From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- net/wireless/lib80211_crypt_wep.c | 256 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 256 insertions(+) create mode 100644 net/wireless/lib80211_crypt_wep.c (limited to 'net/wireless/lib80211_crypt_wep.c') diff --git a/net/wireless/lib80211_crypt_wep.c b/net/wireless/lib80211_crypt_wep.c new file mode 100644 index 000000000..6ab9957b8 --- /dev/null +++ b/net/wireless/lib80211_crypt_wep.c @@ -0,0 +1,256 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * lib80211 crypt: host-based WEP encryption implementation for lib80211 + * + * Copyright (c) 2002-2004, Jouni Malinen + * Copyright (c) 2008, John W. Linville + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +MODULE_AUTHOR("Jouni Malinen"); +MODULE_DESCRIPTION("lib80211 crypt: WEP"); +MODULE_LICENSE("GPL"); + +struct lib80211_wep_data { + u32 iv; +#define WEP_KEY_LEN 13 + u8 key[WEP_KEY_LEN + 1]; + u8 key_len; + u8 key_idx; + struct arc4_ctx tx_ctx; + struct arc4_ctx rx_ctx; +}; + +static void *lib80211_wep_init(int keyidx) +{ + struct lib80211_wep_data *priv; + + if (fips_enabled) + return NULL; + + priv = kzalloc(sizeof(*priv), GFP_ATOMIC); + if (priv == NULL) + return NULL; + priv->key_idx = keyidx; + + /* start WEP IV from a random value */ + get_random_bytes(&priv->iv, 4); + + return priv; +} + +static void lib80211_wep_deinit(void *priv) +{ + kfree_sensitive(priv); +} + +/* Add WEP IV/key info to a frame that has at least 4 bytes of headroom */ +static int lib80211_wep_build_iv(struct sk_buff *skb, int hdr_len, + u8 *key, int keylen, void *priv) +{ + struct lib80211_wep_data *wep = priv; + u32 klen; + u8 *pos; + + if (skb_headroom(skb) < 4 || skb->len < hdr_len) + return -1; + + pos = skb_push(skb, 4); + memmove(pos, pos + 4, hdr_len); + pos += hdr_len; + + klen = 3 + wep->key_len; + + wep->iv++; + + /* 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 ((wep->iv & 0xff00) == 0xff00) { + u8 B = (wep->iv >> 16) & 0xff; + if (B >= 3 && B < klen) + wep->iv += 0x0100; + } + + /* Prepend 24-bit IV to RC4 key and TX frame */ + *pos++ = (wep->iv >> 16) & 0xff; + *pos++ = (wep->iv >> 8) & 0xff; + *pos++ = wep->iv & 0xff; + *pos++ = wep->key_idx << 6; + + return 0; +} + +/* Perform WEP encryption on given skb that has at least 4 bytes of headroom + * for IV and 4 bytes of tailroom for ICV. 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)) + */ +static int lib80211_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv) +{ + struct lib80211_wep_data *wep = priv; + u32 crc, klen, len; + u8 *pos, *icv; + u8 key[WEP_KEY_LEN + 3]; + + /* other checks are in lib80211_wep_build_iv */ + if (skb_tailroom(skb) < 4) + return -1; + + /* add the IV to the frame */ + if (lib80211_wep_build_iv(skb, hdr_len, NULL, 0, priv)) + return -1; + + /* Copy the IV into the first 3 bytes of the key */ + skb_copy_from_linear_data_offset(skb, hdr_len, key, 3); + + /* Copy rest of the WEP key (the secret part) */ + memcpy(key + 3, wep->key, wep->key_len); + + len = skb->len - hdr_len - 4; + pos = skb->data + hdr_len + 4; + klen = 3 + wep->key_len; + + /* Append