/*
* Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3.
* Well, not what's written there, but rather what they meant.
*/
static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
{
struct scatterlist sg_in[1], sg_out[1];
struct blkcipher_desc desc = { .tfm = state->arc4 };
get_new_key_from_sha(state);
if (!initial_key) {
crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
state->keylen);
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 1);
setup_sg(sg_in, state->sha1_digest, state->keylen);
setup_sg(sg_out, state->session_key, state->keylen);
if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
state->keylen) != 0) {
printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
}
} else {
memcpy(state->session_key, state->sha1_digest, state->keylen);
}
if (state->keylen == 8) {
/* See RFC 3078 */
state->session_key[0] = 0xd1;
state->session_key[1] = 0x26;
state->session_key[2] = 0x9e;
}
crypto_blkcipher_setkey(state->arc4, state->session_key, state->keylen);
}
/*
* Allocate space for a (de)compressor.
*/
static void *mppe_alloc(unsigned char *options, int optlen)
{
struct ppp_mppe_state *state;
unsigned int digestsize;
if (optlen != CILEN_MPPE + sizeof(state->master_key) ||
options[0] != CI_MPPE || options[1] != CILEN_MPPE)
goto out;
state = kzalloc(sizeof(*state), GFP_KERNEL);
if (state == NULL)
goto out;
state->arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(state->arc4)) {
state->arc4 = NULL;
goto out_free;
}
state->sha1 = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(state->sha1)) {
state->sha1 = NULL;
goto out_free;
}
digestsize = crypto_hash_digestsize(state->sha1);
if (digestsize < MPPE_MAX_KEY_LEN)
goto out_free;
state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
if (!state->sha1_digest)
goto out_free;
/* Save keys. */
memcpy(state->master_key, &options[CILEN_MPPE],
sizeof(state->master_key));
memcpy(state->session_key, state->master_key,
sizeof(state->master_key));
/*
* We defer initial key generation until mppe_init(), as mppe_alloc()
* is called frequently during negotiation.
*/
return (void *)state;
out_free:
if (state->sha1_digest)
kfree(state->sha1_digest);
if (state->sha1)
crypto_free_hash(state->sha1);
if (state->arc4)
crypto_free_blkcipher(state->arc4);
kfree(state);
out:
return NULL;
}
/*
* Deallocate space for a (de)compressor.
*/
static void mppe_free(void *arg)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
if (state) {
if (state->sha1_digest)
kfree(state->sha1_digest);
if (state->sha1)
crypto_free_hash(state->sha1);
if (state->arc4)
crypto_free_blkcipher(state->arc4);
kfree(state);
}
}
/*
* Initialize (de)compressor state.
*/
static int
mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug,
const char *debugstr)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
unsigned char mppe_opts;
if (optlen != CILEN_MPPE ||
options[0] != CI_MPPE || options[1] != CILEN_MPPE)
return 0;
MPPE_CI_TO_OPTS(&options[2], mppe_opts);
if (mppe_opts & MPPE_OPT_128)
state->keylen = 16;
else if (mppe_opts & MPPE_OPT_40)
state->keylen = 8;
else {
printk(KERN_WARNING "%s[%d]: unknown key length\n", debugstr,
unit);
return 0;
}
if (mppe_opts & MPPE_OPT_STATEFUL)
state->stateful = 1;
/* Generate the initial session key. */
mppe_rekey(state, 1);
if (debug) {
int i;
char mkey[sizeof(state->master_key) * 2 + 1];
char skey[sizeof(state->session_key) * 2 + 1];
printk(KERN_DEBUG "%s[%d]: initialized with %d-bit %s mode\n",
debugstr, unit, (state->keylen == 16) ? 128 : 40,
(state->stateful) ? "stateful" : "stateless");
for (i = 0; i < sizeof(state->master_key); i++)
sprintf(mkey + i * 2, "%02x", state->master_key[i]);
for (i = 0; i < sizeof(state->session_key); i++)
sprintf(skey + i * 2, "%02x", state->session_key[i]);
printk(KERN_DEBUG
"%s[%d]: keys: master: %s initial session: %s\n",
debugstr, unit, mkey, skey);
}
/*
* Initialize the coherency count. The initial value is not specified
* in RFC 3078, but we can make a reasonable assumption that it will
* start at 0. Setting it to the max here makes the comp/decomp code
* do the right thing (determined through experiment).
*/
state->ccount = MPPE_CCOUNT_SPACE - 1;
/*
* Note that even though we have initialized the key table, we don't
* set the FLUSHED bit. This is contrary to RFC 3078, sec. 3.1.
