static krb5_error_code
make_seal_token_v1_iov(krb5_context context,
krb5_gss_ctx_id_rec *ctx,
int conf_req_flag,
int *conf_state,
gss_iov_buffer_desc *iov,
int iov_count,
int toktype)
{
krb5_error_code code = 0;
gss_iov_buffer_t header;
gss_iov_buffer_t padding;
gss_iov_buffer_t trailer;
krb5_checksum md5cksum;
krb5_checksum cksum;
size_t k5_headerlen = 0, k5_trailerlen = 0;
size_t data_length = 0, assoc_data_length = 0;
size_t tmsglen = 0, tlen;
unsigned char *ptr;
krb5_keyusage sign_usage = KG_USAGE_SIGN;
assert(toktype == KG_TOK_WRAP_MSG);
md5cksum.length = cksum.length = 0;
md5cksum.contents = cksum.contents = NULL;
header = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_HEADER);
if (header == NULL)
return EINVAL;
padding = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_PADDING);
if (padding == NULL && (ctx->gss_flags & GSS_C_DCE_STYLE) == 0)
return EINVAL;
trailer = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_TRAILER);
if (trailer != NULL)
trailer->buffer.length = 0;
/* Determine confounder length */
if (toktype == KG_TOK_WRAP_MSG || conf_req_flag)
k5_headerlen = kg_confounder_size(context, ctx->enc);
/* Check padding length */
if (toktype == KG_TOK_WRAP_MSG) {
size_t k5_padlen = (ctx->sealalg == SEAL_ALG_MICROSOFT_RC4) ? 1 : 8;
size_t gss_padlen;
size_t conf_data_length;
kg_iov_msglen(iov, iov_count, &data_length, &assoc_data_length);
conf_data_length = k5_headerlen + data_length - assoc_data_length;
if (k5_padlen == 1)
gss_padlen = 1; /* one byte to indicate one byte of padding */
else
gss_padlen = k5_padlen - (conf_data_length % k5_padlen);
if (ctx->gss_flags & GSS_C_DCE_STYLE) {
/* DCE will pad the actual data itself; padding buffer optional and will be zeroed */
gss_padlen = 0;
if (conf_data_length % k5_padlen)
code = KRB5_BAD_MSIZE;
} else if (padding->type & GSS_IOV_BUFFER_FLAG_ALLOCATE) {
code = kg_allocate_iov(padding, gss_padlen);
} else if (padding->buffer.length < gss_padlen) {
code = KRB5_BAD_MSIZE;
}
if (code != 0)
goto cleanup;
/* Initialize padding buffer to pad itself */
if (padding != NULL) {
padding->buffer.length = gss_padlen;
memset(padding->buffer.value, (int)gss_padlen, gss_padlen);
}
if (ctx->gss_flags & GSS_C_DCE_STYLE)
tmsglen = k5_headerlen; /* confounder length */
else
tmsglen = conf_data_length + padding->buffer.length + assoc_data_length;
}
/* Determine token size */
tlen = g_token_size(ctx->mech_used, 14 + ctx->cksum_size + tmsglen);
k5_headerlen += tlen - tmsglen;
if (header->type & GSS_IOV_BUFFER_FLAG_ALLOCATE)
code = kg_allocate_iov(header, k5_headerlen);
else if (header->buffer.length < k5_headerlen)
code = KRB5_BAD_MSIZE;
if (code != 0)
goto cleanup;
header->buffer.length = k5_headerlen;
ptr = (unsigned char *)header->buffer.value;
g_make_token_header(ctx->mech_used, 14 + ctx->cksum_size + tmsglen, &ptr, toktype);
/* 0..1 SIGN_ALG */
store_16_le(ctx->signalg, &ptr[0]);
/* 2..3 SEAL_ALG or Filler */
if (toktype == KG_TOK_WRAP_MSG && conf_req_flag) {
