postgresql/src/interfaces/libpq/fe-secure-openssl.c

1707 lines
43 KiB
C

/*-------------------------------------------------------------------------
*
* fe-secure-openssl.c
* OpenSSL support
*
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/interfaces/libpq/fe-secure-openssl.c
*
* NOTES
*
* We don't provide informational callbacks here (like
* info_cb() in be-secure.c), since there's no good mechanism to
* display such information to the user.
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include "libpq-fe.h"
#include "fe-auth.h"
#include "libpq-int.h"
#ifdef WIN32
#include "win32.h"
#else
#include <sys/socket.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#endif
#include <arpa/inet.h>
#endif
#include <sys/stat.h>
#ifdef ENABLE_THREAD_SAFETY
#ifdef WIN32
#include "pthread-win32.h"
#else
#include <pthread.h>
#endif
#endif
#include <openssl/ssl.h>
#include <openssl/conf.h>
#ifdef USE_SSL_ENGINE
#include <openssl/engine.h>
#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,
ASN1_STRING *name,
char **store_name);
static void destroy_ssl_system(void);
static int initialize_SSL(PGconn *conn);
static PostgresPollingStatusType open_client_SSL(PGconn *);
static char *SSLerrmessage(unsigned long ecode);
static void SSLerrfree(char *buf);
static int my_sock_read(BIO *h, char *buf, int size);
static int my_sock_write(BIO *h, const char *buf, int size);
static BIO_METHOD *my_BIO_s_socket(void);
static int my_SSL_set_fd(PGconn *conn, int fd);
static bool pq_init_ssl_lib = true;
static bool pq_init_crypto_lib = true;
static bool ssl_lib_initialized = false;
#ifdef ENABLE_THREAD_SAFETY
static long ssl_open_connections = 0;
#ifndef WIN32
static pthread_mutex_t ssl_config_mutex = PTHREAD_MUTEX_INITIALIZER;
#else
static pthread_mutex_t ssl_config_mutex = NULL;
static long win32_ssl_create_mutex = 0;
#endif
#endif /* ENABLE_THREAD_SAFETY */
/* ------------------------------------------------------------ */
/* Procedures common to all secure sessions */
/* ------------------------------------------------------------ */
/*
* Exported function to allow application to tell us it's already
* initialized OpenSSL and/or libcrypto.
*/
void
pgtls_init_library(bool do_ssl, int do_crypto)
{
#ifdef ENABLE_THREAD_SAFETY
/*
* Disallow changing the flags while we have open connections, else we'd
* get completely confused.
*/
if (ssl_open_connections != 0)
return;
#endif
pq_init_ssl_lib = do_ssl;
pq_init_crypto_lib = do_crypto;
}
/*
* Begin or continue negotiating a secure session.
*/
PostgresPollingStatusType
pgtls_open_client(PGconn *conn)
{
/* First time through? */
if (conn->ssl == NULL)
{
/*
* Create a connection-specific SSL object, and load client certificate,
* private key, and trusted CA certs.
*/
if (initialize_SSL(conn) != 0)
{
/* initialize_SSL already put a message in conn->errorMessage */
pgtls_close(conn);
return PGRES_POLLING_FAILED;
}
}
/* Begin or continue the actual handshake */
return open_client_SSL(conn);
}
/*
* Is there unread data waiting in the SSL read buffer?
*/
bool
pgtls_read_pending(PGconn *conn)
{
return SSL_pending(conn->ssl);
}
/*
* Read data from a secure connection.
*
* On failure, this function is responsible for putting a suitable message
* into conn->errorMessage. The caller must still inspect errno, but only
* to determine whether to continue/retry after error.
*/
ssize_t
pgtls_read(PGconn *conn, void *ptr, size_t len)
{
ssize_t n;
int result_errno = 0;
char sebuf[256];
int err;
unsigned long ecode;
rloop:
/*
* Prepare to call SSL_get_error() by clearing thread's OpenSSL error
* queue. In general, the current thread's error queue must be empty
* before the TLS/SSL I/O operation is attempted, or SSL_get_error() will
* not work reliably. Since the possibility exists that other OpenSSL
* clients running in the same thread but not under our control will fail
* to call ERR_get_error() themselves (after their own I/O operations),
* pro-actively clear the per-thread error queue now.
*/
SOCK_ERRNO_SET(0);
ERR_clear_error();
n = SSL_read(conn->ssl, ptr, len);
err = SSL_get_error(conn->ssl, n);
/*
* Other clients of OpenSSL may fail to call ERR_get_error(), but we
* always do, so as to not cause problems for OpenSSL clients that don't
* call ERR_clear_error() defensively. Be sure that this happens by
* calling now. SSL_get_error() relies on the OpenSSL per-thread error
* queue being intact, so this is the earliest possible point
* ERR_get_error() may be called.
