diff options
Diffstat (limited to 'lib/tls13/psk_ext_parser.c')
| -rw-r--r-- | lib/tls13/psk_ext_parser.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/lib/tls13/psk_ext_parser.c b/lib/tls13/psk_ext_parser.c new file mode 100644 index 0000000000..702c060586 --- /dev/null +++ b/lib/tls13/psk_ext_parser.c @@ -0,0 +1,194 @@ +/* + * Copyright (C) 2017 Free Software Foundation, Inc. + * + * Author: Ander Juaristi + * + * This file is part of GnuTLS. + * + * The GnuTLS is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/> + * + */ +#include "tls13/psk_ext_parser.h" + +struct psk_ext_parser_st { + unsigned char *data; + ssize_t len; + uint16_t obj_len; + uint16_t obj_read; + int next_index; +}; + +static int advance_to_end_of_object(psk_ext_parser_t p) +{ + size_t adv; + + /* Advance the pointer to the end of the current object */ + if (p->obj_read < p->obj_len) { + adv = p->obj_len - p->obj_read; + DECR_LEN(p->len, adv); + p->data += adv; + } + + return 0; +} + +int _gnutls13_psk_ext_parser_init(psk_ext_parser_t *p, + const unsigned char *data, size_t len) +{ + uint16_t identities_len; + + if (!p || !data || !len) + return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR); + + *p = gnutls_calloc(1, sizeof(struct psk_ext_parser_st)); + if (!*p) + return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR); + + identities_len = _gnutls_read_uint16(data); + + if (identities_len > 0) { + DECR_LEN(len, 2); + data += 2; + + (*p)->obj_len = identities_len; + (*p)->data = (unsigned char *) data; + (*p)->len = len; + } + + return identities_len; +} + +int _gnutls13_psk_ext_parser_deinit(psk_ext_parser_t *pp, + const unsigned char **data, size_t *len) +{ + psk_ext_parser_t p; + + if (!pp || !*pp) + return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR); + + p = *pp; + + if (p->obj_len == 0) + goto end; + + if (advance_to_end_of_object(p) < 0) + return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH); + + if (data) + *data = p->data; + if (len) + *len = p->len; + +end: + gnutls_free(p); + *pp = NULL; + return 0; +} + +int _gnutls13_psk_ext_parser_next_psk(psk_ext_parser_t p, struct psk_st *psk) +{ + if (p->obj_read >= p->obj_len) + return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE; + + /* Read a PskIdentity structure */ + psk->identity.size = _gnutls_read_uint16(p->data); + if (psk->identity.size == 0) + return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE; + + DECR_LEN(p->len, 2); + p->data += 2; + p->obj_read += 2; + + psk->identity.data = p->data; + + DECR_LEN(p->len, psk->identity.size); + p->data += psk->identity.size; + p->obj_read += psk->identity.size; + + psk->ob_ticket_age = _gnutls_read_uint32(p->data); + DECR_LEN(p->len, 4); + p->data += 4; + p->obj_read += 4; + + psk->selected_index = p->next_index++; + return psk->selected_index; +} + +int _gnutls13_psk_ext_parser_find_binder(psk_ext_parser_t p, int psk_index, + gnutls_datum_t *binder_out) +{ + uint16_t binders_len; + uint8_t binder_len; + int cur_index = 0, binder_found = 0; + + if (p == NULL || psk_index < 0 || binder_out == NULL) + return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR); + + if (p->obj_len == 0) + return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR); + + /* Place the pointer at the start of the binders */ + if (advance_to_end_of_object(p) < 0) + return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH); + + DECR_LEN(p->len, 2); + binders_len = _gnutls_read_uint16(p->data); + if (binders_len > 0) { + p->data += 2; + + p->obj_len = binders_len; + p->obj_read = 0; + } else { + return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE); + } + + /* Start traversing the binders */ + while (!binder_found && p->len > 0) { + DECR_LEN(p->len, 1); + binder_len = *(p->data); + + if (binder_len == 0) + return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS); + + p->data++; + p->obj_read++; + + if (cur_index == psk_index) { + /* We found the binder with the supplied index */ + binder_out->data = gnutls_malloc(binder_len); + if (!binder_out->data) + return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR); + + binder_out->size = binder_len; + DECR_LEN(p->len, binder_len); + memcpy(binder_out->data, p->data, binder_len); + p->data += binder_len; + p->obj_read += binder_len; + + binder_found = 1; + } else { + /* Not our binder - continue to the next one */ + DECR_LEN(p->len, binder_len); + p->data += binder_len; + p->obj_read += binder_len; + + binder_len = 0; + cur_index++; + } + } + + return (binder_found ? + 0 : + gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)); +} |