diff options
Diffstat (limited to 'openwrt/target/linux/package/ieee80211-dscape/src/wep.c')
| -rw-r--r-- | openwrt/target/linux/package/ieee80211-dscape/src/wep.c | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/openwrt/target/linux/package/ieee80211-dscape/src/wep.c b/openwrt/target/linux/package/ieee80211-dscape/src/wep.c new file mode 100644 index 0000000000..57c2f603c0 --- /dev/null +++ b/openwrt/target/linux/package/ieee80211-dscape/src/wep.c @@ -0,0 +1,423 @@ +/* + * Software WEP encryption implementation + * Copyright 2002, Jouni Malinen <jkmaline@cc.hut.fi> + * Copyright 2003, Instant802 Networks, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/config.h> +#include <linux/version.h> +#include <linux/netdevice.h> +#include <linux/types.h> +#include <linux/random.h> +#include <linux/compiler.h> + +#include <net/ieee80211.h> +#include "ieee80211_i.h" +#include "wep.h" + + +static const __u32 crc32_table[256] = { + 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, + 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, + 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, + 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, + 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, + 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, + 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, + 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, + 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, + 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL, + 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, + 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, + 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L, + 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, + 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, + 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L, + 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, + 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L, + 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, + 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L, + 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL, + 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, + 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L, + 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL, + 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L, + 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L, + 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L, + 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L, + 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L, + 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL, + 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, + 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L, + 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, + 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL, + 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, + 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, + 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL, + 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L, + 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, + 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L, + 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL, + 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L, + 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, + 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL, + 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L, + 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, + 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, + 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L, + 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L, + 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L, + 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, + 0x2d02ef8dL +}; + + +void ieee80211_wep_init(struct ieee80211_local *local) +{ + /* start WEP IV from a random value */ + get_random_bytes(&local->wep_iv, WEP_IV_LEN); +} + + +static