*/
ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0;
switch (err)
{
case SSL_ERROR_NONE:
if (n < 0)
{
/* Not supposed to happen, so we don't translate the msg */
printfPQExpBuffer(&conn->errorMessage,
"SSL_read failed but did not provide error information\n");
/* assume the connection is broken */
result_errno = ECONNRESET;
}
break;
case SSL_ERROR_WANT_READ:
n = 0;
break;
case SSL_ERROR_WANT_WRITE:
/*
* Returning 0 here would cause caller to wait for read-ready,
* which is not correct since what SSL wants is wait for
* write-ready. The former could get us stuck in an infinite
* wait, so don't risk it; busy-loop instead.
*/
goto rloop;
case SSL_ERROR_SYSCALL:
if (n < 0)
{
result_errno = SOCK_ERRNO;
if (result_errno == EPIPE ||
result_errno == ECONNRESET)
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
"server closed the connection unexpectedly\n"
"\tThis probably means the server terminated abnormally\n"
"\tbefore or while processing the request.\n"));
else
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: %s\n"),
SOCK_STRERROR(result_errno,
sebuf, sizeof(sebuf)));
}
else
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: EOF detected\n"));
/* assume the connection is broken */
result_errno = ECONNRESET;
n = -1;
}
break;
case SSL_ERROR_SSL:
{
char *errm = SSLerrmessage(ecode);
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL error: %s\n"), errm);
SSLerrfree(errm);
/* assume the connection is broken */
result_errno = ECONNRESET;
n = -1;
break;
}
case SSL_ERROR_ZERO_RETURN:
/*
* Per OpenSSL documentation, this error code is only returned for
* a clean connection closure, so we should not report it as a
* server crash.
*/
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL connection has been closed unexpectedly\n"));
result_errno = ECONNRESET;
n = -1;
break;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("unrecognized SSL error code: %d\n"),
err);
/* assume the connection is broken */
result_errno = ECONNRESET;
n = -1;
break;
}
/* ensure we return the intended errno to caller */
SOCK_ERRNO_SET(result_errno);
return n;
}
/*
* Write data to a secure connection.
*
* On failure, this function is responsible for putting a suitable message
* into conn->errorMessage. The caller must still inspect errno, but only
* to determine whether to continue/retry after error.
*/
ssize_t
pgtls_write(PGconn *conn, const void *ptr, size_t len)
{
ssize_t n;
int result_errno = 0;
char sebuf[256];
int err;
unsigned long ecode;
SOCK_ERRNO_SET(0);
ERR_clear_error();
n = SSL_write(conn->ssl, ptr, len);
err = SSL_get_error(conn->ssl, n);
ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0;
switch (err)
{
case SSL_ERROR_NONE:
if (n < 0)
{
/* Not supposed to happen, so we don't translate the msg */
printfPQExpBuffer(&conn->errorMessage,
"SSL_write failed but did not provide error information\n");
/* assume the connection is broken */
result_errno = ECONNRESET;
}
break;
case SSL_ERROR_WANT_READ:
/*
* Returning 0 here causes caller to wait for write-ready, which
* is not really the right thing, but it's the best we can do.
*/
n = 0;
break;
case SSL_ERROR_WANT_WRITE:
n = 0;
break;
case SSL_ERROR_SYSCALL:
if (n < 0)
{
result_errno = SOCK_ERRNO;
if (result_errno == EPIPE || result_errno == ECONNRESET)
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
"server closed the connection unexpectedly\n"
"\tThis probably means the server terminated abnormally\n"
"\tbefore or while processing the request.\n"));
else
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: %s\n"),
SOCK_STRERROR(result_errno,
sebuf, sizeof(sebuf)));
}
else
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: EOF detected\n"));
/* assume the connection is broken */
result_errno = ECONNRESET;
n = -1;
}
break;
case SSL_ERROR_SSL:
{
char *errm = SSLerrmessage(ecode);
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL error: %s\n"), errm);
SSLerrfree(errm);
/* assume the connection is broken */
result_errno = ECONNRESET;
n = -1;
break;
}
case SSL_ERROR_ZERO_RETURN:
/*
* Per OpenSSL documentation, this error code is only returned for
* a clean connection closure, so we should not report it as a
* server crash.
*/
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL connection has been closed unexpectedly\n"));
result_errno = ECONNRESET;
n = -1;
break;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("unrecognized SSL error code: %d\n"),
err);
/* assume the connection is broken */
result_errno = ECONNRESET;
n = -1;
break;
}
/* ensure we return the intended errno to caller */
SOCK_ERRNO_SET(result_errno);
return n;
}
/* ------------------------------------------------------------ */
/* OpenSSL specific code */
/* ------------------------------------------------------------ */
/*
* Certificate verification callback
*
* This callback allows us to log intermediate problems during
* verification, but there doesn't seem to be a clean way to get
* our PGconn * structure. So we can't log anything!
