diff options
Diffstat (limited to 'drivers/usb/wusbcore/crypto.c')
| -rw-r--r-- | drivers/usb/wusbcore/crypto.c | 522 |
1 files changed, 0 insertions, 522 deletions
diff --git a/drivers/usb/wusbcore/crypto.c b/drivers/usb/wusbcore/crypto.c deleted file mode 100644 index edb7263bff40..000000000000 --- a/drivers/usb/wusbcore/crypto.c +++ /dev/null @@ -1,522 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Ultra Wide Band - * AES-128 CCM Encryption - * - * Copyright (C) 2007 Intel Corporation - * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> - * - * We don't do any encryption here; we use the Linux Kernel's AES-128 - * crypto modules to construct keys and payload blocks in a way - * defined by WUSB1.0[6]. Check the erratas, as typos are are patched - * there. - * - * Thanks a zillion to John Keys for his help and clarifications over - * the designed-by-a-committee text. - * - * So the idea is that there is this basic Pseudo-Random-Function - * defined in WUSB1.0[6.5] which is the core of everything. It works - * by tweaking some blocks, AES crypting them and then xoring - * something else with them (this seems to be called CBC(AES) -- can - * you tell I know jack about crypto?). So we just funnel it into the - * Linux Crypto API. - * - * We leave a crypto test module so we can verify that vectors match, - * every now and then. - * - * Block size: 16 bytes -- AES seems to do things in 'block sizes'. I - * am learning a lot... - * - * Conveniently, some data structures that need to be - * funneled through AES are...16 bytes in size! - */ - -#include <crypto/skcipher.h> -#include <linux/crypto.h> -#include <linux/module.h> -#include <linux/err.h> -#include <linux/uwb.h> -#include <linux/slab.h> -#include <linux/usb/wusb.h> -#include <linux/scatterlist.h> - -static int debug_crypto_verify; - -module_param(debug_crypto_verify, int, 0); -MODULE_PARM_DESC(debug_crypto_verify, "verify the key generation algorithms"); - -static void wusb_key_dump(const void *buf, size_t len) -{ - print_hex_dump(KERN_ERR, " ", DUMP_PREFIX_OFFSET, 16, 1, - buf, len, 0); -} - -/* - * Block of data, as understood by AES-CCM - * - * The code assumes this structure is nothing but a 16 byte array - * (packed in a struct to avoid common mess ups that I usually do with - * arrays and enforcing type checking). - */ -struct aes_ccm_block { - u8 data[16]; -} __attribute__((packed)); - -/* - * Counter-mode Blocks (WUSB1.0[6.4]) - * - * According to CCM (or so it seems), for the purpose of calculating - * the MIC, the message is broken in N counter-mode blocks, B0, B1, - * ... BN. - * - * B0 contains flags, the CCM nonce and l(m). - * - * B1 contains l(a), the MAC header, the encryption offset and padding. - * - * If EO is nonzero, additional blocks are built from payload bytes - * until EO is exhausted (FIXME: padding to 16 bytes, I guess). The - * padding is not xmitted. - */ - -/* WUSB1.0[T6.4] */ -struct aes_ccm_b0 { - u8 flags; /* 0x59, per CCM spec */ - struct aes_ccm_nonce ccm_nonce; - __be16 lm; -} __attribute__((packed)); - -/* WUSB1.0[T6.5] */ -struct aes_ccm_b1 { - __be16 la; - u8 mac_header[10]; - __le16 eo; - u8 security_reserved; /* This is always zero */ - u8 padding; /* 0 */ -} __attribute__((packed)); - -/* - * Encryption Blocks (WUSB1.0[6.4.4]) - * - * CCM uses Ax blocks to