store_16_le(ctx->sealalg, &ptr[2]);
} else {
/* No seal */
ptr[2] = 0xFF;
ptr[3] = 0xFF;
}
/* 4..5 Filler */
ptr[4] = 0xFF;
ptr[5] = 0xFF;
/* pad the plaintext, encrypt if needed, and stick it in the token */
/* initialize the checksum */
switch (ctx->signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_MD2_5:
md5cksum.checksum_type = CKSUMTYPE_RSA_MD5;
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
md5cksum.checksum_type = CKSUMTYPE_HMAC_SHA1_DES3;
break;
case SGN_ALG_HMAC_MD5:
md5cksum.checksum_type = CKSUMTYPE_HMAC_MD5_ARCFOUR;
if (toktype != KG_TOK_WRAP_MSG)
sign_usage = 15;
break;
default:
case SGN_ALG_DES_MAC:
abort ();
}
code = krb5_c_checksum_length(context, md5cksum.checksum_type, &k5_trailerlen);
if (code != 0)
goto cleanup;
md5cksum.length = k5_trailerlen;
if (k5_headerlen != 0) {
code = kg_make_confounder(context, ctx->enc, ptr + 14 + ctx->cksum_size);
if (code != 0)
goto cleanup;
}
/* compute the checksum */
code = kg_make_checksum_iov_v1(context, md5cksum.checksum_type,
ctx->cksum_size, ctx->seq, ctx->enc,
sign_usage, iov, iov_count, toktype,
&md5cksum);
if (code != 0)
goto cleanup;
switch (ctx->signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_3:
code = kg_encrypt(context, ctx->seq, KG_USAGE_SEAL,
(g_OID_equal(ctx->mech_used, gss_mech_krb5_old) ?
ctx->seq->contents : NULL),
md5cksum.contents, md5cksum.contents, 16);
if (code != 0)
goto cleanup;
cksum.length = ctx->cksum_size;
cksum.contents = md5cksum.contents + 16 - cksum.length;
memcpy(ptr + 14, cksum.contents, cksum.length);
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
assert(md5cksum.length == ctx->cksum_size);
memcpy(ptr + 14, md5cksum.contents, md5cksum.length);
break;
case SGN_ALG_HMAC_MD5:
memcpy(ptr + 14, md5cksum.contents, ctx->cksum_size);
break;
}
/* create the seq_num */
code = kg_make_seq_num(context, ctx->seq, ctx->initiate ? 0 : 0xFF,
(OM_uint32)ctx->seq_send, ptr + 14, ptr + 6);
if (code != 0)
goto cleanup;
if (conf_req_flag) {
if (ctx->sealalg == SEAL_ALG_MICROSOFT_RC4) {
unsigned char bigend_seqnum[4];
krb5_keyblock *enc_key;
size_t i;
store_32_be(ctx->seq_send, bigend_seqnum);
code = krb5_copy_keyblock(context, ctx->enc, &enc_key);
if (code != 0)
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, 4,
iov, iov_count);
krb5_free_keyblock(context, enc_key);
} else {
code = kg_encrypt_iov(context, ctx->proto,
((ctx->gss_flags & GSS_C_DCE_STYLE) != 0),
0 /*EC*/, 0 /*RRC*/,
ctx->enc, KG_USAGE_SEAL, NULL,
iov, iov_count);
}
if (code != 0)
goto cleanup;
}
ctx->seq_send++;
ctx->seq_send &= 0xFFFFFFFFL;
code = 0;
if (conf_state != NULL)
*conf_state = conf_req_flag;
cleanup:
if (code != 0)
kg_release_iov(iov, iov_count);
krb5_free_checksum_contents(context, &md5cksum);
return code;
}
OM_uint32
kg_seal_iov_length(OM_uint32 *minor_status,
gss_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
int *conf_state,
gss_iov_buffer_desc *iov,
int iov_count)
{
krb5_gss_ctx_id_rec *ctx;