*
* This callback also allows us to override the default acceptance
* criteria (e.g., accepting self-signed or expired certs), but
* for now we accept the default checks.
*/
static int
verify_cb(int ok, X509_STORE_CTX *ctx)
{
return ok;
}
/*
* 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.
*/
static int
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)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL certificate's name entry is missing\n"));
return -1;
}
/*
* 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);
#else
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;
}
/*
* Verify that the server certificate matches the hostname we connected to.
*
* The certificate's Common Name and Subject Alternative Names are considered.
*/
static bool
verify_peer_name_matches_certificate(PGconn *conn)
{
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;
}
/*
* First, get the Subject Alternative Names (SANs) from the certificate,
* and compare them against the originally given hostname.
*/
peer_san = (STACK_OF(GENERAL_NAME) *)
X509_get_ext_d2i(conn->peer, NID_subject_alt_name, NULL, NULL);
if (peer_san)
{
int san_len = sk_GENERAL_NAME_num(peer_san);
for (i = 0; i < san_len; i++)
{
const GENERAL_NAME *name = sk_GENERAL_NAME_value(peer_san, i);
if (name->type == GEN_DNS)
{
char *alt_name;
names_examined++;
rc = 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;
else
free(alt_name);
}
}
if (found_match || got_error)
break;
}
sk_GENERAL_NAME_free(peer_san);
}
/*
* If there is no subjectAltName extension of type dNSName, check the
* Common Name.
*
* (Per RFC 2818 and RFC 6125, if the subjectAltName extension of type
* dNSName is present, the CN must be ignored.)
*/
if (names_examined == 0)
{
X509_NAME *subject_name;
subject_name = X509_get_subject_name(conn->peer);
if (subject_name != NULL)
{
int cn_index;
cn_index = X509_NAME_get_index_by_NID(subject_name,
NID_commonName, -1);
if (cn_index >= 0)
{
names_examined++;
rc = 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;
}
}
}
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;
}
#if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_CRYPTO_LOCK)
/*
* Callback functions for OpenSSL internal locking. (OpenSSL 1.1.0
* does its own locking, and doesn't need these anymore. The
* CRYPTO_lock() function was removed in 1.1.0, when the callbacks
* were made obsolete, so we assume that if CRYPTO_lock() exists,
* the callbacks are still required.)
*/
static unsigned long
pq_threadidcallback(void)
{
/*
* This is not standards-compliant. pthread_self() returns pthread_t, and
* shouldn't be cast to unsigned long, but CRYPTO_set_id_callback requires
* it, so we have to do it.
*/
return (unsigned long) pthread_self();
}
static pthread_mutex_t *pq_lockarray;
static void
pq_lockingcallback(int mode, int n, const char *file, int line)
{
if (mode & CRYPTO_LOCK)
{
if (pthread_mutex_lock(&pq_lockarray[n]))
PGTHREAD_ERROR("failed to lock mutex");
}
else
{
if (pthread_mutex_unlock(&pq_lockarray[n]))
PGTHREAD_ERROR("failed to unlock mutex");
}
}
#endif /* ENABLE_THREAD_SAFETY && HAVE_CRYPTO_LOCK */
/*
* Initialize SSL library.
*
* In threadsafe mode, this includes setting up libcrypto callback functions
* to do thread locking.
*
* If the caller has told us (through PQinitOpenSSL) that he's taking care
* of libcrypto, we expect that callbacks are already set, and won't try to
* override it.
*
* The conn parameter is only used to be able to pass back an error
* message - no connection-local setup is made here.
*
* Returns 0 if OK, -1 on failure (with a message in conn->errorMessage).
*/
int
pgtls_init(PGconn *conn)
{
#ifdef ENABLE_THREAD_SAFETY
#ifdef WIN32
/* Also see similar code in fe-connect.c, default_threadlock() */
if (ssl_config_mutex == NULL)
{
while (InterlockedExchange(&win32_ssl_create_mutex, 1) == 1)
/* loop, another thread own the lock */ ;
if (ssl_config_mutex == NULL)
{
if (pthread_mutex_init(&ssl_config_mutex, NULL))
return -1;
}
InterlockedExchange(&win32_ssl_create_mutex, 0);
}
#endif
if (pthread_mutex_lock(&ssl_config_mutex))
return -1;
#ifdef HAVE_CRYPTO_LOCK
if (pq_init_crypto_lib)
{
/*
* If necessary, set up an array to hold locks for libcrypto.
* libcrypto will tell us how big to make this array.
