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* Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <ipxe/ieee80211.h>
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#include <ipxe/net80211.h>
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#include <ipxe/sec80211.h>
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* General secured-network routines required whenever any secure
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* network support at all is compiled in. This involves things like
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* installing keys, determining the type of security used by a probed
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* network, and some small helper functions that take advantage of
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* static data in this file.
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/* Unsupported cryptosystem error numbers */
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#define ENOTSUP_WEP __einfo_error ( EINFO_ENOTSUP_WEP )
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#define EINFO_ENOTSUP_WEP __einfo_uniqify ( EINFO_ENOTSUP, \
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( 0x10 | NET80211_CRYPT_WEP ), "WEP not supported" )
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#define ENOTSUP_TKIP __einfo_error ( EINFO_ENOTSUP_TKIP )
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#define EINFO_ENOTSUP_TKIP __einfo_uniqify ( EINFO_ENOTSUP, \
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( 0x10 | NET80211_CRYPT_TKIP ), "TKIP not supported" )
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#define ENOTSUP_CCMP __einfo_error ( EINFO_ENOTSUP_CCMP )
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#define EINFO_ENOTSUP_CCMP __einfo_uniqify ( EINFO_ENOTSUP, \
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( 0x10 | NET80211_CRYPT_CCMP ), "CCMP not supported" )
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#define ENOTSUP_CRYPT( crypt ) \
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EUNIQ ( EINFO_ENOTSUP, ( 0x10 | (crypt) ), \
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ENOTSUP_WEP, ENOTSUP_TKIP, ENOTSUP_CCMP )
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/** Mapping from net80211 crypto/secprot types to RSN OUI descriptors */
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struct descriptor_map {
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/** Value of net80211_crypto_alg or net80211_security_proto */
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/** OUI+type in appropriate byte order, masked to exclude vendor */
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/** Magic number in @a oui_type showing end of list */
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#define END_MAGIC 0xFFFFFFFF
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/** Mapping between net80211 cryptosystems and 802.11i cipher IDs */
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static struct descriptor_map rsn_cipher_map[] = {
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{ .net80211_type = NET80211_CRYPT_WEP,
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.oui_type = IEEE80211_RSN_CTYPE_WEP40 },
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{ .net80211_type = NET80211_CRYPT_WEP,
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.oui_type = IEEE80211_RSN_CTYPE_WEP104 },
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{ .net80211_type = NET80211_CRYPT_TKIP,
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.oui_type = IEEE80211_RSN_CTYPE_TKIP },
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{ .net80211_type = NET80211_CRYPT_CCMP,
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.oui_type = IEEE80211_RSN_CTYPE_CCMP },
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{ .net80211_type = NET80211_CRYPT_UNKNOWN,
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.oui_type = END_MAGIC },
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/** Mapping between net80211 handshakers and 802.11i AKM IDs */
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static struct descriptor_map rsn_akm_map[] = {
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{ .net80211_type = NET80211_SECPROT_EAP,
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.oui_type = IEEE80211_RSN_ATYPE_8021X },
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{ .net80211_type = NET80211_SECPROT_PSK,
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.oui_type = IEEE80211_RSN_ATYPE_PSK },
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{ .net80211_type = NET80211_SECPROT_UNKNOWN,
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.oui_type = END_MAGIC },
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* Install 802.11 cryptosystem
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* @v which Pointer to the cryptosystem structure to install in
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* @v crypt Cryptosystem ID number
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* @v key Encryption key to use
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* @v len Length of encryption key
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* @v rsc Initial receive sequence counter, if applicable
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* @ret rc Return status code
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* The encryption key will not be accessed via the provided pointer
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* after this function returns, so you may keep it on the stack.
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* @a which must point to either @c dev->crypto (for the normal case
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* of installing a unicast cryptosystem) or @c dev->gcrypto (to
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* install a cryptosystem that will be used only for decrypting
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* group-source frames).