gss_iov_buffer_t header, trailer, padding;
size_t data_length, assoc_data_length;
size_t gss_headerlen, gss_padlen, gss_trailerlen;
unsigned int k5_headerlen = 0, k5_trailerlen = 0, k5_padlen = 0;
krb5_error_code code;
krb5_context context;
int dce_style;
if (qop_req != GSS_C_QOP_DEFAULT) {
*minor_status = (OM_uint32)G_UNKNOWN_QOP;
return GSS_S_FAILURE;
}
if (!kg_validate_ctx_id(context_handle)) {
*minor_status = (OM_uint32)G_VALIDATE_FAILED;
return GSS_S_NO_CONTEXT;
}
ctx = (krb5_gss_ctx_id_rec *)context_handle;
if (!ctx->established) {
*minor_status = KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
header = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_HEADER);
if (header == NULL) {
*minor_status = EINVAL;
return GSS_S_FAILURE;
}
INIT_IOV_DATA(header);
trailer = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_TRAILER);
if (trailer != NULL) {
INIT_IOV_DATA(trailer);
}
dce_style = ((ctx->gss_flags & GSS_C_DCE_STYLE) != 0);
/* For CFX, EC is used instead of padding, and is placed in header or trailer */
padding = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_PADDING);
if (padding == NULL) {
if (conf_req_flag && ctx->proto == 0 && !dce_style) {
*minor_status = EINVAL;
return GSS_S_FAILURE;
}
} else {
INIT_IOV_DATA(padding);
}
kg_iov_msglen(iov, iov_count, &data_length, &assoc_data_length);
if (conf_req_flag && kg_integ_only_iov(iov, iov_count))
conf_req_flag = FALSE;
context = ctx->k5_context;
gss_headerlen = gss_padlen = gss_trailerlen = 0;
if (ctx->proto == 1) {
krb5_enctype enctype;
size_t ec;
if (ctx->have_acceptor_subkey)
enctype = ctx->acceptor_subkey->enctype;
else
enctype = ctx->subkey->enctype;
code = krb5_c_crypto_length(context, enctype,
conf_req_flag ?
KRB5_CRYPTO_TYPE_TRAILER : KRB5_CRYPTO_TYPE_CHECKSUM,
&k5_trailerlen);
if (code != 0) {
*minor_status = code;
return GSS_S_FAILURE;
}
if (conf_req_flag) {
code = krb5_c_crypto_length(context, enctype, KRB5_CRYPTO_TYPE_HEADER, &k5_headerlen);
if (code != 0) {
*minor_status = code;
return GSS_S_FAILURE;
}
}
gss_headerlen = 16; /* Header */
if (conf_req_flag) {
gss_headerlen += k5_headerlen; /* Kerb-Header */
gss_trailerlen = 16 /* E(Header) */ + k5_trailerlen; /* Kerb-Trailer */
code = krb5_c_padding_length(context, enctype,
data_length - assoc_data_length + 16 /* E(Header) */, &k5_padlen);
if (code != 0) {
*minor_status = code;
return GSS_S_FAILURE;
}
if (k5_padlen == 0 && dce_style) {
/* Windows rejects AEAD tokens with non-zero EC */
code = krb5_c_block_size(context, enctype, &ec);
if (code != 0) {
*minor_status = code;
return GSS_S_FAILURE;
}
} else
ec = k5_padlen;
gss_trailerlen += ec;
} else {
gss_trailerlen = k5_trailerlen; /* Kerb-Checksum */
}
} else if (!dce_style) {
k5_padlen = (ctx->sealalg == SEAL_ALG_MICROSOFT_RC4) ? 1 : 8;
if (k5_padlen == 1)
gss_padlen = 1;
else
gss_padlen = k5_padlen - ((data_length - assoc_data_length) % k5_padlen);
}
data_length += gss_padlen;
if (ctx->proto == 0) {
