static OM_uint32
kg_unseal_v1_iov(krb5_context context,
OM_uint32 *minor_status,
krb5_gss_ctx_id_rec *ctx,
gss_iov_buffer_desc *iov,
int iov_count,
size_t token_wrapper_len,
int *conf_state,
gss_qop_t *qop_state,
int toktype)
{
OM_uint32 code;
gss_iov_buffer_t header;
gss_iov_buffer_t trailer;
unsigned char *ptr;
int sealalg;
int signalg;
krb5_checksum cksum;
krb5_checksum md5cksum;
size_t cksum_len = 0;
size_t conflen = 0;
int direction;
krb5_ui_4 seqnum;
OM_uint32 retval;
size_t sumlen;
krb5_keyusage sign_usage = KG_USAGE_SIGN;
md5cksum.length = cksum.length = 0;
md5cksum.contents = cksum.contents = NULL;
header = kg_locate_header_iov(iov, iov_count, toktype);
assert(header != NULL);
trailer = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_TRAILER);
if (trailer != NULL && trailer->buffer.length != 0) {
*minor_status = (OM_uint32)KRB5_BAD_MSIZE;
return GSS_S_DEFECTIVE_TOKEN;
}
if (header->buffer.length < token_wrapper_len + 14) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
ptr = (unsigned char *)header->buffer.value + token_wrapper_len;
signalg = ptr[0];
signalg |= ptr[1] << 8;
sealalg = ptr[2];
sealalg |= ptr[3] << 8;
if (ptr[4] != 0xFF || ptr[5] != 0xFF) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
if (toktype != KG_TOK_WRAP_MSG && sealalg != 0xFFFF) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
if (toktype == KG_TOK_WRAP_MSG &&
!(sealalg == 0xFFFF || sealalg == ctx->sealalg)) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
if ((ctx->sealalg == SEAL_ALG_NONE && signalg > 1) ||
(ctx->sealalg == SEAL_ALG_1 && signalg != SGN_ALG_3) ||
(ctx->sealalg == SEAL_ALG_DES3KD &&
signalg != SGN_ALG_HMAC_SHA1_DES3_KD)||
(ctx->sealalg == SEAL_ALG_MICROSOFT_RC4 &&
signalg != SGN_ALG_HMAC_MD5)) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
switch (signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_MD2_5:
case SGN_ALG_HMAC_MD5:
cksum_len = 8;
if (toktype != KG_TOK_WRAP_MSG)
sign_usage = 15;
break;
case SGN_ALG_3:
cksum_len = 16;
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
cksum_len = 20;
break;
default:
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
/* get the token parameters */
code = kg_get_seq_num(context, ctx->seq, ptr + 14, ptr + 6, &direction,
&seqnum);
if (code != 0) {
*minor_status = code;
return GSS_S_BAD_SIG;
}
/* decode the message, if SEAL */
if (toktype == KG_TOK_WRAP_MSG) {
if (sealalg != 0xFFFF) {
if (ctx->sealalg == SEAL_ALG_MICROSOFT_RC4) {
unsigned char bigend_seqnum[4];
krb5_keyblock *enc_key;
size_t i;
store_32_be(seqnum, bigend_seqnum);
code = krb5_k_key_keyblock(context, ctx->enc, &enc_key);
if (code != 0) {
retval = GSS_S_FAILURE;
goto cleanup;
}
assert(enc_key->length == 16);
for (i = 0; i < enc_key->length; i++)
((char *)enc_key->contents)[i] ^= 0xF0;
code = kg_arcfour_docrypt_iov(context, enc_key, 0,
&bigend_seqnum[0], 4,
iov, iov_count);
krb5_free_keyblock(context, enc_key);
} else {
code = kg_decrypt_iov(context, 0,
((ctx->gss_flags & GSS_C_DCE_STYLE) != 0),
0 /*EC*/, 0 /*RRC*/,
ctx->enc, KG_USAGE_SEAL, NULL,
iov, iov_count);
}
if (code != 0) {
retval = GSS_S_FAILURE;
goto cleanup;
}
}
conflen = kg_confounder_size(context, ctx->enc->keyblock.enctype);
}
if (header->buffer.length != token_wrapper_len + 14 + cksum_len + conflen) {
retval = GSS_S_DEFECTIVE_TOKEN;
goto cleanup;
}
/* compute the checksum of the message */
/* initialize the checksum */
switch (signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_MD2_5:
case SGN_ALG_DES_MAC:
case SGN_ALG_3:
md5cksum.checksum_type = CKSUMTYPE_RSA_MD5;
break;
case SGN_ALG_HMAC_MD5:
md5cksum.checksum_type = CKSUMTYPE_HMAC_MD5_ARCFOUR;
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
md5cksum.checksum_type = CKSUMTYPE_HMAC_SHA1_DES3;
break;
default:
abort();
}
code = krb5_c_checksum_length(context, md5cksum.checksum_type, &sumlen);
if (code != 0) {
retval = GSS_S_FAILURE;
goto cleanup;
}
md5cksum.length = sumlen;
/* compute the checksum of the message */
code = kg_make_checksum_iov_v1(context, md5cksum.checksum_type,
cksum_len, ctx->seq, ctx->enc,
sign_usage, iov, iov_count, toktype,
&md5cksum);
if (code != 0) {
retval = GSS_S_FAILURE;
goto cleanup;
}
switch (signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_3:
code = kg_encrypt_inplace(context, ctx->seq, KG_USAGE_SEAL,
(g_OID_equal(ctx->mech_used,
gss_mech_krb5_old) ?