*/
state->bits = MPPE_BIT_ENCRYPTED;
state->unit = unit;
state->debug = debug;
return 1;
}
static int
mppe_comp_init(void *arg, unsigned char *options, int optlen, int unit,
int hdrlen, int debug)
{
/* ARGSUSED */
return mppe_init(arg, options, optlen, unit, debug, "mppe_comp_init");
}
/*
* We received a CCP Reset-Request (actually, we are sending a Reset-Ack),
* tell the compressor to rekey. Note that we MUST NOT rekey for
* every CCP Reset-Request; we only rekey on the next xmit packet.
* We might get multiple CCP Reset-Requests if our CCP Reset-Ack is lost.
* So, rekeying for every CCP Reset-Request is broken as the peer will not
* know how many times we've rekeyed. (If we rekey and THEN get another
* CCP Reset-Request, we must rekey again.)
*/
static void mppe_comp_reset(void *arg)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
state->bits |= MPPE_BIT_FLUSHED;
}
/*
* Compress (encrypt) a packet.
* It's strange to call this a compressor, since the output is always
* MPPE_OVHD + 2 bytes larger than the input.
*/
static int
mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
int isize, int osize)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
struct blkcipher_desc desc = { .tfm = state->arc4 };
int proto;
struct scatterlist sg_in[1], sg_out[1];
/*
* Check that the protocol is in the range we handle.
*/
proto = PPP_PROTOCOL(ibuf);
if (proto < 0x0021 || proto > 0x00fa)
return 0;
/* Make sure we have enough room to generate an encrypted packet. */
if (osize < isize + MPPE_OVHD + 2) {
/* Drop the packet if we should encrypt it, but can't. */
printk(KERN_DEBUG "mppe_compress[%d]: osize too small! "
"(have: %d need: %d)\n", state->unit,
osize, osize + MPPE_OVHD + 2);
return -1;
}
osize = isize + MPPE_OVHD + 2;
/*
* Copy over the PPP header and set control bits.
*/
obuf[0] = PPP_ADDRESS(ibuf);
obuf[1] = PPP_CONTROL(ibuf);
put_unaligned_be16(PPP_COMP, obuf + 2);
obuf += PPP_HDRLEN;
state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
if (state->debug >= 7)
printk(KERN_DEBUG "mppe_compress[%d]: ccount %d\n", state->unit,
state->ccount);
put_unaligned_be16(state->ccount, obuf);
if (!state->stateful || /* stateless mode */
((state->ccount & 0xff) == 0xff) || /* "flag" packet */
(state->bits & MPPE_BIT_FLUSHED)) { /* CCP Reset-Request */
/* We must rekey */
if (state->debug && state->stateful)
printk(KERN_DEBUG "mppe_compress[%d]: rekeying\n",
state->unit);
mppe_rekey(state, 0);
state->bits |= MPPE_BIT_FLUSHED;
}
obuf[0] |= state->bits;
state->bits &= ~MPPE_BIT_FLUSHED; /* reset for next xmit */
obuf += MPPE_OVHD;
ibuf += 2; /* skip to proto field */
isize -= 2;
/* Encrypt packet */
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 1);
setup_sg(sg_in, ibuf, isize);
setup_sg(sg_out, obuf, osize);
if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in, isize) != 0) {
printk(KERN_DEBUG "crypto_cypher_encrypt failed\n");
return -1;
}
state->stats.unc_bytes += isize;
state->stats.unc_packets++;
state->stats.comp_bytes += osize;
state->stats.comp_packets++;
return osize;
}
/*
* Since every frame grows by MPPE_OVHD + 2 bytes, this is always going
* to look bad ... and the longer the link is up the worse it will get.
*/
static void mppe_comp_stats(void *arg, struct compstat *stats)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
*stats = state->stats;
}
static int
mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit,
int hdrlen, int mru, int debug)
{
/* ARGSUSED */
return mppe_init(arg, options, optlen, unit, debug, "mppe_decomp_init");
}
/*
* We received a CCP Reset-Ack. Just ignore it.
*/
static void mppe_decomp_reset(void *arg)
{
/* ARGSUSED */
return;
}
/*
* Decompress (decrypt) an MPPE packet.
*/
static int
mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf,
int osize)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
struct blkcipher_desc desc = { .tfm = state->arc4 };
unsigned ccount;
int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED;
int sanity = 0;
struct scatterlist sg_in[1], sg_out[1];
if (isize <= PPP_HDRLEN + MPPE_OVHD) {
if (state->debug)
printk(KERN_DEBUG
"mppe_decompress[%d]: short pkt (%d)\n",
state->unit, isize);
return DECOMP_ERROR;
}
/*
* Make sure we have enough room to decrypt the packet.
* Note that for our test we only subtract 1 byte whereas in
* mppe_compress() we added 2 bytes (+MPPE_OVHD);
* this is to account for possible PFC.