little-endian CRC32 over only the data and encrypt it to produce ICV */ + crc = ~crc32_le(~0, pos, len); + icv = skb_put(skb, 4); + icv[0] = crc; + icv[1] = crc >> 8; + icv[2] = crc >> 16; + icv[3] = crc >> 24; + + arc4_setkey(&wep->tx_ctx, key, klen); + arc4_crypt(&wep->tx_ctx, pos, pos, len + 4); + + return 0; +} + +/* Perform WEP decryption on given buffer. Buffer includes whole WEP part of + * the frame: IV (4 bytes), encrypted payload (including SNAP header), + * ICV (4 bytes). 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. + */ +static int lib80211_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv) +{ + struct lib80211_wep_data *wep = priv; + u32 crc, klen, plen; + u8 key[WEP_KEY_LEN + 3]; + u8 keyidx, *pos, icv[4]; + + if (skb->len < hdr_len + 8) + return -1; + + pos = skb->data + hdr_len; + key[0] = *pos++; + key[1] = *pos++; + key[2] = *pos++; + keyidx = *pos++ >> 6; + if (keyidx != wep->key_idx) + return -1; + + klen = 3 + wep->key_len; + + /* Copy rest of the WEP key (the secret part) */ + memcpy(key + 3, wep->key, wep->key_len); + + /* Apply RC4 to data and compute CRC32 over decrypted data */ + plen = skb->len - hdr_len - 8; + + arc4_setkey(&wep->rx_ctx, key, klen); + arc4_crypt(&wep->rx_ctx, pos, pos, plen + 4); + + crc = ~crc32_le(~0, pos, plen); + icv[0] = crc; + icv[1] = crc >> 8; + icv[2] = crc >> 16; + icv[3] = crc >> 24; + if (memcmp(icv, pos + plen, 4) != 0) { + /* ICV mismatch - drop frame */ + return -2; + } + + /* Remove IV and ICV */ + memmove(skb->data + 4, skb->data, hdr_len); + skb_pull(skb, 4); + skb_trim(skb, skb->len - 4); + + return 0; +} + +static int lib80211_wep_set_key(void *key, int len, u8 * seq, void *priv) +{ + struct lib80211_wep_data *wep = priv; + + if (len < 0 || len > WEP_KEY_LEN) + return -1; + + memcpy(wep->key, key, len); + wep->key_len = len; + + return 0; +} + +static int lib80211_wep_get_key(void *key, int len, u8 * seq, void *priv) +{ + struct lib80211_wep_data *wep = priv; + + if (len < wep->key_len) + return -1; + + memcpy(key, wep->key, wep->key_len); + + return wep->key_len; +} + +static void lib80211_wep_print_stats(struct seq_file *m, void *priv) +{ + struct lib80211_wep_data *wep = priv; + seq_printf(m, "key[%d] alg=WEP len=%d\n", wep->key_idx, wep->key_len); +} + +static struct lib80211_crypto_ops lib80211_crypt_wep = { + .name = "WEP", + .init = lib80211_wep_init, + .deinit = lib80211_wep_deinit, + .encrypt_mpdu = lib80211_wep_encrypt, + .decrypt_mpdu = lib80211_wep_decrypt, + .encrypt_msdu = NULL, + .decrypt_msdu = NULL, + .set_key = lib80211_wep_set_key, + .get_key = lib80211_wep_get_key, + .print_stats = lib80211_wep_print_stats, + .extra_mpdu_prefix_len = 4, /* IV */ + .extra_mpdu_postfix_len = 4, /* ICV */ + .owner = THIS_MODULE, +}; + +static int __init lib80211_crypto_wep_init(void) +{ + return lib80211_register_crypto_ops(&lib80211_crypt_wep); +} + +static void __exit lib80211_crypto_wep_exit(void) +{ + lib80211_unregister_crypto_ops(&lib80211_crypt_wep); +} + +module_init(lib80211_crypto_wep_init); +module_exit(lib80211_crypto_wep_exit); -- cgit v1.2.3