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/*
* Copyright (C) 2010 Martin Willi
* Copyright (C) 2010 revosec AG
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* 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.
*/
#include "af_alg_signer.h"
#include <unistd.h>
#include <errno.h>
#include <linux/socket.h>
#include <linux/if_alg.h>
#include <debug.h>
#ifndef AF_ALG
#define AF_ALG 38
#endif /* AF_ALG */
#ifndef SOL_ALG
#define SOL_ALG 279
#endif /* SOL_ALG */
typedef struct private_af_alg_signer_t private_af_alg_signer_t;
/**
* Private data structure with signing context.
*/
struct private_af_alg_signer_t {
/**
* Public interface of af_alg_signer_t.
*/
af_alg_signer_t public;
/**
* Transform fd
*/
int tfm;
/**
* Current operation fd, -1 if none
*/
int op;
/**
* Size of the truncated signature
*/
size_t block_size;
/**
* Default key size
*/
size_t key_size;
};
/**
* Get the kernel algorithm string and block/key size for our identifier
*/
static size_t lookup_alg(integrity_algorithm_t algo, char *name,
size_t *key_size)
{
static struct {
integrity_algorithm_t id;
char *name;
size_t block_size;
size_t key_size;
} algs[] = {
{AUTH_HMAC_MD5_96, "hmac(md5)", 12, 16, },
{AUTH_HMAC_MD5_128, "hmac(md5)", 16, 16, },
{AUTH_HMAC_SHA1_96, "hmac(sha1)", 12, 20, },
{AUTH_HMAC_SHA1_128, "hmac(sha1)", 16, 20, },
{AUTH_HMAC_SHA1_160, "hmac(sha1)", 20, 20, },
{AUTH_HMAC_SHA2_256_96, "hmac(sha256)", 12, 32, },
{AUTH_HMAC_SHA2_256_128, "hmac(sha256)", 16, 32, },
{AUTH_HMAC_SHA2_256_256, "hmac(sha384)", 32, 32, },
{AUTH_HMAC_SHA2_384_192, "hmac(sha384)", 24, 48, },
{AUTH_HMAC_SHA2_384_384, "hmac(sha384)", 48, 48, },
{AUTH_HMAC_SHA2_512_256, "hmac(sha512)", 32, 64, },
{AUTH_AES_XCBC_96, "xcbc(aes)", 12, 16, },
{AUTH_CAMELLIA_XCBC_96, "xcbc(camellia)", 12, 16, },
};
int i;
for (i = 0; i < countof(algs); i++)
{
if (algs[i].id == algo)
{
strcpy(name, algs[i].name);
*key_size = algs[i].key_size;
return algs[i].block_size;
}
}
return 0;
}
METHOD(signer_t, get_signature, void,
private_af_alg_signer_t *this, chunk_t data, u_int8_t *buffer)
{
ssize_t len;
while (this->op == -1)
{
this->op = accept(this->tfm, NULL, 0);
if (this->op == -1)
{
DBG1(DBG_LIB, "opening AF_ALG signer failed: %s", strerror(errno));
sleep(1);
}
}
do
{
len = send(this->op, data.ptr, data.len, buffer ? 0 : MSG_MORE);
if (len == -1)
{
DBG1(DBG_LIB, "writing to AF_ALG signer failed: %s", strerror(errno));
sleep(1);
}
else
{
data = chunk_skip(data, len);
}
}
while (data.len);
if (buffer)
{
while (read(this->op, buffer, this->block_size) != this->block_size)
{
DBG1(DBG_LIB, "reading AF_ALG signer failed: %s", strerror(errno));
sleep(1);
}
close(this->op);
this->op = -1;
}
}
METHOD(signer_t, allocate_signature, void,
private_af_alg_signer_t *this, chunk_t data, chunk_t *chunk)
{
if (chunk)
{
*chunk = chunk_alloc(this->block_size);
get_signature(this, data, chunk->ptr);
}
else
{
get_signature(this, data, NULL);
}
}
METHOD(signer_t, verify_signature, bool,
private_af_alg_signer_t *this, chunk_t data, chunk_t signature)
{
char sig[this->block_size];
if (signature.len != this->block_size)
{
return FALSE;
}
get_signature(this, data, sig);
return memeq(signature.ptr, sig, signature.len);
}
METHOD(signer_t, get_key_size, size_t,
private_af_alg_signer_t *this)
{
return this->key_size;
}
METHOD(signer_t, get_block_size, size_t,
private_af_alg_signer_t *this)
{
return this->block_size;
}
METHOD(signer_t, set_key, void,
private_af_alg_signer_t *this, chunk_t key)
{
if (setsockopt(this->tfm, SOL_ALG, ALG_SET_KEY, key.ptr, key.len) == -1)
{
DBG1(DBG_LIB, "setting AF_ALG key failed: %s", strerror(errno));
}
}
METHOD(signer_t, destroy, void,
private_af_alg_signer_t *this)
{
if (this->op != -1)
{
close(this->op);
}
close(this->tfm);
free(this);
}
/*
* Described in header
*/
af_alg_signer_t *af_alg_signer_create(integrity_algorithm_t algo)
{
private_af_alg_signer_t *this;
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "hash",
};
size_t block_size, key_size;
block_size = lookup_alg(algo, sa.salg_name, &key_size);
if (!block_size)
{ /* not supported by kernel */
return NULL;
}
INIT(this,
.public = {
.signer = {
.get_signature = _get_signature,
.allocate_signature = _allocate_signature,
.verify_signature = _verify_signature,
.get_key_size = _get_key_size,
.get_block_size = _get_block_size,
.set_key = _set_key,
.destroy = _destroy,
},
},
.tfm = socket(AF_ALG, SOCK_SEQPACKET, 0),
.op = -1,
.block_size = block_size,
.key_size = key_size,
);
if (this->tfm == -1)
{
DBG1(DBG_LIB, "opening AF_ALG socket failed: %s", strerror(errno));
free(this);
return NULL;
}
if (bind(this->tfm, (struct sockaddr*)&sa, sizeof(sa)) == -1)
{
DBG1(DBG_LIB, "binding AF_ALG socket for '%s' failed: %s",
sa.salg_name, strerror(errno));
destroy(this);
return NULL;
}
return &this->public;
}
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