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solanum-vs-hackint-and-char.../modules/m_challenge.c
jailbird777 8e9a741832 OpenSSL 3.0 compatibility 
Edited by @aaronmdjones:

- Correct some data types and casts

- Minor style fixups (e.g. we put * on the variable name not the type)

- librb/src/openssl.c:

  - Defer call of BIO_free(3ssl) to the end of the conditional block
    to avoid having calls to it in multiple paths

  - Check the return value of SSL_CTX_set0_tmp_dh_pkey(3ssl) because if
    it fails then we must use EVP_PKEY_free(3ssl) to avoid a memory leak

    This could fail if, for example, the user supplied DSA parameters
    in the DH parameters file instead.

- ircd/newconf.c:

  - Check whether OSSL_DECODER_CTX_new_for_pkey(3ssl) was able to parse
    the given CHALLANGE public key as a valid RSA public key, and then
    check whether OSSL_DECODER_from_bio(3ssl) actually loads it
    successfully

- ircd/s_newconf.c:

  - Use EVP_PKEY_free(3ssl) instead of OPENSSL_free(3ssl) on EVP_PKEY
    pointers; this will avoid inadvertent memory leaks if the EVP_PKEY
    structure contains any dynamically-allocated child members

- modules/m_challenge.c:

  - Unconditionally use EVP(3ssl) to generate the SHA-1 digest of the
    random challenge; this API has been around for a very long time and
    is available in all supported versions of OpenSSL

  - Add lots of error checking to all steps of the process

Tested against 1.1.1 and 3.0; both with missing and provided DH parameters
(which works as you'd expect; the server will not negotiate a DHE cipher
without them), and CHALLENGE, including missing keys or keys of the wrong
type (e.g. when you supply an EdDSA key instead of an RSA key).

This does break compatibility with OpenSSL 1.1.0 and below, which are now
all end-of-life and unsupported anyway.

