                        return -ENOMEM;

                len = cifs_strtoUTF16((__le16 *)domain, ses->domainName, len,
                                      nls_cp);
                hmac_md5_update(&hmac_ctx, (const u8 *)domain, 2 * len);
                kfree(domain);
        } 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)
                        return -ENOMEM;

                len = cifs_strtoUTF16((__le16 *)server, ses->ip_addr, len, nls_cp);
                hmac_md5_update(&hmac_ctx, (const u8 *)server, 2 * len);
                kfree(server);
        }

        hmac_md5_final(&hmac_ctx, ntlmv2_hash);
        return 0;
}

static void CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
{
        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->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);

        /* Note that the HMAC-MD5 value overwrites ntlmv2->challenge.key */
        hmac_md5_usingrawkey(ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE,
                             ntlmv2->challenge.key, hash_len,
                             ntlmv2->ntlmv2_hash);
}

/*
 * Set up NTLMv2 response blob with SPN (cifs/<hostname>) appended to the
 * existing list of AV pairs.
 */
static int set_auth_key_response(struct cifs_ses *ses)
{
        size_t baselen = CIFS_SESS_KEY_SIZE + sizeof(struct ntlmv2_resp);
        size_t len, spnlen, tilen = 0, num_avs = 2 /* SPN + EOL */;
        struct TCP_Server_Info *server = ses->server;
        char *spn __free(kfree) = NULL;
        struct ntlmssp2_name *av;
        char *rsp = NULL;
        int rc;

        spnlen = strlen(server->hostname);
        len = sizeof("cifs/") + spnlen;
        spn = kmalloc(len, GFP_KERNEL);
        if (!spn) {
                rc = -ENOMEM;
                goto out;
        }

        spnlen = scnprintf(spn, len, "cifs/%.*s",
                           (int)spnlen, server->hostname);

        av_for_each_entry(ses, av)
                tilen += sizeof(*av) + AV_LEN(av);

        len = baselen + tilen + spnlen * sizeof(__le16) + num_avs * sizeof(*av);
        rsp = kmalloc(len, GFP_KERNEL);
        if (!rsp) {
                rc = -ENOMEM;
                goto out;
        }

        memcpy(rsp + baselen, ses->auth_key.response, tilen);
        av = (void *)(rsp + baselen + tilen);
        av->type = cpu_to_le16(NTLMSSP_AV_TARGET_NAME);
        av->length = cpu_to_le16(spnlen * sizeof(__le16));
        cifs_strtoUTF16((__le16 *)av->data, spn, spnlen, ses->local_nls);
        av = (void *)((__u8 *)av + sizeof(*av) + AV_LEN(av));
        av->type = cpu_to_le16(NTLMSSP_AV_EOL);
        av->length = 0;

        rc = 0;
        ses->auth_key.len = len;
out:
        ses->auth_key.response = rsp;
        return rc;
}

int
setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
{
        unsigned char *tiblob = NULL; /* target info blob */
        struct ntlmv2_resp *ntlmv2;
        char ntlmv2_hash[16];
        __le64 rsp_timestamp;
        __u64 cc;
        int rc;

        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) {
                                /*
                                 * Domain (workgroup) hasn't been specified in
                                 * mount options, so try to find it in
                                 * CHALLENGE_MESSAGE message and then use it as
                                 * part of NTLMv2 authentication.
                                 */
                                rc = find_av_name(ses, NTLMSSP_AV_NB_DOMAIN_NAME,
                                                  &ses->domainName,
                                                  CIFS_MAX_DOMAINNAME_LEN);
                                if (rc)
                                        goto setup_ntlmv2_rsp_ret;
                        } else {
                                ses->domainName = kstrdup("", GFP_KERNEL);
                                if (!ses->domainName) {
                                        rc = -ENOMEM;
                                        goto setup_ntlmv2_rsp_ret;
                                }
                        }
                }
                rc = find_av_name(ses, NTLMSSP_AV_DNS_DOMAIN_NAME,
                                  &ses->dns_dom, CIFS_MAX_DOMAINNAME_LEN);
                if (rc)
                        goto setup_ntlmv2_rsp_ret;
        } 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);
        get_random_bytes(&cc, sizeof(cc));

        cifs_server_lock(ses->server);

        tiblob = ses->auth_key.response;
        rc = set_auth_key_response(ses);
        if (rc) {
                ses->auth_key.len = 0;
                goto unlock;
        }

        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;
        ntlmv2->client_chal = cc;
        ntlmv2->reserved2 = 0;

        if (fips_enabled) {
                cifs_dbg(VFS, "NTLMv2 support is disabled due to FIPS\n");
                rc = -EOPNOTSUPP;
                goto unlock;
        }

        /* calculate ntlmv2_hash */
        rc = calc_ntlmv2_hash(ses, ntlmv2_hash, nls_cp);
        if (rc) {
                cifs_dbg(VFS, "Could not get NTLMv2 hash, rc=%d\n", rc);
                goto unlock;
        }

        /* calculate first part of the client response (CR1) */
        CalcNTLMv2_response(ses, ntlmv2_hash);

        /* now calculate the session key for NTLMv2 */
        hmac_md5_usingrawkey(ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE,
                             ntlmv2->ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE,
                             ses->auth_key.response);
        rc = 0;
unlock:
        cifs_server_unlock(ses->server);
setup_ntlmv2_rsp_ret:
        kfree_sensitive(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_obj(*ctx_arc4);
        if (!ctx_arc4) {
                cifs_dbg(VFS, "Could not allocate arc4 context\n");
                return -ENOMEM;
        }

        arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);
        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)
{
        cifs_free_hash(&server->secmech.aes_cmac);

        if (server->secmech.enc) {
                crypto_free_aead(server->secmech.enc);
                server->secmech.enc = NULL;
        }
        if (server->secmech.dec) {
                crypto_free_aead(server->secmech.dec);
                server->secmech.dec = NULL;
        }
}