[winpr,sspi] refactor kerberos_rd_tgt_token

the function was quite complex, split it up into multiple subfunctions:

* kerberos_rd_tgt_req
  * kerberos_rd_tgt_req_tag2
  * kerberos_rd_tgt_req_tag3
* kerberos_rd_tgt_rep
This commit is contained in:
akallabeth 2024-09-19 13:16:56 +02:00
parent ab31eb7a50
commit b253e6ba0a
No known key found for this signature in database
GPG Key ID: A49454A3FC909FD5

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@ -659,116 +659,189 @@ cleanup:
return ret; return ret;
} }
static BOOL append(char* dst, size_t dstSize, const char* src)
{
const size_t dlen = strnlen(dst, dstSize);
const size_t slen = strlen(src);
if (dlen + slen >= dstSize)
return FALSE;
if (!strncat(dst, src, slen))
return FALSE;
return TRUE;
}
static BOOL kerberos_rd_tgt_req_tag2(WinPrAsn1Decoder* dec, char* buf, size_t len)
{
BOOL rc = FALSE;
WinPrAsn1Decoder seq = { 0 };
/* server-name [2] PrincipalName (SEQUENCE) */
if (!WinPrAsn1DecReadSequence(dec, &seq))
goto end;
/* name-type [0] INTEGER */
BOOL error = FALSE;
WinPrAsn1_INTEGER val = 0;
if (!WinPrAsn1DecReadContextualInteger(&seq, 0, &error, &val))
goto end;
/* name-string [1] SEQUENCE OF GeneralString */
if (!WinPrAsn1DecReadContextualSequence(&seq, 1, &error, dec))
goto end;
WinPrAsn1_tag tag = 0;
BOOL first = TRUE;
while (WinPrAsn1DecPeekTag(dec, &tag))
{
char* lstr = NULL;
if (!WinPrAsn1DecReadGeneralString(dec, &lstr))
goto end;
if (!first)
{
if (!append(buf, len, "/"))
goto end;
}
first = FALSE;
if (!append(buf, len, lstr))
goto end;
free(lstr);
}
rc = TRUE;
end:
return rc;
}
static BOOL kerberos_rd_tgt_req_tag3(WinPrAsn1Decoder* dec, char* buf, size_t len)
{
/* realm [3] Realm */
BOOL rc = FALSE;
WinPrAsn1_STRING str = NULL;
if (!WinPrAsn1DecReadGeneralString(dec, &str))
goto end;
if (!append(buf, len, "@"))
goto end;
if (!append(buf, len, str))
goto end;
rc = TRUE;
end:
free(str);
return rc;
}
static BOOL kerberos_rd_tgt_req(WinPrAsn1Decoder* dec, char** target)
{
BOOL rc = FALSE;
if (!target)
return FALSE;
*target = NULL;
wStream s = WinPrAsn1DecGetStream(dec);
const size_t len = Stream_Length(&s);
if (len == 0)
return TRUE;
WinPrAsn1Decoder dec2 = { 0 };
WinPrAsn1_tagId tag = 0;
if (WinPrAsn1DecReadContextualTag(dec, &tag, &dec2) == 0)
return FALSE;
char* buf = calloc(len + 1, sizeof(char));
if (!buf)
return FALSE;
/* We expect ASN1 context tag values 2 or 3.
*
* In case we got value 2 an (optional) context tag value 3 might follow.
*/
BOOL checkForTag3 = TRUE;
if (tag == 2)
{
rc = kerberos_rd_tgt_req_tag2(&dec2, buf, len);
if (rc)
{
const size_t res = WinPrAsn1DecReadContextualTag(dec, &tag, dec);
if (res == 0)
checkForTag3 = FALSE;
}
}
if (checkForTag3)
{
if (tag == 3)
rc = kerberos_rd_tgt_req_tag3(&dec2, buf, len);
else
rc = FALSE;
}
end:
if (rc)
*target = buf;
else
free(buf);
return rc;
}
static BOOL kerberos_rd_tgt_rep(WinPrAsn1Decoder* dec, krb5_data* ticket)
{
if (!ticket)
return FALSE;
/* ticket [2] Ticket */
WinPrAsn1Decoder asnTicket = { 0 };
WinPrAsn1_tagId tag = 0;
if (WinPrAsn1DecReadContextualTag(dec, &tag, &asnTicket) == 0)
return FALSE;
if (tag != 2)
