int sftp_auth_hostbased(struct ssh2_packet *pkt, cmd_rec *pass_cmd, const char *orig_user, const char *user, const char *service, unsigned char **buf, uint32_t *buflen, int *send_userauth_fail) { struct passwd *pw; char *hostkey_algo, *host_fqdn, *host_user, *host_user_utf8; const char *fp = NULL; unsigned char *hostkey_data, *signature_data; unsigned char *buf2, *ptr2; const unsigned char *id; uint32_t buflen2, bufsz2, hostkey_datalen, id_len, signature_len; enum sftp_key_type_e pubkey_type; if (pr_cmd_dispatch_phase(pass_cmd, PRE_CMD, 0) < 0) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "authentication request for user '%s' blocked by '%s' handler", orig_user, (char *) pass_cmd->argv[0]); pr_cmd_dispatch_phase(pass_cmd, POST_CMD_ERR, 0); pr_cmd_dispatch_phase(pass_cmd, LOG_CMD_ERR, 0); *send_userauth_fail = TRUE; errno = EPERM; return 0; } hostkey_algo = sftp_msg_read_string(pkt->pool, buf, buflen); if (hostkey_algo == NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "missing required host key algorithm, rejecting request"); *send_userauth_fail = TRUE; errno = EINVAL; return 0; } hostkey_datalen = sftp_msg_read_int(pkt->pool, buf, buflen); hostkey_data = sftp_msg_read_data(pkt->pool, buf, buflen, hostkey_datalen); host_fqdn = sftp_msg_read_string(pkt->pool, buf, buflen); host_user_utf8 = sftp_msg_read_string(pkt->pool, buf, buflen); host_user = sftp_utf8_decode_str(pkt->pool, host_user_utf8); signature_len = sftp_msg_read_int(pkt->pool, buf, buflen); signature_data = sftp_msg_read_data(pkt->pool, buf, buflen, signature_len); pr_trace_msg(trace_channel, 9, "client sent '%s' host key, FQDN %s, and remote user '%s'", hostkey_algo, host_fqdn, host_user); if (strncmp(hostkey_algo, "ssh-rsa", 8) == 0) { pubkey_type = SFTP_KEY_RSA; } else if (strncmp(hostkey_algo, "ssh-dss", 8) == 0) { pubkey_type = SFTP_KEY_DSA; #ifdef PR_USE_OPENSSL_ECC } else if (strncmp(hostkey_algo, "ecdsa-sha2-nistp256", 20) == 0) { pubkey_type = SFTP_KEY_ECDSA_256; } else if (strncmp(hostkey_algo, "ecdsa-sha2-nistp256", 20) == 0) { pubkey_type = SFTP_KEY_ECDSA_384; } else if (strncmp(hostkey_algo, "ecdsa-sha2-nistp256", 20) == 0) { pubkey_type = SFTP_KEY_ECDSA_521; #endif /* PR_USE_OPENSSL_ECC */ /* XXX Need to support X509v3 certs here */ } else { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "unsupported host key algorithm '%s' requested, rejecting request", hostkey_algo); *send_userauth_fail = TRUE; errno = EINVAL; return 0; } if (sftp_keys_verify_pubkey_type(pkt->pool, hostkey_data, hostkey_datalen, pubkey_type) != TRUE) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "unable to verify that given host key matches given '%s' algorithm", hostkey_algo); *send_userauth_fail = TRUE; errno = EINVAL; return 0; } #ifdef OPENSSL_FIPS if (FIPS_mode()) { fp = sftp_keys_get_fingerprint(pkt->pool, hostkey_data, hostkey_datalen, SFTP_KEYS_FP_DIGEST_SHA1); if (fp != NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "public key SHA1 fingerprint: %s", fp); } else { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error obtaining public key SHA1 fingerprint: %s", strerror(errno)); } } else { #endif /* OPENSSL_FIPS */ fp = sftp_keys_get_fingerprint(pkt->pool, hostkey_data, hostkey_datalen, SFTP_KEYS_FP_DIGEST_MD5); if (fp != NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "public key MD5 fingerprint: %s", fp); } else { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error obtaining public key MD5 fingerprint: %s", strerror(errno)); } #ifdef OPENSSL_FIPS } #endif /* OPENSSL_FIPS */ pw = pr_auth_getpwnam(pkt->pool, user); if (pw == NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "no account for user '%s' found", user); pr_log_auth(PR_LOG_NOTICE, "USER %s: no such user found from %s [%s] to %s:%d", user, session.c->remote_name, pr_netaddr_get_ipstr(session.c->remote_addr), pr_netaddr_get_ipstr(session.c->local_addr), session.c->local_port); *send_userauth_fail = TRUE; errno = ENOENT; return 0; } /* XXX Should we check the given FQDN here against the client's actual * DNS name and/or IP address? Or leave that up to the keystore's * verify_host_key() function? */ if (sftp_blacklist_reject_key(pkt->pool, hostkey_data, hostkey_datalen)) { *send_userauth_fail = TRUE; errno = EACCES; return 0; } /* The client signed the request as well; we need to authenticate the * host with the given key now. If that succeeds, we use the signature to * verify the request. And if that succeeds, then we're done authenticating. */ if (sftp_keystore_verify_host_key(pkt->pool, user, host_fqdn, host_user, hostkey_data, hostkey_datalen) < 0) { *send_userauth_fail = TRUE; errno = EACCES; return 0; } /* Make sure the signature matches as well. */ id_len = sftp_session_get_id(&id); /* XXX Is this buffer large enough? Too large? */ bufsz2 = buflen2 = 2048; ptr2 = buf2 = sftp_msg_getbuf(pkt->pool, bufsz2); sftp_msg_write_data(&buf2, &buflen2, id, id_len, TRUE); sftp_msg_write_byte(&buf2, &buflen2, SFTP_SSH2_MSG_USER_AUTH_REQUEST); sftp_msg_write_string(&buf2, &buflen2, orig_user); if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_SERVICE_IN_HOST_SIG)) { sftp_msg_write_string(&buf2, &buflen2, service); } else { sftp_msg_write_string(&buf2, &buflen2, "ssh-userauth"); } sftp_msg_write_string(&buf2, &buflen2, "hostbased"); sftp_msg_write_string(&buf2, &buflen2, hostkey_algo); sftp_msg_write_data(&buf2, &buflen2, hostkey_data, hostkey_datalen, TRUE); sftp_msg_write_string(&buf2, &buflen2, host_fqdn); sftp_msg_write_string(&buf2, &buflen2, host_user_utf8); if (sftp_keys_verify_signed_data(pkt->pool, hostkey_algo, hostkey_data, hostkey_datalen, signature_data, signature_len, (unsigned char *) ptr2, (bufsz2 - buflen2)) < 0) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "failed to verify '%s' signature on hostbased auth request for " "user '%s', host %s", hostkey_algo, orig_user, host_fqdn); *send_userauth_fail = TRUE; return 0; } /* Make sure the user is authorized to login. Normally this is checked * as part of the password verification process, but in the case of * hostbased authentication, there is no password to verify. */ if (pr_auth_authorize(pkt->pool, user) != PR_AUTH_OK) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "authentication for user '%s' failed: User not authorized", user); pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): User not authorized " "for login", user); *send_userauth_fail = TRUE; errno = EACCES; return 0; } return 1; }
int sftp_auth_publickey(struct ssh2_packet *pkt, cmd_rec *pass_cmd, const char *orig_user, const char *user, const char *service, char **buf, uint32_t *buflen, int *send_userauth_fail) { int have_signature, pubkey_type; char *pubkey_algo = NULL, *pubkey_data; const char *fp = NULL; uint32_t pubkey_len; struct passwd *pw; if (pr_cmd_dispatch_phase(pass_cmd, PRE_CMD, 0) < 0) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "authentication request for user '%s' blocked by '%s' handler", orig_user, pass_cmd->argv[0]); pr_cmd_dispatch_phase(pass_cmd, POST_CMD_ERR, 0); pr_cmd_dispatch_phase(pass_cmd, LOG_CMD_ERR, 0); *send_userauth_fail = TRUE; errno = EPERM; return 0; } have_signature = sftp_msg_read_bool(pkt->pool, buf, buflen); if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_HAVE_PUBKEY_ALGO)) { pubkey_algo = sftp_msg_read_string(pkt->pool, buf, buflen); } pubkey_len = sftp_msg_read_int(pkt->pool, buf, buflen); pubkey_data = sftp_msg_read_data(pkt->pool, buf, buflen, pubkey_len); if (pubkey_algo == NULL) { /* The client did not send the string identifying the public key algorithm. * Thus we need to extract the algorithm string from the public key data. */ pubkey_algo = sftp_msg_read_string(pkt->pool, &pubkey_data, &pubkey_len); } pr_trace_msg(trace_channel, 9, "client sent '%s' public key %s", pubkey_algo, have_signature ? "with signature" : "without signature"); if (strncmp(pubkey_algo, "ssh-rsa", 8) == 0) { pubkey_type = EVP_PKEY_RSA; } else if (strncmp(pubkey_algo, "ssh-dss", 8) == 0) { pubkey_type = EVP_PKEY_DSA; /* XXX This is where we would add support for X509 public keys, e.g.: * * x509v3-ssh-dss * x509v3-ssh-rsa * x509v3-sign (older) * */ } else { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "unsupported public key algorithm '%s' requested, rejecting request", pubkey_algo); *send_userauth_fail = TRUE; errno = EINVAL; return 0; } if (sftp_keys_verify_pubkey_type(pkt->pool, pubkey_data, pubkey_len, pubkey_type) != TRUE) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "unable to verify that given public key matches given '%s' algorithm", pubkey_algo); *send_userauth_fail = TRUE; errno = EINVAL; return 0; } #ifdef OPENSSL_FIPS if (FIPS_mode()) { fp = sftp_keys_get_fingerprint(pkt->pool, pubkey_data, pubkey_len, SFTP_KEYS_FP_DIGEST_SHA1); if (fp != NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "public key SHA1 fingerprint: %s", fp); } else { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error obtaining public key SHA1 fingerprint: %s", strerror(errno)); } } else { #endif /* OPENSSL_FIPS */ fp = sftp_keys_get_fingerprint(pkt->pool, pubkey_data, pubkey_len, SFTP_KEYS_FP_DIGEST_MD5); if (fp != NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "public key MD5 fingerprint: %s", fp); } else { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error obtaining public key MD5 fingerprint: %s", strerror(errno)); } #ifdef OPENSSL_FIPS } #endif /* OPENSSL_FIPS */ pw = pr_auth_getpwnam(pkt->pool, user); if (pw == NULL) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "no account for user '%s' found", user); pr_log_auth(PR_LOG_NOTICE, "USER %s: no such user found from %s [%s] to %s:%d", user, session.c->remote_name, pr_netaddr_get_ipstr(session.c->remote_addr), pr_netaddr_get_ipstr(session.c->local_addr), session.c->local_port); *send_userauth_fail = TRUE; errno = ENOENT; return 0; } if (!have_signature) { /* We don't perform the actual authentication just yet; we need to * let the client know that the pubkey algorithms are acceptable. */ if (send_pubkey_ok(pubkey_algo, pubkey_data, pubkey_len) < 0) { return -1; } return 0; } else { const unsigned char *id; char *buf2, *ptr2, *signature_data; uint32_t buflen2, bufsz2, id_len, signature_len; /* XXX This should become a more generic "is this key data * usable/acceptable?" check (and take the pubkey_type parameter), so that * that is where we would check the validity/usability of an X509v3 cert * (if a cert), or if the key is on the blacklist (if a key). */ if (sftp_blacklist_reject_key(pkt->pool, pubkey_data, pubkey_len)) { *send_userauth_fail = TRUE; errno = EPERM; return 0; } signature_len = sftp_msg_read_int(pkt->pool, buf, buflen); signature_data = sftp_msg_read_data(pkt->pool, buf, buflen, signature_len); /* The client signed the request as well; we need to authenticate the * user with the given pubkey now. If that succeeds, we use the * signature to verify the request. And if that succeeds, then we're * done authenticating. */ /* XXX Need to pass the pubkey_type here as well, so that the * verification routines can handle different databases of keys/certs. * * For X509v3 certs, we will want a way to enforce/restrict which * user names can be used with the provided cert. Perhaps a database * mapping cert fingerprints to user names/UIDs? Configurable callback * check (HOOK?), for modules to enforce. */ if (sftp_keystore_verify_user_key(pkt->pool, user, pubkey_data, pubkey_len) < 0) { *send_userauth_fail = TRUE; return 0; } /* Make sure the signature matches as well. */ id_len = sftp_session_get_id(&id); /* Make sure to allocate a buffer large enough to hold the publickey * signature and data we want to send back. */ bufsz2 = buflen2 = pubkey_len + 1024; ptr2 = buf2 = sftp_msg_getbuf(pkt->pool, bufsz2); sftp_msg_write_data(&buf2, &buflen2, (char *) id, id_len, TRUE); sftp_msg_write_byte(&buf2, &buflen2, SFTP_SSH2_MSG_USER_AUTH_REQUEST); sftp_msg_write_string(&buf2, &buflen2, orig_user); if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_SERVICE_IN_PUBKEY_SIG)) { sftp_msg_write_string(&buf2, &buflen2, service); } else { sftp_msg_write_string(&buf2, &buflen2, "ssh-userauth"); } if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_HAVE_PUBKEY_ALGO)) { sftp_msg_write_string(&buf2, &buflen2, "publickey"); sftp_msg_write_bool(&buf2, &buflen2, TRUE); sftp_msg_write_string(&buf2, &buflen2, pubkey_algo); } else { sftp_msg_write_bool(&buf2, &buflen2, TRUE); } sftp_msg_write_data(&buf2, &buflen2, pubkey_data, pubkey_len, TRUE); if (sftp_keys_verify_signed_data(pkt->pool, pubkey_algo, pubkey_data, pubkey_len, signature_data, signature_len, (unsigned