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wusb: add the Wireless USB core (security)

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Add the WUSB security (authentication) code.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
This commit is contained in:
Inaky Perez-Gonzalez 2008-09-17 16:34:25 +01:00 committed by David Vrabel
parent b69fada68b
commit d59db761b8
2 changed files with 1180 additions and 0 deletions
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538
drivers/usb/wusbcore/crypto.c Normal file
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/*
* Ultra Wide Band
* AES-128 CCM Encryption
*
* Copyright (C) 2007 Intel Corporation
* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*
* 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 <linux/crypto.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/uwb.h>
#include <linux/usb/wusb.h>
#include <linux/scatterlist.h>
#define D_LOCAL 0
#include <linux/uwb/debug.h>
/*
* 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 exahusted (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 sucesive 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];
}
/*
* 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 definiton 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_blkcipher *tfm_cbc,
struct crypto_cipher *tfm_aes, void *mic,
const struct aes_ccm_nonce *n,
const struct aes_ccm_label *a, const void *b,
size_t blen)
{
int result = 0;
struct blkcipher_desc desc;
struct aes_ccm_b0 b0;
struct aes_ccm_b1 b1;
struct aes_ccm_a ax;
struct scatterlist sg[4], sg_dst;
void *iv, *dst_buf;
size_t ivsize, dst_size;
const u8 bzero[16] = { 0 };
size_t zero_padding;
d_fnstart(3, NULL, "(tfm_cbc %p, tfm_aes %p, mic %p, "
"n %p, a %p, b %p, blen %zu)\n",
tfm_cbc, tfm_aes, mic, n, a, b, blen);
/*
* These checks should be compile time optimized out
* ensure @a fills b1's mac_header and following fields
*/
WARN_ON(sizeof(*a) != sizeof(b1) - sizeof(b1.la));
WARN_ON(sizeof(b0) != sizeof(struct aes_ccm_block));
WARN_ON(sizeof(b1) != sizeof(struct aes_ccm_block));
WARN_ON(sizeof(ax) != sizeof(struct aes_ccm_block));
result = -ENOMEM;
zero_padding = sizeof(struct aes_ccm_block)
- blen % sizeof(struct aes_ccm_block);
zero_padding = blen % sizeof(struct aes_ccm_block);
if (zero_padding)
zero_padding = sizeof(struct aes_ccm_block) - zero_padding;
dst_size = blen + sizeof(b0) + sizeof(b1) + zero_padding;
dst_buf = kzalloc(dst_size, GFP_KERNEL);
if (dst_buf == NULL) {
printk(KERN_ERR "E: can't alloc destination buffer\n");
goto error_dst_buf;
}
iv = crypto_blkcipher_crt(tfm_cbc)->iv;
ivsize = crypto_blkcipher_ivsize(tfm_cbc);
memset(iv, 0, ivsize);
/* Setup B0 */
b0.flags = 0x59; /* Format B0 */
b0.ccm_nonce = *n;
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.
*/
b1.la = cpu_to_be16(blen + 14);
memcpy(&b1.mac_header, a, sizeof(*a));
d_printf(4, NULL, "I: B0 (%zu bytes)\n", sizeof(b0));
d_dump(4, NULL, &b0, sizeof(b0));
d_printf(4, NULL, "I: B1 (%zu bytes)\n", sizeof(b1));
d_dump(4, NULL, &b1, sizeof(b1));
d_printf(4, NULL, "I: B (%zu bytes)\n", blen);
d_dump(4, NULL, b, blen);
d_printf(4, NULL, "I: B 0-padding (%zu bytes)\n", zero_padding);
d_printf(4, NULL, "D: IV before crypto (%zu)\n", ivsize);
d_dump(4, NULL, iv, ivsize);
sg_init_table(sg, ARRAY_SIZE(sg));
sg_set_buf(&sg[0], &b0, sizeof(b0));
sg_set_buf(&sg[1], &b1, sizeof(b1));
sg_set_buf(&sg[2], b, blen);
/* 0 if well behaved :) */
sg_set_buf(&sg[3], bzero, zero_padding);
sg_init_one(&sg_dst, dst_buf, dst_size);