*/
if (pq_lockarray == NULL)
{
int i;
pq_lockarray = malloc(sizeof(pthread_mutex_t) * CRYPTO_num_locks());
if (!pq_lockarray)
{
pthread_mutex_unlock(&ssl_config_mutex);
return -1;
}
for (i = 0; i < CRYPTO_num_locks(); i++)
{
if (pthread_mutex_init(&pq_lockarray[i], NULL))
{
free(pq_lockarray);
pq_lockarray = NULL;
pthread_mutex_unlock(&ssl_config_mutex);
return -1;
}
}
}
if (ssl_open_connections++ == 0)
{
/*
* These are only required for threaded libcrypto applications,
* but make sure we don't stomp on them if they're already set.
*/
if (CRYPTO_get_id_callback() == NULL)
CRYPTO_set_id_callback(pq_threadidcallback);
if (CRYPTO_get_locking_callback() == NULL)
CRYPTO_set_locking_callback(pq_lockingcallback);
}
}
#endif /* HAVE_CRYPTO_LOCK */
#endif /* ENABLE_THREAD_SAFETY */
if (!ssl_lib_initialized)
{
if (pq_init_ssl_lib)
{
#ifdef HAVE_OPENSSL_INIT_SSL
OPENSSL_init_ssl(OPENSSL_INIT_LOAD_CONFIG, NULL);
#else
OPENSSL_config(NULL);
SSL_library_init();
SSL_load_error_strings();
#endif
}
ssl_lib_initialized = true;
}
#ifdef ENABLE_THREAD_SAFETY
pthread_mutex_unlock(&ssl_config_mutex);
#endif
return 0;
}
/*
* This function is needed because if the libpq library is unloaded
* from the application, the callback functions will no longer exist when
* libcrypto is used by other parts of the system. For this reason,
* we unregister the callback functions when the last libpq
* connection is closed. (The same would apply for OpenSSL callbacks
* if we had any.)
*
* Callbacks are only set when we're compiled in threadsafe mode, so
* we only need to remove them in this case. They are also not needed
* with OpenSSL 1.1.0 anymore.
*/
static void
destroy_ssl_system(void)
{
#if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_CRYPTO_LOCK)
/* Mutex is created in initialize_ssl_system() */
if (pthread_mutex_lock(&ssl_config_mutex))
return;
if (pq_init_crypto_lib && ssl_open_connections > 0)
--ssl_open_connections;
if (pq_init_crypto_lib && ssl_open_connections == 0)
{
/*
* No connections left, unregister libcrypto callbacks, if no one
* registered different ones in the meantime.
*/
if (CRYPTO_get_locking_callback() == pq_lockingcallback)
CRYPTO_set_locking_callback(NULL);
if (CRYPTO_get_id_callback() == pq_threadidcallback)
CRYPTO_set_id_callback(NULL);
/*
* We don't free the lock array. If we get another connection in
* this process, we will just re-use them with the existing mutexes.
*
* This means we leak a little memory on repeated load/unload of the
* library.
*/
}
pthread_mutex_unlock(&ssl_config_mutex);
#endif
}
/*
* Create per-connection SSL object, and load the client certificate,
* private key, and trusted CA certs.
*
* Returns 0 if OK, -1 on failure (with a message in conn->errorMessage).
*/
static int
initialize_SSL(PGconn *conn)
{
SSL_CTX *SSL_context;
struct stat buf;
char homedir[MAXPGPATH];
char fnbuf[MAXPGPATH];
char sebuf[256];
bool have_homedir;
bool have_cert;
bool have_rootcert;
EVP_PKEY *pkey = NULL;
/*
* We'll need the home directory if any of the relevant parameters are
* defaulted. If pqGetHomeDirectory fails, act as though none of the
* files could be found.
*/
if (!(conn->sslcert && strlen(conn->sslcert) > 0) ||
!(conn->sslkey && strlen(conn->sslkey) > 0) ||
!(conn->sslrootcert && strlen(conn->sslrootcert) > 0) ||
!(conn->sslcrl && strlen(conn->sslcrl) > 0))
have_homedir = pqGetHomeDirectory(homedir, sizeof(homedir));
else /* won't need it */
have_homedir = false;
/*
* Create a new SSL_CTX object.
*
* We used to share a single SSL_CTX between all connections, but it was
* complicated if connections used different certificates. So now we create
* a separate context for each connection, and accept the overhead.
*/
SSL_context = SSL_CTX_new(SSLv23_method());
if (!SSL_context)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not create SSL context: %s\n"),
err);
SSLerrfree(err);
return -1;
}
/* Disable old protocol versions */
SSL_CTX_set_options(SSL_context, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
/*
* Disable OpenSSL's moving-write-buffer sanity check, because it
* causes unnecessary failures in nonblocking send cases.
*/
SSL_CTX_set_mode(SSL_context, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
/*
* If the root cert file exists, load it so we can perform certificate
* verification. If sslmode is "verify-full" we will also do further
* verification after the connection has been completed.