/* Header | Checksum | Confounder | Data | Pad */
size_t data_size;
k5_headerlen = kg_confounder_size(context, ctx->enc);
data_size = 14 /* Header */ + ctx->cksum_size + k5_headerlen;
if (!dce_style)
data_size += data_length;
gss_headerlen = g_token_size(ctx->mech_used, data_size);
/* g_token_size() will include data_size as well as the overhead, so
* subtract data_length just to get the overhead (ie. token size) */
if (!dce_style)
gss_headerlen -= data_length;
}
if (minor_status != NULL)
*minor_status = 0;
if (trailer == NULL)
gss_headerlen += gss_trailerlen;
else
trailer->buffer.length = gss_trailerlen;
assert(gss_padlen == 0 || padding != NULL);
if (padding != NULL)
padding->buffer.length = gss_padlen;
header->buffer.length = gss_headerlen;
if (conf_state != NULL)
*conf_state = conf_req_flag;
return GSS_S_COMPLETE;
}
krb5_error_code
gss_krb5int_make_seal_token_v3_iov(krb5_context context,
krb5_gss_ctx_id_rec *ctx,
int conf_req_flag,
int *conf_state,
gss_iov_buffer_desc *iov,
int iov_count,
int toktype)
{
krb5_error_code code = 0;
gss_iov_buffer_t header;
gss_iov_buffer_t padding;
gss_iov_buffer_t trailer;
unsigned char acceptor_flag;
unsigned short tok_id;
unsigned char *outbuf = NULL;
unsigned char *tbuf = NULL;
int key_usage;
size_t rrc = 0;
unsigned int gss_headerlen, gss_trailerlen;
krb5_key key;
krb5_cksumtype cksumtype;
size_t data_length, assoc_data_length;
assert(ctx->big_endian == 0);
assert(ctx->proto == 1);
acceptor_flag = ctx->initiate ? 0 : FLAG_SENDER_IS_ACCEPTOR;
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));
if (ctx->have_acceptor_subkey) {
key = ctx->acceptor_subkey;
cksumtype = ctx->acceptor_subkey_cksumtype;
} else {
key = ctx->subkey;
cksumtype = ctx->cksumtype;
}
assert(key != NULL);
assert(cksumtype != 0);
kg_iov_msglen(iov, iov_count, &data_length, &assoc_data_length);
header = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_HEADER);
if (header == NULL)
return EINVAL;
padding = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_PADDING);
if (padding != NULL)
padding->buffer.length = 0;
trailer = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_TRAILER);
if (toktype == KG_TOK_WRAP_MSG && conf_req_flag) {
unsigned int k5_headerlen, k5_trailerlen, k5_padlen;
size_t ec = 0;
size_t conf_data_length = data_length - assoc_data_length;
code = krb5_c_crypto_length(context, key->keyblock.enctype,
KRB5_CRYPTO_TYPE_HEADER, &k5_headerlen);
if (code != 0)
goto cleanup;
code = krb5_c_padding_length(context, key->keyblock.enctype,
conf_data_length + 16 /* E(Header) */, &k5_padlen);
if (code != 0)
goto cleanup;
if (k5_padlen == 0 && (ctx->gss_flags & GSS_C_DCE_STYLE)) {
/* Windows rejects AEAD tokens with non-zero EC */
code = krb5_c_block_size(context, key->keyblock.enctype, &ec);
if (code != 0)
goto cleanup;
} else
ec = k5_padlen;
code = krb5_c_crypto_length(context, key->keyblock.enctype,
KRB5_CRYPTO_TYPE_TRAILER, &k5_trailerlen);
if (code != 0)
goto cleanup;
