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Code Issues Releases Wiki Activity

Add debugging statements to certificate checks.

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This commit is contained in:
Todd C. Miller 2020-01-18 12:57:24 -07:00
parent 5a86073bd0
commit 47d9504716
4 changed files with 72 additions and 47 deletions
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3
include/hostcheck.h
View File

@ -20,7 +20,6 @@
#if defined(HAVE_OPENSSL)
# include <openssl/x509v3.h>
# include "sudo_compat.h"
typedef enum {
MatchFound,
@ -35,4 +34,4 @@ validate_hostname(const X509 *cert, const char *hostname, const char *ipaddr, in
#endif /* HAVE_OPENSSL */
#endif /* SUDO_HOSTCHECK_H */
#endif /* SUDO_HOSTCHECK_H */

98
lib/iolog/hostcheck.c
View File

@ -14,15 +14,22 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include "config.h"
#if defined(HAVE_OPENSSL)
# include <string.h>
# include <netdb.h>
# include <sys/socket.h>
# include <arpa/inet.h>
# include <openssl/x509v3.h>
# include <string.h>
# include <netdb.h>
# include "sudo_compat.h"
# include "sudo_debug.h"
# include "sudo_util.h"
# include "hostcheck.h"
/**
@ -30,14 +37,14 @@
*
* @param hostname hostname to be resolved
* @param ipaddr ip address to be checked
*
*
* @return 1 if hostname resolves to the given IP address
* 0 otherwise
*/
static int
forward_lookup_match(const char *hostname, const char *ipaddr)
{
int ret = 0;
int rc, ret = 0;
struct addrinfo *res = NULL, *p;
void *addr;
struct sockaddr_in *ipv4;
@ -47,17 +54,23 @@ forward_lookup_match(const char *hostname, const char *ipaddr)
#else
char ipstr[INET_ADDRSTRLEN];
#endif
debug_decl(forward_lookup_match, SUDO_DEBUG_UTIL);
if (getaddrinfo(hostname, NULL, NULL, &res) != 0) {
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"verify %s resolves to %s", hostname, ipaddr);
if ((rc = getaddrinfo(hostname, NULL, NULL, &res)) != 0) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to resolve %s: %s", hostname, gai_strerror(rc));
goto exit;
}
for(p = res ;p != NULL; p = p->ai_next) {
if(p->ai_family == AF_INET) {
for (p = res; p != NULL; p = p->ai_next) {
if (p->ai_family == AF_INET) {
ipv4 = (struct sockaddr_in *)p->ai_addr;
addr = &(ipv4->sin_addr);
#if defined(HAVE_STRUCT_IN6_ADDR)
} else if(p->ai_family == AF_INET6) {
} else if (p->ai_family == AF_INET6) {
ipv6 = (struct sockaddr_in6 *)p->ai_addr;
addr = &(ipv6->sin6_addr);
#endif
@ -66,6 +79,8 @@ forward_lookup_match(const char *hostname, const char *ipaddr)
}
if (inet_ntop(p->ai_family, addr, ipstr, sizeof(ipstr)) != 0) {
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"comparing %s to %s", ipstr, ipaddr);
if (strcmp(ipaddr, ipstr) == 0) {
ret = 1;
break;
@ -77,7 +92,7 @@ exit:
if (res != NULL) {
freeaddrinfo(res);
}
return ret;
debug_return_int(ret);
}
/**
@ -89,24 +104,30 @@ exit:
* - foo.bar.example.com
* - *.example.com
* - *.bar.example.com
*
*
* @param hostname peer's name
* @param certname_asn1 hostname in the certificate
*
*
* @return MatchFound
* MatchNotFound
*/
static HostnameValidationResult
validate_name(const char *hostname, ASN1_STRING *certname_asn1) {
char *certname_s = (char *) ASN1_STRING_get0_data(certname_asn1);
int certname_len = ASN1_STRING_length(certname_asn1);
validate_name(const char *hostname, ASN1_STRING *certname_asn1)
{
char *certname_s = (char *) ASN1_STRING_get0_data(certname_asn1);
int certname_len = ASN1_STRING_length(certname_asn1);
int hostname_len = strlen(hostname);
debug_decl(validate_name, SUDO_DEBUG_UTIL);
/* remove last '.' from hostname if exists */
if (hostname_len != 0 && hostname[hostname_len - 1] == '.') {
--hostname_len;
}
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"comparing %.*s to %.*s in cert", hostname_len, hostname,
certname_len, certname_s);
/* skip the first label if wildcard */
if (certname_len > 2 && certname_s[0] == '*' && certname_s[1] == '.') {
if (hostname_len != 0) {
@ -122,18 +143,18 @@ validate_name(const char *hostname, ASN1_STRING *certname_asn1) {
}
/* Compare expected hostname with the DNS name */
if (certname_len != hostname_len) {
return MatchNotFound;
debug_return_int(MatchNotFound);
}
if (strncasecmp(hostname, certname_s, hostname_len) != 0) {
return MatchNotFound;
debug_return_int(MatchNotFound);
}
return MatchFound;
debug_return_int(MatchFound);
}
/**
* @brief Matches a hostname with the cert's CN.
*
*
* @param hostname peer's name
* on client side: it is the name where the client is connected to
* on server side, it is in fact an IP address of the remote client
@ -141,7 +162,7 @@ validate_name(const char *hostname, ASN1_STRING *certname_asn1) {
* @param cert peer's X509 certificate
* @param resolve if the value is not 0, the function checks that the value of the CN
* resolves to the given ipaddr or not.
*
*
* @return MatchFound
* MatchNotFound
* MalformedCertificate
@ -153,41 +174,42 @@ matches_common_name(const char *hostname, const char *ipaddr, const X509 *cert,
X509_NAME_ENTRY *common_name_entry = NULL;
ASN1_STRING *common_name_asn1 = NULL;
