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/*
* Copyright (c) 2015 Proofpoint, Inc. and its suppliers.
* All rights reserved.
*
* By using this file, you agree to the terms and conditions set
* forth in the LICENSE file which can be found at the top level of
* the sendmail distribution.
*
*/
#include <sendmail.h>
SM_RCSID("@(#)$Id: tls.c,v 8.127 2013-11-27 02:51:11 gshapiro Exp $")
#if STARTTLS
# include <tls.h>
/*
** DATA2HEX -- create a printable hex string from binary data ("%02X:")
**
** Parameters:
** buf -- data
** len -- length of data
** hex -- output buffer
** hlen -- length of output buffer
**
** Returns:
** <0: errno
** >0: length of data in hex
*/
int
data2hex(buf, blen, hex, hlen)
unsigned char *buf;
int blen;
unsigned char *hex;
int hlen;
{
int r, h;
static const char hexcodes[] = "0123456789ABCDEF";
SM_REQUIRE(buf != NULL);
SM_REQUIRE(hex != NULL);
if (blen * 3 + 2 > hlen)
return -ERANGE;
for (r = 0, h = 0; r < blen && h + 3 < hlen; r++)
{
hex[h++] = hexcodes[(buf[r] & 0xf0) >> 4];
hex[h++] = hexcodes[(buf[r] & 0x0f)];
if (r + 1 < blen)
hex[h++] = ':';
}
if (h >= hlen)
return -ERANGE;
hex[h] = '\0';
return h;
}
# if DANE
/*
** TLS_DATA_MD -- calculate MD for data
**
** Parameters:
** buf -- data (in and out!)
** len -- length of data
** md -- digest algorithm
**
** Returns:
** <=0: cert fp calculation failed
** >0: len of fp
**
** Side Effects:
** writes digest to buf
*/
static int
tls_data_md(buf, len, md)
unsigned char *buf;
int len;
const EVP_MD *md;
{
unsigned int md_len;
EVP_MD_CTX *mdctx;
unsigned char md_buf[EVP_MAX_MD_SIZE];
SM_REQUIRE(buf != NULL);
SM_REQUIRE(md != NULL);
SM_REQUIRE(len >= EVP_MAX_MD_SIZE);
mdctx = EVP_MD_CTX_create();
if (EVP_DigestInit_ex(mdctx, md, NULL) != 1)
return -EINVAL;
if (EVP_DigestUpdate(mdctx, (void *)buf, len) != 1)
return -EINVAL;
if (EVP_DigestFinal_ex(mdctx, md_buf, &md_len) != 1)
return -EINVAL;
EVP_MD_CTX_destroy(mdctx);
if (md_len > len)
return -ERANGE;
(void) memcpy(buf, md_buf, md_len);
return (int)md_len;
}
/*
** PUBKEY_FP -- get public key fingerprint
**
** Parameters:
** cert -- TLS cert
** mdalg -- name of digest algorithm
** fp -- (pointer to) fingerprint buffer
**
** Returns:
** <=0: cert fp calculation failed
** >0: len of fp
*/
int
pubkey_fp(cert, mdalg, fp)
X509 *cert;
const char *mdalg;
char **fp;
{
int len, r;
unsigned char *buf, *end;
const EVP_MD *md;
SM_ASSERT(cert != NULL);
SM_ASSERT(fp != NULL);
SM_ASSERT(mdalg != NULL);
len = i2d_X509_PUBKEY(X509_get_X509_PUBKEY(cert), NULL);
/* what's an acceptable upper limit? */
if (len <= 0 || len >= 8192)
return -EINVAL;
if (len < EVP_MAX_MD_SIZE)
len = EVP_MAX_MD_SIZE;
end = buf = sm_malloc(len);
if (NULL == buf)
return -ENOMEM;
if ('\0' == mdalg[0])
{
r = i2d_X509_PUBKEY(X509_get_X509_PUBKEY(cert), &end);
if (r <= 0 || r != len)
return -EINVAL;
*fp = (char *)buf;
return len;
}
md = EVP_get_digestbyname(mdalg);
if (NULL == md)
{
SM_FREE(buf);
return DANE_VRFY_FAIL;
}
len = i2d_X509_PUBKEY(X509_get_X509_PUBKEY(cert), &end);
r = tls_data_md(buf, len, md);
if (r < 0)
sm_free(buf);
else
*fp = (char *)buf;
return r;
}
/*
** DANE_TLSA_CHK -- check whether a TLSA RR is ok to use
**
** Parameters:
** rr -- RR
** len -- length of RR
** host -- name of host for RR (only for logging)
** log -- whether to log problems
**
** Returns:
** TLSA_*, see tls.h
*/
int
dane_tlsa_chk(rr, len, host, log)
const char *rr;
int len;
const char *host;
bool log;
{
int alg;
if (len < 4)
{
if (log && LogLevel > 8)
sm_syslog(LOG_WARNING, NOQID,
"TLSA=%s, len=%d, status=bogus",
host, len);
return TLSA_BOGUS;
}
SM_ASSERT(rr != NULL);
alg = (int)rr[2];
if ((int)rr[0] == 3 && (int)rr[1] == 1 && (alg >= 0 && alg <= 2))
return alg;
if (log && LogLevel > 9)
sm_syslog(LOG_NOTICE, NOQID,
"TLSA=%s, type=%d-%d-%d:%02x, status=unsupported",
host, (int)rr[0], (int)rr[1], (int)rr[2],
(int)rr[3]);
return TLSA_UNSUPP;
}
/*
** DANE_TLSA_CLR -- clear data in a dane_tlsa structure (for use)
**
** Parameters:
** dane_tlsa -- dane_tlsa to clear
**
** Returns:
** 1 if NULL
** 0 if ok
*/
int
dane_tlsa_clr(dane_tlsa)
dane_tlsa_P dane_tlsa;
{
int i;
if (dane_tlsa == NULL)
return 1;
for (i = 0; i < dane_tlsa->dane_tlsa_n; i++)
{
SM_FREE(dane_tlsa->dane_tlsa_rr[i]);
dane_tlsa->dane_tlsa_len[i] = 0;
}
SM_FREE(dane_tlsa->dane_tlsa_sni);
memset(dane_tlsa, '\0', sizeof(*dane_tlsa));
return 0;
}
/*
** DANE_TLSA_FREE -- free a dane_tlsa structure
**
** Parameters:
** dane_tlsa -- dane_tlsa to free
**
** Returns:
** 0 if ok
** 1 if NULL
*/
int
dane_tlsa_free(dane_tlsa)
dane_tlsa_P dane_tlsa;
{
if (dane_tlsa == NULL)
return 1;
dane_tlsa_clr(dane_tlsa);
SM_FREE(dane_tlsa);
return 0;
}
# endif /* DANE */
#endif /* STARTTLS */
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