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int sec80211_install ( struct net80211_crypto **which,
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enum net80211_crypto_alg crypt,
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const void *key, int len, const void *rsc )
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struct net80211_crypto *crypto = *which;
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struct net80211_crypto *tbl_crypto;
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/* Remove old crypto if it exists */
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if ( crypt == NET80211_CRYPT_NONE ) {
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DBG ( "802.11-Sec not installing null cryptography\n" );
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/* Find cryptosystem to use */
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for_each_table_entry ( tbl_crypto, NET80211_CRYPTOS ) {
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if ( tbl_crypto->algorithm == crypt ) {
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crypto = zalloc ( sizeof ( *crypto ) +
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tbl_crypto->priv_len );
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DBG ( "802.11-Sec out of memory\n" );
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memcpy ( crypto, tbl_crypto, sizeof ( *crypto ) );
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crypto->priv = ( ( void * ) crypto +
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sizeof ( *crypto ) );
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DBG ( "802.11-Sec no support for cryptosystem %d\n", crypt );
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return -ENOTSUP_CRYPT ( crypt );
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DBG ( "802.11-Sec installing cryptosystem %d as %p with key of "
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"length %d\n", crypt, crypto, len );
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return crypto->init ( crypto, key, len, rsc );
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* Determine net80211 crypto or handshaking type value to return for RSN info
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* @v rsnp Pointer to next descriptor count field in RSN IE
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* @v rsn_end Pointer to end of RSN IE
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* @v map Descriptor map to use
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* @v tbl_start Start of linker table to examine for iPXE support
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* @v tbl_end End of linker table to examine for iPXE support
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* @ret rsnp Updated to point to first byte after descriptors
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* @ret map_ent Descriptor map entry of translation to use
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* The entries in the linker table must be either net80211_crypto or
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* net80211_handshaker structures, and @a tbl_stride must be set to
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* sizeof() the appropriate one.
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* This function expects @a rsnp to point at a two-byte descriptor
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* count followed by a list of four-byte cipher or AKM descriptors; it
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* will return @c NULL if the input packet is malformed, and otherwise
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* set @a rsnp to the first byte it has not looked at. It will return
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* the first cipher in the list that is supported by the current build
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* of iPXE, or the first of all if none are supported.
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* We play rather fast and loose with type checking, because this
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* function is only called from two well-defined places in the
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* RSN-checking code. Don't try to use it for anything else.
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static struct descriptor_map * rsn_pick_desc ( u8 **rsnp, u8 *rsn_end,
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struct descriptor_map *map,
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void *tbl_start, void *tbl_end )
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struct descriptor_map *map_ent, *map_ret = NULL;
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size_t tbl_stride = ( map == rsn_cipher_map ?
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sizeof ( struct net80211_crypto ) :
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sizeof ( struct net80211_handshaker ) );
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if ( map != rsn_cipher_map && map != rsn_akm_map )
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/* Determine which types we support */
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for ( tblp = tbl_start; tblp < tbl_end; tblp += tbl_stride ) {
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struct net80211_crypto *crypto = tblp;
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struct net80211_handshaker *hs = tblp;
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if ( map == rsn_cipher_map )
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ok |= ( 1 << crypto->algorithm );
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ok |= ( 1 << hs->protocol );
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/* RSN sanity checks */
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if ( rsn + 2 > rsn_end ) {
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DBG ( "RSN detect: malformed descriptor count\n" );
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ndesc = *( u16 * ) rsn;
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DBG ( "RSN detect: no descriptors\n" );
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/* Determine which net80211 crypto types are listed */
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if ( rsn + 4 > rsn_end ) {
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DBG ( "RSN detect: malformed descriptor (%d left)\n",
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desc = *( u32 * ) rsn;
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for ( map_ent = map; map_ent->oui_type != END_MAGIC; map_ent++ )
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if ( map_ent->oui_type == ( desc & OUI_TYPE_MASK ) )
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/* Use first cipher as a fallback */
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/* Once we find one we support, use it */
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if ( ok & ( 1 << map_ent->net80211_type ) ) {
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* Find the RSN or WPA information element in the provided beacon frame
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* @v ie Pointer to first information element to check
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* @v ie_end Pointer to end of information element space
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* @ret is_rsn TRUE if returned IE is RSN, FALSE if it's WPA
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* @ret end Pointer to byte immediately after last byte of data
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* @ret data Pointer to first byte of data (the `version' field)
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* If both an RSN and a WPA information element are found, this
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* function will return the first one seen, which by ordering rules
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* should always prefer the newer RSN IE.