generate a keystream with which the MIC and - * the message's payload are encoded. A0 always encrypts/decrypts the - * MIC. Ax (x>0) are used for the successive payload blocks. - * - * The x is the counter, and is increased for each block. - */ -struct aes_ccm_a { - u8 flags; /* 0x01, per CCM spec */ - struct aes_ccm_nonce ccm_nonce; - __be16 counter; /* Value of x */ -} __attribute__((packed)); - -static void bytewise_xor(void *_bo, const void *_bi1, const void *_bi2, - size_t size) -{ - u8 *bo = _bo; - const u8 *bi1 = _bi1, *bi2 = _bi2; - size_t itr; - for (itr = 0; itr < size; itr++) - bo[itr] = bi1[itr] ^ bi2[itr]; -} - -/* Scratch space for MAC calculations. */ -struct wusb_mac_scratch { - struct aes_ccm_b0 b0; - struct aes_ccm_b1 b1; - struct aes_ccm_a ax; -}; - -/* - * CC-MAC function WUSB1.0[6.5] - * - * Take a data string and produce the encrypted CBC Counter-mode MIC - * - * Note the names for most function arguments are made to (more or - * less) match those used in the pseudo-function definition given in - * WUSB1.0[6.5]. - * - * @tfm_cbc: CBC(AES) blkcipher handle (initialized) - * - * @tfm_aes: AES cipher handle (initialized) - * - * @mic: buffer for placing the computed MIC (Message Integrity - * Code). This is exactly 8 bytes, and we expect the buffer to - * be at least eight bytes in length. - * - * @key: 128 bit symmetric key - * - * @n: CCM nonce - * - * @a: ASCII string, 14 bytes long (I guess zero padded if needed; - * we use exactly 14 bytes). - * - * @b: data stream to be processed; cannot be a global or const local - * (will confuse the scatterlists) - * - * @blen: size of b... - * - * Still not very clear how this is done, but looks like this: we - * create block B0 (as WUSB1.0[6.5] says), then we AES-crypt it with - * @key. We bytewise xor B0 with B1 (1) and AES-crypt that. Then we - * take the payload and divide it in blocks (16 bytes), xor them with - * the previous crypto result (16 bytes) and crypt it, repeat the next - * block with the output of the previous one, rinse wash (I guess this - * is what AES CBC mode means...but I truly have no idea). So we use - * the CBC(AES) blkcipher, that does precisely that. The IV (Initial - * Vector) is 16 bytes and is set to zero, so - * - * See rfc3610. Linux crypto has a CBC implementation, but the - * documentation is scarce, to say the least, and the example code is - * so intricated that is difficult to understand how things work. Most - * of this is guess work -- bite me. - * - * (1) Created as 6.5 says, again, using as l(a) 'Blen + 14', and - * using the 14 bytes of @a to fill up - * b1.{mac_header,e0,security_reserved,padding}. - * - * NOTE: The definition of l(a) in WUSB1.0[6.5] vs the definition of - * l(m) is orthogonal, they bear no relationship, so it is not - * in conflict with the parameter's relation that - * WUSB1.0[6.4.2]) defines. - * - * NOTE: WUSB1.0[A.1]: Host Nonce is missing a nibble? (1e); fixed in - * first errata released on 2005/07. - * - * NOTE: we need to clean IV to zero at each invocation to make sure - * we start with a fresh empty Initial Vector, so that the CBC - * works ok. - * - * NOTE: blen is not aligned to a block size, we'll pad zeros, that's - * what sg[4] is for. Maybe there is a smarter way to do this. - */ -static int wusb_ccm_mac(struct crypto_sync_skcipher *tfm_cbc, - struct crypto_cipher *tfm_aes, - struct wusb_mac_scratch *scratch, - void *mic, - const struct aes_ccm_nonce *n, - const struct aes_ccm_label *a, const void *b, - size_t blen) -{ - int result = 0; - SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm_cbc); - struct scatterlist sg[4], sg_dst; - void *dst_buf; - size_t dst_size; - u8 *iv; - size_t zero_padding; - - /* - * These checks should be compile time optimized out - * ensure @a fills b1's mac_header and following fields - */ - WARN_ON(sizeof(*a) != sizeof(scratch->b1) - sizeof(scratch->b1.la)); - WARN_ON(sizeof(scratch->b0) != sizeof(struct aes_ccm_block)); - WARN_ON(sizeof(scratch->b1) != sizeof(struct aes_ccm_block)); - WARN_ON(sizeof(scratch->ax) != sizeof(struct aes_ccm_block)); - - result = -ENOMEM; - zero_padding = blen % sizeof(struct aes_ccm_block); - if (zero_padding) - zero_padding = sizeof(struct aes_ccm_block) - zero_padding; - dst_size = blen + sizeof(scratch->b0) + sizeof(scratch->b1) + - zero_padding; - dst_buf = kzalloc(dst_size, GFP_KERNEL); - if (!dst_buf) - goto error_dst_buf; - - iv = kzalloc(crypto_sync_skcipher_ivsize(tfm_cbc), GFP_KERNEL); - if (!iv) - goto error_iv; - - /* Setup B0 */ - scratch->b0.flags = 0x59; /* Format B0 */ - scratch->b0.ccm_nonce = *n; - scratch->b0.lm = cpu_to_be16(0); /* WUSB1.0[6.5] sez l(m) is 0 */ - - /* Setup B1 - * - * The WUSB spec is anything but clear! WUSB1.0[6.5] - * says that to initialize B1 from A with 'l(a) = blen + - * 14'--after clarification, it means to use A's contents - * for MAC Header, EO, sec reserved and padding. - */ - scratch->b1.la = cpu_to_be16(blen + 14); - memcpy(&scratch->b1.mac_header, a, sizeof(*a)); - - sg_init_table(sg, ARRAY_SIZE(sg)); - sg_set_buf(&sg[0], &scratch->b0, sizeof(scratch->b0)); - sg_set_buf(&sg[1], &scratch->b1, sizeof(scratch->b1)); - sg_set_buf(&sg[2], b, blen); - /* 0 if well behaved :) */ - sg_set_page(&sg[3], ZERO_PAGE(0), zero_padding, 0); - sg_init_one(&sg_dst, dst_buf, dst_size); - - skcipher_request_set_sync_tfm(req, tfm_cbc); - skcipher_request_set_callback(req, 0, NULL, NULL); - skcipher_request_set_crypt(req, sg, &sg_dst, dst_size, iv); - result = crypto_skcipher_encrypt(req); - skcipher_request_zero(req); - if (result < 0) { - printk(KERN_ERR "E: can't compute CBC-MAC tag (MIC): %d\n", - result); - goto error_cbc_crypt; - } - - /* Now we crypt the MIC Tag (*iv) with Ax -- values per WUSB1.0[6.5] - * The procedure is to AES crypt the A0 block and XOR the MIC - * Tag against it; we only do the first 8 bytes and place it - * directly in the destination buffer. - * - * POS Crypto API: size is assumed to be AES's block size. - * Thanks for documenting it -- tip taken from airo.c - */ - scratch->ax.flags = 0x01; /* as per WUSB 1.0 spec */ - scratch->ax.ccm_nonce = *n; - scratch->ax.counter = 0; - crypto_cipher_encrypt_one(tfm_aes, (void *)&scratch->ax, - (void *)&scratch->ax); - bytewise_xor(mic, &scratch->ax, iv, 8); - result = 8; -error_cbc_crypt: - kfree(iv); -error_iv: - kfree(dst_buf); -error_dst_buf: - return result; -} - -/* - * WUSB Pseudo Random Function (WUSB1.0[6.5]) - * - * @b: buffer to the source data; cannot be a global or const local - * (will confuse the scatterlists) - */ -ssize_t wusb_prf(void *out, size_t out_size, - const u8 key[16], const struct aes_ccm_nonce *_n, - const