secure.c File Reference

#include "rdesktop.h"
#include <string.h>
#include <openssl/rc4.h>
#include <openssl/md5.h>
#include <openssl/sha.h>
#include <openssl/bn.h>
#include <openssl/x509v3.h>

Include dependency graph for secure.c:

Go to the source code of this file.

Functions
void	sec_hash_48 (uint8 *out, uint8 *in, uint8 *salt1, uint8 *salt2, uint8 salt)
void	sec_hash_16 (uint8 *out, uint8 *in, uint8 *salt1, uint8 *salt2)
static void	sec_make_40bit (uint8 *key)
static void	sec_generate_keys (RDPCLIENT *This, uint8 *client_random, uint8 *server_random, int rc4_key_size)
void	buf_out_uint32 (uint8 *buffer, uint32 value)
void	sec_sign (uint8 *signature, int siglen, uint8 *session_key, int keylen, uint8 *data, int datalen)
static void	sec_update (RDPCLIENT *This, uint8 *key, uint8 *update_key)
static void	sec_encrypt (RDPCLIENT *This, uint8 *data, int length)
void	sec_decrypt (RDPCLIENT *This, uint8 *data, int length)
static void	reverse (uint8 *p, int len)
static void	sec_rsa_encrypt (uint8 *out, uint8 *in, int len, uint32 modulus_size, uint8 *modulus, uint8 *exponent)
STREAM	sec_init (RDPCLIENT *This, uint32 flags, int maxlen)
BOOL	sec_send_to_channel (RDPCLIENT *This, STREAM s, uint32 flags, uint16 channel)
BOOL	sec_send (RDPCLIENT *This, STREAM s, uint32 flags)
static void	sec_establish_key (RDPCLIENT *This)
static void	sec_out_mcs_data (RDPCLIENT *This, STREAM s, wchar_t *hostname)
static BOOL	sec_parse_public_key (RDPCLIENT *This, STREAM s, uint8 **modulus, uint8 **exponent)
static BOOL	sec_parse_x509_key (RDPCLIENT *This, X509 *cert)
static BOOL	sec_parse_crypt_info (RDPCLIENT *This, STREAM s, uint32 *rc4_key_size, uint8 **server_random, uint8 **modulus, uint8 **exponent)
static void	sec_process_crypt_info (RDPCLIENT *This, STREAM s)
static void	sec_process_srv_info (RDPCLIENT *This, STREAM s)
void	sec_process_mcs_data (RDPCLIENT *This, STREAM s)
STREAM	sec_recv (RDPCLIENT *This, uint8 *rdpver)
BOOL	sec_connect (RDPCLIENT *This, char *server, wchar_t *hostname, char *cookie)
BOOL	sec_reconnect (RDPCLIENT *This, char *server, wchar_t *hostname, char *cookie)
void	sec_disconnect (RDPCLIENT *This)
void	sec_reset_state (RDPCLIENT *This)

Variables
static const uint8	pad_54 [40]
static const uint8	pad_92 [48]

Function Documentation

buf_out_uint32()

void buf_out_uint32	(	uint8 *	buffer,
		uint32	value
	)

Definition at line 158 of file secure.c.

{
    buffer[0] = (value) & 0xff;
    buffer[1] = (value >> 8) & 0xff;
    buffer[2] = (value >> 16) & 0xff;
    buffer[3] = (value >> 24) & 0xff;
}

Referenced by cliprdr_send_data_request(), cliprdr_send_simple_native_format_announce(), and licence_generate_hwid().

reverse()

static void reverse ( uint8 *  p, int  len  )

static

Definition at line 253 of file secure.c.

{
    int i, j;
    uint8 temp;

    for (i = 0, j = len - 1; i < j; i++, j--)
    {
        temp = p[i];
        p[i] = p[j];
        p[j] = temp;
    }
}

Referenced by sec_process_crypt_info(), and sec_rsa_encrypt().

sec_connect()

BOOL sec_connect	(	RDPCLIENT *	This,
		char *	server,
		wchar_t *	hostname,
		char *	cookie
	)

Definition at line 905 of file secure.c.