gss_headerlen = 16 /* Header */ + k5_headerlen;
gss_trailerlen = ec + 16 /* E(Header) */ + k5_trailerlen;
if (trailer == NULL) {
rrc = gss_trailerlen;
/* Workaround for Windows bug where it rotates by EC + RRC */
if (ctx->gss_flags & GSS_C_DCE_STYLE)
rrc -= ec;
gss_headerlen += gss_trailerlen;
}
if (header->type & GSS_IOV_BUFFER_FLAG_ALLOCATE) {
code = kg_allocate_iov(header, (size_t) gss_headerlen);
} else if (header->buffer.length < gss_headerlen)
code = KRB5_BAD_MSIZE;
if (code != 0)
goto cleanup;
outbuf = (unsigned char *)header->buffer.value;
header->buffer.length = (size_t) gss_headerlen;
if (trailer != NULL) {
if (trailer->type & GSS_IOV_BUFFER_FLAG_ALLOCATE)
code = kg_allocate_iov(trailer, (size_t) gss_trailerlen);
else if (trailer->buffer.length < gss_trailerlen)
code = KRB5_BAD_MSIZE;
if (code != 0)
goto cleanup;
trailer->buffer.length = (size_t) gss_trailerlen;
}
/* TOK_ID */
store_16_be(KG2_TOK_WRAP_MSG, outbuf);
/* flags */
outbuf[2] = (acceptor_flag
| (conf_req_flag ? FLAG_WRAP_CONFIDENTIAL : 0)
| (ctx->have_acceptor_subkey ? FLAG_ACCEPTOR_SUBKEY : 0));
/* filler */
outbuf[3] = 0xFF;
/* EC */
store_16_be(ec, outbuf + 4);
/* RRC */
store_16_be(0, outbuf + 6);
store_64_be(ctx->seq_send, outbuf + 8);
/* EC | copy of header to be encrypted, located in (possibly rotated) trailer */
if (trailer == NULL)
tbuf = (unsigned char *)header->buffer.value + 16; /* Header */
else
tbuf = (unsigned char *)trailer->buffer.value;
memset(tbuf, 0xFF, ec);
memcpy(tbuf + ec, header->buffer.value, 16);
code = kg_encrypt_iov(context, ctx->proto,
((ctx->gss_flags & GSS_C_DCE_STYLE) != 0),
ec, rrc, key, key_usage, 0, iov, iov_count);
if (code != 0)
goto cleanup;
/* RRC */
store_16_be(rrc, outbuf + 6);
ctx->seq_send++;
} else if (toktype == KG_TOK_WRAP_MSG && !conf_req_flag) {
tok_id = KG2_TOK_WRAP_MSG;
wrap_with_checksum:
gss_headerlen = 16;
code = krb5_c_crypto_length(context, key->keyblock.enctype,
KRB5_CRYPTO_TYPE_CHECKSUM,
&gss_trailerlen);
if (code != 0)
goto cleanup;
assert(gss_trailerlen <= 0xFFFF);
if (trailer == NULL) {
rrc = gss_trailerlen;
gss_headerlen += gss_trailerlen;
}
if (header->type & GSS_IOV_BUFFER_FLAG_ALLOCATE)
code = kg_allocate_iov(header, (size_t) gss_headerlen);
else if (header->buffer.length < gss_headerlen)
code = KRB5_BAD_MSIZE;
if (code != 0)
goto cleanup;
outbuf = (unsigned char *)header->buffer.value;
header->buffer.length = (size_t) gss_headerlen;
if (trailer != NULL) {
if (trailer->type & GSS_IOV_BUFFER_FLAG_ALLOCATE)
code = kg_allocate_iov(trailer, (size_t) gss_trailerlen);
else if (trailer->buffer.length < gss_trailerlen)
code = KRB5_BAD_MSIZE;
if (code != 0)
goto cleanup;
trailer->buffer.length = (size_t) gss_trailerlen;
}
/* TOK_ID */
store_16_be(tok_id, outbuf);
/* flags */
outbuf[2] = (acceptor_flag
| (ctx->have_acceptor_subkey ? FLAG_ACCEPTOR_SUBKEY : 0));
/* filler */
outbuf[3] = 0xFF;
if (toktype == KG_TOK_WRAP_MSG) {
/* Use 0 for checksum calculation, substitute
* checksum length later.