desc.tfm = tfm_cbc;
desc.flags = 0;
result = crypto_blkcipher_encrypt(&desc, &sg_dst, sg, dst_size);
if (result < 0) {
printk(KERN_ERR "E: can't compute CBC-MAC tag (MIC): %d\n",
result);
goto error_cbc_crypt;
}
d_printf(4, NULL, "D: MIC tag\n");
d_dump(4, NULL, iv, ivsize);
/* 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 agains 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
*/
ax.flags = 0x01; /* as per WUSB 1.0 spec */
ax.ccm_nonce = *n;
ax.counter = 0;
crypto_cipher_encrypt_one(tfm_aes, (void *)&ax, (void *)&ax);
bytewise_xor(mic, &ax, iv, 8);
d_printf(4, NULL, "D: CTR[MIC]\n");
d_dump(4, NULL, &ax, 8);
d_printf(4, NULL, "D: CCM-MIC tag\n");
d_dump(4, NULL, mic, 8);
result = 8;
error_cbc_crypt:
kfree(dst_buf);
error_dst_buf:
d_fnend(3, NULL, "(tfm_cbc %p, tfm_aes %p, mic %p, "
"n %p, a %p, b %p, blen %zu)\n",
tfm_cbc, tfm_aes, mic, n, a, b, blen);
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_blkcipher *tfm_cbc;
struct crypto_cipher *tfm_aes;
u64 sfn = 0;
__le64 sfn_le;
d_fnstart(3, NULL, "(out %p, out_size %zu, key %p, _n %p, "
"a %p, b %p, blen %zu, len %zu)\n", out, out_size,
key, _n, a, b, blen, len);
tfm_cbc = crypto_alloc_blkcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
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_blkcipher_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, CRYPTO_ALG_ASYNC);
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;
}
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, out + bytes,
&n, a, b, blen);
if (result < 0)
goto error_ccm_mac;
bytes += result;
}
result = bytes;
error_ccm_mac:
error_setkey_aes:
crypto_free_cipher(tfm_aes);
error_alloc_aes:
error_setkey_cbc:
crypto_free_blkcipher(tfm_cbc);
error_alloc_cbc:
d_fnend(3, NULL, "(out %p, out_size %zu, key %p, _n %p, "
"a %p, b %p, blen %zu, len %zu) = %d\n", out, out_size,
key, _n, a, b, blen, len, (int)bytes);
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);
dump_bytes(NULL, &stv_hsmic_hs, hs_size);
printk(KERN_ERR "E: CCM Nonce in: (%zu bytes)\n",
sizeof(stv_hsmic_n));
dump_bytes(NULL, &stv_hsmic_n, sizeof(stv_hsmic_n));
printk(KERN_ERR "E: MIC out:\n");
dump_bytes(NULL, mic, sizeof(mic));
printk(KERN_ERR "E: MIC out (from WUSB1.0[A.2]):\n");
dump_bytes(NULL, 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 (%zu bytes)\n",
sizeof(stv_key_a1));
dump_bytes(NULL, stv_key_a1, sizeof(stv_key_a1));
printk(KERN_ERR "E: keydvt in: nonce (%zu bytes)\n",
sizeof(stv_keydvt_n_a1));
dump_bytes(NULL, &stv_keydvt_n_a1, sizeof(stv_keydvt_n_a1));
printk(KERN_ERR "E: keydvt in: hnonce & dnonce (%zu bytes)\n",
sizeof(stv_keydvt_in_a1));
dump_bytes(NULL, &stv_keydvt_in_a1, sizeof(stv_keydvt_in_a1));
printk(KERN_ERR "E: keydvt out: KCK\n");
dump_bytes(NULL, &keydvt_out.kck, sizeof(keydvt_out.kck));
printk(KERN_ERR "E: keydvt out: PTK\n");
dump_bytes(NULL, &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;
result = wusb_key_derive_verify();
if (result < 0)
return result;
return wusb_oob_mic_verify();
}
void wusb_crypto_exit(void)
{
/* FIXME: free cached crypto transforms */
}

642
drivers/usb/wusbcore/security.c Normal file
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@ -0,0 +1,642 @@
/*
* Wireless USB Host Controller
* Security support: encryption enablement, etc
*
* Copyright (C) 2006 Intel Corporation
* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*
* FIXME: docs
*/
#include <linux/types.h>
#include <linux/usb/ch9.h>
#include <linux/random.h>
#include "wusbhc.h"
/*
* DEBUG & SECURITY WARNING!!!!
