| /* |
| * EAP common peer/server definitions |
| * Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi> |
| * |
| * This software may be distributed under the terms of the BSD license. |
| * See README for more details. |
| */ |
| |
| #include "includes.h" |
| |
| #include "common.h" |
| #include "eap_defs.h" |
| #include "eap_common.h" |
| |
| /** |
| * eap_hdr_len_valid - Validate EAP header length field |
| * @msg: EAP frame (starting with EAP header) |
| * @min_payload: Minimum payload length needed |
| * Returns: 1 for valid header, 0 for invalid |
| * |
| * This is a helper function that does minimal validation of EAP messages. The |
| * length field is verified to be large enough to include the header and not |
| * too large to go beyond the end of the buffer. |
| */ |
| int eap_hdr_len_valid(const struct wpabuf *msg, size_t min_payload) |
| { |
| const struct eap_hdr *hdr; |
| size_t len; |
| |
| if (msg == NULL) |
| return 0; |
| |
| hdr = wpabuf_head(msg); |
| |
| if (wpabuf_len(msg) < sizeof(*hdr)) { |
| wpa_printf(MSG_INFO, "EAP: Too short EAP frame"); |
| return 0; |
| } |
| |
| len = be_to_host16(hdr->length); |
| if (len < sizeof(*hdr) + min_payload || len > wpabuf_len(msg)) { |
| wpa_printf(MSG_INFO, "EAP: Invalid EAP length"); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| |
| /** |
| * eap_hdr_validate - Validate EAP header |
| * @vendor: Expected EAP Vendor-Id (0 = IETF) |
| * @eap_type: Expected EAP type number |
| * @msg: EAP frame (starting with EAP header) |
| * @plen: Pointer to variable to contain the returned payload length |
| * Returns: Pointer to EAP payload (after type field), or %NULL on failure |
| * |
| * This is a helper function for EAP method implementations. This is usually |
| * called in the beginning of struct eap_method::process() function to verify |
| * that the received EAP request packet has a valid header. This function is |
| * able to process both legacy and expanded EAP headers and in most cases, the |
| * caller can just use the returned payload pointer (into *plen) for processing |
| * the payload regardless of whether the packet used the expanded EAP header or |
| * not. |
| */ |
| const u8 * eap_hdr_validate(int vendor, EapType eap_type, |
| const struct wpabuf *msg, size_t *plen) |
| { |
| const struct eap_hdr *hdr; |
| const u8 *pos; |
| size_t len; |
| |
| if (!eap_hdr_len_valid(msg, 1)) |
| return NULL; |
| |
| hdr = wpabuf_head(msg); |
| len = be_to_host16(hdr->length); |
| pos = (const u8 *) (hdr + 1); |
| |
| if (*pos == EAP_TYPE_EXPANDED) { |
| int exp_vendor; |
| u32 exp_type; |
| if (len < sizeof(*hdr) + 8) { |
| wpa_printf(MSG_INFO, "EAP: Invalid expanded EAP " |
| "length"); |
| return NULL; |
| } |
| pos++; |
| exp_vendor = WPA_GET_BE24(pos); |
| pos += 3; |
| exp_type = WPA_GET_BE32(pos); |
| pos += 4; |
| if (exp_vendor != vendor || exp_type != (u32) eap_type) { |
| wpa_printf(MSG_INFO, "EAP: Invalid expanded frame " |
| "type"); |
| return NULL; |
| } |
| |
| *plen = len - sizeof(*hdr) - 8; |
| return pos; |
| } else { |
| if (vendor != EAP_VENDOR_IETF || *pos != eap_type) { |
| wpa_printf(MSG_INFO, "EAP: Invalid frame type"); |
| return NULL; |
| } |
| *plen = len - sizeof(*hdr) - 1; |
| return pos + 1; |
| } |
| } |
| |
| |
| /** |
| * eap_msg_alloc - Allocate a buffer for an EAP message |
| * @vendor: Vendor-Id (0 = IETF) |
| * @type: EAP type |
| * @payload_len: Payload length in bytes (data after Type) |
| * @code: Message Code (EAP_CODE_*) |
| * @identifier: Identifier |
| * Returns: Pointer to the allocated message buffer or %NULL on error |
| * |
| * This function can be used to allocate a buffer for an EAP message and fill |
| * in the EAP header. This function is automatically using expanded EAP header |
| * if the selected Vendor-Id is not IETF. In other words, most EAP methods do |
| * not need to separately select which header type to use when using this |
| * function to allocate the message buffers. The returned buffer has room for |
| * payload_len bytes and has the EAP header and Type field already filled in. |
| */ |
| struct wpabuf * eap_msg_alloc(int vendor, EapType type, size_t payload_len, |
| u8 code, u8 identifier) |
| { |
| struct wpabuf *buf; |
| struct eap_hdr *hdr; |
| size_t len; |
| |
| len = sizeof(struct eap_hdr) + (vendor == EAP_VENDOR_IETF ? 1 : 8) + |
| payload_len; |
| buf = wpabuf_alloc(len); |
| if (buf == NULL) |
| return NULL; |
| |
| hdr = wpabuf_put(buf, sizeof(*hdr)); |
| hdr->code = code; |
| hdr->identifier = identifier; |
| hdr->length = host_to_be16(len); |
| |
| if (vendor == EAP_VENDOR_IETF) { |
| wpabuf_put_u8(buf, type); |
| } else { |
| wpabuf_put_u8(buf, EAP_TYPE_EXPANDED); |
| wpabuf_put_be24(buf, vendor); |
| wpabuf_put_be32(buf, type); |
| } |
| |
| return buf; |
| } |
| |
| |
| /** |
| * eap_update_len - Update EAP header length |
| * @msg: EAP message from eap_msg_alloc |
| * |
| * This function updates the length field in the EAP header to match with the |
| * current length for the buffer. This allows eap_msg_alloc() to be used to |
| * allocate a larger buffer than the exact message length (e.g., if exact |
| * message length is not yet known). |
| */ |
| void eap_update_len(struct wpabuf *msg) |
| { |
| struct eap_hdr *hdr; |
| hdr = wpabuf_mhead(msg); |
| if (wpabuf_len(msg) < sizeof(*hdr)) |
| return; |
| hdr->length = host_to_be16(wpabuf_len(msg)); |
| } |
| |
| |
| /** |
| * eap_get_id - Get EAP Identifier from wpabuf |
| * @msg: Buffer starting with an EAP header |
| * Returns: The Identifier field from the EAP header |
| */ |
| u8 eap_get_id(const struct wpabuf *msg) |
| { |
| const struct eap_hdr *eap; |
| |
| if (wpabuf_len(msg) < sizeof(*eap)) |
| return 0; |
| |
| eap = wpabuf_head(msg); |
| return eap->identifier; |
| } |
| |
| |
| /** |
| * eap_get_id - Get EAP Type from wpabuf |
| * @msg: Buffer starting with an EAP header |
| * Returns: The EAP Type after the EAP header |
| */ |
| EapType eap_get_type(const struct wpabuf *msg) |
| { |
| if (wpabuf_len(msg) < sizeof(struct eap_hdr) + 1) |
| return EAP_TYPE_NONE; |
| |
| return ((const u8 *) wpabuf_head(msg))[sizeof(struct eap_hdr)]; |
| } |