*/
if (osize < isize - MPPE_OVHD - 1) {
printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! "
"(have: %d need: %d)\n", state->unit,
osize, isize - MPPE_OVHD - 1);
return DECOMP_ERROR;
}
osize = isize - MPPE_OVHD - 2; /* assume no PFC */
ccount = MPPE_CCOUNT(ibuf);
if (state->debug >= 7)
printk(KERN_DEBUG "mppe_decompress[%d]: ccount %d\n",
state->unit, ccount);
/* sanity checks -- terminate with extreme prejudice */
if (!(MPPE_BITS(ibuf) & MPPE_BIT_ENCRYPTED)) {
printk(KERN_DEBUG
"mppe_decompress[%d]: ENCRYPTED bit not set!\n",
state->unit);
state->sanity_errors += 100;
sanity = 1;
}
if (!state->stateful && !flushed) {
printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set in "
"stateless mode!\n", state->unit);
state->sanity_errors += 100;
sanity = 1;
}
if (state->stateful && ((ccount & 0xff) == 0xff) && !flushed) {
printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set on "
"flag packet!\n", state->unit);
state->sanity_errors += 100;
sanity = 1;
}
if (sanity) {
if (state->sanity_errors < SANITY_MAX)
return DECOMP_ERROR;
else
/*
* Take LCP down if the peer is sending too many bogons.
* We don't want to do this for a single or just a few
* instances since it could just be due to packet corruption.
*/
return DECOMP_FATALERROR;
}
/*
* Check the coherency count.
*/
if (!state->stateful) {
/* RFC 3078, sec 8.1. Rekey for every packet. */
while (state->ccount != ccount) {
mppe_rekey(state, 0);
state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
}
} else {
/* RFC 3078, sec 8.2. */
if (!state->discard) {
/* normal state */
state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
if (ccount != state->ccount) {
/*
* (ccount > state->ccount)
* Packet loss detected, enter the discard state.
* Signal the peer to rekey (by sending a CCP Reset-Request).
*/
state->discard = 1;
return DECOMP_ERROR;
}
} else {
/* discard state */
if (!flushed) {
/* ccp.c will be silent (no additional CCP Reset-Requests). */
return DECOMP_ERROR;
} else {
/* Rekey for every missed "flag" packet. */
while ((ccount & ~0xff) !=
(state->ccount & ~0xff)) {
mppe_rekey(state, 0);
state->ccount =
(state->ccount +
256) % MPPE_CCOUNT_SPACE;
}
/* reset */
state->discard = 0;
state->ccount = ccount;
/*
* Another problem with RFC 3078 here. It implies that the
* peer need not send a Reset-Ack packet. But RFC 1962
* requires it. Hopefully, M$ does send a Reset-Ack; even
* though it isn't required for MPPE synchronization, it is
* required to reset CCP state.
*/
}
}
if (flushed)
mppe_rekey(state, 0);
}
/*
* Fill in the first part of the PPP header. The protocol field
* comes from the decrypted data.
*/
obuf[0] = PPP_ADDRESS(ibuf); /* +1 */
obuf[1] = PPP_CONTROL(ibuf); /* +1 */
obuf += 2;
ibuf += PPP_HDRLEN + MPPE_OVHD;
isize -= PPP_HDRLEN + MPPE_OVHD; /* -6 */
/* net osize: isize-4 */
/*
* Decrypt the first byte in order to check if it is
* a compressed or uncompressed protocol field.
*/
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 1);
setup_sg(sg_in, ibuf, 1);
setup_sg(sg_out, obuf, 1);
if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, 1) != 0) {
printk(KERN_DEBUG "crypto_cypher_decrypt failed\n");
return DECOMP_ERROR;
}
/*
* Do PFC decompression.
* This would be nicer if we were given the actual sk_buff
* instead of a char *.
*/
if ((obuf[0] & 0x01) != 0) {
obuf[1] = obuf[0];
obuf[0] = 0;
obuf++;
osize++;
}
/* And finally, decrypt the rest of the packet. */
setup_sg(sg_in, ibuf + 1, isize - 1);
setup_sg(sg_out, obuf + 1, osize - 1);
if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, isize - 1)) {
printk(KERN_DEBUG "crypto_cypher_decrypt failed\n");
return DECOMP_ERROR;
}
state->stats.unc_bytes += osize;
state->stats.unc_packets++;
state->stats.comp_bytes += isize;
state->stats.comp_packets++;
/* good packet credit */
state->sanity_errors >>= 1;
return osize;
}
/*
* Incompressible data has arrived (this should never happen!).
* We should probably drop the link if the protocol is in the range
* of what should be encrypted. At the least, we should drop this
* packet. (How to do this?)
