Separate the parts specific to the SSL library from the general logic.
The previous code structure was
open_client_SSL()
calls verify_peer_name_matches_certificate()
calls verify_peer_name_matches_certificate_name()
calls wildcard_certificate_match()
and was completely in fe-secure-openssl.c. The new structure is
open_client_SSL() [openssl]
calls pq_verify_peer_name_matches_certificate() [generic]
calls pgtls_verify_peer_name_matches_certificate_guts() [openssl]
calls openssl_verify_peer_name_matches_certificate_name() [openssl]
calls pq_verify_peer_name_matches_certificate_name() [generic]
calls wildcard_certificate_match() [generic]
Move the generic functions into a new file fe-secure-common.c, so the
calls generally go fe-connect.c -> fe-secure.c -> fe-secure-${impl}.c ->
fe-secure-common.c, although there is a bit of back-and-forth between
the last two.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
OBJS += base64.o ip.o md5.o scram-common.o saslprep.o unicode_norm.o
ifeq ($(with_openssl),yes)
-OBJS += fe-secure-openssl.o sha2_openssl.o
+OBJS += fe-secure-openssl.o fe-secure-common.o sha2_openssl.o
else
OBJS += sha2.o
endif
--- /dev/null
+/*-------------------------------------------------------------------------
+ *
+ * fe-secure-common.c
+ *
+ * common implementation-independent SSL support code
+ *
+ * While fe-secure.c contains the interfaces that the rest of libpq call, this
+ * file contains support routines that are used by the library-specific
+ * implementations such as fe-secure-openssl.c.
+ *
+ * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/interfaces/libpq/fe-secure-common.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+#include "fe-secure-common.h"
+
+#include "libpq-int.h"
+#include "pqexpbuffer.h"
+
+/*
+ * Check if a wildcard certificate matches the server hostname.
+ *
+ * The rule for this is:
+ * 1. We only match the '*' character as wildcard
+ * 2. We match only wildcards at the start of the string
+ * 3. The '*' character does *not* match '.', meaning that we match only
+ * a single pathname component.
+ * 4. We don't support more than one '*' in a single pattern.
+ *
+ * This is roughly in line with RFC2818, but contrary to what most browsers
+ * appear to be implementing (point 3 being the difference)
+ *
+ * Matching is always case-insensitive, since DNS is case insensitive.
+ */
+static bool
+wildcard_certificate_match(const char *pattern, const char *string)
+{
+ int lenpat = strlen(pattern);
+ int lenstr = strlen(string);
+
+ /* If we don't start with a wildcard, it's not a match (rule 1 & 2) */
+ if (lenpat < 3 ||
+ pattern[0] != '*' ||
+ pattern[1] != '.')
+ return false;
+
+ /* If pattern is longer than the string, we can never match */
+ if (lenpat > lenstr)
+ return false;
+
+ /*
+ * If string does not end in pattern (minus the wildcard), we don't match
+ */
+ if (pg_strcasecmp(pattern + 1, string + lenstr - lenpat + 1) != 0)
+ return false;
+
+ /*
+ * If there is a dot left of where the pattern started to match, we don't
+ * match (rule 3)
+ */
+ if (strchr(string, '.') < string + lenstr - lenpat)
+ return false;
+
+ /* String ended with pattern, and didn't have a dot before, so we match */
+ return true;
+}
+
+/*
+ * Check if a name from a server's certificate matches the peer's hostname.
+ *
+ * Returns 1 if the name matches, and 0 if it does not. On error, returns
+ * -1, and sets the libpq error message.
+ *
+ * The name extracted from the certificate is returned in *store_name. The
+ * caller is responsible for freeing it.
+ */
+int
+pq_verify_peer_name_matches_certificate_name(PGconn *conn,
+ const char *namedata, size_t namelen,
+ char **store_name)
+{
+ char *name;
+ int result;
+ char *host = PQhost(conn);
+
+ *store_name = NULL;
+
+ /*
+ * There is no guarantee the string returned from the certificate is
+ * NULL-terminated, so make a copy that is.
+ */
+ name = malloc(namelen + 1);
+ if (name == NULL)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("out of memory\n"));
+ return -1;
+ }
+ memcpy(name, namedata, namelen);
+ name[namelen] = '\0';
+
+ /*
+ * Reject embedded NULLs in certificate common or alternative name to
+ * prevent attacks like CVE-2009-4034.