{
    struct stream mcs_data;
    void * p = malloc(512);

    if(p == NULL)
    {
        This->disconnect_reason = 262;
        return False;
    }

    /* We exchange some RDP data during the MCS-Connect */
    mcs_data.size = 512;
    mcs_data.p = mcs_data.data = (uint8 *) p;
    sec_out_mcs_data(This, &mcs_data, hostname);

    if (!mcs_connect(This, server, cookie, &mcs_data))
        return False;

    /*      sec_process_mcs_data(&mcs_data); */
    if (This->encryption)
        sec_establish_key(This);
    free(mcs_data.data);
    return True;
}

sec_decrypt()

void sec_decrypt	(	RDPCLIENT *	This,
		uint8 *	data,
		int	length
	)

Definition at line 239 of file secure.c.

{
    if (This->secure.decrypt_use_count == 4096)
    {
        sec_update(This, This->secure.decrypt_key, This->secure.decrypt_update_key);
        RC4_set_key(&This->secure.rc4_decrypt_key, This->secure.rc4_key_len, This->secure.decrypt_key);
        This->secure.decrypt_use_count = 0;
    }

    RC4(&This->secure.rc4_decrypt_key, length, data, data);
    This->secure.decrypt_use_count++;
}

sec_disconnect()

void sec_disconnect

(

RDPCLIENT *

This

)

Definition at line 961 of file secure.c.

{
    mcs_disconnect(This);
}

sec_encrypt()

static void sec_encrypt ( RDPCLIENT *  This, uint8 *  data, int  length  )

static

Definition at line 224 of file secure.c.

{
    if (This->secure.encrypt_use_count == 4096)
    {
        sec_update(This, This->secure.encrypt_key, This->secure.encrypt_update_key);
        RC4_set_key(&This->secure.rc4_encrypt_key, This->secure.rc4_key_len, This->secure.encrypt_key);
        This->secure.encrypt_use_count = 0;
    }

    RC4(&This->secure.rc4_encrypt_key, length, data, data);
    This->secure.encrypt_use_count++;
}

Referenced by sec_send_to_channel().

sec_establish_key()

static void sec_establish_key ( RDPCLIENT *  This )

static

Definition at line 364 of file secure.c.

{
    uint32 length = This->secure.server_public_key_len + SEC_PADDING_SIZE;
    uint32 flags = SEC_CLIENT_RANDOM;
    STREAM s;

    s = sec_init(This, flags, length + 4);

    out_uint32_le(s, length);
    out_uint8p(s, This->secure.crypted_random, This->secure.server_public_key_len);
    out_uint8s(s, SEC_PADDING_SIZE);

    s_mark_end(s);
    sec_send(This, s, flags);
}

Referenced by sec_connect(), and sec_reconnect().

sec_generate_keys()

static void sec_generate_keys ( RDPCLIENT *  This, uint8 *  client_random, uint8 *  server_random, int  rc4_key_size  )

static

Definition at line 98 of file secure.c.

{
    uint8 pre_master_secret[48];
    uint8 master_secret[48];
    uint8 key_block[48];

    /* Construct pre-master secret */
    memcpy(pre_master_secret, client_random, 24);
    memcpy(pre_master_secret + 24, server_random, 24);

    /* Generate master secret and then key material */
    sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
    sec_hash_48(key_block, master_secret, client_random, server_random, 'X');

    /* First 16 bytes of key material is MAC secret */
    memcpy(This->secure.sign_key, key_block, 16);

    /* Generate export keys from next two blocks of 16 bytes */
    sec_hash_16(This->secure.decrypt_key, &key_block[16], client_random, server_random);
    sec_hash_16(This->secure.encrypt_key, &key_block[32], client_random, server_random);

    if (rc4_key_size == 1)
    {
        DEBUG(("40-bit encryption enabled\n"));
        sec_make_40bit(This->secure.sign_key);
        sec_make_40bit(This->secure.decrypt_key);
        sec_make_40bit(This->secure.encrypt_key);
        This->secure.rc4_key_len = 8;
    }
    else
    {
        DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size));
        This->secure.rc4_key_len = 16;
    }

    /* Save initial RC4 keys as update keys */
    memcpy(This->secure.decrypt_update_key, This->secure.decrypt_key, 16);
    memcpy(This->secure.encrypt_update_key, This->secure.encrypt_key, 16);

    /* Initialise RC4 state arrays */
    RC4_set_key(&This->secure.rc4_decrypt_key, This->secure.rc4_key_len, This->secure.decrypt_key);
    RC4_set_key(&This->secure.rc4_encrypt_key, This->secure.rc4_key_len, This->secure.encrypt_key);
}

Referenced by sec_process_crypt_info().

sec_hash_16()

void sec_hash_16	(	uint8 *	out,
		uint8 *	in,
		uint8 *	salt1,
		uint8 *	salt2
	)

Definition at line 76 of file secure.c.