ctx->seq->keyblock.contents : NULL),
md5cksum.contents, 16);
if (code != 0) {
retval = GSS_S_FAILURE;
goto cleanup;
}
cksum.length = cksum_len;
cksum.contents = md5cksum.contents + 16 - cksum.length;
code = k5_bcmp(cksum.contents, ptr + 14, cksum.length);
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
case SGN_ALG_HMAC_MD5:
code = k5_bcmp(md5cksum.contents, ptr + 14, cksum_len);
break;
default:
code = 0;
retval = GSS_S_DEFECTIVE_TOKEN;
goto cleanup;
break;
}
if (code != 0) {
code = 0;
retval = GSS_S_BAD_SIG;
goto cleanup;
}
/*
* For GSS_C_DCE_STYLE, the caller manages the padding, because the
* pad length is in the RPC PDU. The value of the padding may be
* uninitialized. For normal GSS, the last bytes of the decrypted
* data contain the pad length. kg_fixup_padding_iov() will find
* this and fixup the last data IOV appropriately.
*/
if (toktype == KG_TOK_WRAP_MSG &&
(ctx->gss_flags & GSS_C_DCE_STYLE) == 0) {
retval = kg_fixup_padding_iov(&code, iov, iov_count);
if (retval != GSS_S_COMPLETE)
goto cleanup;
}
if (conf_state != NULL)
*conf_state = (sealalg != 0xFFFF);
if (qop_state != NULL)
*qop_state = GSS_C_QOP_DEFAULT;
if ((ctx->initiate && direction != 0xff) ||
(!ctx->initiate && direction != 0)) {
*minor_status = (OM_uint32)G_BAD_DIRECTION;
retval = GSS_S_BAD_SIG;
}
code = 0;
retval = g_order_check(&ctx->seqstate, (gssint_uint64)seqnum);
cleanup:
krb5_free_checksum_contents(context, &md5cksum);
*minor_status = code;
return retval;
}
OM_uint32
gss_krb5int_unseal_v3_iov(krb5_context context,
OM_uint32 *minor_status,
krb5_gss_ctx_id_rec *ctx,
gss_iov_buffer_desc *iov,
int iov_count,
int *conf_state,
gss_qop_t *qop_state,
int toktype)
{
OM_uint32 code;
gss_iov_buffer_t header;
gss_iov_buffer_t padding;
gss_iov_buffer_t trailer;
unsigned char acceptor_flag;
unsigned char *ptr = NULL;
int key_usage;
size_t rrc, ec;
size_t data_length, assoc_data_length;
krb5_key key;
gssint_uint64 seqnum;
krb5_boolean valid;
krb5_cksumtype cksumtype;
int conf_flag = 0;
if (ctx->big_endian != 0)
return GSS_S_DEFECTIVE_TOKEN;
if (qop_state != NULL)
*qop_state = GSS_C_QOP_DEFAULT;
header = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_HEADER);
assert(header != NULL);
padding = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_PADDING);
if (padding != NULL && padding->buffer.length != 0)
return GSS_S_DEFECTIVE_TOKEN;
trailer = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_TRAILER);
acceptor_flag = ctx->initiate ? FLAG_SENDER_IS_ACCEPTOR : 0;
key_usage = (toktype == KG_TOK_WRAP_MSG
? (!ctx->initiate
? KG_USAGE_INITIATOR_SEAL
: KG_USAGE_ACCEPTOR_SEAL)
: (!ctx->initiate
? KG_USAGE_INITIATOR_SIGN
: KG_USAGE_ACCEPTOR_SIGN));
kg_iov_msglen(iov, iov_count, &data_length, &assoc_data_length);
ptr = (unsigned char *)header->buffer.value;
if (header->buffer.length < 16) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
if ((ptr[2] & FLAG_SENDER_IS_ACCEPTOR) != acceptor_flag) {