int common_name_loc = -1;
debug_decl(matches_common_name, SUDO_DEBUG_UTIL);
/* Find the position of the CN field in the Subject field of the certificate */
common_name_loc = X509_NAME_get_index_by_NID(X509_get_subject_name((X509 *) cert), NID_commonName, -1);
if (common_name_loc < 0) {
return Error;
debug_return_int(Error);
}
/* Extract the CN field */
common_name_entry = X509_NAME_get_entry(X509_get_subject_name((X509 *) cert), common_name_loc);
if (common_name_entry == NULL) {
return Error;
debug_return_int(Error);
}
/* Convert the CN field to a C string */
common_name_asn1 = X509_NAME_ENTRY_get_data(common_name_entry);
if (common_name_asn1 == NULL) {
return Error;
debug_return_int(Error);
}
const unsigned char *common_name_str = ASN1_STRING_get0_data(common_name_asn1);
/* Make sure there isn't an embedded NUL character in the CN */
if (memchr(common_name_str, '\0', ASN1_STRING_length(common_name_asn1)) != NULL) {
return MalformedCertificate;
debug_return_int(MalformedCertificate);
}
/* Compare expected hostname with the CN */
if (validate_name(hostname, common_name_asn1) == MatchFound) {
return MatchFound;
debug_return_int(MatchFound);
}
int common_name_length = ASN1_STRING_length(common_name_asn1);
unsigned char *nullterm_common_name = malloc(common_name_length + 1);
if (nullterm_common_name == NULL) {
return Error;
debug_return_int(Error);
}
memcpy(nullterm_common_name, common_name_str, common_name_length);
@ -197,11 +219,11 @@ matches_common_name(const char *hostname, const char *ipaddr, const X509 *cert,
/* check if hostname in the CN field resolves to the given ip address */
if (resolve && forward_lookup_match(nullterm_common_name, ipaddr)) {
free(nullterm_common_name);
return MatchFound;
debug_return_int(MatchFound);
}
free(nullterm_common_name);
return MatchNotFound;
debug_return_int(MatchNotFound);
}
/**
@ -211,7 +233,7 @@ matches_common_name(const char *hostname, const char *ipaddr, const X509 *cert,
* for IP address matching, the GEN_IPADD field is used.
* Since SAN is an X503 v3 extension, it can happen that the cert does
* not contain SAN at all.
*
*
* @param hostname remote peer's name
* on client side: it is the name where the client is connected to
* on server side, it is in fact an IP address of the remote client
@ -219,7 +241,7 @@ matches_common_name(const char *hostname, const char *ipaddr, const X509 *cert,
* @param cert peer's X509 certificate
* @param resolve if the value is not 0, the function checks that the value of the
* SAN GEN_DNS resolves to the given ipaddr or not.
*
*
* @return MatchFound
* MatchNotFound
* NoSANPresent
@ -233,11 +255,12 @@ matches_subject_alternative_name(const char *hostname, const char *ipaddr, const
int i;
int san_names_nb = -1;
STACK_OF(GENERAL_NAME) *san_names = NULL;
debug_decl(matches_subject_alternative_name, SUDO_DEBUG_UTIL);
/* Try to extract the names within the SAN extension from the certificate */
san_names = X509_get_ext_d2i((X509 *) cert, NID_subject_alt_name, NULL, NULL);
if (san_names == NULL) {
return NoSANPresent;
debug_return_int(NoSANPresent);
}
san_names_nb = sk_GENERAL_NAME_num(san_names);
@ -263,7 +286,7 @@ matches_subject_alternative_name(const char *hostname, const char *ipaddr, const
unsigned char *nullterm_dns_name = malloc(dns_name_length + 1);
if (nullterm_dns_name == NULL) {
return Error;
debug_return_int(Error);
}
memcpy(nullterm_dns_name, dns_name, dns_name_length);
@ -311,7 +334,7 @@ matches_subject_alternative_name(const char *hostname, const char *ipaddr, const
}
sk_GENERAL_NAME_pop_free(san_names, GENERAL_NAME_free);
return result;
debug_return_int(result);
}
/**
@ -320,7 +343,7 @@ matches_subject_alternative_name(const char *hostname, const char *ipaddr, const
* According to RFC 6125 section 6.4.4, first the certificate's SAN field
* has to be checked. If there is no SAN field, the certificate's CN field
* has to be checked.
*
*
* @param cert X509 certificate
* @param hostname remote peer's name
* on client side: it is the name where the client is connected to
@ -328,7 +351,7 @@ matches_subject_alternative_name(const char *hostname, const char *ipaddr, const
* @param ipaddr remote peer's IP address
* @param resolve if the value is not 0, the function checks that the value of the
* SAN GEN_DNS or the value of CN resolves to the given ipaddr or not.
*
*
* @return MatchFound
* MatchNotFound
* MalformedCertificate
@ -338,12 +361,13 @@ HostnameValidationResult
validate_hostname(const X509 *cert, const char *hostname, const char *ipaddr, int resolve)
{
HostnameValidationResult res = MatchFound;
debug_decl(validate_hostname, SUDO_DEBUG_UTIL);
/* hostname can be also an ip address, if client connects
* to ip instead of FQDN
*/
if((ipaddr == NULL) || (cert == NULL)) {
return Error;
debug_return_int(Error);
}
/* check SAN first if exists */
@ -356,6 +380,6 @@ validate_hostname(const X509 *cert, const char *hostname, const char *ipaddr, in
res = matches_common_name(hostname, ipaddr, cert, resolve);
}
return res;
debug_return_int(res);
}
#endif /* HAVE_OPENSSL */