*/
/* EC */
store_16_be(0, outbuf + 4);
/* RRC */
store_16_be(0, outbuf + 6);
} else {
/* MIC and DEL store 0xFF in EC and RRC */
store_16_be(0xFFFF, outbuf + 4);
store_16_be(0xFFFF, outbuf + 6);
}
store_64_be(ctx->seq_send, outbuf + 8);
code = kg_make_checksum_iov_v3(context, cksumtype,
rrc, key, key_usage,
iov, iov_count);
if (code != 0)
goto cleanup;
ctx->seq_send++;
if (toktype == KG_TOK_WRAP_MSG) {
/* Fix up EC field */
store_16_be(gss_trailerlen, outbuf + 4);
/* Fix up RRC field */
store_16_be(rrc, outbuf + 6);
}
} else if (toktype == KG_TOK_MIC_MSG) {
tok_id = KG2_TOK_MIC_MSG;
trailer = NULL;
goto wrap_with_checksum;
} else if (toktype == KG_TOK_DEL_CTX) {
tok_id = KG2_TOK_DEL_CTX;
goto wrap_with_checksum;
} else {
abort();
}
code = 0;
if (conf_state != NULL)
*conf_state = conf_req_flag;
cleanup:
if (code != 0)
kg_release_iov(iov, iov_count);
return code;
}
/*
* Caller must provide TOKEN | DATA | PADDING | TRAILER, except
* for DCE in which case it can just provide TOKEN | DATA (must
* guarantee that DATA is padded)
*/
static OM_uint32
kg_unseal_iov_token(OM_uint32 *minor_status,
krb5_gss_ctx_id_rec *ctx,
int *conf_state,
gss_qop_t *qop_state,
gss_iov_buffer_desc *iov,
int iov_count,
int toktype)
{
krb5_error_code code;
krb5_context context = ctx->k5_context;
unsigned char *ptr;
gss_iov_buffer_t header;
gss_iov_buffer_t padding;
gss_iov_buffer_t trailer;
size_t input_length;
unsigned int bodysize;
int toktype2;
header = kg_locate_header_iov(iov, iov_count, toktype);
if (header == NULL) {
*minor_status = EINVAL;
return GSS_S_FAILURE;
}
padding = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_PADDING);
trailer = kg_locate_iov(iov, iov_count, GSS_IOV_BUFFER_TYPE_TRAILER);
ptr = (unsigned char *)header->buffer.value;
input_length = header->buffer.length;
if ((ctx->gss_flags & GSS_C_DCE_STYLE) == 0 &&
toktype == KG_TOK_WRAP_MSG) {
size_t data_length, assoc_data_length;
kg_iov_msglen(iov, iov_count, &data_length, &assoc_data_length);
input_length += data_length - assoc_data_length;
if (padding != NULL)
input_length += padding->buffer.length;
if (trailer != NULL)
input_length += trailer->buffer.length;
}
code = g_verify_token_header(ctx->mech_used,
&bodysize, &ptr, -1,
input_length, 0);
if (code != 0) {
*minor_status = code;
return GSS_S_DEFECTIVE_TOKEN;
}
if (bodysize < 2) {
*minor_status = (OM_uint32)G_BAD_TOK_HEADER;
return GSS_S_DEFECTIVE_TOKEN;
}
toktype2 = load_16_be(ptr);
ptr += 2;
bodysize -= 2;
switch (toktype2) {
case KG2_TOK_MIC_MSG:
case KG2_TOK_WRAP_MSG:
case KG2_TOK_DEL_CTX:
code = gss_krb5int_unseal_v3_iov(context, minor_status, ctx, iov, iov_count,
conf_state, qop_state, toktype);
break;
case KG_TOK_MIC_MSG:
case KG_TOK_WRAP_MSG:
case KG_TOK_DEL_CTX:
code = kg_unseal_v1_iov(context, minor_status, ctx, iov, iov_count,
(size_t)(ptr - (unsigned char *)header->buffer.value),
conf_state, qop_state, toktype);
break;
default:
*minor_status = (OM_uint32)G_BAD_TOK_HEADER;
code = GSS_S_DEFECTIVE_TOKEN;
break;
}
if (code != 0)
save_error_info(*minor_status, context);
return code;
}
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;
}