*minor_status = (OM_uint32)G_BAD_DIRECTION;
return GSS_S_BAD_SIG;
}
if (ctx->have_acceptor_subkey && (ptr[2] & FLAG_ACCEPTOR_SUBKEY)) {
key = ctx->acceptor_subkey;
cksumtype = ctx->acceptor_subkey_cksumtype;
} else {
key = ctx->subkey;
cksumtype = ctx->cksumtype;
}
assert(key != NULL);
if (toktype == KG_TOK_WRAP_MSG) {
unsigned int k5_trailerlen;
if (load_16_be(ptr) != KG2_TOK_WRAP_MSG)
goto defective;
conf_flag = ((ptr[2] & FLAG_WRAP_CONFIDENTIAL) != 0);
if (ptr[3] != 0xFF)
goto defective;
ec = load_16_be(ptr + 4);
rrc = load_16_be(ptr + 6);
seqnum = load_64_be(ptr + 8);
code = krb5_c_crypto_length(context, key->keyblock.enctype,
conf_flag ? KRB5_CRYPTO_TYPE_TRAILER :
KRB5_CRYPTO_TYPE_CHECKSUM,
&k5_trailerlen);
if (code != 0) {
*minor_status = code;
return GSS_S_FAILURE;
}
/* Deal with RRC */
if (trailer == NULL) {
size_t desired_rrc = k5_trailerlen;
if (conf_flag) {
desired_rrc += 16; /* E(Header) */
if ((ctx->gss_flags & GSS_C_DCE_STYLE) == 0)
desired_rrc += ec;
}
/* According to MS, we only need to deal with a fixed RRC for DCE */
if (rrc != desired_rrc)
goto defective;
} else if (rrc != 0) {
/* Should have been rotated by kg_unseal_stream_iov() */
goto defective;
}
if (conf_flag) {
unsigned char *althdr;
/* Decrypt */
code = kg_decrypt_iov(context, ctx->proto,
((ctx->gss_flags & GSS_C_DCE_STYLE) != 0),
ec, rrc,
key, key_usage, 0, iov, iov_count);
if (code != 0) {
*minor_status = code;
return GSS_S_BAD_SIG;
}
/* Validate header integrity */
if (trailer == NULL)
althdr = (unsigned char *)header->buffer.value + 16 + ec;
else
althdr = (unsigned char *)trailer->buffer.value + ec;
if (load_16_be(althdr) != KG2_TOK_WRAP_MSG
|| althdr[2] != ptr[2]
|| althdr[3] != ptr[3]
|| memcmp(althdr + 8, ptr + 8, 8) != 0) {
*minor_status = 0;
return GSS_S_BAD_SIG;
}
} else {
/* Verify checksum: note EC is checksum size here, not padding */
if (ec != k5_trailerlen)
goto defective;
/* Zero EC, RRC before computing checksum */
store_16_be(0, ptr + 4);
store_16_be(0, ptr + 6);
code = kg_verify_checksum_iov_v3(context, cksumtype, rrc,
key, key_usage,
iov, iov_count, &valid);
if (code != 0 || valid == FALSE) {
*minor_status = code;
return GSS_S_BAD_SIG;
}
}
code = g_order_check(&ctx->seqstate, seqnum);
} else if (toktype == KG_TOK_MIC_MSG) {
if (load_16_be(ptr) != KG2_TOK_MIC_MSG)
goto defective;
verify_mic_1:
if (ptr[3] != 0xFF)
goto defective;
seqnum = load_64_be(ptr + 8);
code = kg_verify_checksum_iov_v3(context, cksumtype, 0,
key, key_usage,
iov, iov_count, &valid);
if (code != 0 || valid == FALSE) {
*minor_status = code;
return GSS_S_BAD_SIG;
}
code = g_order_check(&ctx->seqstate, seqnum);
} else if (toktype == KG_TOK_DEL_CTX) {
if (load_16_be(ptr) != KG2_TOK_DEL_CTX)
goto defective;
goto verify_mic_1;
} else {
goto defective;
}
*minor_status = 0;
if (conf_state != NULL)
*conf_state = conf_flag;
return code;
defective:
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