*
* If you enable this past 1, the debug code will weaken the
* cryptographic safety of the system (on purpose, for debugging).
*
* Weaken means:
* we print secret keys and intermediate values all the way,
*/
#undef D_LOCAL
#define D_LOCAL 2
#include <linux/uwb/debug.h>
static void wusbhc_set_gtk_callback(struct urb *urb);
static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
int wusbhc_sec_create(struct wusbhc *wusbhc)
{
wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
wusbhc->gtk.descr.bReserved = 0;
wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
WUSB_KEY_INDEX_ORIGINATOR_HOST);
INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
return 0;
}
/* Called when the HC is destroyed */
void wusbhc_sec_destroy(struct wusbhc *wusbhc)
{
}
/**
* wusbhc_next_tkid - generate a new, currently unused, TKID
* @wusbhc: the WUSB host controller
* @wusb_dev: the device whose PTK the TKID is for
* (or NULL for a TKID for a GTK)
*
* The generated TKID consist of two parts: the device's authenicated
* address (or 0 or a GTK); and an incrementing number. This ensures
* that TKIDs cannot be shared between devices and by the time the
* incrementing number wraps around the older TKIDs will no longer be
* in use (a maximum of two keys may be active at any one time).
*/
static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
{
u32 *tkid;
u32 addr;
if (wusb_dev == NULL) {
tkid = &wusbhc->gtk_tkid;
addr = 0;
} else {
tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
addr = wusb_dev->addr & 0x7f;
}
*tkid = (addr << 8) | ((*tkid + 1) & 0xff);
return *tkid;
}
static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
{
const size_t key_size = sizeof(wusbhc->gtk.data);
u32 tkid;
tkid = wusbhc_next_tkid(wusbhc, NULL);
wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
}
/**
* wusbhc_sec_start - start the security management process
* @wusbhc: the WUSB host controller
*
* Generate and set an initial GTK on the host controller.
*
* Called when the HC is started.
*/
int wusbhc_sec_start(struct wusbhc *wusbhc)
{
const size_t key_size = sizeof(wusbhc->gtk.data);
int result;
wusbhc_generate_gtk(wusbhc);
result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
&wusbhc->gtk.descr.bKeyData, key_size);
if (result < 0)
dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
result);
return result;
}
/**
* wusbhc_sec_stop - stop the security management process
* @wusbhc: the WUSB host controller
*
* Wait for any pending GTK rekeys to stop.
*/
void wusbhc_sec_stop(struct wusbhc *wusbhc)
{
cancel_work_sync(&wusbhc->gtk_rekey_done_work);
}
/** @returns encryption type name */
const char *wusb_et_name(u8 x)
{
switch (x) {
case USB_ENC_TYPE_UNSECURE: return "unsecure";
case USB_ENC_TYPE_WIRED: return "wired";
case USB_ENC_TYPE_CCM_1: return "CCM-1";
case USB_ENC_TYPE_RSA_1: return "RSA-1";
default: return "unknown";
}
}
EXPORT_SYMBOL_GPL(wusb_et_name);
/*
* Set the device encryption method
*
* We tell the device which encryption method to use; we do this when
* setting up the device's security.
*/
static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
{
int result;
struct device *dev = &usb_dev->dev;
struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
if (value) {
value = wusb_dev->ccm1_etd.bEncryptionValue;
} else {
/* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
value = 0;
}
/* Set device's */
result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
USB_REQ_SET_ENCRYPTION,
USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
value, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
if (result < 0)
dev_err(dev, "Can't set device's WUSB encryption to "
"%s (value %d): %d\n",
wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
wusb_dev->ccm1_etd.bEncryptionValue, result);
return result;
}
/*
* Set the GTK to be used by a device.
*
* The device must be authenticated.
