diff options
Diffstat (limited to 'drivers/staging/wlan-ng/p80211wep.c')
| -rw-r--r-- | drivers/staging/wlan-ng/p80211wep.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/drivers/staging/wlan-ng/p80211wep.c b/drivers/staging/wlan-ng/p80211wep.c new file mode 100644 index 0000000000..e7b26b0571 --- /dev/null +++ b/drivers/staging/wlan-ng/p80211wep.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: (GPL-2.0 OR MPL-1.1) +/* + * + * WEP encode/decode for P80211. + * + * Copyright (C) 2002 AbsoluteValue Systems, Inc. All Rights Reserved. + * -------------------------------------------------------------------- + * + * linux-wlan + * + * -------------------------------------------------------------------- + * + * Inquiries regarding the linux-wlan Open Source project can be + * made directly to: + * + * AbsoluteValue Systems Inc. + * info@linux-wlan.com + * http://www.linux-wlan.com + * + * -------------------------------------------------------------------- + * + * Portions of the development of this software were funded by + * Intersil Corporation as part of PRISM(R) chipset product development. + * + * -------------------------------------------------------------------- + */ + +/*================================================================*/ +/* System Includes */ + +#include <linux/crc32.h> +#include <linux/netdevice.h> +#include <linux/wireless.h> +#include <linux/random.h> +#include <linux/kernel.h> +#include "p80211hdr.h" +#include "p80211types.h" +#include "p80211msg.h" +#include "p80211conv.h" +#include "p80211netdev.h" + +#define WEP_KEY(x) (((x) & 0xC0) >> 6) + +/* keylen in bytes! */ + +int wep_change_key(struct wlandevice *wlandev, int keynum, u8 *key, int keylen) +{ + if (keylen < 0) + return -1; + if (keylen >= MAX_KEYLEN) + return -1; + if (!key) + return -1; + if (keynum < 0) + return -1; + if (keynum >= NUM_WEPKEYS) + return -1; + + wlandev->wep_keylens[keynum] = keylen; + memcpy(wlandev->wep_keys[keynum], key, keylen); + + return 0; +} + +/* + * 4-byte IV at start of buffer, 4-byte ICV at end of buffer. + * if successful, buf start is payload begin, length -= 8; + */ +int wep_decrypt(struct wlandevice *wlandev, u8 *buf, u32 len, int key_override, + u8 *iv, u8 *icv) +{ + u32 i, j, k, crc, keylen; + u8 s[256], key[64], c_crc[4]; + u8 keyidx; + + /* Needs to be at least 8 bytes of payload */ + if (len <= 0) + return -1; + + /* initialize the first bytes of the key from the IV */ + key[0] = iv[0]; + key[1] = iv[1]; + key[2] = iv[2]; + keyidx = WEP_KEY(iv[3]); + + if (key_override >= 0) + keyidx = key_override; + + if (keyidx >= NUM_WEPKEYS) + return -2; + + keylen = wlandev->wep_keylens[keyidx]; + + if (keylen == 0) + return -3; + + /* copy the rest of the key over from the designated key */ + memcpy(key + 3, wlandev->wep_keys[keyidx], keylen); + + keylen += 3; /* add in IV bytes */ + + /* set up the RC4 state */ + for (i = 0; i < 256; i++) + s[i] = i; + j = 0; + for (i = 0; i < 256; i++) { + j = (j + s[i] + key[i % keylen]) & 0xff; + swap(i, j); + } + + /* Apply the RC4 to the data, update the CRC32 */ + i = 0; + j = 0; + for (k = 0; k < len; k++) { + i = (i + 1) & 0xff; + j = (j + s[i]) & 0xff; + swap(i, j); + buf[k] ^= s[(s[i] + s[j]) & 0xff]; + } + crc = ~crc32_le(~0, buf, len); + + /* now let's check the crc */ + c_crc[0] = crc; + c_crc[1] = crc >> 8; + c_crc[2] = crc >> 16; + c_crc[3] = crc >> 24; + + for (k = 0; k < 4; k++) { + i = (i + 1) & 0xff; + j = (j + s[i]) & 0xff; + swap(i, j); + if ((c_crc[k] ^ s[(s[i] + s[j]) & 0xff]) != icv[k]) + return -(4 | (k << 4)); /* ICV mismatch */ + } + + return 0; +} + +/* encrypts in-place. */ +int wep_encrypt(struct wlandevice *wlandev, u8 *buf, + u8 *dst, u32 len, int keynum, u8 *iv, u8 *icv) +{ + u32 i, j, k, crc, keylen; + u8 s[256], key[64]; + + /* no point in WEPping an empty frame */ + if (len <= 0) + return -1; + + /* we need to have a real key.. */ + if (keynum >= NUM_WEPKEYS) + return -2; + keylen = wlandev->wep_keylens[keynum]; + if (keylen <= 0) + return -3; + + /* use a random IV. And skip known weak ones. */ + get_random_bytes(iv, 3); + while ((iv[1] == 0xff) && (iv[0] >= 3) && (iv[0] < keylen)) + get_random_bytes(iv, 3); + + iv[3] = (keynum & 0x03) << 6; + + key[0] = iv[0]; + key[1] = iv[1]; + key[2] = iv[2]; + + /* copy the rest of the key over from the designated key */ + memcpy(key + 3, wlandev->wep_keys[keynum], keylen); + + keylen += 3; /* add in IV bytes */ + + /* set up the RC4 state */ + for (i = 0; i < 256; i++) + s[i] = i; + j = 0; + for (i = 0; i < 256; i++) { + j = (j + s[i] + key[i % keylen]) & 0xff; + swap(i, j); + } + + /* Update CRC32 then apply RC4 to the data */ + i = 0; + j = 0; + for (k = 0; k < len; k++) { + i = (i + 1) & 0xff; + j = (j + s[i]) & 0xff; + swap(i, j); + dst[k] = buf[k] ^ s[(s[i] + s[j]) & 0xff]; + } + crc = ~crc32_le(~0, buf, len); + + /* now let's encrypt the crc */ + icv[0] = crc; + icv[1] = crc >> 8; + icv[2] = crc >> 16; + icv[3] = crc >> 24; + + for (k = 0; k < 4; k++) { + i = (i + 1) & 0xff; + j = (j + s[i]) & 0xff; + swap(i, j); + icv[k] ^= s[(s[i] + s[j]) & 0xff]; + } + + return 0; +} |