*/
if (conn->sslrootcert && strlen(conn->sslrootcert) > 0)
strlcpy(fnbuf, conn->sslrootcert, sizeof(fnbuf));
else if (have_homedir)
snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, ROOT_CERT_FILE);
else
fnbuf[0] = '\0';
if (fnbuf[0] != '\0' &&
stat(fnbuf, &buf) == 0)
{
X509_STORE *cvstore;
if (SSL_CTX_load_verify_locations(SSL_context, fnbuf, NULL) != 1)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not read root certificate file \"%s\": %s\n"),
fnbuf, err);
SSLerrfree(err);
SSL_CTX_free(SSL_context);
return -1;
}
if ((cvstore = SSL_CTX_get_cert_store(SSL_context)) != NULL)
{
if (conn->sslcrl && strlen(conn->sslcrl) > 0)
strlcpy(fnbuf, conn->sslcrl, sizeof(fnbuf));
else if (have_homedir)
snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, ROOT_CRL_FILE);
else
fnbuf[0] = '\0';
/* Set the flags to check against the complete CRL chain */
if (fnbuf[0] != '\0' &&
X509_STORE_load_locations(cvstore, fnbuf, NULL) == 1)
{
/* OpenSSL 0.96 does not support X509_V_FLAG_CRL_CHECK */
#ifdef X509_V_FLAG_CRL_CHECK
X509_STORE_set_flags(cvstore,
X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
#else
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL library does not support CRL certificates (file \"%s\")\n"),
fnbuf);
SSLerrfree(err);
SSL_CTX_free(SSL_context);
return -1;
#endif
}
/* if not found, silently ignore; we do not require CRL */
ERR_clear_error();
}
have_rootcert = true;
}
else
{
/*
* stat() failed; assume root file doesn't exist. If sslmode is
* verify-ca or verify-full, this is an error. Otherwise, continue
* without performing any server cert verification.
*/
if (conn->sslmode[0] == 'v') /* "verify-ca" or "verify-full" */
{
/*
* The only way to reach here with an empty filename is if
* pqGetHomeDirectory failed. That's a sufficiently unusual case
* that it seems worth having a specialized error message for it.
*/
if (fnbuf[0] == '\0')
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not get home directory to locate root certificate file\n"
"Either provide the file or change sslmode to disable server certificate verification.\n"));
else
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("root certificate file \"%s\" does not exist\n"
"Either provide the file or change sslmode to disable server certificate verification.\n"), fnbuf);
SSL_CTX_free(SSL_context);
return -1;
}
have_rootcert = false;
}
/* Read the client certificate file */
if (conn->sslcert && strlen(conn->sslcert) > 0)
strlcpy(fnbuf, conn->sslcert, sizeof(fnbuf));
else if (have_homedir)
snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, USER_CERT_FILE);
else
fnbuf[0] = '\0';
if (fnbuf[0] == '\0')
{
/* no home directory, proceed without a client cert */
have_cert = false;
}
else if (stat(fnbuf, &buf) != 0)
{
/*
* If file is not present, just go on without a client cert; server
* might or might not accept the connection. Any other error,
* however, is grounds for complaint.
*/
if (errno != ENOENT && errno != ENOTDIR)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not open certificate file \"%s\": %s\n"),
fnbuf, pqStrerror(errno, sebuf, sizeof(sebuf)));
SSL_CTX_free(SSL_context);
return -1;
}
have_cert = false;
}
else
{
/*
* Cert file exists, so load it. Since OpenSSL doesn't provide the
* equivalent of "SSL_use_certificate_chain_file", we have to load
* it into the SSL context, rather than the SSL object.
*/
if (SSL_CTX_use_certificate_chain_file(SSL_context, fnbuf) != 1)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not read certificate file \"%s\": %s\n"),
fnbuf, err);
SSLerrfree(err);
SSL_CTX_free(SSL_context);
return -1;
}
/* need to load the associated private key, too */
have_cert = true;
}
/*
* The SSL context is now loaded with the correct root and client certificates.
* Create a connection-specific SSL object. The private key is loaded directly
* into the SSL object. (We could load the private key into the context, too, but
* we have done it this way historically, and it doesn't really matter.)
*/
if (!(conn->ssl = SSL_new(SSL_context)) ||
!SSL_set_app_data(conn->ssl, conn) ||
!my_SSL_set_fd(conn, conn->sock))
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not establish SSL connection: %s\n"),
err);
SSLerrfree(err);
SSL_CTX_free(SSL_context);
return -1;
}
conn->ssl_in_use = true;
/*
* SSL contexts are reference counted by OpenSSL. We can free it as soon as we
* have created the SSL object, and it will stick around for as long as it's
* actually needed.