{
    MD5_CTX md5;

    MD5_Init(&md5);
    MD5_Update(&md5, in, 16);
    MD5_Update(&md5, salt1, 32);
    MD5_Update(&md5, salt2, 32);
    MD5_Final(out, &md5);
}

Referenced by licence_generate_keys().

sec_hash_48()

void sec_hash_48	(	uint8 *	out,
		uint8 *	in,
		uint8 *	salt1,
		uint8 *	salt2,
		uint8	salt
	)

Definition at line 46 of file secure.c.

{
    uint8 shasig[20];
    uint8 pad[4];
    SHA_CTX sha;
    MD5_CTX md5;
    int i;

    for (i = 0; i < 3; i++)
    {
        memset(pad, salt + i, i + 1);

        SHA1_Init(&sha);
        SHA1_Update(&sha, pad, i + 1);
        SHA1_Update(&sha, in, 48);
        SHA1_Update(&sha, salt1, 32);
        SHA1_Update(&sha, salt2, 32);
        SHA1_Final(shasig, &sha);

        MD5_Init(&md5);
        MD5_Update(&md5, in, 48);
        MD5_Update(&md5, shasig, 20);
        MD5_Final(&out[i * 16], &md5);
    }
}

Referenced by licence_generate_keys().

sec_init()

STREAM sec_init	(	RDPCLIENT *	This,
		uint32	flags,
		int	maxlen
	)

Definition at line 305 of file secure.c.

{
    int hdrlen;
    STREAM s;

    if (!This->licence_issued)
        hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4;
    else
        hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0;
    s = mcs_init(This, maxlen + hdrlen);

    if(s == NULL)
        return s;

    s_push_layer(s, sec_hdr, hdrlen);

    return s;
}

sec_make_40bit()

static void sec_make_40bit ( uint8 *  key )

static

Definition at line 89 of file secure.c.

{
    key[0] = 0xd1;
    key[1] = 0x26;
    key[2] = 0x9e;
}

Referenced by sec_generate_keys(), and sec_update().

sec_out_mcs_data()

static void sec_out_mcs_data ( RDPCLIENT *  This, STREAM  s, wchar_t *  hostname  )

static

Definition at line 382 of file secure.c.

{
    int hostlen = 2 * (int)wcslen(hostname);
    int length = 158 + 76 + 12 + 4;
    unsigned int i;

    if (This->num_channels > 0)
        length += This->num_channels * 12 + 8;

    if (hostlen > 30)
        hostlen = 30;

    /* Generic Conference Control (T.124) ConferenceCreateRequest */
    out_uint16_be(s, 5);
    out_uint16_be(s, 0x14);
    out_uint8(s, 0x7c);
    out_uint16_be(s, 1);

    out_uint16_be(s, (length | 0x8000));    /* remaining length */

    out_uint16_be(s, 8);    /* length? */
    out_uint16_be(s, 16);
    out_uint8(s, 0);
    out_uint16_le(s, 0xc001);
    out_uint8(s, 0);

    out_uint32_le(s, 0x61637544);   /* OEM ID: "Duca", as in Ducati. */
    out_uint16_be(s, ((length - 14) | 0x8000)); /* remaining length */

    /* Client information */
    out_uint16_le(s, SEC_TAG_CLI_INFO);
    out_uint16_le(s, 212);  /* length */
    out_uint16_le(s, This->use_rdp5 ? 4 : 1);   /* RDP version. 1 == RDP4, 4 == RDP5. */
    out_uint16_le(s, 8);
    out_uint16_le(s, This->width);
    out_uint16_le(s, This->height);
    out_uint16_le(s, 0xca01);
    out_uint16_le(s, 0xaa03);
    out_uint32_le(s, This->keylayout);
    out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */

    /* Unicode name of client, padded to 32 bytes */
    rdp_out_unistr(This, s, hostname, hostlen);
    out_uint8s(s, 30 - hostlen);