*/
static void mppe_incomp(void *arg, unsigned char *ibuf, int icnt)
{
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
if (state->debug &&
(PPP_PROTOCOL(ibuf) >= 0x0021 && PPP_PROTOCOL(ibuf) <= 0x00fa))
printk(KERN_DEBUG
"mppe_incomp[%d]: incompressible (unencrypted) data! "
"(proto %04x)\n", state->unit, PPP_PROTOCOL(ibuf));
state->stats.inc_bytes += icnt;
state->stats.inc_packets++;
state->stats.unc_bytes += icnt;
state->stats.unc_packets++;
}
/*************************************************************
* Module interface table
*************************************************************/
/*
* Procedures exported to if_ppp.c.
*/
static struct compressor ppp_mppe = {
.compress_proto = CI_MPPE,
.comp_alloc = mppe_alloc,
.comp_free = mppe_free,
.comp_init = mppe_comp_init,
.comp_reset = mppe_comp_reset,
.compress = mppe_compress,
.comp_stat = mppe_comp_stats,
.decomp_alloc = mppe_alloc,
.decomp_free = mppe_free,
.decomp_init = mppe_decomp_init,
.decomp_reset = mppe_decomp_reset,
.decompress = mppe_decompress,
.incomp = mppe_incomp,
.decomp_stat = mppe_comp_stats,
.owner = THIS_MODULE,
.comp_extra = MPPE_PAD,
};
/*
* ppp_mppe_init()
*
* Prior to allowing load, try to load the arc4 and sha1 crypto
* libraries. The actual use will be allocated later, but
* this way the module will fail to insmod if they aren't available.
*/
static int __init ppp_mppe_init(void)
{
int answer;
if (!(crypto_has_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC) &&
crypto_has_hash("sha1", 0, CRYPTO_ALG_ASYNC)))
return -ENODEV;
sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL);
if (!sha_pad)
return -ENOMEM;
sha_pad_init(sha_pad);
answer = ppp_register_compressor(&ppp_mppe);
if (answer == 0)
printk(KERN_INFO "PPP MPPE Compression module registered\n");
else
kfree(sha_pad);
return answer;
}
static void __exit ppp_mppe_cleanup(void)
{
ppp_unregister_compressor(&ppp_mppe);
kfree(sha_pad);
}
module_init(ppp_mppe_init);
module_exit(ppp_mppe_cleanup);
static int esp_init_state(struct xfrm_state *x)
{
struct esp_data *esp = NULL;
struct crypto_blkcipher *tfm;
/* null auth and encryption can have zero length keys */
if (x->aalg) {
if (x->aalg->alg_key_len > 512)
goto error;
}
if (x->ealg == NULL)
goto error;
esp = kzalloc(sizeof(*esp), GFP_KERNEL);
if (esp == NULL)
return -ENOMEM;
if (x->aalg) {
struct xfrm_algo_desc *aalg_desc;
struct crypto_hash *hash;
esp->auth.key = x->aalg->alg_key;
esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
hash = crypto_alloc_hash(x->aalg->alg_name, 0,
CRYPTO_ALG_ASYNC);
if (IS_ERR(hash))
goto error;
esp->auth.tfm = hash;
if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
goto error;
aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
BUG_ON(!aalg_desc);
if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
crypto_hash_digestsize(hash)) {
NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
x->aalg->alg_name,
crypto_hash_digestsize(hash),
aalg_desc->uinfo.auth.icv_fullbits/8);
goto error;
}
esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
if (!esp->auth.work_icv)
goto error;
}
esp->conf.key = x->ealg->alg_key;
esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm))
goto error;
esp->conf.tfm = tfm;
esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
esp->conf.padlen = 0;
if (esp->conf.ivlen) {
esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
if (unlikely(esp->conf.ivec == NULL))
goto error;
esp->conf.ivinitted = 0;
}
if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
goto error;
x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
if (x->props.mode == XFRM_MODE_TUNNEL)