+ */
+ if (namelen != strlen(name))
+ {
+ free(name);
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("SSL certificate's name contains embedded null\n"));
+ return -1;
+ }
+
+ if (pg_strcasecmp(name, host) == 0)
+ {
+ /* Exact name match */
+ result = 1;
+ }
+ else if (wildcard_certificate_match(name, host))
+ {
+ /* Matched wildcard name */
+ result = 1;
+ }
+ else
+ {
+ result = 0;
+ }
+
+ *store_name = name;
+ return result;
+}
+
+/*
+ * Verify that the server certificate matches the hostname we connected to.
+ *
+ * The certificate's Common Name and Subject Alternative Names are considered.
+ */
+bool
+pq_verify_peer_name_matches_certificate(PGconn *conn)
+{
+ char *host = PQhost(conn);
+ int rc;
+ int names_examined = 0;
+ char *first_name = NULL;
+
+ /*
+ * If told not to verify the peer name, don't do it. Return true
+ * indicating that the verification was successful.
+ */
+ if (strcmp(conn->sslmode, "verify-full") != 0)
+ return true;
+
+ /* Check that we have a hostname to compare with. */
+ if (!(host && host[0] != '\0'))
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("host name must be specified for a verified SSL connection\n"));
+ return false;
+ }
+
+ rc = pgtls_verify_peer_name_matches_certificate_guts(conn, &names_examined, &first_name);
+
+ if (rc == 0)
+ {
+ /*
+ * No match. Include the name from the server certificate in the error
+ * message, to aid debugging broken configurations. If there are
+ * multiple names, only print the first one to avoid an overly long
+ * error message.
+ */
+ if (names_examined > 1)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_ngettext("server certificate for \"%s\" (and %d other name) does not match host name \"%s\"\n",
+ "server certificate for \"%s\" (and %d other names) does not match host name \"%s\"\n",
+ names_examined - 1),
+ first_name, names_examined - 1, host);
+ }
+ else if (names_examined == 1)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("server certificate for \"%s\" does not match host name \"%s\"\n"),
+ first_name, host);
+ }
+ else
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("could not get server's host name from server certificate\n"));
+ }
+ }
+
+ /* clean up */
+ if (first_name)
+ free(first_name);
+
+ return (rc == 1);
+}
--- /dev/null
+/*-------------------------------------------------------------------------
+ *
+ * fe-secure-common.h
+ *
+ * common implementation-independent SSL support code
+ *
+ * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/interfaces/libpq/fe-secure-common.h
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef FE_SECURE_COMMON_H
+#define FE_SECURE_COMMON_H
+
+#include "libpq-fe.h"
+
+extern int pq_verify_peer_name_matches_certificate_name(PGconn *conn,
+ const char *namedata, size_t namelen,
+ char **store_name);
+extern bool pq_verify_peer_name_matches_certificate(PGconn *conn);
+
+#endif /* FE_SECURE_COMMON_H */
#include "libpq-fe.h"
#include "fe-auth.h"
+#include "fe-secure-common.h"
#include "libpq-int.h"
#ifdef WIN32
#endif
#include <openssl/x509v3.h>
-static bool verify_peer_name_matches_certificate(PGconn *);
static int verify_cb(int ok, X509_STORE_CTX *ctx);
-static int verify_peer_name_matches_certificate_name(PGconn *conn,
+static int openssl_verify_peer_name_matches_certificate_name(PGconn *conn,
ASN1_STRING *name,
char **store_name);
static void destroy_ssl_system(void);
/*
- * Check if a wildcard certificate matches the server hostname.
- *
- * The rule for this is:
- * 1. We only match the '*' character as wildcard
- * 2. We match only wildcards at the start of the string
- * 3. The '*' character does *not* match '.', meaning that we match only
- * a single pathname component.
- * 4. We don't support more than one '*' in a single pattern.
- *
- * This is roughly in line with RFC2818, but contrary to what most browsers
- * appear to be implementing (point 3 being the difference)
- *
- * Matching is always case-insensitive, since DNS is case insensitive.