*/
static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
{
struct usb_device *usb_dev = wusb_dev->usb_dev;
return usb_control_msg(
usb_dev, usb_sndctrlpipe(usb_dev, 0),
USB_REQ_SET_DESCRIPTOR,
USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
&wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
1000);
}
/* FIXME: prototype for adding security */
int wusb_dev_sec_add(struct wusbhc *wusbhc,
struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
{
int result, bytes, secd_size;
struct device *dev = &usb_dev->dev;
struct usb_security_descriptor secd;
const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
void *secd_buf;
const void *itr, *top;
char buf[64];
d_fnstart(3, dev, "(usb_dev %p, wusb_dev %p)\n", usb_dev, wusb_dev);
result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
0, &secd, sizeof(secd));
if (result < sizeof(secd)) {
dev_err(dev, "Can't read security descriptor or "
"not enough data: %d\n", result);
goto error_secd;
}
secd_size = le16_to_cpu(secd.wTotalLength);
d_printf(5, dev, "got %d bytes of sec descriptor, total is %d\n",
result, secd_size);
secd_buf = kmalloc(secd_size, GFP_KERNEL);
if (secd_buf == NULL) {
dev_err(dev, "Can't allocate space for security descriptors\n");
goto error_secd_alloc;
}
result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
0, secd_buf, secd_size);
if (result < secd_size) {
dev_err(dev, "Can't read security descriptor or "
"not enough data: %d\n", result);
goto error_secd_all;
}
d_printf(5, dev, "got %d bytes of sec descriptors\n", result);
bytes = 0;
itr = secd_buf + sizeof(secd);
top = secd_buf + result;
while (itr < top) {
etd = itr;
if (top - itr < sizeof(*etd)) {
dev_err(dev, "BUG: bad device security descriptor; "
"not enough data (%zu vs %zu bytes left)\n",
top - itr, sizeof(*etd));
break;
}
if (etd->bLength < sizeof(*etd)) {
dev_err(dev, "BUG: bad device encryption descriptor; "
"descriptor is too short "
"(%u vs %zu needed)\n",
etd->bLength, sizeof(*etd));
break;
}
itr += etd->bLength;
bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
"%s (0x%02x/%02x) ",
wusb_et_name(etd->bEncryptionType),
etd->bEncryptionValue, etd->bAuthKeyIndex);
if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
ccm1_etd = etd;
}
/* This code only supports CCM1 as of now. */
/* FIXME: user has to choose which sec mode to use?
* In theory we want CCM */
if (ccm1_etd == NULL) {
dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
"can't use!\n");
result = -EINVAL;
goto error_no_ccm1;
}
wusb_dev->ccm1_etd = *ccm1_etd;
dev_info(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
buf, wusb_et_name(ccm1_etd->bEncryptionType),
ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
result = 0;
kfree(secd_buf);
out:
d_fnend(3, dev, "(usb_dev %p, wusb_dev %p) = %d\n",
usb_dev, wusb_dev, result);
return result;
error_no_ccm1:
error_secd_all:
kfree(secd_buf);
error_secd_alloc:
error_secd:
goto out;
}
void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
{
/* Nothing so far */
}
static void hs_printk(unsigned level, struct device *dev,
struct usb_handshake *hs)
{
d_printf(level, dev,
" bMessageNumber: %u\n"
" bStatus: %u\n"
" tTKID: %02x %02x %02x\n"
" CDID: %02x %02x %02x %02x %02x %02x %02x %02x\n"
" %02x %02x %02x %02x %02x %02x %02x %02x\n"
" nonce: %02x %02x %02x %02x %02x %02x %02x %02x\n"
" %02x %02x %02x %02x %02x %02x %02x %02x\n"
" MIC: %02x %02x %02x %02x %02x %02x %02x %02x\n",
hs->bMessageNumber, hs->bStatus,
hs->tTKID[2], hs->tTKID[1], hs->tTKID[0],
hs->CDID[0], hs->CDID[1], hs->CDID[2], hs->CDID[3],
hs->CDID[4], hs->CDID[5], hs->CDID[6], hs->CDID[7],
hs->CDID[8], hs->CDID[9], hs->CDID[10], hs->CDID[11],
hs->CDID[12], hs->CDID[13], hs->CDID[14], hs->CDID[15],
hs->nonce[0], hs->nonce[1], hs->nonce[2], hs->nonce[3],
hs->nonce[4], hs->nonce[5], hs->nonce[6], hs->nonce[7],
hs->nonce[8], hs->nonce[9], hs->nonce[10], hs->nonce[11],
hs->nonce[12], hs->nonce[13], hs->nonce[14], hs->nonce[15],
hs->MIC[0], hs->MIC[1], hs->MIC[2], hs->MIC[3],
hs->MIC[4], hs->MIC[5], hs->MIC[6], hs->MIC[7]);
}
/**
* Update the address of an unauthenticated WUSB device
*
* Once we have successfully authenticated, we take it to addr0 state
* and then to a normal address.