x->props.header_len += sizeof(struct iphdr);
if (x->encap) {
struct xfrm_encap_tmpl *encap = x->encap;
switch (encap->encap_type) {
default:
goto error;
case UDP_ENCAP_ESPINUDP:
x->props.header_len += sizeof(struct udphdr);
break;
case UDP_ENCAP_ESPINUDP_NON_IKE:
x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
break;
}
}
x->data = esp;
x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
return 0;
error:
x->data = esp;
esp_destroy(x);
x->data = NULL;
return -EINVAL;
}
static struct crypto_blkcipher *ceph_crypto_alloc_cipher(void)
{
return crypto_alloc_blkcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
}
static int tf_self_test_perform_blkcipher(
const char *alg_name,
const struct blkcipher_test_vector *tv,
bool decrypt)
{
struct blkcipher_desc desc = {0};
struct scatterlist sg_in, sg_out;
unsigned char *in = NULL;
unsigned char *out = NULL;
unsigned in_size, out_size;
int error;
desc.tfm = crypto_alloc_blkcipher(alg_name, 0, 0);
if (IS_ERR_OR_NULL(desc.tfm)) {
ERROR("crypto_alloc_blkcipher(%s) failed", alg_name);
error = (desc.tfm == NULL ? -ENOMEM : (int)desc.tfm);
goto abort;
}
INFO("%s alg_name=%s driver_name=%s key_size=%u block_size=%u",
decrypt ? "decrypt" : "encrypt", alg_name,
crypto_tfm_alg_driver_name(crypto_blkcipher_tfm(desc.tfm)),
tv->key_length * 8,
crypto_blkcipher_blocksize(desc.tfm));
in_size = tv->length;
in = kmalloc(in_size, GFP_KERNEL);
if (IS_ERR_OR_NULL(in)) {
ERROR("kmalloc(%u) failed: %d", in_size, (int)in);
error = (in == NULL ? -ENOMEM : (int)in);
goto abort;
}
memcpy(in, decrypt ? tv->ciphertext : tv->plaintext,
tv->length);
out_size = tv->length + crypto_blkcipher_blocksize(desc.tfm);
out = kmalloc(out_size, GFP_KERNEL);
if (IS_ERR_OR_NULL(out)) {
ERROR("kmalloc(%u) failed: %d", out_size, (int)out);
error = (out == NULL ? -ENOMEM : (int)out);
goto abort;
}
error = crypto_blkcipher_setkey(desc.tfm, tv->key, tv->key_length);
if (error) {
ERROR("crypto_alloc_setkey(%s) failed", alg_name);
goto abort;
}
TF_TRACE_ARRAY(tv->key, tv->key_length);
if (tv->iv != NULL) {
unsigned iv_length = crypto_blkcipher_ivsize(desc.tfm);
crypto_blkcipher_set_iv(desc.tfm, tv->iv, iv_length);
TF_TRACE_ARRAY(tv->iv, iv_length);
}
sg_init_one(&sg_in, in, tv->length);
sg_init_one(&sg_out, out, tv->length);
TF_TRACE_ARRAY(in, tv->length);
(decrypt ? crypto_blkcipher_decrypt : crypto_blkcipher_encrypt)
(&desc, &sg_out, &sg_in, tv->length);
if (error) {
ERROR("crypto_blkcipher_%s(%s) failed",
decrypt ? "decrypt" : "encrypt", alg_name);
goto abort;
}
TF_TRACE_ARRAY(out, tv->length);
crypto_free_blkcipher(desc.tfm);
if (memcmp((decrypt ? tv->plaintext : tv->ciphertext),
out, tv->length)) {
ERROR("Wrong %s/%u %s result", alg_name, tv->key_length * 8,
decrypt ? "decryption" : "encryption");
error = -EINVAL;
} else {
INFO("%s/%u: %s successful", alg_name, tv->key_length * 8,
decrypt ? "decryption" : "encryption");
error = 0;
}
kfree(in);
kfree(out);
return error;
abort:
if (!IS_ERR_OR_NULL(desc.tfm))
crypto_free_blkcipher(desc.tfm);
if (!IS_ERR_OR_NULL(out))
kfree(out);
if (!IS_ERR_OR_NULL(in))
kfree(in);
return error;
}
/*
* Function definition for sys_xcrypt.
* This function encrypts/decrypts files using AES Block Cipher algorithm using CBC mode.
*/
asmlinkage int sys_xcrypt( const char * const infile, const char * const opfile, const char * const keybuf, const int keylen, const short int flags ) {
const char algo[] = "cbc(aes)";
char *ipBuf = NULL, *opBuf = NULL, *iv = NULL, *inFile = NULL, *opFile = NULL, *keyBuf = NULL;
int errno = 0, ret = 0;