    /* See
       http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */
    out_uint32_le(s, This->keyboard_type);
    out_uint32_le(s, This->keyboard_subtype);
    out_uint32_le(s, This->keyboard_functionkeys);
    out_uint8s(s, 64);  /* reserved? 4 + 12 doublewords */
    out_uint16_le(s, 0xca01);   /* colour depth? */
    out_uint16_le(s, 1);

    out_uint32(s, 0);
    out_uint8(s, This->server_depth);
    out_uint16_le(s, 0x0700);
    out_uint8(s, 0);
    out_uint32_le(s, 1);
    out_uint8s(s, 64);  /* End of client info */

    out_uint16_le(s, SEC_TAG_CLI_4);
    out_uint16_le(s, 12);
    out_uint32_le(s, This->console_session ? 0xb : 9);
    out_uint32(s, 0);

    /* Client encryption settings */
    out_uint16_le(s, SEC_TAG_CLI_CRYPT);
    out_uint16_le(s, 12);   /* length */
    out_uint32_le(s, This->encryption ? 0x3 : 0);   /* encryption supported, 128-bit supported */
    out_uint32(s, 0);   /* Unknown */

    DEBUG_RDP5(("This->num_channels is %d\n", This->num_channels));
    if (This->num_channels > 0)
    {
        out_uint16_le(s, SEC_TAG_CLI_CHANNELS);
        out_uint16_le(s, This->num_channels * 12 + 8);  /* length */
        out_uint32_le(s, This->num_channels);   /* number of virtual channels */
        for (i = 0; i < This->num_channels; i++)
        {
            DEBUG_RDP5(("Requesting channel %s\n", This->channels[i].name));
            out_uint8a(s, This->channel_defs[i].name, 8);
            out_uint32_be(s, This->channel_defs[i].options);
        }
    }

    s_mark_end(s);
}

Referenced by sec_connect(), and sec_reconnect().

sec_parse_crypt_info()

static BOOL sec_parse_crypt_info ( RDPCLIENT *  This, STREAM  s, uint32 *  rc4_key_size, uint8 **  server_random, uint8 **  modulus, uint8 **  exponent  )

static

Definition at line 539 of file secure.c.

{
    uint32 crypt_level, random_len, rsa_info_len;
    uint32 cacert_len, cert_len, flags;
    X509 *cacert, *server_cert;
    uint16 tag, length;
    uint8 *next_tag, *end;

    in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */
    in_uint32_le(s, crypt_level);   /* 1 = low, 2 = medium, 3 = high */
    if (crypt_level == 0)   /* no encryption */
        return False;
    in_uint32_le(s, random_len);
    in_uint32_le(s, rsa_info_len);

    if (random_len != SEC_RANDOM_SIZE)
    {
        error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE);
        return False;
    }

    in_uint8p(s, *server_random, random_len);

    /* RSA info */
    end = s->p + rsa_info_len;
    if (end > s->end)
        return False;

    in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */
    if (flags & 1)
    {
        DEBUG_RDP5(("We're going for the RDP4-style encryption\n"));
        in_uint8s(s, 8);    /* unknown */

        while (s->p < end)
        {
            in_uint16_le(s, tag);
            in_uint16_le(s, length);

            next_tag = s->p + length;

            switch (tag)
            {
                case SEC_TAG_PUBKEY:
                    if (!sec_parse_public_key(This, s, modulus, exponent))
                        return False;
                    DEBUG_RDP5(("Got Public key, RDP4-style\n"));

                    break;

                case SEC_TAG_KEYSIG:
                    /* Is this a Microsoft key that we just got? */
                    /* Care factor: zero! */
                    /* Actually, it would probably be a good idea to check if the public key is signed with this key, and then store this
                       key as a known key of the hostname. This would prevent some MITM-attacks. */
                    break;

                default:
                    unimpl("crypt tag 0x%x\n", tag);
            }

            s->p = next_tag;
        }
    }
    else
    {
        uint32 certcount;

        DEBUG_RDP5(("We're going for the RDP5-style encryption\n"));
        in_uint32_le(s, certcount); /* Number of certificates */

        if (certcount < 2)
        {
            error("Server didn't send enough X509 certificates\n");
            This->disconnect_reason = 1798;
            return False;
        }

        for (; certcount > 2; certcount--)
        {       /* ignore all the certificates between the root and the signing CA */
            uint32 ignorelen;
            X509 *ignorecert;