*
* Before the device's address (as known by it) was usb_dev->devnum |
* 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
*/
static int wusb_dev_update_address(struct wusbhc *wusbhc,
struct wusb_dev *wusb_dev)
{
int result = -ENOMEM;
struct usb_device *usb_dev = wusb_dev->usb_dev;
struct device *dev = &usb_dev->dev;
u8 new_address = wusb_dev->addr & 0x7F;
/* Set address 0 */
result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
USB_REQ_SET_ADDRESS, 0,
0, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "auth failed: can't set address 0: %d\n",
result);
goto error_addr0;
}
result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
if (result < 0)
goto error_addr0;
usb_ep0_reinit(usb_dev);
/* Set new (authenticated) address. */
result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
USB_REQ_SET_ADDRESS, 0,
new_address, 0, NULL, 0,
1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "auth failed: can't set address %u: %d\n",
new_address, result);
goto error_addr;
}
result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
if (result < 0)
goto error_addr;
usb_ep0_reinit(usb_dev);
usb_dev->authenticated = 1;
error_addr:
error_addr0:
return result;
}
/*
*
*
*/
/* FIXME: split and cleanup */
int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
struct wusb_ckhdid *ck)
{
int result = -ENOMEM;
struct usb_device *usb_dev = wusb_dev->usb_dev;
struct device *dev = &usb_dev->dev;
u32 tkid;
__le32 tkid_le;
struct usb_handshake *hs;
struct aes_ccm_nonce ccm_n;
u8 mic[8];
struct wusb_keydvt_in keydvt_in;
struct wusb_keydvt_out keydvt_out;
hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
if (hs == NULL) {
dev_err(dev, "can't allocate handshake data\n");
goto error_kzalloc;
}
/* We need to turn encryption before beginning the 4way
* hshake (WUSB1.0[.3.2.2]) */
result = wusb_dev_set_encryption(usb_dev, 1);
if (result < 0)
goto error_dev_set_encryption;
tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
tkid_le = cpu_to_le32(tkid);
hs[0].bMessageNumber = 1;
hs[0].bStatus = 0;
memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
hs[0].bReserved = 0;
memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
d_printf(1, dev, "I: sending hs1:\n");
hs_printk(2, dev, &hs[0]);
result = usb_control_msg(
usb_dev, usb_sndctrlpipe(usb_dev, 0),
USB_REQ_SET_HANDSHAKE,
USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "Handshake1: request failed: %d\n", result);
goto error_hs1;
}
/* Handshake 2, from the device -- need to verify fields */
result = usb_control_msg(
usb_dev, usb_rcvctrlpipe(usb_dev, 0),
USB_REQ_GET_HANDSHAKE,
USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "Handshake2: request failed: %d\n", result);
goto error_hs2;
}
d_printf(1, dev, "got HS2:\n");
hs_printk(2, dev, &hs[1]);
result = -EINVAL;
if (hs[1].bMessageNumber != 2) {
dev_err(dev, "Handshake2 failed: bad message number %u\n",
hs[1].bMessageNumber);
goto error_hs2;
}
if (hs[1].bStatus != 0) {
dev_err(dev, "Handshake2 failed: bad status %u\n",
hs[1].bStatus);
goto error_hs2;
}
if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
dev_err(dev, "Handshake2 failed: TKID mismatch "
"(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
goto error_hs2;
}
if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
dev_err(dev, "Handshake2 failed: CDID mismatch\n");
goto error_hs2;
}
/* Setup the CCM nonce */
memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
ccm_n.dest_addr.data[0] = wusb_dev->addr;
ccm_n.dest_addr.data[1] = 0;
/* Derive the KCK and PTK from CK, the CCM, H and D nonces */
memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
if (result < 0) {
dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
result);
goto error_hs2;
}
d_printf(2, dev, "KCK:\n");
d_dump(2, dev, keydvt_out.kck, sizeof(keydvt_out.kck));
d_printf(2, dev, "PTK:\n");
d_dump(2, dev, keydvt_out.ptk, sizeof(keydvt_out.ptk));