- */
-static int
-wildcard_certificate_match(const char *pattern, const char *string)
-{
- int lenpat = strlen(pattern);
- int lenstr = strlen(string);
-
- /* If we don't start with a wildcard, it's not a match (rule 1 & 2) */
- if (lenpat < 3 ||
- pattern[0] != '*' ||
- pattern[1] != '.')
- return 0;
-
- if (lenpat > lenstr)
- /* If pattern is longer than the string, we can never match */
- return 0;
-
- if (pg_strcasecmp(pattern + 1, string + lenstr - lenpat + 1) != 0)
-
- /*
- * If string does not end in pattern (minus the wildcard), we don't
- * match
- */
- return 0;
-
- if (strchr(string, '.') < string + lenstr - lenpat)
-
- /*
- * If there is a dot left of where the pattern started to match, we
- * don't match (rule 3)
- */
- return 0;
-
- /* String ended with pattern, and didn't have a dot before, so we match */
- return 1;
-}
-
-/*
- * Check if a name from a server's certificate matches the peer's hostname.
- *
- * Returns 1 if the name matches, and 0 if it does not. On error, returns
- * -1, and sets the libpq error message.
- *
- * The name extracted from the certificate is returned in *store_name. The
- * caller is responsible for freeing it.
+ * OpenSSL-specific wrapper around
+ * pq_verify_peer_name_matches_certificate_name(), converting the ASN1_STRING
+ * into a plain C string.
*/
static int
-verify_peer_name_matches_certificate_name(PGconn *conn, ASN1_STRING *name_entry,
- char **store_name)
+openssl_verify_peer_name_matches_certificate_name(PGconn *conn, ASN1_STRING *name_entry,
+ char **store_name)
{
int len;
- char *name;
const unsigned char *namedata;
- int result;
- char *host = PQhost(conn);
-
- *store_name = NULL;
/* Should not happen... */
if (name_entry == NULL)
/*
* GEN_DNS can be only IA5String, equivalent to US ASCII.
- *
- * There is no guarantee the string returned from the certificate is
- * NULL-terminated, so make a copy that is.
*/
#ifdef HAVE_ASN1_STRING_GET0_DATA
namedata = ASN1_STRING_get0_data(name_entry);
namedata = ASN1_STRING_data(name_entry);
#endif
len = ASN1_STRING_length(name_entry);
- name = malloc(len + 1);
- if (name == NULL)
- {
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("out of memory\n"));
- return -1;
- }
- memcpy(name, namedata, len);
- name[len] = '\0';
-
- /*
- * Reject embedded NULLs in certificate common or alternative name to
- * prevent attacks like CVE-2009-4034.
- */
- if (len != strlen(name))
- {
- free(name);
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("SSL certificate's name contains embedded null\n"));
- return -1;
- }
- if (pg_strcasecmp(name, host) == 0)
- {
- /* Exact name match */
- result = 1;
- }
- else if (wildcard_certificate_match(name, host))
- {
- /* Matched wildcard name */
- result = 1;
- }
- else
- {
- result = 0;
- }
-
- *store_name = name;
- return result;
+ /* OK to cast from unsigned to plain char, since it's all ASCII. */
+ return pq_verify_peer_name_matches_certificate_name(conn, (const char *) namedata, len, store_name);
}
/*
*
* The certificate's Common Name and Subject Alternative Names are considered.
*/
-static bool
-verify_peer_name_matches_certificate(PGconn *conn)
+int
+pgtls_verify_peer_name_matches_certificate_guts(PGconn *conn,
+ int *names_examined,
+ char **first_name)
{
- int names_examined = 0;
- bool found_match = false;
- bool got_error = false;
- char *first_name = NULL;
-
STACK_OF(GENERAL_NAME) *peer_san;
int i;
- int rc;
- char *host = PQhost(conn);
-
- /*
- * If told not to verify the peer name, don't do it. Return true
- * indicating that the verification was successful.