*/
SSL_CTX_free(SSL_context);
SSL_context = NULL;
/*
* Read the SSL key. If a key is specified, treat it as an engine:key
* combination if there is colon present - we don't support files with
* colon in the name. The exception is if the second character is a colon,
* in which case it can be a Windows filename with drive specification.
*/
if (have_cert && conn->sslkey && strlen(conn->sslkey) > 0)
{
#ifdef USE_SSL_ENGINE
if (strchr(conn->sslkey, ':')
#ifdef WIN32
&& conn->sslkey[1] != ':'
#endif
)
{
/* Colon, but not in second character, treat as engine:key */
char *engine_str = strdup(conn->sslkey);
char *engine_colon;
if (engine_str == NULL)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory\n"));
return -1;
}
/* cannot return NULL because we already checked before strdup */
engine_colon = strchr(engine_str, ':');
*engine_colon = '\0'; /* engine_str now has engine name */
engine_colon++; /* engine_colon now has key name */
conn->engine = ENGINE_by_id(engine_str);
if (conn->engine == NULL)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not load SSL engine \"%s\": %s\n"),
engine_str, err);
SSLerrfree(err);
free(engine_str);
return -1;
}
if (ENGINE_init(conn->engine) == 0)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not initialize SSL engine \"%s\": %s\n"),
engine_str, err);
SSLerrfree(err);
ENGINE_free(conn->engine);
conn->engine = NULL;
free(engine_str);
return -1;
}
pkey = ENGINE_load_private_key(conn->engine, engine_colon,
NULL, NULL);
if (pkey == NULL)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not read private SSL key \"%s\" from engine \"%s\": %s\n"),
engine_colon, engine_str, err);
SSLerrfree(err);
ENGINE_finish(conn->engine);
ENGINE_free(conn->engine);
conn->engine = NULL;
free(engine_str);
return -1;
}
if (SSL_use_PrivateKey(conn->ssl, pkey) != 1)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not load private SSL key \"%s\" from engine \"%s\": %s\n"),
engine_colon, engine_str, err);
SSLerrfree(err);
ENGINE_finish(conn->engine);
ENGINE_free(conn->engine);
conn->engine = NULL;
free(engine_str);
return -1;
}
free(engine_str);
fnbuf[0] = '\0'; /* indicate we're not going to load from a
* file */
}
else
#endif /* USE_SSL_ENGINE */
{
/* PGSSLKEY is not an engine, treat it as a filename */
strlcpy(fnbuf, conn->sslkey, sizeof(fnbuf));
}
}
else if (have_homedir)
{
/* No PGSSLKEY specified, load default file */
snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, USER_KEY_FILE);
}
else
fnbuf[0] = '\0';
if (have_cert && fnbuf[0] != '\0')
{
/* read the client key from file */
if (stat(fnbuf, &buf) != 0)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("certificate present, but not private key file \"%s\"\n"),
fnbuf);
return -1;
}
#ifndef WIN32
if (!S_ISREG(buf.st_mode) || buf.st_mode & (S_IRWXG | S_IRWXO))
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("private key file \"%s\" has group or world access; permissions should be u=rw (0600) or less\n"),
fnbuf);
return -1;
}
#endif
if (SSL_use_PrivateKey_file(conn->ssl, fnbuf, SSL_FILETYPE_PEM) != 1)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not load private key file \"%s\": %s\n"),
fnbuf, err);
SSLerrfree(err);
return -1;
}
}
/* verify that the cert and key go together */
if (have_cert &&
SSL_check_private_key(conn->ssl) != 1)
{
char *err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("certificate does not match private key file \"%s\": %s\n"),
fnbuf, err);
SSLerrfree(err);
return -1;
}
/*
* If a root cert was loaded, also set our certificate verification callback.
*/
if (have_rootcert)
SSL_set_verify(conn->ssl, SSL_VERIFY_PEER, verify_cb);
/*
* If the OpenSSL version used supports it (from 1.0.0 on) and the user
* requested it, disable SSL compression.
*/
#ifdef SSL_OP_NO_COMPRESSION
if (conn->sslcompression && conn->sslcompression[0] == '0')
{
SSL_set_options(conn->ssl, SSL_OP_NO_COMPRESSION);
}
#endif
return 0;
}
/*
* Attempt to negotiate SSL connection.
