eap_tlv.c

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#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "common.h"
#include "wpa_supplicant.h"
#include "eap_i.h"
#include "eap_tlv.h"


u8 * eap_tlv_build_nak(int id, u16 nak_type, size_t *resp_len)
{
        struct eap_hdr *hdr;
        u8 *pos;

        *resp_len = sizeof(struct eap_hdr) + 1 + 10;
        hdr = malloc(*resp_len);
        if (hdr == NULL)
                return NULL;

        hdr->code = EAP_CODE_RESPONSE;
        hdr->identifier = id;
        hdr->length = host_to_be16(*resp_len);
        pos = (u8 *) (hdr + 1);
        *pos++ = EAP_TYPE_TLV;
        *pos++ = 0x80; /* Mandatory */
        *pos++ = EAP_TLV_NAK_TLV;
        /* Length */
        *pos++ = 0;
        *pos++ = 6;
        /* Vendor-Id */
        *pos++ = 0;
        *pos++ = 0;
        *pos++ = 0;
        *pos++ = 0;
        /* NAK-Type */
        WPA_PUT_BE16(pos, nak_type);

        return (u8 *) hdr;
}


u8 * eap_tlv_build_result(int id, u16 status, size_t *resp_len)
{
        struct eap_hdr *hdr;
        u8 *pos;

        *resp_len = sizeof(struct eap_hdr) + 1 + 6;
        hdr = malloc(*resp_len);
        if (hdr == NULL)
                return NULL;

        hdr->code = EAP_CODE_RESPONSE;
        hdr->identifier = id;
        hdr->length = host_to_be16(*resp_len);
        pos = (u8 *) (hdr + 1);
        *pos++ = EAP_TYPE_TLV;
        *pos++ = 0x80; /* Mandatory */
        *pos++ = EAP_TLV_RESULT_TLV;
        /* Length */
        *pos++ = 0;
        *pos++ = 2;
        /* Status */
        WPA_PUT_BE16(pos, status);

        return (u8 *) hdr;
}


int eap_tlv_process(struct eap_sm *sm, struct eap_method_ret *ret,
                    const struct eap_hdr *hdr, u8 **resp, size_t *resp_len)
{
        size_t left;
        const u8 *pos;
        const u8 *result_tlv = NULL;
        size_t result_tlv_len = 0;
        int tlv_type, mandatory, tlv_len;

        /* Parse TLVs */
        left = be_to_host16(hdr->length) - sizeof(struct eap_hdr) - 1;
        pos = (const u8 *) (hdr + 1);
        pos++;
        wpa_hexdump(MSG_DEBUG, "EAP-TLV: Received TLVs", pos, left);
        while (left >= 4) {
                mandatory = !!(pos[0] & 0x80);
                tlv_type = WPA_GET_BE16(pos) & 0x3fff;
                pos += 2;
                tlv_len = WPA_GET_BE16(pos);
                pos += 2;
                left -= 4;
                if (tlv_len > left) {
                        wpa_printf(MSG_DEBUG, "EAP-TLV: TLV underrun "
                                   "(tlv_len=%d left=%lu)", tlv_len,
                                   (unsigned long) left);
                        return -1;
                }
                switch (tlv_type) {
                case EAP_TLV_RESULT_TLV:
                        result_tlv = pos;
                        result_tlv_len = tlv_len;
                        break;
                default:
                        wpa_printf(MSG_DEBUG, "EAP-TLV: Unsupported TLV Type "
                                   "%d%s", tlv_type,
                                   mandatory ? " (mandatory)" : "");
                        if (mandatory) {
                                /* NAK TLV and ignore all TLVs in this packet.
                                 */
                                *resp = eap_tlv_build_nak(hdr->identifier,
                                                          tlv_type, resp_len);
                                return *resp == NULL ? -1 : 0;
                        }
                        /* Ignore this TLV, but process other TLVs */
                        break;
                }

                pos += tlv_len;
                left -= tlv_len;
        }
        if (left) {
                wpa_printf(MSG_DEBUG, "EAP-TLV: Last TLV too short in "
                           "Request (left=%lu)", (unsigned long) left);
                return -1;
        }

        /* Process supported TLVs */
        if (result_tlv) {
                int status, resp_status;
                wpa_hexdump(MSG_DEBUG, "EAP-TLV: Result TLV",
                            result_tlv, result_tlv_len);
                if (result_tlv_len < 2) {
                        wpa_printf(MSG_INFO, "EAP-TLV: Too short Result TLV "
                                   "(len=%lu)",
                                   (unsigned long) result_tlv_len);
                        return -1;
                }
                status = WPA_GET_BE16(result_tlv);
                if (status == EAP_TLV_RESULT_SUCCESS) {
                        wpa_printf(MSG_INFO, "EAP-TLV: TLV Result - Success "
                                   "- EAP-TLV/Phase2 Completed");
                        resp_status = EAP_TLV_RESULT_SUCCESS;
                        ret->decision = DECISION_UNCOND_SUCC;
                } else if (status == EAP_TLV_RESULT_FAILURE) {
                        wpa_printf(MSG_INFO, "EAP-TLV: TLV Result - Failure");
                        resp_status = EAP_TLV_RESULT_FAILURE;
                        ret->decision = DECISION_FAIL;
                } else {
                        wpa_printf(MSG_INFO, "EAP-TLV: Unknown TLV Result "
                                   "Status %d", status);
                        resp_status = EAP_TLV_RESULT_FAILURE;
                        ret->decision = DECISION_FAIL;
                }
                ret->methodState = METHOD_DONE;

                *resp = eap_tlv_build_result(hdr->identifier, resp_status,
                                             resp_len);
        }

        return 0;
}

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