int actReadLen = 0, actWriteLen = 0, padLen = 0, blkSiz = 0, ipFileLen = 0, opFileLen = 0, keyLen = 0;
int delOpFile = 0, prmbLen = 0, idx = 0;
unsigned int fileSize = 0, factor = 1;
struct file *inFilePtr = NULL, *opFilePtr = NULL;
struct crypto_blkcipher *tfm = NULL;
struct blkcipher_desc desc;
struct scatterlist sg[2];
struct dentry *tmpDentry;
struct inode *tmpInode = NULL;
mm_segment_t oldfs;
/* Check for NULL pointers or invalid values */
if( ( NULL == infile ) || ( NULL == opfile ) || ( NULL == keybuf ) || ( ( _FLAG_ENCRYPT_ != flags ) && ( _FLAG_DECRYPT_ != flags ) ) ) {
printk( KERN_ALERT "Invalid I/P" );
errno = -EINVAL;
goto OUT_OK;
}
/* Verify if all the pointers belong to the user's own address space */
ret = access_ok( VERIFY_READ, infile, 0 );
if( !ret ) {
printk( KERN_ALERT "Invalid pointer to I/P file passed as argument" );
errno = -EFAULT;
goto OUT_OK;
}
ret = access_ok( VERIFY_READ, opfile, 0 );
if( !ret ) {
printk( KERN_ALERT "Invalid pointer to O/P file passed as argument" );
errno = -EFAULT;
goto OUT_OK;
}
ret = access_ok( VERIFY_READ, keybuf, 0 );
if( !ret ) {
printk( KERN_ALERT "Invalid pointer to Password passed as argument" );
errno = -EFAULT;
goto OUT_OK;
}
/* Find out the length of the i/p buffers */
ipFileLen = strlen_user( infile );
opFileLen = strlen_user( opfile );
keyLen = strlen_user( keybuf );
/* Allocate buffers to copy i/p arguments from user space to kernel space */
inFile = kmalloc( ipFileLen, GFP_KERNEL );
if( NULL == inFile ) {
errno = -ENOMEM;
goto OUT_OK;
}
else {
ret = strncpy_from_user( inFile, infile, ipFileLen );
if( ret < 0 ) {
errno = ret;
goto OUT_IP;
}
}
opFile = kmalloc( opFileLen, GFP_KERNEL );
if( NULL == opFile ) {
errno = -ENOMEM;
goto OUT_IP;
}
else {
ret = strncpy_from_user( opFile, opfile, opFileLen );
if( ret < 0 ) {
errno = ret;
goto OUT_IP;
}
}
keyBuf = kmalloc( keyLen, GFP_KERNEL );
if( NULL == keyBuf ) {
errno = -ENOMEM;
goto OUT_IP;
}
else {
ret = strncpy_from_user( keyBuf, keybuf, keyLen );
if( ret < 0 ) {
errno = ret;
goto OUT_IP;
}
}
/* Open I/P file. It will report error in case of non-existing file and bad permissions but not bad owner */
inFilePtr = filp_open( inFile, O_RDONLY, 0 );
if ( !inFilePtr || IS_ERR( inFilePtr ) ) {
errno = (int)PTR_ERR( inFilePtr );
printk( KERN_ALERT "Error opening i/p file: %d\n", errno );
inFilePtr = NULL;
goto OUT_IP;
}
/* Check if the file is a regular file or not */
if( !S_ISREG( inFilePtr->f_path.dentry->d_inode->i_mode ) ) {
printk( KERN_ALERT "Error as file is not a regular one" );
errno = -EBADF;
goto OUT_FILE;
}
/* Check if the I/p file and the process owner match */
if( ( current->real_cred->uid != inFilePtr->f_path.dentry->d_inode->i_uid ) && ( current->real_cred->uid != 0 ) ) {
printk( KERN_ALERT "Error as owner of file and process does not match" );
errno = -EACCES;
goto OUT_FILE;
}
/* Open O/P file with error handling */
opFilePtr = filp_open( opFile, O_WRONLY | O_CREAT | O_EXCL, 0 );
if ( !opFilePtr || IS_ERR( opFilePtr ) ) {
errno = (int)PTR_ERR( opFilePtr );
printk( KERN_ALERT "Error opening o/p file: %d\n", errno );
opFilePtr = NULL;
goto OUT_FILE;
}
/*
* Check if the infile and opfile point to the same file
* If they reside on the different file partition and have same name then it should be allowed else not
*/
if( ( inFilePtr->f_path.dentry->d_inode->i_sb == opFilePtr->f_path.dentry->d_inode->i_sb ) &&
( inFilePtr->f_path.dentry->d_inode->i_ino == opFilePtr->f_path.dentry->d_inode->i_ino ) ) {
printk( KERN_ALERT "I/p and O/p file cannot be same" );
errno = -EINVAL;
goto OUT_FILE;
}
/* Set the o/p file permission to i/p file */