            DEBUG_RDP5(("Ignored certs left: %d\n", certcount));

            in_uint32_le(s, ignorelen);
            DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen));
            ignorecert = d2i_X509(NULL, &(s->p), ignorelen);

            if (ignorecert == NULL)
            {   /* XXX: error out? */
                DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n"));
            }

#ifdef WITH_DEBUG_RDP5
            DEBUG_RDP5(("cert #%d (ignored):\n", certcount));
            X509_print_fp(stdout, ignorecert);
#endif
        }

        /* Do da funky X.509 stuffy

           "How did I find out about this?  I looked up and saw a
           bright light and when I came to I had a scar on my forehead
           and knew about X.500"
           - Peter Gutman in a early version of
           http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt
         */

        in_uint32_le(s, cacert_len);
        DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len));
        cacert = d2i_X509(NULL, &(s->p), cacert_len);
        /* Note: We don't need to move s->p here - d2i_X509 is
           "kind" enough to do it for us */
        if (NULL == cacert)
        {
            error("Couldn't load CA Certificate from server\n");
            This->disconnect_reason = 1798;
            return False;
        }

        /* Currently, we don't use the CA Certificate.
           FIXME:
           *) Verify the server certificate (server_cert) with the
           CA certificate.
           *) Store the CA Certificate with the hostname of the
           server we are connecting to as key, and compare it
           when we connect the next time, in order to prevent
           MITM-attacks.
         */

        X509_free(cacert);

        in_uint32_le(s, cert_len);
        DEBUG_RDP5(("Certificate length is %d\n", cert_len));
        server_cert = d2i_X509(NULL, &(s->p), cert_len);
        if (NULL == server_cert)
        {
            error("Couldn't load Certificate from server\n");
            This->disconnect_reason = 1798;
            return False;
        }

        in_uint8s(s, 16);   /* Padding */

        /* Note: Verifying the server certificate must be done here,
           before sec_parse_public_key since we'll have to apply
           serious violence to the key after this */

        if (!sec_parse_x509_key(This, server_cert))
        {
            DEBUG_RDP5(("Didn't parse X509 correctly\n"));
            X509_free(server_cert);
            This->disconnect_reason = 1798;
            return False;
        }
        X509_free(server_cert);
        return True;    /* There's some garbage here we don't care about */
    }
    return s_check_end(s);
}

Referenced by sec_process_crypt_info().

sec_parse_public_key()

static BOOL sec_parse_public_key ( RDPCLIENT *  This, STREAM  s, uint8 **  modulus, uint8 **  exponent  )

static

Definition at line 473 of file secure.c.

{
    uint32 magic, modulus_len;

    in_uint32_le(s, magic);
    if (magic != SEC_RSA_MAGIC)
    {
        error("RSA magic 0x%x\n", magic);
        return False;
    }

    in_uint32_le(s, modulus_len);
    modulus_len -= SEC_PADDING_SIZE;
    if ((modulus_len < 64) || (modulus_len > SEC_MAX_MODULUS_SIZE))
    {
        error("Bad server public key size (%u bits)\n", modulus_len * 8);
        return False;
    }

    in_uint8s(s, 8);    /* modulus_bits, unknown */
    in_uint8p(s, *exponent, SEC_EXPONENT_SIZE);
    in_uint8p(s, *modulus, modulus_len);
    in_uint8s(s, SEC_PADDING_SIZE);
    This->secure.server_public_key_len = modulus_len;

    return s_check(s);
}

Referenced by sec_parse_crypt_info().

sec_parse_x509_key()

static BOOL sec_parse_x509_key ( RDPCLIENT *  This, X509 *  cert  )

static

Definition at line 502 of file secure.c.

{
    EVP_PKEY *epk = NULL;
    /* By some reason, Microsoft sets the OID of the Public RSA key to
       the oid for "MD5 with RSA Encryption" instead of "RSA Encryption"

       Kudos to Richard Levitte for the following (. intiutive .)
       lines of code that resets the OID and let's us extract the key. */
    if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption)
    {
        DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n"));
        ASN1_OBJECT_free(cert->cert_info->key->algor->algorithm);
        cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption);
    }
    epk = X509_get_pubkey(cert);
    if (NULL == epk)
    {
        error("Failed to extract public key from certificate\n");
        return False;
    }

    This->secure.server_public_key = RSAPublicKey_dup((RSA *) epk->pkey.ptr);
    EVP_PKEY_free(epk);

    This->secure.server_public_key_len = RSA_size(This->secure.server_public_key);
    if ((This->secure.server_public_key_len < 64) || (This->secure.server_public_key_len > SEC_MAX_MODULUS_SIZE))
    {
        error("Bad server public key size (%u bits)\n", This->secure.server_public_key_len * 8);
        return False;
    }

    return True;
}

Referenced by sec_parse_crypt_info().

sec_process_crypt_info()

static void sec_process_crypt_info ( RDPCLIENT *  This, STREAM  s  )

static

Definition at line 704 of file secure.c.