inline int ieee80211_wep_weak_iv(u32 iv, int keylen) +{ + /* Fluhrer, Mantin, and Shamir have reported weaknesses in the + * key scheduling algorithm of RC4. At least IVs (KeyByte + 3, + * 0xff, N) can be used to speedup attacks, so avoid using them. */ + if ((iv & 0xff00) == 0xff00) { + u8 B = (iv >> 16) & 0xff; + if (B >= 3 && B < 3 + keylen) + return 1; + } + return 0; +} + + +void ieee80211_wep_get_iv(struct ieee80211_local *local, + struct ieee80211_key *key, u8 *iv) +{ + local->wep_iv++; + if (ieee80211_wep_weak_iv(local->wep_iv, key->keylen)) + local->wep_iv += 0x0100; + + if (iv == NULL) + return; + + *iv++ = (local->wep_iv >> 16) & 0xff; + *iv++ = (local->wep_iv >> 8) & 0xff; + *iv++ = local->wep_iv & 0xff; + *iv++ = key->keyidx << 6; +} + + +u8 * ieee80211_wep_add_iv(struct ieee80211_local *local, + struct sk_buff *skb, + struct ieee80211_key *key) +{ + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + u16 fc; + int hdrlen; + u8 *newhdr; + + fc = le16_to_cpu(hdr->frame_control); + fc |= WLAN_FC_ISWEP; + hdr->frame_control = cpu_to_le16(fc); + + if ((skb_headroom(skb) < WEP_IV_LEN || + skb_tailroom(skb) < WEP_ICV_LEN)) { + I802_DEBUG_INC(local->tx_expand_skb_head); + if (unlikely(pskb_expand_head(skb, WEP_IV_LEN, WEP_ICV_LEN, + GFP_ATOMIC))) + return NULL; + } + + hdrlen = ieee80211_get_hdrlen(fc); + newhdr = skb_push(skb, WEP_IV_LEN); + memmove(newhdr, newhdr + WEP_IV_LEN, hdrlen); + ieee80211_wep_get_iv(local, key, newhdr + hdrlen); + return newhdr + hdrlen; +} + + +void ieee80211_wep_remove_iv(struct ieee80211_local *local, + struct sk_buff *skb, + struct ieee80211_key *key) +{ + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + u16 fc; + int hdrlen; + + fc = le16_to_cpu(hdr->frame_control); + hdrlen = ieee80211_get_hdrlen(fc); + memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen); + skb_pull(skb, WEP_IV_LEN); +} + + +/* Perform WEP encryption using given key. data buffer must have tailroom + * for 4-byte ICV. data_len must not include this ICV. Note: this function + * does _not_ add IV. data = RC4(data | CRC32(data)) */ +void ieee80211_wep_encrypt_data(u8 *rc4key, size_t klen, u8 *data, + size_t data_len) +{ + u32 i, j, k, crc; + u8 S[256]; + u8 kpos, *pos; +#define S_SWAP(a,b) do { u8 t = S[a]; S[a] = S[b]; S[b] = t; } while(0) + + /* Setup RC4 state */ + for (i = 0; i < 256; i++) + S[i] = i; + j = 0; + kpos = 0; + for (i = 0; i < 256; i++) { + j = (j + S[i] + rc4key[kpos]) & 0xff; + kpos++; + if (kpos >= klen) + kpos = 0; + S_SWAP(i, j); + } + + /* Compute CRC32 over unencrypted data and apply RC4 to data */ + pos = data; + crc = ~0; + i = j = 0; + for (k = 0; k < data_len; k++) { + crc = crc32_table[(crc ^ *pos) & 0xff] ^ (crc >> 8); + i = (i + 1) & 0xff; + j = (j + S[i]) & 0xff; + S_SWAP(i, j); + *pos++ ^= S[(S[i] + S[j]) & 0xff]; + } + crc = ~crc; + + /* Append little-endian CRC32 and encrypt it to produce ICV */ + pos[0] = crc; + pos[1] = crc >> 8; + pos[2] = crc >> 16; + pos[3] = crc >> 24; + for (k = 0; k < 4; k++) { + i = (i + 1) & 0xff; + j = (j + S[i]) & 0xff; + S_SWAP(i, j); + *pos++ ^= S[(S[i] + S[j]) & 0xff]; + } +} + + +/* Perform WEP encryption on given skb. 4 bytes of extra space (IV) in the + * beginning of the buffer 4 bytes of extra space (ICV) in the end of the + * buffer will be added. Both IV and ICV will be transmitted, so the + * payload length increases with 8 bytes. + * + * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data)) + */ +int ieee80211_wep_encrypt(struct ieee80211_local *local, struct sk_buff *skb, + struct ieee80211_key *key) +{ + u32 klen; + u8 *rc4key, *iv; + size_t len; + + if (key == NULL || key->alg != ALG_WEP) + return -1; + + klen = 3 + key->keylen; + rc4key = kmalloc(klen, GFP_ATOMIC); + if (rc4key == NULL) + return -1; + + iv = ieee80211_wep_add_iv(local, skb, key); + if (iv == NULL) { + kfree(rc4key); + return -1; + } + + len = skb->len - (iv + WEP_IV_LEN - skb->data); + + /* Prepend 24-bit IV to RC4 key */ + memcpy(rc4key, iv, 3); + + /* Copy rest