9
logsrvd/logsrvd.c
View File

@ -919,10 +919,11 @@ verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
SSL *ssl;
X509 *current_cert;
X509 *peer_cert;
debug_decl(verify_peer_identity, SUDO_DEBUG_UTIL);
/* if pre-verification of the cert failed, just propagate that result back */
if (preverify_ok != 1) {
return 0;
debug_return_int(0);
}
/* since this callback is called for each cert in the chain,
@ -932,7 +933,7 @@ verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
peer_cert = X509_STORE_CTX_get0_cert(ctx);
if (current_cert != peer_cert) {
return 1;
debug_return_int(1);
}
/* read out the attached object (closure) from the ssl connection object */
@ -944,9 +945,9 @@ verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
switch(result)
{
case MatchFound:
return 1;
debug_return_int(1);
default:
return 0;
debug_return_int(0);
}
}

9
plugins/sudoers/iolog_client.c
View File

@ -228,10 +228,11 @@ verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
SSL *ssl;
X509 *current_cert;
X509 *peer_cert;
debug_decl(verify_peer_identity, SUDOERS_DEBUG_UTIL);
/* if pre-verification of the cert failed, just propagate that result back */
if (preverify_ok != 1) {
return 0;
debug_return_int(0);
}
/* since this callback is called for each cert in the chain,
@ -241,7 +242,7 @@ verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
peer_cert = X509_STORE_CTX_get0_cert(ctx);
if (current_cert != peer_cert) {
return 1;
debug_return_int(1);
}
/* read out the attached object (closure) from the ssl connection object */
@ -253,9 +254,9 @@ verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
switch(result)
{
case MatchFound:
return 1;
debug_return_int(1);
default:
return 0;
debug_return_int(0);
}
}