diff options
Diffstat (limited to 'drivers/staging/rtl8192e/rtllib_crypt_wep.c')
-rw-r--r-- | drivers/staging/rtl8192e/rtllib_crypt_wep.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/staging/rtl8192e/rtllib_crypt_wep.c b/drivers/staging/rtl8192e/rtllib_crypt_wep.c new file mode 100644 index 0000000000..062285e4d9 --- /dev/null +++ b/drivers/staging/rtl8192e/rtllib_crypt_wep.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Host AP crypt: host-based WEP encryption implementation for Host AP driver + * + * Copyright (c) 2002-2004, Jouni Malinen <jkmaline@cc.hut.fi> + */ + +#include <crypto/arc4.h> +#include <linux/fips.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/random.h> +#include <linux/skbuff.h> +#include <linux/string.h> +#include "rtllib.h" + +#include <linux/crc32.h> + +struct prism2_wep_data { + u32 iv; +#define WEP_KEY_LEN 13 + u8 key[WEP_KEY_LEN + 1]; + u8 key_len; + u8 key_idx; + struct arc4_ctx rx_ctx_arc4; + struct arc4_ctx tx_ctx_arc4; +}; + +static void *prism2_wep_init(int keyidx) +{ + struct prism2_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 prism2_wep_deinit(void *priv) +{ + kfree_sensitive(priv); +} + +/* 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 prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv) +{ + struct prism2_wep_data *wep = priv; + u32 klen, len; + u8 key[WEP_KEY_LEN + 3]; + u8 *pos; + struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + + MAX_DEV_ADDR_SIZE); + u32 crc; + u8 *icv; + + if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 || + skb->len < hdr_len){ + pr_err("Error!!! headroom=%d tailroom=%d skblen=%d hdr_len=%d\n", + skb_headroom(skb), skb_tailroom(skb), skb->len, hdr_len); + return -1; + } + len = skb->len - hdr_len; + 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++ = key[0] = (wep->iv >> 16) & 0xff; + *pos++ = key[1] = (wep->iv >> 8) & 0xff; + *pos++ = key[2] = wep->iv & 0xff; + *pos++ = wep->key_idx << 6; + + /* Copy rest of the WEP key (the secret part) */ + memcpy(key + 3, wep->key, wep->key_len); + + if (!tcb_desc->bHwSec) { + /* Append little-endian CRC32 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_arc4, key, klen); + arc4_crypt(&wep->tx_ctx_arc4, pos, pos, len + 4); + } + + return 0; +} + +/* Perform WEP decryption on given struct 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 prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv) +{ + struct prism2_wep_data *wep = priv; + u32 klen, plen; + u8 key[WEP_KEY_LEN + 3]; + u8 keyidx, *pos; + struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + + MAX_DEV_ADDR_SIZE); + u32 crc; + u8 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; + + if (!tcb_desc->bHwSec) { + arc4_setkey(&wep->rx_ctx_arc4, key, klen); + arc4_crypt(&wep->rx_ctx_arc4, 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 prism2_wep_set_key(void *key, int len, u8 *seq, void *priv) +{ + struct prism2_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 prism2_wep_get_key(void *key, int len, u8 *seq, void *priv) +{ + struct prism2_wep_data *wep = priv; + + if (len < wep->key_len) + return -1; + + memcpy(key, wep->key, wep->key_len); + + return wep->key_len; +} + +static void prism2_wep_print_stats(struct seq_file *m, void *priv) +{ + struct prism2_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 rtllib_crypt_wep = { + .name = "R-WEP", + .init = prism2_wep_init, + .deinit = prism2_wep_deinit, + .encrypt_mpdu = prism2_wep_encrypt, + .decrypt_mpdu = prism2_wep_decrypt, + .encrypt_msdu = NULL, + .decrypt_msdu = NULL, + .set_key = prism2_wep_set_key, + .get_key = prism2_wep_get_key, + .print_stats = prism2_wep_print_stats, + .extra_mpdu_prefix_len = 4, /* IV */ + .extra_mpdu_postfix_len = 4, /* ICV */ + .owner = THIS_MODULE, +}; + +static int __init rtllib_crypto_wep_init(void) +{ + return lib80211_register_crypto_ops(&rtllib_crypt_wep); +} + +static void __exit rtllib_crypto_wep_exit(void) +{ + lib80211_unregister_crypto_ops(&rtllib_crypt_wep); +} + +module_init(rtllib_crypto_wep_init); +module_exit(rtllib_crypto_wep_exit); + +MODULE_LICENSE("GPL"); |