/* Compute MIC and verify it */
result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
if (result < 0) {
dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
result);
goto error_hs2;
}
d_printf(2, dev, "MIC:\n");
d_dump(2, dev, mic, sizeof(mic));
if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
dev_err(dev, "Handshake2 failed: MIC mismatch\n");
goto error_hs2;
}
/* Send Handshake3 */
hs[2].bMessageNumber = 3;
hs[2].bStatus = 0;
memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
hs[2].bReserved = 0;
memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
if (result < 0) {
dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
result);
goto error_hs2;
}
d_printf(1, dev, "I: sending hs3:\n");
hs_printk(2, dev, &hs[2]);
result = usb_control_msg(
usb_dev, usb_sndctrlpipe(usb_dev, 0),
USB_REQ_SET_HANDSHAKE,
USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "Handshake3: request failed: %d\n", result);
goto error_hs3;
}
d_printf(1, dev, "I: turning on encryption on host for device\n");
d_dump(2, dev, keydvt_out.ptk, sizeof(keydvt_out.ptk));
result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
keydvt_out.ptk, sizeof(keydvt_out.ptk));
if (result < 0)
goto error_wusbhc_set_ptk;
d_printf(1, dev, "I: setting a GTK\n");
result = wusb_dev_set_gtk(wusbhc, wusb_dev);
if (result < 0) {
dev_err(dev, "Set GTK for device: request failed: %d\n",
result);
goto error_wusbhc_set_gtk;
}
/* Update the device's address from unauth to auth */
if (usb_dev->authenticated == 0) {
d_printf(1, dev, "I: updating addres to auth from non-auth\n");
result = wusb_dev_update_address(wusbhc, wusb_dev);
if (result < 0)
goto error_dev_update_address;
}
result = 0;
d_printf(1, dev, "I: 4way handshke done, device authenticated\n");
error_dev_update_address:
error_wusbhc_set_gtk:
error_wusbhc_set_ptk:
error_hs3:
error_hs2:
error_hs1:
memset(hs, 0, 3*sizeof(hs[0]));
memset(&keydvt_out, 0, sizeof(keydvt_out));
memset(&keydvt_in, 0, sizeof(keydvt_in));
memset(&ccm_n, 0, sizeof(ccm_n));
memset(mic, 0, sizeof(mic));
if (result < 0) {
/* error path */
wusb_dev_set_encryption(usb_dev, 0);
}
error_dev_set_encryption:
kfree(hs);
error_kzalloc:
return result;
}
/*
* Once all connected and authenticated devices have received the new
* GTK, switch the host to using it.
*/
static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
{
struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
size_t key_size = sizeof(wusbhc->gtk.data);
mutex_lock(&wusbhc->mutex);
if (--wusbhc->pending_set_gtks == 0)
wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
mutex_unlock(&wusbhc->mutex);
}
static void wusbhc_set_gtk_callback(struct urb *urb)
{
struct wusbhc *wusbhc = urb->context;
queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
}
/**
* wusbhc_gtk_rekey - generate and distribute a new GTK
* @wusbhc: the WUSB host controller
*
* Generate a new GTK and distribute it to all connected and
* authenticated devices. When all devices have the new GTK, the host
* starts using it.
*
* This must be called after every device disconnect (see [WUSB]
* section 6.2.11.2).
*/
void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
{
static const size_t key_size = sizeof(wusbhc->gtk.data);
int p;
wusbhc_generate_gtk(wusbhc);
for (p = 0; p < wusbhc->ports_max; p++) {
struct wusb_dev *wusb_dev;
wusb_dev = wusbhc->port[p].wusb_dev;
if (!wusb_dev || !wusb_dev->usb_dev | !wusb_dev->usb_dev->authenticated)
continue;
usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
usb_sndctrlpipe(wusb_dev->usb_dev, 0),
(void *)wusb_dev->set_gtk_req,
&wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
wusbhc_set_gtk_callback, wusbhc);
if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
wusbhc->pending_set_gtks++;
}
if (wusbhc->pending_set_gtks == 0)
wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
}