*/
static PostgresPollingStatusType
open_client_SSL(PGconn *conn)
{
int r;
ERR_clear_error();
r = SSL_connect(conn->ssl);
if (r <= 0)
{
int err = SSL_get_error(conn->ssl, r);
unsigned long ecode;
ecode = ERR_get_error();
switch (err)
{
case SSL_ERROR_WANT_READ:
return PGRES_POLLING_READING;
case SSL_ERROR_WANT_WRITE:
return PGRES_POLLING_WRITING;
case SSL_ERROR_SYSCALL:
{
char sebuf[256];
if (r == -1)
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: %s\n"),
SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
else
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: EOF detected\n"));
pgtls_close(conn);
return PGRES_POLLING_FAILED;
}
case SSL_ERROR_SSL:
{
char *err = SSLerrmessage(ecode);
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL error: %s\n"),
err);
SSLerrfree(err);
pgtls_close(conn);
return PGRES_POLLING_FAILED;
}
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("unrecognized SSL error code: %d\n"),
err);
pgtls_close(conn);
return PGRES_POLLING_FAILED;
}
}
/*
* We already checked the server certificate in initialize_SSL() using
* SSL_CTX_set_verify(), if root.crt exists.
*/
/* get server certificate */
conn->peer = SSL_get_peer_certificate(conn->ssl);
if (conn->peer == NULL)
{
char *err;
err = SSLerrmessage(ERR_get_error());
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("certificate could not be obtained: %s\n"),
err);
SSLerrfree(err);
pgtls_close(conn);
return PGRES_POLLING_FAILED;
}
if (!verify_peer_name_matches_certificate(conn))
{
pgtls_close(conn);
return PGRES_POLLING_FAILED;
}
/* SSL handshake is complete */
return PGRES_POLLING_OK;
}
/*
* Close SSL connection.
*/
void
pgtls_close(PGconn *conn)
{
bool destroy_needed = false;
if (conn->ssl)
{
/*
* We can't destroy everything SSL-related here due to the possible
* later calls to OpenSSL routines which may need our thread
* callbacks, so set a flag here and check at the end.
*/
destroy_needed = true;
SSL_shutdown(conn->ssl);
SSL_free(conn->ssl);
conn->ssl = NULL;
conn->ssl_in_use = false;
}
if (conn->peer)
{
X509_free(conn->peer);
conn->peer = NULL;
}
#ifdef USE_SSL_ENGINE
if (conn->engine)
{
ENGINE_finish(conn->engine);
ENGINE_free(conn->engine);
conn->engine = NULL;
}
#endif
/*
* This will remove our SSL locking hooks, if this is the last SSL
* connection, which means we must wait to call it until after all SSL
* calls have been made, otherwise we can end up with a race condition and
* possible deadlocks.
*
* See comments above destroy_ssl_system().
*/
if (destroy_needed)
destroy_ssl_system();
}
/*
* Obtain reason string for passed SSL errcode
*
* ERR_get_error() is used by caller to get errcode to pass here.
*
* Some caution is needed here since ERR_reason_error_string will
* return NULL if it doesn't recognize the error code. We don't
* want to return NULL ever.
*/
static char ssl_nomem[] = "out of memory allocating error description";
#define SSL_ERR_LEN 128
static char *
SSLerrmessage(unsigned long ecode)
{
const char *errreason;
char *errbuf;
errbuf = malloc(SSL_ERR_LEN);
if (!errbuf)
return ssl_nomem;
if (ecode == 0)
{
snprintf(errbuf, SSL_ERR_LEN, libpq_gettext("no SSL error reported"));
return errbuf;
}
errreason = ERR_reason_error_string(ecode);
if (errreason != NULL)
{
strlcpy(errbuf, errreason, SSL_ERR_LEN);
return errbuf;
}
snprintf(errbuf, SSL_ERR_LEN, libpq_gettext("SSL error code %lu"), ecode);
return errbuf;
}
static void
SSLerrfree(char *buf)
{
if (buf != ssl_nomem)
free(buf);
}
/* ------------------------------------------------------------ */
/* SSL information functions */
/* ------------------------------------------------------------ */
int
PQsslInUse(PGconn *conn)
{
if (!conn)
return 0;
return conn->ssl_in_use;
}
/*
* Return pointer to OpenSSL object.
*/
void *
PQgetssl(PGconn *conn)
{
if (!conn)
return NULL;
return conn->ssl;
}
void *
PQsslStruct(PGconn *conn, const char *struct_name)
{
if (!conn)
return NULL;
if (strcmp(struct_name, "OpenSSL") == 0)
return conn->ssl;
return NULL;
}
const char *const *
PQsslAttributeNames(PGconn *conn)
{
static const char *const result[] = {
"library",
"key_bits",
"cipher",
"compression",
"protocol",
NULL
};
return result;
}
const char *
PQsslAttribute(PGconn *conn, const char *attribute_name)
{
if (!conn)
return NULL;
if (conn->ssl == NULL)
return NULL;
if (strcmp(attribute_name, "library") == 0)
return "OpenSSL";
if (strcmp(attribute_name, "key_bits") == 0)
{
static char sslbits_str[10];
int sslbits;
SSL_get_cipher_bits(conn->ssl, &sslbits);
snprintf(sslbits_str, sizeof(sslbits_str), "%d", sslbits);
return sslbits_str;
}
if (strcmp(attribute_name, "cipher") == 0)
return SSL_get_cipher(conn->ssl);
if (strcmp(attribute_name, "compression") == 0)
return SSL_get_current_compression(conn->ssl) ? "on" : "off";
if (strcmp(attribute_name, "protocol") == 0)
return SSL_get_version(conn->ssl);
return NULL; /* unknown attribute */
}
/*
* Private substitute BIO: this does the sending and receiving using
* pqsecure_raw_write() and pqsecure_raw_read() instead, to allow those
* functions to disable SIGPIPE and give better error messages on I/O errors.