char *) ptr2, (bufsz2 - buflen2)) < 0) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "failed to verify '%s' signature on public key auth request for " "user '%s'", pubkey_algo, orig_user); *send_userauth_fail = TRUE; return 0; } } /* Make sure the user is authorized to login. Normally this is checked * as part of the password verification process, but in the case of * publickey authentication, there is no password to verify. */ if (pr_auth_authorize(pkt->pool, user) != PR_AUTH_OK) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "authentication for user '%s' failed: User not authorized", user); pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): User not authorized " "for login", user); *send_userauth_fail = TRUE; errno = EACCES; return 0; } return 1; }
static int set_mac_key(struct sftp_mac *mac, const EVP_MD *hash, const char *k, uint32_t klen, const char *h, uint32_t hlen, char *letter, const unsigned char *id, uint32_t id_len) { EVP_MD_CTX ctx; unsigned char *key = NULL; size_t key_sz; uint32_t key_len = 0; key_sz = sftp_crypto_get_size(EVP_MD_block_size(mac->digest), EVP_MD_size(hash)); if (key_sz == 0) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "unable to determine key length for MAC '%s'", mac->algo); errno = EINVAL; return -1; } key = malloc(key_sz); if (key == NULL) { pr_log_pri(PR_LOG_CRIT, MOD_SFTP_VERSION ": Out of memory!"); _exit(1); } /* In OpenSSL 0.9.6, many of the EVP_Digest* functions returned void, not * int. Without these ugly OpenSSL version preprocessor checks, the * compiler will error out with "void value not ignored as it ought to be". */ #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestInit(&ctx, hash) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error initializing message digest: %s", sftp_crypto_get_errors()); free(key); return -1; } #else EVP_DigestInit(&ctx, hash); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, k, klen) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with K: %s", sftp_crypto_get_errors()); free(key); return -1; } #else EVP_DigestUpdate(&ctx, k, klen); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, h, hlen) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with H: %s", sftp_crypto_get_errors()); free(key); return -1; } #else EVP_DigestUpdate(&ctx, h, hlen); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, letter, sizeof(char)) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with '%c': %s", *letter, sftp_crypto_get_errors()); free(key); return -1; } #else EVP_DigestUpdate(&ctx, letter, sizeof(char)); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, (char *) id, id_len) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with ID: %s", sftp_crypto_get_errors()); free(key); return -1; } #else EVP_DigestUpdate(&ctx, (char *) id, id_len); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestFinal(&ctx, key, &key_len) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error finalizing message digest: %s", sftp_crypto_get_errors()); pr_memscrub(key, key_sz); free(key); return -1; } #else EVP_DigestFinal(&ctx, key, &key_len); #endif /* If we need more, keep hashing, as per RFC, until we have enough * material. */ while (key_sz > key_len) { uint32_t len = key_len; pr_signals_handle(); #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestInit(&ctx, hash) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error initializing message digest: %s", sftp_crypto_get_errors()); pr_memscrub(key, key_sz); free(key); return -1; } #else EVP_DigestInit(&ctx, hash); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, k, klen) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with K: %s", sftp_crypto_get_errors()); pr_memscrub(key, key_sz); free(key); return -1; } #else EVP_DigestUpdate(&ctx, k, klen); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, h, hlen) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with H: %s", sftp_crypto_get_errors()); pr_memscrub(key, key_sz); free(key); return -1; } #else EVP_DigestUpdate(&ctx, h, hlen); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestUpdate(&ctx, key, len) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error