- */
- if (strcmp(conn->sslmode, "verify-full") != 0)
- return true;
-
- /* Check that we have a hostname to compare with. */
- if (!(host && host[0] != '\0'))
- {
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("host name must be specified for a verified SSL connection\n"));
- return false;
- }
+ int rc = 0;
/*
* First, get the Subject Alternative Names (SANs) from the certificate,
{
char *alt_name;
- names_examined++;
- rc = verify_peer_name_matches_certificate_name(conn,
+ (*names_examined)++;
+ rc = openssl_verify_peer_name_matches_certificate_name(conn,
name->d.dNSName,
&alt_name);
- if (rc == -1)
- got_error = true;
- if (rc == 1)
- found_match = true;
if (alt_name)
{
- if (!first_name)
- first_name = alt_name;
+ if (!*first_name)
+ *first_name = alt_name;
else
free(alt_name);
}
}
- if (found_match || got_error)
+ if (rc != 0)
break;
}
sk_GENERAL_NAME_free(peer_san);
* (Per RFC 2818 and RFC 6125, if the subjectAltName extension of type
* dNSName is present, the CN must be ignored.)
*/
- if (names_examined == 0)
+ if (*names_examined == 0)
{
X509_NAME *subject_name;
NID_commonName, -1);
if (cn_index >= 0)
{
- names_examined++;
- rc = verify_peer_name_matches_certificate_name(
+ (*names_examined)++;
+ rc = openssl_verify_peer_name_matches_certificate_name(
conn,
X509_NAME_ENTRY_get_data(
X509_NAME_get_entry(subject_name, cn_index)),
- &first_name);
-
- if (rc == -1)
- got_error = true;
- else if (rc == 1)
- found_match = true;
+ first_name);
}
}
}
- if (!found_match && !got_error)
- {
- /*
- * No match. Include the name from the server certificate in the error
- * message, to aid debugging broken configurations. If there are
- * multiple names, only print the first one to avoid an overly long
- * error message.
- */
- if (names_examined > 1)
- {
- printfPQExpBuffer(&conn->errorMessage,
- libpq_ngettext("server certificate for \"%s\" (and %d other name) does not match host name \"%s\"\n",
- "server certificate for \"%s\" (and %d other names) does not match host name \"%s\"\n",
- names_examined - 1),
- first_name, names_examined - 1, host);
- }
- else if (names_examined == 1)
- {
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("server certificate for \"%s\" does not match host name \"%s\"\n"),
- first_name, host);
- }
- else
- {
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("could not get server's host name from server certificate\n"));
- }
- }
-
- /* clean up */
- if (first_name)
- free(first_name);
-
- return found_match && !got_error;
+ return rc;
}
#if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_CRYPTO_LOCK)
return PGRES_POLLING_FAILED;
}
- if (!verify_peer_name_matches_certificate(conn))
+ if (!pq_verify_peer_name_matches_certificate(conn))
{
pgtls_close(conn);
return PGRES_POLLING_FAILED;
*/
extern char *pgtls_get_peer_certificate_hash(PGconn *conn, size_t *len);
+/*
+ * Verify that the server certificate matches the host name we connected to.
+ *
+ * The certificate's Common Name and Subject Alternative Names are considered.
+ *
+ * Returns 1 if the name matches, and 0 if it does not. On error, returns
+ * -1, and sets the libpq error message.
+ *
+ */
+extern int pgtls_verify_peer_name_matches_certificate_guts(PGconn *conn,
+ int *names_examined,
+ char **first_name);
+
/* === miscellaneous macros === */
/*
# src/interfaces/libpq/nls.mk
CATALOG_NAME = libpq
AVAIL_LANGUAGES = cs de es fr he it ja ko pl pt_BR ru sv tr zh_CN zh_TW
-GETTEXT_FILES = fe-auth.c fe-auth-scram.c fe-connect.c fe-exec.c fe-lobj.c fe-misc.c fe-protocol2.c fe-protocol3.c fe-secure.c fe-secure-openssl.c win32.c
+GETTEXT_FILES = fe-auth.c fe-auth-scram.c fe-connect.c fe-exec.c fe-lobj.c fe-misc.c fe-protocol2.c fe-protocol3.c fe-secure.c fe-secure-common.c fe-secure-openssl.c win32.c
GETTEXT_TRIGGERS = libpq_gettext pqInternalNotice:2
GETTEXT_FLAGS = libpq_gettext:1:pass-c-format pqInternalNotice:2:c-format
# building with OpenSSL.
if (!$solution->{options}->{openssl})
{
+ $libpq->RemoveFile('src/interfaces/libpq/fe-secure-common.c');
$libpq->RemoveFile('src/interfaces/libpq/fe-secure-openssl.c');
$libpq->RemoveFile('src/common/sha2_openssl.c');
}
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