{
    uint8 *server_random, *modulus, *exponent;
    uint8 client_random[SEC_RANDOM_SIZE];
    uint32 rc4_key_size;

    if (!sec_parse_crypt_info(This, s, &rc4_key_size, &server_random, &modulus, &exponent))
    {
        DEBUG(("Failed to parse crypt info\n"));
        return;
    }

    DEBUG(("Generating client random\n"));
    generate_random(client_random);

    if (NULL != This->secure.server_public_key)
    {           /* Which means we should use
                   RDP5-style encryption */
        uint8 inr[SEC_MAX_MODULUS_SIZE];
        uint32 padding_len = This->secure.server_public_key_len - SEC_RANDOM_SIZE;

        /* This is what the MS client do: */
        memset(inr, 0, padding_len);
        /*  *ARIGL!* Plaintext attack, anyone?
           I tried doing:
           generate_random(inr);
           ..but that generates connection errors now and then (yes,
           "now and then". Something like 0 to 3 attempts needed before a
           successful connection. Nice. Not!
         */
        memcpy(inr + padding_len, client_random, SEC_RANDOM_SIZE);
        reverse(inr + padding_len, SEC_RANDOM_SIZE);

        RSA_public_encrypt(This->secure.server_public_key_len,
                   inr, This->secure.crypted_random, This->secure.server_public_key, RSA_NO_PADDING);

        reverse(This->secure.crypted_random, This->secure.server_public_key_len);

        RSA_free(This->secure.server_public_key);
        This->secure.server_public_key = NULL;
    }
    else
    {           /* RDP4-style encryption */
        sec_rsa_encrypt(This->secure.crypted_random,
                client_random, SEC_RANDOM_SIZE, This->secure.server_public_key_len, modulus,
                exponent);
    }
    sec_generate_keys(This, client_random, server_random, rc4_key_size);
}

Referenced by sec_process_mcs_data().

sec_process_mcs_data()

void sec_process_mcs_data	(	RDPCLIENT *	This,
		STREAM	s
	)

Definition at line 771 of file secure.c.

{
    uint16 tag, length;
    uint8 *next_tag;
    uint8 len;

    in_uint8s(s, 21);   /* header (T.124 ConferenceCreateResponse) */
    in_uint8(s, len);
    if (len & 0x80)
        in_uint8(s, len);

    while (s->p < s->end)
    {
        in_uint16_le(s, tag);
        in_uint16_le(s, length);

        if (length <= 4)
            return;

        next_tag = s->p + length - 4;

        switch (tag)
        {
            case SEC_TAG_SRV_INFO:
                sec_process_srv_info(This, s);
                break;

            case SEC_TAG_SRV_CRYPT:
                sec_process_crypt_info(This, s);
                break;

            case SEC_TAG_SRV_CHANNELS:
                /* FIXME: We should parse this information and
                   use it to map RDP5 channels to MCS
                   channels */
                break;

            default:
                unimpl("response tag 0x%x\n", tag);
        }

        s->p = next_tag;
    }
}

sec_process_srv_info()

static void sec_process_srv_info ( RDPCLIENT *  This, STREAM  s  )

static

Definition at line 757 of file secure.c.

{
    in_uint16_le(s, This->server_rdp_version);
    DEBUG_RDP5(("Server RDP version is %d\n", This->server_rdp_version));
    if (1 == This->server_rdp_version)
    {
        This->use_rdp5 = 0;
        This->server_depth = 8;
    }
}

Referenced by sec_process_mcs_data().

sec_reconnect()

BOOL sec_reconnect	(	RDPCLIENT *	This,
		char *	server,
		wchar_t *	hostname,
		char *	cookie
	)

Definition at line 933 of file secure.c.