struct aes_ccm_label *a, - const void *b, size_t blen, size_t len) -{ - ssize_t result, bytes = 0, bitr; - struct aes_ccm_nonce n = *_n; - struct crypto_sync_skcipher *tfm_cbc; - struct crypto_cipher *tfm_aes; - struct wusb_mac_scratch *scratch; - u64 sfn = 0; - __le64 sfn_le; - - tfm_cbc = crypto_alloc_sync_skcipher("cbc(aes)", 0, 0); - if (IS_ERR(tfm_cbc)) { - result = PTR_ERR(tfm_cbc); - printk(KERN_ERR "E: can't load CBC(AES): %d\n", (int)result); - goto error_alloc_cbc; - } - result = crypto_sync_skcipher_setkey(tfm_cbc, key, 16); - if (result < 0) { - printk(KERN_ERR "E: can't set CBC key: %d\n", (int)result); - goto error_setkey_cbc; - } - - tfm_aes = crypto_alloc_cipher("aes", 0, 0); - if (IS_ERR(tfm_aes)) { - result = PTR_ERR(tfm_aes); - printk(KERN_ERR "E: can't load AES: %d\n", (int)result); - goto error_alloc_aes; - } - result = crypto_cipher_setkey(tfm_aes, key, 16); - if (result < 0) { - printk(KERN_ERR "E: can't set AES key: %d\n", (int)result); - goto error_setkey_aes; - } - scratch = kmalloc(sizeof(*scratch), GFP_KERNEL); - if (!scratch) { - result = -ENOMEM; - goto error_alloc_scratch; - } - - for (bitr = 0; bitr < (len + 63) / 64; bitr++) { - sfn_le = cpu_to_le64(sfn++); - memcpy(&n.sfn, &sfn_le, sizeof(n.sfn)); /* n.sfn++... */ - result = wusb_ccm_mac(tfm_cbc, tfm_aes, scratch, out + bytes, - &n, a, b, blen); - if (result < 0) - goto error_ccm_mac; - bytes += result; - } - result = bytes; - - kfree(scratch); -error_alloc_scratch: -error_ccm_mac: -error_setkey_aes: - crypto_free_cipher(tfm_aes); -error_alloc_aes: -error_setkey_cbc: - crypto_free_sync_skcipher(tfm_cbc); -error_alloc_cbc: - return result; -} - -/* WUSB1.0[A.2] test vectors */ -static const u8 stv_hsmic_key[16] = { - 0x4b, 0x79, 0xa3, 0xcf, 0xe5, 0x53, 0x23, 0x9d, - 0xd7, 0xc1, 0x6d, 0x1c, 0x2d, 0xab, 0x6d, 0x3f -}; - -static const struct aes_ccm_nonce stv_hsmic_n = { - .sfn = { 0 }, - .tkid = { 0x76, 0x98, 0x01, }, - .dest_addr = { .data = { 0xbe, 0x00 } }, - .src_addr = { .data = { 0x76, 0x98 } }, -}; - -/* - * Out-of-band MIC Generation verification code - * - */ -static int wusb_oob_mic_verify(void) -{ - int result; - u8 mic[8]; - /* WUSB1.0[A.2] test vectors - * - * Need to keep it in the local stack as GCC 4.1.3something - * messes up and generates noise. - */ - struct usb_handshake stv_hsmic_hs = { - .bMessageNumber = 2, - .bStatus = 00, - .tTKID = { 0x76, 0x98, 0x01 }, - .bReserved = 00, - .CDID = { 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, - 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, - 0x3c, 0x3d, 0x3e, 0x3f }, - .nonce = { 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, - 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, - 0x2c, 0x2d, 0x2e, 0x2f }, - .MIC = { 0x75, 0x6a, 0x97, 0x51, 0x0c, 0x8c, - 0x14, 0x7b }, - }; - size_t hs_size; - - result = wusb_oob_mic(mic, stv_hsmic_key, &stv_hsmic_n, &stv_hsmic_hs); - if (result < 0) - printk(KERN_ERR "E: WUSB OOB MIC test: failed: %d\n", result); - else if (memcmp(stv_hsmic_hs.MIC, mic, sizeof(mic))) { - printk(KERN_ERR "E: OOB MIC test: " - "mismatch between MIC result and WUSB1.0[A2]\n"); - hs_size = sizeof(stv_hsmic_hs) - sizeof(stv_hsmic_hs.MIC); - printk(KERN_ERR "E: Handshake2 in: (%zu bytes)\n", hs_size); - wusb_key_dump(&stv_hsmic_hs, hs_size); - printk(KERN_ERR "E: CCM Nonce in: (%zu