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* If no RSN or WPA infomration element is found, returns @c NULL and
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* leaves @a is_rsn and @a end in an undefined state.
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* This function will not return a pointer to an information element
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* that states it extends past the tail of the io_buffer, or whose @a
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* version field is incorrect.
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u8 * sec80211_find_rsn ( union ieee80211_ie *ie, void *ie_end,
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int *is_rsn, u8 **end )
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if ( ! ieee80211_ie_bound ( ie, ie_end ) )
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if ( ie->id == IEEE80211_IE_VENDOR &&
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ie->vendor.oui == IEEE80211_WPA_OUI_VEN ) {
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DBG ( "RSN detect: old-style WPA IE found\n" );
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rsn = &ie->vendor.data[0];
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*end = rsn + ie->len - 4;
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} else if ( ie->id == IEEE80211_IE_RSN ) {
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DBG ( "RSN detect: 802.11i RSN IE found\n" );
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rsn = ( u8 * ) &ie->rsn.version;
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*end = rsn + ie->len;
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if ( rsn && ( *end > ( u8 * ) ie_end || rsn >= *end ||
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*( u16 * ) rsn != IEEE80211_RSN_VERSION ) ) {
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DBG ( "RSN detect: malformed RSN IE or unknown "
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"version, keep trying\n" );
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ie = ieee80211_next_ie ( ie, ie_end );
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DBG ( "RSN detect: no RSN IE found\n" );
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* Detect crypto and AKM types from RSN information element
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* @v is_rsn If TRUE, IE is a new-style RSN information element
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* @v start Pointer to first byte of @a version field
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* @v end Pointer to first byte not in the RSN IE
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* @ret secprot Security handshaking protocol used by network
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* @ret crypt Cryptosystem used by network
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* @ret rc Return status code
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* If the IE cannot be parsed, returns an error indication and leaves
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* @a secprot and @a crypt unchanged.
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int sec80211_detect_ie ( int is_rsn, u8 *start, u8 *end,
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enum net80211_security_proto *secprot,
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enum net80211_crypto_alg *crypt )
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enum net80211_security_proto sp;
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enum net80211_crypto_alg cr;
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struct descriptor_map *map;
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/* Set some defaults */
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cr = ( is_rsn ? NET80211_CRYPT_CCMP : NET80211_CRYPT_TKIP );
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sp = NET80211_SECPROT_EAP;
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rsn += 2; /* version - already checked */
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rsn += 4; /* group cipher - we don't use it here */
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/* Pick crypto algorithm */
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map = rsn_pick_desc ( &rsn, end, rsn_cipher_map,
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table_start ( NET80211_CRYPTOS ),
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table_end ( NET80211_CRYPTOS ) );
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cr = map->net80211_type;
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/* Pick handshaking algorithm */
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map = rsn_pick_desc ( &rsn, end, rsn_akm_map,
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table_start ( NET80211_HANDSHAKERS ),
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table_end ( NET80211_HANDSHAKERS ) );
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sp = map->net80211_type;
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DBG ( "RSN detect: OK, crypto type %d, secprot type %d\n", cr, sp );
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DBG ( "RSN detect: invalid RSN IE\n" );
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* Detect the cryptosystem and handshaking protocol used by an 802.11 network
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* @v iob I/O buffer containing beacon frame
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* @ret secprot Security handshaking protocol used by network
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* @ret crypt Cryptosystem used by network
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* @ret rc Return status code
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* This function uses weak linkage, as it must be called from generic
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* contexts but should only be linked in if some encryption is
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* supported; you must test its address against @c NULL before calling
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* it. If it does not exist, any network with the PRIVACY bit set in
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* beacon->capab should be considered unknown.