of the WEP key (the secret part) */ + memcpy(rc4key + 3, key->key, key->keylen); + + /* Add room for ICV */ + skb_put(skb, WEP_ICV_LEN); + + ieee80211_wep_encrypt_data(rc4key, klen, iv + WEP_IV_LEN, len); + + kfree(rc4key); + + return 0; +} + + +/* Perform WEP decryption using given key. data buffer includes encrypted + * payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV. + * Return 0 on success and -1 on ICV mismatch. */ +int ieee80211_wep_decrypt_data(u8 *rc4key, size_t klen, u8 *data, + size_t data_len) +{ + u32 i, j, k, crc; + u8 S[256]; + u8 kpos, *pos, crcbuf[WEP_ICV_LEN], *cpos; + + /* Setup RC4 state */ + for (i = 0; i < 256; i++) + S[i] = i; + j = 0; + kpos = 0; + for (i = 0; i < 256; i++) { + j = (j + S[i] + rc4key[kpos]) & 0xff; + kpos++; + if (kpos >= klen) + kpos = 0; + S_SWAP(i, j); + } + + /* Apply RC4 to data and compute CRC32 over decrypted data */ + pos = data; + crc = ~0; + i = j = 0; + for (k = 0; k < data_len; k++) { + i = (i + 1) & 0xff; + j = (j + S[i]) & 0xff; + S_SWAP(i, j); + *pos ^= S[(S[i] + S[j]) & 0xff]; + crc = crc32_table[(crc ^ *pos++) & 0xff] ^ (crc >> 8); + } + crc = ~crc; + + /* Decrypt little-endian CRC32 and verify that it matches with the + * received ICV */ + cpos = crcbuf; + crcbuf[0] = crc; + crcbuf[1] = crc >> 8; + crcbuf[2] = crc >> 16; + crcbuf[3] = crc >> 24; + for (k = 0; k < WEP_ICV_LEN; k++) { + i = (i + 1) & 0xff; + j = (j + S[i]) & 0xff; + S_SWAP(i, j); + if (*cpos++ != (*pos++ ^ S[(S[i] + S[j]) & 0xff])) { + /* ICV mismatch */ + return -1; + } + } + + return 0; +} + + +/* Perform WEP decryption on given skb. Buffer includes whole WEP part of + * the frame: IV (4 bytes), encrypted payload (including SNAP header), + * ICV (4 bytes). skb->len includes both IV and ICV. + * + * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on + * failure. If frame is OK, IV and ICV will be removed, i.e., decrypted payload + * is moved to the beginning of the skb and skb length will be reduced. + */ +int ieee80211_wep_decrypt(struct ieee80211_local *local, struct sk_buff *skb, + struct ieee80211_key *key) +{ + u32 klen; + u8 *rc4key; + u8 keyidx; + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + u16 fc; + int hdrlen; + size_t len; + int ret = 0; + + fc = le16_to_cpu(hdr->frame_control); + if (!(fc & WLAN_FC_ISWEP)) + return -1; + + hdrlen = ieee80211_get_hdrlen(fc); + + if (skb->len < 8 + hdrlen) + return -1; + + len = skb->len - hdrlen - 8; + + keyidx = skb->data[hdrlen + 3] >> 6; + + if (key == NULL || keyidx != key->keyidx || key->alg != ALG_WEP) + return -1; + + klen = 3 + key->keylen; + + rc4key = kmalloc(klen, GFP_ATOMIC); + if (rc4key == NULL) + return -1; + + /* Prepend 24-bit IV to RC4 key */ + memcpy(rc4key, skb->data + hdrlen, 3); + + /* Copy rest of the WEP key (the secret part) */ + memcpy(rc4key + 3, key->key, key->keylen); + + if (ieee80211_wep_decrypt_data(rc4key, klen, + skb->data + hdrlen + WEP_IV_LEN, + len)) { + printk(KERN_DEBUG "WEP decrypt failed (ICV)\n"); + ret = -1; + } + + kfree(rc4key); + + /* Trim ICV */ + skb_trim(skb, skb->len - WEP_ICV_LEN); + + /* Remove IV */ + memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen); + skb_pull(skb, WEP_IV_LEN); + + return ret; +} + + +int ieee80211_wep_get_keyidx(struct sk_buff *skb) +{ + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + u16 fc; + int hdrlen; + + fc = le16_to_cpu(hdr->frame_control); + if (!(fc & WLAN_FC_ISWEP)) + return -1; + + hdrlen = ieee80211_get_hdrlen(fc); + + if (skb->len < 8 + hdrlen) + return -1; + + return skb->data[hdrlen + 3] >> 6; +} + + +u8 * ieee80211_wep_is_weak_iv(struct sk_buff *skb, struct ieee80211_key *key) +{ + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + u16 fc; + int hdrlen; + u8 *ivpos; + u32 iv; + + fc = le16_to_cpu(hdr->frame_control); + if (!(fc & WLAN_FC_ISWEP)) + return NULL; + + hdrlen = ieee80211_get_hdrlen(fc); + ivpos = skb->data + hdrlen; + iv = (ivpos[0] << 16) | (ivpos[1] << 8) | ivpos[2]; + + if (ieee80211_wep_weak_iv(iv, key->keylen)) + return ivpos; + + return NULL; +} |