Closes #357
2022-08-25 00:36:47 +00:00

389 lines
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/*
* ircd-ratbox: A slightly useful ircd.
* m_challenge.c: Allows an IRC Operator to securely authenticate.
*
* Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
* Copyright (C) 1996-2002 Hybrid Development Team
* Copyright (C) 2002-2005 ircd-ratbox development team
*
* 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.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*/
#include "stdinc.h"
#ifdef HAVE_LIBCRYPTO
# include <openssl/err.h>
# include <openssl/evp.h>
# include <openssl/pem.h>
# include <openssl/rsa.h>
# include <openssl/sha.h>
#endif
#include "client.h"
#include "ircd.h"
#include "modules.h"
#include "numeric.h"
#include "send.h"
#include "s_conf.h"
#include "msg.h"
#include "parse.h"
#include "match.h"
#include "logger.h"
#include "s_user.h"
#include "cache.h"
#include "s_newconf.h"
#define CHALLENGE_WIDTH BUFSIZE - (NICKLEN + HOSTLEN + 12)
#define CHALLENGE_EXPIRES 180 /* 180 seconds should be more than long enough */
#define CHALLENGE_SECRET_LENGTH 128 /* how long our challenge secret should be */
#ifndef HAVE_LIBCRYPTO
static const char challenge_desc[] = "Does nothing as OpenSSL was not enabled.";
/* Maybe this should be an error or something?-davidt */
/* now it is -larne */
static int challenge_load(void)
{
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Challenge module not loaded because OpenSSL is not available.");
ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available.");
return -1;
}
DECLARE_MODULE_AV2(challenge, challenge_load, NULL, NULL, NULL, NULL, NULL, NULL, challenge_desc);
#else
static const char challenge_desc[] =
"Provides the challenge-response facility used for becoming an IRC operator";
static void m_challenge(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
/* We have openssl support, so include /CHALLENGE */
struct Message challenge_msgtab = {
"CHALLENGE", 0, 0, 0, 0,
{mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}}
};
mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL };
DECLARE_MODULE_AV2(challenge, NULL, NULL, challenge_clist, NULL, NULL, NULL, NULL, challenge_desc);
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
static bool generate_challenge(char **r_challenge, unsigned char **r_response, EVP_PKEY *key);
#else
static bool generate_challenge(char **r_challenge, unsigned char **r_response, RSA *key);
#endif
static void
cleanup_challenge(struct Client *target_p)
{
if(target_p->localClient == NULL)
return;
rb_free(target_p->localClient->challenge);
rb_free(target_p->user->opername);
target_p->localClient->challenge = NULL;
target_p->user->opername = NULL;
target_p->localClient->chal_time = 0;
}
/*
* m_challenge - generate RSA challenge for wouldbe oper
* parv[1] = operator to challenge for, or +response
*/
static void
m_challenge(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
struct oper_conf *oper_p;
char *challenge = NULL; /* to placate gcc */
char chal_line[CHALLENGE_WIDTH];
unsigned char *b_response;
size_t cnt;
int len = 0;
if (ConfigFileEntry.oper_secure_only && !IsSecureClient(source_p))
{
sendto_one_notice(source_p, ":You must be using a secure connection to /CHALLENGE on this server");
if (ConfigFileEntry.failed_oper_notice)
{
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt - missing secure connection by %s (%s@%s)",
source_p->name, source_p->username, source_p->host);
}
return;
}
/* if theyre an oper, reprint oper motd and ignore */
if(IsOper(source_p))
{
sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name);
send_oper_motd(source_p);
return;
}
if(*parv[1] == '+')
{
/* Ignore it if we aren't expecting this... -A1kmm */
if(!source_p->localClient->challenge)
return;
if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES)
{
sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)",
source_p->user->opername, source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Expired CHALLENGE attempt by %s (%s@%s)",
source_p->name, source_p->username,
source_p->host);
cleanup_challenge(source_p);
return;
}
parv[1]++;
b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len);
if(len != SHA_DIGEST_LENGTH ||
memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))
{
sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)",
source_p->user->opername, source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt by %s (%s@%s)",
source_p->name, source_p->username,
source_p->host);
rb_free(b_response);
cleanup_challenge(source_p);
return;
}
rb_free(b_response);
oper_p = find_oper_conf(source_p->username, source_p->orighost,
source_p->sockhost,
source_p->user->opername);
if(oper_p == NULL)
{
sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
source_p->user->opername, source_p->name,
source_p->username, source_p->host,
source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
source_p->name, source_p->username,
source_p->host);
cleanup_challenge(source_p);
return;
}
cleanup_challenge(source_p);
oper_up(source_p, oper_p);
ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)",
source_p->user->opername, source_p->name,
source_p->username, source_p->host, source_p->sockhost);
return;
}
cleanup_challenge(source_p);
oper_p = find_oper_conf(source_p->username, source_p->orighost,
source_p->sockhost, parv[1]);
if(oper_p == NULL)
{
sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
parv[1], source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
source_p->name, source_p->username, source_p->host);
return;
}
if(!oper_p->rsa_pubkey)
{
sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block.");
return;
}
if(IsOperConfNeedSSL(oper_p) && !IsSecureClient(source_p))
{
sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS",
parv[1], source_p->name, source_p->username, source_p->host,
source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
{
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)",
source_p->name, source_p->username, source_p->host);
}
return;
}
if (oper_p->certfp != NULL)
{
if (source_p->certfp == NULL || rb_strcasecmp(source_p->certfp, oper_p->certfp))
{
sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch",
parv[1], source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
{
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)",
source_p->name, source_p->username, source_p->host);
}
return;
}
}
if(generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey))
{
char *chal = challenge;
source_p->localClient->chal_time = rb_current_time();
for(;;)
{
cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH);
sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line);
if(cnt >= CHALLENGE_WIDTH)
chal += CHALLENGE_WIDTH - 1;
else
break;
}
sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2),
me.name, source_p->name);
rb_free(challenge);
source_p->user->opername = rb_strdup(oper_p->name);
}
else
sendto_one_notice(source_p, ":Failed to generate challenge.");
}
static bool
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
generate_challenge(char **r_challenge, unsigned char **r_response, EVP_PKEY *key)
#else
generate_challenge(char **r_challenge, unsigned char **r_response, RSA *key)
#endif
{
unsigned char secret[CHALLENGE_SECRET_LENGTH];
unsigned char *tmp = NULL;
unsigned long e = 0;
unsigned long cnt = 0;
bool retval = false;
size_t length;
EVP_MD_CTX *mctx = NULL;
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
EVP_PKEY_CTX *pctx = NULL;
#endif
if(!rb_get_random(secret, sizeof secret))
return false;
if((*r_response = rb_malloc(SHA_DIGEST_LENGTH)) == NULL)
return false;
if((mctx = EVP_MD_CTX_new()) == NULL)
goto fail;
if(EVP_DigestInit(mctx, EVP_sha1()) < 1)
goto fail;
if(EVP_DigestUpdate(mctx, secret, sizeof secret) < 1)
goto fail;
if(EVP_DigestFinal(mctx, *r_response, NULL) < 1)
goto fail;
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
if((length = (size_t) EVP_PKEY_get_size(key)) < 1)
goto fail;
if((tmp = rb_malloc(length)) == NULL)
goto fail;
if((pctx = EVP_PKEY_CTX_new(key, NULL)) == NULL)
goto fail;
if(EVP_PKEY_encrypt_init(pctx) < 1)
goto fail;
if(EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_OAEP_PADDING) < 1)
goto fail;
if(EVP_PKEY_encrypt(pctx, tmp, &length, secret, sizeof secret) < 1)
goto fail;
#else
if((length = (size_t) RSA_size(key)) < 1)
goto fail;
if((tmp = rb_malloc(length)) == NULL)
goto fail;
if(RSA_public_encrypt(sizeof secret, secret, tmp, key, RSA_PKCS1_OAEP_PADDING) < 1)
goto fail;
#endif
if((*r_challenge = (char *) rb_base64_encode(tmp, (int) length)) == NULL)
goto fail;
retval = true;
goto done;
fail:
while ((cnt < 100) && (e = ERR_get_error()))
{
ilog(L_MAIN, "OpenSSL Error (CHALLENGE): %s", ERR_error_string(e, 0));
cnt++;
}
rb_free(*r_response);
*r_response = NULL;
done:
EVP_MD_CTX_free(mctx);
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
EVP_PKEY_CTX_free(pctx);
#endif
rb_free(tmp);
return retval;
}
#endif /* HAVE_LIBCRYPTO */
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