updating message digest with data: %s", sftp_crypto_get_errors()); pr_memscrub(key, key_sz); free(key); return -1; } #else EVP_DigestUpdate(&ctx, key, len); #endif #if OPENSSL_VERSION_NUMBER >= 0x000907000L if (EVP_DigestFinal(&ctx, key + len, &len) != 1) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "error finalizing message digest: %s", sftp_crypto_get_errors()); pr_memscrub(key, key_sz); free(key); return -1; } #else EVP_DigestFinal(&ctx, key + len, &len); #endif key_len += len; } mac->key = key; mac->keysz = key_sz; mac->key_len = EVP_MD_size(mac->digest); if (!sftp_interop_supports_feature(SFTP_SSH2_FEAT_MAC_LEN)) { mac->key_len = 16; } return 0; }
int sftp_tap_send_packet(void) { int chance; if (!sftp_interop_supports_feature(SFTP_SSH2_FEAT_IGNORE_MSG)) { pr_trace_msg(trace_channel, 3, "unable to send TAP packet: IGNORE not supported by client"); return 0; } if (curr_policy.chance_max == 0) { /* The "none" policy is in effect; nothing to do. */ return 0; } /* Calculate our odds of sending a tap packet, based on the configured * policy. */ if (curr_policy.chance_max != 1) { chance = (int) (rand() / (RAND_MAX / curr_policy.chance_max + 1)); } else { chance = 1; } if (chance == curr_policy.chance) { unsigned char *rand_data; char *buf, *ptr; uint32_t bufsz, buflen, rand_datalen; struct ssh2_packet *pkt; unsigned int max_datalen = 8192; if (curr_policy.max_datalen) { max_datalen = curr_policy.max_datalen; } rand_datalen = (uint32_t) (curr_policy.min_datalen + rand() / (RAND_MAX / (max_datalen - curr_policy.min_datalen) + 1)); pr_trace_msg(trace_channel, 20, "sending random SSH2_MSG_IGNORE message " "(%lu bytes) based on '%s' TAP policy", (unsigned long) rand_datalen, curr_policy.policy); pkt = sftp_ssh2_packet_create(tap_pool); bufsz = buflen = rand_datalen + 32; ptr = buf = palloc(pkt->pool, bufsz); rand_data = palloc(pkt->pool, rand_datalen); /* We don't need cryptographically secure random bytes here, just * pseudo-random data. */ RAND_pseudo_bytes(rand_data, rand_datalen); sftp_msg_write_byte(&buf, &buflen, SFTP_SSH2_MSG_IGNORE); sftp_msg_write_data(&buf, &buflen, (char *) rand_data, rand_datalen, TRUE); pkt->payload = ptr; pkt->payload_len = (bufsz - buflen); if (sftp_ssh2_packet_send(sftp_conn->wfd, pkt) < 0) { int xerrno = errno; pr_trace_msg(trace_channel, 12, "error writing TAP packet: %s", strerror(xerrno)); } destroy_pool(pkt->pool); } return 0; }
static int set_cipher_iv(struct sftp_cipher *cipher, const EVP_MD *hash, const unsigned char *k, uint32_t klen, const char *h, uint32_t hlen, char *letter, const unsigned char *id, uint32_t id_len) { EVP_MD_CTX *ctx; unsigned char *iv = NULL; size_t cipher_iv_len = 0, iv_sz = 0; uint32_t iv_len = 0; if (strncmp(cipher->algo, "none", 5) == 0) { cipher->iv = iv; cipher->iv_len = iv_len; return 0; } /* Some ciphers do not use IVs; handle this case. */ cipher_iv_len = EVP_CIPHER_iv_length(cipher->cipher); if (cipher_iv_len != 0) { iv_sz = sftp_crypto_get_size(cipher_iv_len, EVP_MD_size(hash)); } else { iv_sz = EVP_MD_size(hash); } if (iv_sz == 0) { (void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "unable to determine IV length for cipher '%s'", cipher->algo); errno = EINVAL; return -1; } iv = malloc(iv_sz); if (iv == NULL) { pr_log_pri(PR_LOG_ALERT, MOD_SFTP_VERSION ": Out of memory!"); _exit(1); } ctx = EVP_MD_CTX_create(); EVP_DigestInit(ctx, hash); if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_CIPHER_USE_K)) { EVP_DigestUpdate(ctx, k, klen); } EVP_DigestUpdate(ctx, h, hlen); EVP_DigestUpdate(ctx, letter, sizeof(char)); EVP_DigestUpdate(ctx, (char *) id, id_len); EVP_DigestFinal(ctx, iv, &iv_len); EVP_MD_CTX_destroy(ctx); /* If we need more, keep hashing, as per RFC, until we have enough * material. */ while (iv_sz > iv_len) { uint32_t len = iv_len; pr_signals_handle(); ctx = EVP_MD_CTX_create(); EVP_DigestInit(ctx, hash); if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_CIPHER_USE_K)) { EVP_DigestUpdate(ctx, k, klen); } EVP_DigestUpdate(ctx, h, hlen); EVP_DigestUpdate(ctx, iv, len); EVP_DigestFinal(ctx, iv + len, &len); EVP_MD_CTX_destroy(ctx); iv_len += len; } cipher->iv = iv; cipher->iv_len = iv_len; return 0; }