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#include <sys/socket.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/un.h>
#include <unistd.h>
#include <openssl/bn.h>
#include <openssl/sha.h>
#include <lib/base/eerror.h>
#include "etpm.h"
eTPM::eTPM()
{
struct sockaddr_un addr;
unsigned char buf[8];
unsigned int tag;
size_t len;
unsigned char *val;
level2_cert_read = level3_cert_read = false;
addr.sun_family = AF_UNIX;
strcpy(addr.sun_path, TPMD_SOCKET);
fd = socket(PF_UNIX, SOCK_STREAM, 0);
if (fd < 0)
{
eDebug("[eTPM] socket error");
return;
}
if (connect(fd, (const struct sockaddr *)&addr, SUN_LEN(&addr)) < 0)
{
eDebug("[eTPM] connect error");
return;
}
buf[0] = TPMD_DT_LEVEL2_CERT;
buf[1] = TPMD_DT_LEVEL3_CERT;
if (!send_cmd(TPMD_CMD_GET_DATA, buf, 2))
{
return;
}
val = (unsigned char*)recv_cmd(&tag, &len);
if (val == NULL)
{
return;
}
parse_data(val, len);
free(val);
}
eTPM::~eTPM()
{
}
bool eTPM::send_cmd(enum tpmd_cmd cmd, const void *data, size_t len)
{
unsigned char buf[len + 4];
buf[0] = (cmd >> 8) & 0xff;
buf[1] = (cmd >> 0) & 0xff;
buf[2] = (len >> 8) & 0xff;
buf[3] = (len >> 0) & 0xff;
memcpy(&buf[4], data, len);
if (write(fd, buf, sizeof(buf)) != (ssize_t)sizeof(buf))
{
fprintf(stderr, "%s: incomplete write\n", __func__);
return false;
}
return true;
}
void* eTPM::recv_cmd(unsigned int *tag, size_t *len)
{
unsigned char buf[4];
void *val;
if (read(fd, buf, 4) != 4)
{
fprintf(stderr, "%s: incomplete read\n", __func__);
return NULL;
}
*tag = (buf[0] << 8) | buf[1];
*len = (buf[2] << 8) | buf[3];
val = malloc(*len);
if (val == NULL)
return NULL;
ssize_t rd = read(fd, val, *len);
if (rd < 0)
{
perror("eTPM::recv_cmd read");
free(val);
}
else if ((size_t)rd != *len) {
fprintf(stderr, "%s: incomplete read\n", __func__);
free(val);
return NULL;
}
return val;
}
void eTPM::parse_data(const unsigned char *data, size_t datalen)
{
unsigned int i;
unsigned int tag;
unsigned int len;
const unsigned char *val;
for (i = 0; i < datalen; i += len) {
tag = data[i++];
len = data[i++];
val = &data[i];
switch (tag) {
case TPMD_DT_LEVEL2_CERT:
if (len != 210)
break;
memcpy(level2_cert, val, 210);
level2_cert_read = true;
break;
case TPMD_DT_LEVEL3_CERT:
if (len != 210)
break;
memcpy(level3_cert, val, 210);
level3_cert_read = true;
break;
}
}
}
std::string eTPM::getCert(cert_type type)
{
if (type == TPMD_DT_LEVEL2_CERT && level2_cert_read)
return std::string((char*)level2_cert, 210);
else if (type == TPMD_DT_LEVEL3_CERT && level3_cert_read)
return std::string((char*)level3_cert, 210);
return "";
}
std::string eTPM::challenge(std::string rnd)
{
if (rnd.length() == 8)
{
if (!send_cmd(TPMD_CMD_COMPUTE_SIGNATURE, rnd.c_str(), 8))
return "";
unsigned int tag;
size_t len;
unsigned char *val = (unsigned char*)recv_cmd(&tag, &len);
if (tag != TPMD_CMD_COMPUTE_SIGNATURE)
return "";
std::string ret((char*)val, len);
free(val);
return ret;
}
return "";
}
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