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int sec80211_detect ( struct io_buffer *iob,
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enum net80211_security_proto *secprot,
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enum net80211_crypto_alg *crypt )
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struct ieee80211_frame *hdr = iob->data;
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struct ieee80211_beacon *beacon =
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( struct ieee80211_beacon * ) hdr->data;
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*crypt = NET80211_CRYPT_UNKNOWN;
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*secprot = NET80211_SECPROT_UNKNOWN;
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/* Find RSN or WPA IE */
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if ( ! ( rsn = sec80211_find_rsn ( beacon->info_element, iob->tail,
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&is_rsn, &rsn_end ) ) ) {
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/* No security IE at all; either WEP or no security. */
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*secprot = NET80211_SECPROT_NONE;
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if ( beacon->capability & IEEE80211_CAPAB_PRIVACY )
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*crypt = NET80211_CRYPT_WEP;
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*crypt = NET80211_CRYPT_NONE;
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/* Determine type of security */
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if ( ( rc = sec80211_detect_ie ( is_rsn, rsn, rsn_end, secprot,
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/* If we get here, the RSN IE was invalid */
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*crypt = NET80211_CRYPT_UNKNOWN;
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*secprot = NET80211_SECPROT_UNKNOWN;
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DBG ( "Failed to handle RSN IE:\n" );
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DBG_HD ( rsn, rsn_end - rsn );
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* Determine RSN descriptor for specified net80211 ID
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* @v id net80211 ID value
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* @v rsnie Whether to return a new-format (RSN IE) descriptor
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* @v map Map to use in translation
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* @ret desc RSN descriptor, or 0 on error
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* If @a rsnie is false, returns an old-format (WPA vendor IE)
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static u32 rsn_get_desc ( unsigned id, int rsnie, struct descriptor_map *map )
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u32 vendor = ( rsnie ? IEEE80211_RSN_OUI : IEEE80211_WPA_OUI );
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for ( ; map->oui_type != END_MAGIC; map++ ) {
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if ( map->net80211_type == id )
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return map->oui_type | vendor;
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* Determine RSN descriptor for specified net80211 cryptosystem number
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* @v crypt Cryptosystem number
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* @v rsnie Whether to return a new-format (RSN IE) descriptor
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* @ret desc RSN descriptor
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* If @a rsnie is false, returns an old-format (WPA vendor IE)
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u32 sec80211_rsn_get_crypto_desc ( enum net80211_crypto_alg crypt, int rsnie )
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return rsn_get_desc ( crypt, rsnie, rsn_cipher_map );
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* Determine RSN descriptor for specified net80211 handshaker number
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* @v secprot Handshaker number
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* @v rsnie Whether to return a new-format (RSN IE) descriptor
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* @ret desc RSN descriptor
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* If @a rsnie is false, returns an old-format (WPA vendor IE)
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u32 sec80211_rsn_get_akm_desc ( enum net80211_security_proto secprot,
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return rsn_get_desc ( secprot, rsnie, rsn_akm_map );
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* Determine net80211 cryptosystem number from RSN descriptor
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* @v desc RSN descriptor
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* @ret crypt net80211 cryptosystem enumeration value
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enum net80211_crypto_alg sec80211_rsn_get_net80211_crypt ( u32 desc )
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struct descriptor_map *map = rsn_cipher_map;
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for ( ; map->oui_type != END_MAGIC; map++ ) {
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if ( map->oui_type == ( desc & OUI_TYPE_MASK ) )
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return map->net80211_type;