*
* These functions are closely modelled on the standard socket BIO in OpenSSL;
* see sock_read() and sock_write() in OpenSSL's crypto/bio/bss_sock.c.
* XXX OpenSSL 1.0.1e considers many more errcodes than just EINTR as reasons
* to retry; do we need to adopt their logic for that?
*/
#ifndef HAVE_BIO_GET_DATA
#define BIO_get_data(bio) (bio->ptr)
#define BIO_set_data(bio, data) (bio->ptr = data)
#endif
static BIO_METHOD *my_bio_methods;
static int
my_sock_read(BIO *h, char *buf, int size)
{
int res;
res = pqsecure_raw_read((PGconn *) BIO_get_data(h), buf, size);
BIO_clear_retry_flags(h);
if (res < 0)
{
/* If we were interrupted, tell caller to retry */
switch (SOCK_ERRNO)
{
#ifdef EAGAIN
case EAGAIN:
#endif
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
case EWOULDBLOCK:
#endif
case EINTR:
BIO_set_retry_read(h);
break;
default:
break;
}
}
return res;
}
static int
my_sock_write(BIO *h, const char *buf, int size)
{
int res;
res = pqsecure_raw_write((PGconn *) BIO_get_data(h), buf, size);
BIO_clear_retry_flags(h);
if (res <= 0)
{
/* If we were interrupted, tell caller to retry */
switch (SOCK_ERRNO)
{
#ifdef EAGAIN
case EAGAIN:
#endif
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
case EWOULDBLOCK:
#endif
case EINTR:
BIO_set_retry_write(h);
break;
default:
break;
}
}
return res;
}
static BIO_METHOD *
my_BIO_s_socket(void)
{
if (!my_bio_methods)
{
BIO_METHOD *biom = (BIO_METHOD *) BIO_s_socket();
#ifdef HAVE_BIO_METH_NEW
int my_bio_index;
my_bio_index = BIO_get_new_index();
if (my_bio_index == -1)
return NULL;
my_bio_methods = BIO_meth_new(my_bio_index, "libpq socket");
if (!my_bio_methods)
return NULL;
/*
* As of this writing, these functions never fail. But check anyway, like
* OpenSSL's own examples do.
*/
if (!BIO_meth_set_write(my_bio_methods, my_sock_write) ||
!BIO_meth_set_read(my_bio_methods, my_sock_read) ||
!BIO_meth_set_gets(my_bio_methods, BIO_meth_get_gets(biom)) ||
!BIO_meth_set_puts(my_bio_methods, BIO_meth_get_puts(biom)) ||
!BIO_meth_set_ctrl(my_bio_methods, BIO_meth_get_ctrl(biom)) ||
!BIO_meth_set_create(my_bio_methods, BIO_meth_get_create(biom)) ||
!BIO_meth_set_destroy(my_bio_methods, BIO_meth_get_destroy(biom)) ||
!BIO_meth_set_callback_ctrl(my_bio_methods, BIO_meth_get_callback_ctrl(biom)))
{
BIO_meth_free(my_bio_methods);
my_bio_methods = NULL;
return NULL;
}
#else
my_bio_methods = malloc(sizeof(BIO_METHOD));
if (!my_bio_methods)
return NULL;
memcpy(my_bio_methods, biom, sizeof(BIO_METHOD));
my_bio_methods->bread = my_sock_read;
my_bio_methods->bwrite = my_sock_write;
#endif
}
return my_bio_methods;
}
/* This should exactly match openssl's SSL_set_fd except for using my BIO */
static int
my_SSL_set_fd(PGconn *conn, int fd)
{
int ret = 0;
BIO *bio;
BIO_METHOD *bio_method;
bio_method = my_BIO_s_socket();
if (bio_method == NULL)
{
SSLerr(SSL_F_SSL_SET_FD, ERR_R_BUF_LIB);
goto err;
}
bio = BIO_new(bio_method);
if (bio == NULL)
{
SSLerr(SSL_F_SSL_SET_FD, ERR_R_BUF_LIB);
goto err;
}
BIO_set_data(bio, conn);
SSL_set_bio(conn->ssl, bio, bio);
BIO_set_fd(bio, fd, BIO_NOCLOSE);
ret = 1;
err:
return ret;
}