{
    struct stream mcs_data;
    void * p = malloc(512);

    if(p == NULL)
    {
        This->disconnect_reason = 262;
        return False;
    }

    /* We exchange some RDP data during the MCS-Connect */
    mcs_data.size = 512;
    mcs_data.p = mcs_data.data = (uint8 *) p;
    sec_out_mcs_data(This, &mcs_data, hostname);

    if (!mcs_reconnect(This, server, cookie, &mcs_data))
        return False;

    /*      sec_process_mcs_data(&mcs_data); */
    if (This->encryption)
        sec_establish_key(This);
    free(mcs_data.data);
    return True;
}

Referenced by rdp_reconnect().

sec_recv()

STREAM sec_recv	(	RDPCLIENT *	This,
		uint8 *	rdpver
	)

Definition at line 818 of file secure.c.

{
    uint32 sec_flags;
    uint16 channel;
    STREAM s;

    while ((s = mcs_recv(This, &channel, rdpver)) != NULL)
    {
        if (rdpver != NULL)
        {
            if (*rdpver != 3)
            {
                if (*rdpver & 0x80)
                {
                    in_uint8s(s, 8);    /* signature */
                    sec_decrypt(This, s->p, (int)(s->end - s->p));
                }
                return s;
            }
        }
        if (This->encryption || !This->licence_issued)
        {
            in_uint32_le(s, sec_flags);

            if (sec_flags & SEC_ENCRYPT)
            {
                in_uint8s(s, 8);    /* signature */
                sec_decrypt(This, s->p, (int)(s->end - s->p));
            }

            if (sec_flags & SEC_LICENCE_NEG)
            {
                licence_process(This, s);
                continue;
            }

            if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */
            {
                uint8 swapbyte;

                in_uint8s(s, 8);    /* signature */
                sec_decrypt(This, s->p, (int)(s->end - s->p));

                /* Check for a redirect packet, starts with 00 04 */
                if (s->p[0] == 0 && s->p[1] == 4)
                {
                    /* for some reason the PDU and the length seem to be swapped.
                       This isn't good, but we're going to do a byte for byte
                       swap.  So the first foure value appear as: 00 04 XX YY,
                       where XX YY is the little endian length. We're going to
                       use 04 00 as the PDU type, so after our swap this will look
                       like: XX YY 04 00 */
                    swapbyte = s->p[0];
                    s->p[0] = s->p[2];
                    s->p[2] = swapbyte;

                    swapbyte = s->p[1];
                    s->p[1] = s->p[3];
                    s->p[3] = swapbyte;

                    swapbyte = s->p[2];
                    s->p[2] = s->p[3];
                    s->p[3] = swapbyte;
                }
#ifdef WITH_DEBUG
                /* warning!  this debug statement will show passwords in the clear! */
                hexdump(s->p, s->end - s->p);
#endif
            }

        }

        if (channel != MCS_GLOBAL_CHANNEL)
        {
            channel_process(This, s, channel);
            *rdpver = 0xff;
            return s;
        }

        return s;
    }

    return NULL;
}

sec_reset_state()

void sec_reset_state

(

RDPCLIENT *

This

)

Definition at line 968 of file secure.c.

{
    This->server_rdp_version = 0;
    This->secure.encrypt_use_count = 0;
    This->secure.decrypt_use_count = 0;
    mcs_reset_state(This);
}

sec_rsa_encrypt()

static void sec_rsa_encrypt ( uint8 *  out, uint8 *  in, int  len, uint32  modulus_size, uint8 *  modulus, uint8 *  exponent  )

static

Definition at line 268 of file secure.c.

{
    BN_CTX *ctx;
    BIGNUM mod, exp, x, y;
    uint8 inr[SEC_MAX_MODULUS_SIZE];
    int outlen;

    reverse(modulus, modulus_size);
    reverse(exponent, SEC_EXPONENT_SIZE);
    memcpy(inr, in, len);
    reverse(inr, len);

    ctx = BN_CTX_new();
    BN_init(&mod);
    BN_init(&exp);
    BN_init(&x);
    BN_init(&y);

    BN_bin2bn(modulus, modulus_size, &mod);
    BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp);
    BN_bin2bn(inr, len, &x);
    BN_mod_exp(&y, &x, &exp, &mod, ctx);
    outlen = BN_bn2bin(&y, out);
    reverse(out, outlen);
    if ((uint32)outlen < modulus_size)
        memset(out + outlen, 0, modulus_size - outlen);

    BN_free(&y);
    BN_clear_free(&x);
    BN_free(&exp);
    BN_free(&mod);
    BN_CTX_free(ctx);
}

Referenced by sec_process_crypt_info().

sec_send()

BOOL sec_send	(	RDPCLIENT *	This,
		STREAM	s,
		uint32	flags
	)

Definition at line 356 of file secure.c.