return FALSE;
wStream s = WinPrAsn1DecGetStream(&asnTicket);
ticket->data = Stream_BufferAs(&s, char);
ticket->length = Stream_Length(&s);
return TRUE;
}
static BOOL kerberos_rd_tgt_token(const sspi_gss_data* token, char** target, krb5_data* ticket) static BOOL kerberos_rd_tgt_token(const sspi_gss_data* token, char** target, krb5_data* ticket)
{ {
WinPrAsn1Decoder dec;
WinPrAsn1Decoder dec2;
BOOL error = 0; BOOL error = 0;
WinPrAsn1_tagId tag = 0;
WinPrAsn1_INTEGER val = 0; WinPrAsn1_INTEGER val = 0;
size_t len = 0;
wStream s;
char* buf = NULL;
char* str = NULL;
WINPR_ASSERT(token); WINPR_ASSERT(token);
WinPrAsn1Decoder_InitMem(&dec, WINPR_ASN1_DER, (BYTE*)token->data, token->length); if (target)
*target = NULL;
WinPrAsn1Decoder der = { 0 };
WinPrAsn1Decoder_InitMem(&der, WINPR_ASN1_DER, (BYTE*)token->data, token->length);
/* KERB-TGT-REQUEST (SEQUENCE) */ /* KERB-TGT-REQUEST (SEQUENCE) */
if (!WinPrAsn1DecReadSequence(&dec, &dec2)) WinPrAsn1Decoder seq = { 0 };
if (!WinPrAsn1DecReadSequence(&der, &seq))
return FALSE; return FALSE;
dec = dec2;
/* pvno [0] INTEGER */ /* pvno [0] INTEGER */
if (!WinPrAsn1DecReadContextualInteger(&dec, 0, &error, &val) || val != 5) if (!WinPrAsn1DecReadContextualInteger(&seq, 0, &error, &val) || val != 5)
return FALSE; return FALSE;
/* msg-type [1] INTEGER */ /* msg-type [1] INTEGER */
if (!WinPrAsn1DecReadContextualInteger(&dec, 1, &error, &val)) if (!WinPrAsn1DecReadContextualInteger(&seq, 1, &error, &val))
return FALSE; return FALSE;
if (val == KRB_TGT_REQ) switch (val)
{ {
if (!target) case KRB_TGT_REQ:
return FALSE; return kerberos_rd_tgt_req(&seq, target);
*target = NULL; case KRB_TGT_REP:
return kerberos_rd_tgt_rep(&seq, ticket);
s = WinPrAsn1DecGetStream(&dec); default:
len = Stream_Length(&s); break;
if (len == 0)
return TRUE;
buf = malloc(len);
if (!buf)
return FALSE;
*buf = 0;
*target = buf;
if (!WinPrAsn1DecReadContextualTag(&dec, &tag, &dec2))
goto fail;
if (tag == 2)
{
WinPrAsn1Decoder seq;
/* server-name [2] PrincipalName (SEQUENCE) */
if (!WinPrAsn1DecReadSequence(&dec2, &seq))
goto fail;
/* name-type [0] INTEGER */
if (!WinPrAsn1DecReadContextualInteger(&seq, 0, &error, &val))
goto fail;
/* name-string [1] SEQUENCE OF GeneralString */
if (!WinPrAsn1DecReadContextualSequence(&seq, 1, &error, &dec2))
goto fail;
while (WinPrAsn1DecPeekTag(&dec2, &tag))
{
if (!WinPrAsn1DecReadGeneralString(&dec2, &str))
goto fail;
if (buf != *target)
*buf++ = '/';
buf = stpcpy(buf, str);
free(str);
}
if (!WinPrAsn1DecReadContextualTag(&dec, &tag, &dec2))
return TRUE;
}
/* realm [3] Realm */
if (tag != 3 || !WinPrAsn1DecReadGeneralString(&dec2, &str))
goto fail;
*buf++ = '@';
strcpy(buf, str);
free(str);
return TRUE;
} }
else if (val == KRB_TGT_REP)
{
if (!ticket)
return FALSE;
/* ticket [2] Ticket */
if (!WinPrAsn1DecReadContextualTag(&dec, &tag, &dec2) || tag != 2)
return FALSE;
s = WinPrAsn1DecGetStream(&dec2);
ticket->data = Stream_BufferAs(&s, char);
ticket->length = Stream_Length(&s);
return TRUE;
}
else
return FALSE;
fail:
free(buf);
if (target)
*target = NULL;
return FALSE; return FALSE;
} }