opFilePtr->f_path.dentry->d_inode->i_mode = inFilePtr->f_path.dentry->d_inode->i_mode;
/* Set the file position to the beginning of the file */
inFilePtr->f_pos = 0;
opFilePtr->f_pos = 0;
/* Allocate buffer to read data into and to write data to. For performance reasons, set its size equal to PAGE_SIZE */
ipBuf = kmalloc( PAGE_SIZE, GFP_KERNEL );
if( NULL == ipBuf ) {
errno = -ENOMEM;
goto OUT_FILE;
}
memset( ipBuf, _NULL_CHAR_, PAGE_SIZE );
opBuf = kmalloc( PAGE_SIZE, GFP_KERNEL );
if( NULL == opBuf ) {
errno = -ENOMEM;
goto OUT_DATA_PAGE;
}
memset( opBuf, _NULL_CHAR_, PAGE_SIZE );
/* Allocate tfm */
tfm = crypto_alloc_blkcipher( algo, 0, CRYPTO_ALG_ASYNC );
if ( NULL == tfm ) {
printk( KERN_ALERT "Failed to load transform for %s: %ld\n", algo, PTR_ERR( tfm ) );
errno = -EINVAL;
goto OUT_DATA_PAGE;
}
/* Initialize desc */
desc.tfm = tfm;
desc.flags = 0;
ret = crypto_blkcipher_setkey( tfm, keybuf, keylen );
if( ret ) {
printk( "Setkey() failed. Flags=%x\n", crypto_blkcipher_get_flags( tfm ) );
errno = -EINVAL;
goto OUT_CIPHER;
}
/* Initialize sg structure */
FILL_SG( &sg[0], ipBuf, PAGE_SIZE );
FILL_SG( &sg[1], opBuf, PAGE_SIZE );
/* Get the block size */
blkSiz = ((tfm->base).__crt_alg)->cra_blocksize;
/* Initialize IV */
iv = kmalloc( blkSiz, GFP_KERNEL );
if( NULL == iv ) {
errno = -ENOMEM;
goto OUT_CIPHER;
}
memset( iv, _NULL_CHAR_, blkSiz );
crypto_blkcipher_set_iv( tfm, iv, crypto_blkcipher_ivsize( tfm ) );
/* Store the key and file size in encrypted form in the preamble */
switch( flags ) {
case _FLAG_ENCRYPT_:
memcpy( ipBuf, keybuf, keylen );
prmbLen = keylen;
fileSize = (unsigned int)inFilePtr->f_path.dentry->d_inode->i_size;
while( fileSize ) {
ipBuf[ prmbLen + idx ] = fileSize % 10;
fileSize /= 10;
++idx;
}
prmbLen += idx;
#ifdef _DEBUG_
printk( KERN_ALERT "idx=%d prmbLen=%d\n", idx, prmbLen );
#endif
memset( ipBuf + prmbLen, _ETX_, _UL_MAX_SIZE_ - idx );
prmbLen += ( _UL_MAX_SIZE_ - idx );
#ifdef _DEBUG_
printk( KERN_ALERT "prmbLen=%d\n", prmbLen );
#endif
padLen = blkSiz - ( prmbLen % blkSiz );
memset( ipBuf + prmbLen, _ETX_, padLen );
prmbLen += padLen;
#ifdef _DEBUG_
printk( KERN_ALERT "padLen=%d prmbLen=%d\n", padLen, prmbLen );
#endif
ret = crypto_blkcipher_encrypt( &desc, &sg[1], &sg[0], prmbLen );
if (ret) {
printk( KERN_ALERT "Encryption failed. Flags=0x%x\n", tfm->base.crt_flags );
delOpFile = 1;
goto OUT_IV;
}
oldfs = get_fs();
set_fs( KERNEL_DS );
opFilePtr->f_op->write( opFilePtr, opBuf, prmbLen, &opFilePtr->f_pos );
/* Reset the address space to user one */
set_fs( oldfs );
break;
case _FLAG_DECRYPT_:
/* Set the address space to kernel one */
oldfs = get_fs();
set_fs( KERNEL_DS );
prmbLen = keylen + _UL_MAX_SIZE_;
padLen = blkSiz - ( prmbLen % blkSiz );
prmbLen += padLen;
#ifdef _DEBUG_
printk( KERN_ALERT "padLen=%d prmbLen=%d\n", padLen, prmbLen );
#endif
actReadLen = inFilePtr->f_op->read( inFilePtr, ipBuf, prmbLen, &inFilePtr->f_pos );
if( actReadLen != prmbLen ) {
printk( KERN_ALERT "Requested number of bytes for preamble are lesser" );
delOpFile = 1;
goto OUT_IV;
}
#ifdef _DEBUG_
printk( KERN_ALERT "actReadLen=%d\n", actReadLen );
#endif
/* Reset the address space to user one */
set_fs( oldfs );
ret = crypto_blkcipher_decrypt( &desc, &sg[1], &sg[0], prmbLen );
if (ret) {
printk( KERN_ALERT "Decryption failed. Flags=0x%x\n", tfm->base.crt_flags );
delOpFile = 1;
goto OUT_IV;
}
ret = memcmp( keybuf, opBuf, keylen );
if( ret ) {
printk( "Wrong password entered." );
errno = -EKEYREJECTED;
goto OUT_IV;
}
idx = 0;
fileSize = 0;
while( opBuf[ keylen + idx ] != _ETX_ ) {
fileSize += opBuf[ keylen + idx ] * factor;