{
    return sec_send_to_channel(This, s, flags, MCS_GLOBAL_CHANNEL);
}

sec_send_to_channel()

BOOL sec_send_to_channel	(	RDPCLIENT *	This,
		STREAM	s,
		uint32	flags,
		uint16	channel
	)

Definition at line 328 of file secure.c.

{
    int datalen;

    s_pop_layer(s, sec_hdr);
    if (!This->licence_issued || (flags & SEC_ENCRYPT))
        out_uint32_le(s, flags);

    if (flags & SEC_ENCRYPT)
    {
        flags &= ~SEC_ENCRYPT;
        datalen = (int)(s->end - s->p - 8);

#if WITH_DEBUG
        DEBUG(("Sending encrypted packet:\n"));
        hexdump(s->p + 8, datalen);
#endif

        sec_sign(s->p, 8, This->secure.sign_key, This->secure.rc4_key_len, s->p + 8, datalen);
        sec_encrypt(This, s->p + 8, datalen);
    }

    return mcs_send_to_channel(This, s, channel);
}

sec_sign()

void sec_sign	(	uint8 *	signature,
		int	siglen,
		uint8 *	session_key,
		int	keylen,
		uint8 *	data,
		int	datalen
	)

Definition at line 168 of file secure.c.

{
    uint8 shasig[20];
    uint8 md5sig[16];
    uint8 lenhdr[4];
    SHA_CTX sha;
    MD5_CTX md5;

    buf_out_uint32(lenhdr, datalen);

    SHA1_Init(&sha);
    SHA1_Update(&sha, session_key, keylen);
    SHA1_Update(&sha, pad_54, 40);
    SHA1_Update(&sha, lenhdr, 4);
    SHA1_Update(&sha, data, datalen);
    SHA1_Final(shasig, &sha);

    MD5_Init(&md5);
    MD5_Update(&md5, session_key, keylen);
    MD5_Update(&md5, pad_92, 48);
    MD5_Update(&md5, shasig, 20);
    MD5_Final(md5sig, &md5);

    memcpy(signature, md5sig, siglen);
}

Referenced by licence_process_authreq(), licence_process_demand(), licence_process_platform_challenge(), and licence_process_request().

sec_update()

static void sec_update ( RDPCLIENT *  This, uint8 *  key, uint8 *  update_key  )

static

Definition at line 196 of file secure.c.

{
    uint8 shasig[20];
    SHA_CTX sha;
    MD5_CTX md5;
    RC4_KEY update;

    SHA1_Init(&sha);
    SHA1_Update(&sha, update_key, This->secure.rc4_key_len);
    SHA1_Update(&sha, pad_54, 40);
    SHA1_Update(&sha, key, This->secure.rc4_key_len);
    SHA1_Final(shasig, &sha);

    MD5_Init(&md5);
    MD5_Update(&md5, update_key, This->secure.rc4_key_len);
    MD5_Update(&md5, pad_92, 48);
    MD5_Update(&md5, shasig, 20);
    MD5_Final(key, &md5);

    RC4_set_key(&update, This->secure.rc4_key_len, key);
    RC4(&update, This->secure.rc4_key_len, key, key);

    if (This->secure.rc4_key_len == 8)
        sec_make_40bit(key);
}

Referenced by sec_decrypt(), and sec_encrypt().

Variable Documentation

pad_54

const uint8 pad_54[40]

static

Initial value:

= {
    54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
    54, 54, 54,
    54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
    54, 54, 54
}

Definition at line 142 of file secure.c.

Referenced by sec_sign(), and sec_update().

pad_92

const uint8 pad_92[48]

static

Initial value:

= {
    92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
    92, 92, 92, 92, 92, 92, 92,
    92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
    92, 92, 92, 92, 92, 92, 92
}

Definition at line 149 of file secure.c.

Referenced by sec_sign(), and sec_update().