bytes)\n", - sizeof(stv_hsmic_n)); - wusb_key_dump(&stv_hsmic_n, sizeof(stv_hsmic_n)); - printk(KERN_ERR "E: MIC out:\n"); - wusb_key_dump(mic, sizeof(mic)); - printk(KERN_ERR "E: MIC out (from WUSB1.0[A.2]):\n"); - wusb_key_dump(stv_hsmic_hs.MIC, sizeof(stv_hsmic_hs.MIC)); - result = -EINVAL; - } else - result = 0; - return result; -} - -/* - * Test vectors for Key derivation - * - * These come from WUSB1.0[6.5.1], the vectors in WUSB1.0[A.1] - * (errata corrected in 2005/07). - */ -static const u8 stv_key_a1[16] __attribute__ ((__aligned__(4))) = { - 0xf0, 0xe1, 0xd2, 0xc3, 0xb4, 0xa5, 0x96, 0x87, - 0x78, 0x69, 0x5a, 0x4b, 0x3c, 0x2d, 0x1e, 0x0f -}; - -static const struct aes_ccm_nonce stv_keydvt_n_a1 = { - .sfn = { 0 }, - .tkid = { 0x76, 0x98, 0x01, }, - .dest_addr = { .data = { 0xbe, 0x00 } }, - .src_addr = { .data = { 0x76, 0x98 } }, -}; - -static const struct wusb_keydvt_out stv_keydvt_out_a1 = { - .kck = { - 0x4b, 0x79, 0xa3, 0xcf, 0xe5, 0x53, 0x23, 0x9d, - 0xd7, 0xc1, 0x6d, 0x1c, 0x2d, 0xab, 0x6d, 0x3f - }, - .ptk = { - 0xc8, 0x70, 0x62, 0x82, 0xb6, 0x7c, 0xe9, 0x06, - 0x7b, 0xc5, 0x25, 0x69, 0xf2, 0x36, 0x61, 0x2d - } -}; - -/* - * Performa a test to make sure we match the vectors defined in - * WUSB1.0[A.1](Errata2006/12) - */ -static int wusb_key_derive_verify(void) -{ - int result = 0; - struct wusb_keydvt_out keydvt_out; - /* These come from WUSB1.0[A.1] + 2006/12 errata - * NOTE: can't make this const or global -- somehow it seems - * the scatterlists for crypto get confused and we get - * bad data. There is no doc on this... */ - struct wusb_keydvt_in stv_keydvt_in_a1 = { - .hnonce = { - 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, - 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f - }, - .dnonce = { - 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, - 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f - } - }; - - result = wusb_key_derive(&keydvt_out, stv_key_a1, &stv_keydvt_n_a1, - &stv_keydvt_in_a1); - if (result < 0) - printk(KERN_ERR "E: WUSB key derivation test: " - "derivation failed: %d\n", result); - if (memcmp(&stv_keydvt_out_a1, &keydvt_out, sizeof(keydvt_out))) { - printk(KERN_ERR "E: WUSB key derivation test: " - "mismatch between key derivation result " - "and WUSB1.0[A1] Errata 2006/12\n"); - printk(KERN_ERR "E: keydvt in: key\n"); - wusb_key_dump(stv_key_a1, sizeof(stv_key_a1)); - printk(KERN_ERR "E: keydvt in: nonce\n"); - wusb_key_dump(&stv_keydvt_n_a1, sizeof(stv_keydvt_n_a1)); - printk(KERN_ERR "E: keydvt in: hnonce & dnonce\n"); - wusb_key_dump(&stv_keydvt_in_a1, sizeof(stv_keydvt_in_a1)); - printk(KERN_ERR "E: keydvt out: KCK\n"); - wusb_key_dump(&keydvt_out.kck, sizeof(keydvt_out.kck)); - printk(KERN_ERR "E: keydvt out: PTK\n"); - wusb_key_dump(&keydvt_out.ptk, sizeof(keydvt_out.ptk)); - result = -EINVAL; - } else - result = 0; - return result; -} - -/* - * Initialize crypto system - * - * FIXME: we do nothing now, other than verifying. Later on we'll - * cache the encryption stuff, so that's why we have a separate init. - */ -int wusb_crypto_init(void) -{ - int result; - - if (debug_crypto_verify) { - result = wusb_key_derive_verify(); - if (result < 0) - return result; - return wusb_oob_mic_verify(); - } - return 0; -} - -void wusb_crypto_exit(void) -{ - /* FIXME: free cached crypto transforms */ -} |