factor *= 10;
++idx;
}
#ifdef _DEBUG_
printk( KERN_ALERT "idx=%d fileSize=%u\n", idx, fileSize );
#endif
break;
}
/* Read file till the file pointer reaches to the EOF */
while( inFilePtr->f_pos < inFilePtr->f_path.dentry->d_inode->i_size ) {
/* Initialize it to NULL char */
memset( ipBuf, _NULL_CHAR_, PAGE_SIZE );
memset( opBuf, _NULL_CHAR_, PAGE_SIZE );
/* Set the address space to kernel one */
oldfs = get_fs();
set_fs( KERNEL_DS );
actReadLen = inFilePtr->f_op->read( inFilePtr, ipBuf, PAGE_SIZE, &inFilePtr->f_pos );
/* Reset the address space to user one */
set_fs( oldfs );
/* As per the i/p flag, do encryption/decryption */
switch( flags ) {
case _FLAG_ENCRYPT_:
/* For encryption ensure padding as per the block size */
#ifdef _DEBUG_
printk( KERN_ALERT "Bytes read from I/P file ::%d::\n", actReadLen );
#endif
if( actReadLen % blkSiz ) {
padLen = blkSiz - ( actReadLen % blkSiz );
memset( ipBuf + actReadLen, _ETX_, padLen );
actReadLen += padLen;
}
#ifdef _DEBUG_
printk( KERN_ALERT "Pad Length ::%d::\n", padLen );
printk( KERN_ALERT "Data read from I/P file ::%s::\n", ipBuf );
#endif
/* Encrypt the data */
ret = crypto_blkcipher_encrypt( &desc, &sg[1], &sg[0], PAGE_SIZE );
if (ret) {
printk( KERN_ALERT "Encryption failed. Flags=0x%x\n", tfm->base.crt_flags );
delOpFile = 1;
goto OUT_IV;
}
break;
case _FLAG_DECRYPT_:
/* Decrypt the data */
ret = crypto_blkcipher_decrypt( &desc, &sg[1], &sg[0], PAGE_SIZE );
if (ret) {
printk( KERN_ALERT "Decryption failed. Flags=0x%x\n", tfm->base.crt_flags );
delOpFile = 1;
goto OUT_IV;
}
#ifdef _DEBUG_
printk( KERN_ALERT "Bytes read from I/P file ::%d::\n", actReadLen );
#endif
while( _ETX_ == opBuf[ actReadLen - 1 ] ) {
opBuf[ actReadLen - 1 ] = _NULL_CHAR_;
--actReadLen;
}
#ifdef _DEBUG_
printk( KERN_ALERT "Bytes read from I/P file ::%d::\n", actReadLen );
printk( KERN_ALERT "Data read from I/P file ::%s::\n", opBuf );
#endif
break;
}
/*
* Start writing to the o/p file
* Set the address space to kernel one
*/
oldfs = get_fs();
set_fs( KERNEL_DS );
actWriteLen = opFilePtr->f_op->write( opFilePtr, opBuf, actReadLen, &opFilePtr->f_pos );
/* Reset the address space to user one */
set_fs( oldfs );
#ifdef _DEBUG_
printk( KERN_ALERT "Bytes written to O/P file ::%d::\n", actWriteLen );
#endif
}
/* Free iv */
OUT_IV:
kfree( iv );
iv = NULL;
printk( KERN_ALERT "Memory for IV freed ..." );
/* Free tfm */
OUT_CIPHER:
crypto_free_blkcipher( tfm );
printk( KERN_ALERT "Encryption Transform freed ..." );
/* Free i/p and o/p buffers */
OUT_DATA_PAGE:
if( ipBuf ) {
kfree( ipBuf );
ipBuf = NULL;
}
if( opBuf ) {
kfree( opBuf );
opBuf = NULL;
}
printk( KERN_ALERT "Memory for encrption/decryption freed ..." );
/* Close any open files */
OUT_FILE:
if( inFilePtr ) {
filp_close( inFilePtr, NULL );
inFilePtr = NULL;
printk( KERN_ALERT "I/p file closed ..." );
}
if( opFilePtr ) {
filp_close( opFilePtr, NULL );
opFilePtr = NULL;
printk( KERN_ALERT "O/p file closed ..." );
}
if( delOpFile ) {
opFilePtr = filp_open( opFile, O_WRONLY , 0 );
if ( !opFilePtr || IS_ERR( opFilePtr ) ) {
opFilePtr = NULL;
goto OUT_IP;
}
tmpDentry = opFilePtr->f_path.dentry;
tmpInode = tmpDentry->d_parent->d_inode;
filp_close( opFilePtr, NULL );
vfs_unlink( tmpInode, tmpDentry );
printk( KERN_ALERT "O/p file deleted ..." );
}
OUT_IP:
if( inFile ) {
kfree( inFile );
inFile = NULL;
}
if( opFile ) {
kfree( opFile );
opFile = NULL;
}
if( keyBuf ) {
kfree( keyBuf );
keyBuf = NULL;
}
printk( KERN_ALERT "Memory for I/P parameters freed ..." );
/* Return final status */
OUT_OK:
printk( KERN_ALERT "Exiting function sys_xcrypt ..." );
return errno;
}
