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postgres/src/backend/libpq/be-secure.c

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/*-------------------------------------------------------------------------
*
* be-secure.c
* functions related to setting up a secure connection to the frontend.
* Secure connections are expected to provide confidentiality,
* message integrity and endpoint authentication.
*
*
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.101 2010/05/26 16:15:57 tgl Exp $
*
* Since the server static private key ($DataDir/server.key)
* will normally be stored unencrypted so that the database
* backend can restart automatically, it is important that
* we select an algorithm that continues to provide confidentiality
* even if the attacker has the server's private key. Ephemeral
* DH (EDH) keys provide this, and in fact provide Perfect Forward
* Secrecy (PFS) except for situations where the session can
* be hijacked during a periodic handshake/renegotiation.
* Even that backdoor can be closed if client certificates
* are used (since the imposter will be unable to successfully
* complete renegotiation).
*
* N.B., the static private key should still be protected to
* the largest extent possible, to minimize the risk of
* impersonations.
*
* Another benefit of EDH is that it allows the backend and
* clients to use DSA keys. DSA keys can only provide digital
* signatures, not encryption, and are often acceptable in
* jurisdictions where RSA keys are unacceptable.
*
* The downside to EDH is that it makes it impossible to
* use ssldump(1) if there's a problem establishing an SSL
* session. In this case you'll need to temporarily disable
* EDH by commenting out the callback.
*
* ...
*
* Because the risk of cryptanalysis increases as large
* amounts of data are sent with the same session key, the
* session keys are periodically renegotiated.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/stat.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#include <arpa/inet.h>
#endif
#ifdef USE_SSL
#include <openssl/ssl.h>
#include <openssl/dh.h>
#if SSLEAY_VERSION_NUMBER >= 0x0907000L
#include <openssl/conf.h>
#endif
#endif /* USE_SSL */
#include "libpq/libpq.h"
#include "tcop/tcopprot.h"
#ifdef USE_SSL
#define ROOT_CERT_FILE "root.crt"
#define ROOT_CRL_FILE "root.crl"
#define SERVER_CERT_FILE "server.crt"
#define SERVER_PRIVATE_KEY_FILE "server.key"
static DH *load_dh_file(int keylength);
static DH *load_dh_buffer(const char *, size_t);
static DH *tmp_dh_cb(SSL *s, int is_export, int keylength);
static int verify_cb(int, X509_STORE_CTX *);
static void info_cb(const SSL *ssl, int type, int args);
static void initialize_SSL(void);
static int open_server_SSL(Port *);
static void close_SSL(Port *);
static const char *SSLerrmessage(void);
#endif
/*
* How much data can be sent across a secure connection
* (total in both directions) before we require renegotiation.
* Set to 0 to disable renegotiation completely.
*/
int ssl_renegotiation_limit;
#ifdef USE_SSL
static SSL_CTX *SSL_context = NULL;
static bool ssl_loaded_verify_locations = false;
/* GUC variable controlling SSL cipher list */
char *SSLCipherSuites = NULL;
#endif
/* ------------------------------------------------------------ */
/* Hardcoded values */
/* ------------------------------------------------------------ */
/*
* Hardcoded DH parameters, used in ephemeral DH keying.
* As discussed above, EDH protects the confidentiality of
* sessions even if the static private key is compromised,
* so we are *highly* motivated to ensure that we can use
* EDH even if the DBA... or an attacker... deletes the
* $DataDir/dh*.pem files.
*
* We could refuse SSL connections unless a good DH parameter
* file exists, but some clients may quietly renegotiate an
* unsecured connection without fully informing the user.
* Very uncool.
*
* Alternatively, the backend could attempt to load these files
* on startup if SSL is enabled - and refuse to start if any
* do not exist - but this would tend to piss off DBAs.
*
* If you want to create your own hardcoded DH parameters
* for fun and profit, review "Assigned Number for SKIP
* Protocols" (http://www.skip-vpn.org/spec/numbers.html)
* for suggestions.
*/
#ifdef USE_SSL
static const char file_dh512[] =
"-----BEGIN DH PARAMETERS-----\n\
MEYCQQD1Kv884bEpQBgRjXyEpwpy1obEAxnIByl6ypUM2Zafq9AKUJsCRtMIPWak\n\
XUGfnHy9iUsiGSa6q6Jew1XpKgVfAgEC\n\
-----END DH PARAMETERS-----\n";
static const char file_dh1024[] =
"-----BEGIN DH PARAMETERS-----\n\
MIGHAoGBAPSI/VhOSdvNILSd5JEHNmszbDgNRR0PfIizHHxbLY7288kjwEPwpVsY\n\
jY67VYy4XTjTNP18F1dDox0YbN4zISy1Kv884bEpQBgRjXyEpwpy1obEAxnIByl6\n\
ypUM2Zafq9AKUJsCRtMIPWakXUGfnHy9iUsiGSa6q6Jew1XpL3jHAgEC\n\
-----END DH PARAMETERS-----\n";
static const char file_dh2048[] =
"-----BEGIN DH PARAMETERS-----\n\
MIIBCAKCAQEA9kJXtwh/CBdyorrWqULzBej5UxE5T7bxbrlLOCDaAadWoxTpj0BV\n\
89AHxstDqZSt90xkhkn4DIO9ZekX1KHTUPj1WV/cdlJPPT2N286Z4VeSWc39uK50\n\
T8X8dryDxUcwYc58yWb/Ffm7/ZFexwGq01uejaClcjrUGvC/RgBYK+X0iP1YTknb\n\
zSC0neSRBzZrM2w4DUUdD3yIsxx8Wy2O9vPJI8BD8KVbGI2Ou1WMuF040zT9fBdX\n\
Q6MdGGzeMyEstSr/POGxKUAYEY18hKcKctaGxAMZyAcpesqVDNmWn6vQClCbAkbT\n\
CD1mpF1Bn5x8vYlLIhkmuquiXsNV6TILOwIBAg==\n\
-----END DH PARAMETERS-----\n";
static const char file_dh4096[] =
"-----BEGIN DH PARAMETERS-----\n\
MIICCAKCAgEA+hRyUsFN4VpJ1O8JLcCo/VWr19k3BCgJ4uk+d+KhehjdRqNDNyOQ\n\
l/MOyQNQfWXPeGKmOmIig6Ev/nm6Nf9Z2B1h3R4hExf+zTiHnvVPeRBhjdQi81rt\n\
Xeoh6TNrSBIKIHfUJWBh3va0TxxjQIs6IZOLeVNRLMqzeylWqMf49HsIXqbcokUS\n\
Vt1BkvLdW48j8PPv5DsKRN3tloTxqDJGo9tKvj1Fuk74A+Xda1kNhB7KFlqMyN98\n\
VETEJ6c7KpfOo30mnK30wqw3S8OtaIR/maYX72tGOno2ehFDkq3pnPtEbD2CScxc\n\
alJC+EL7RPk5c/tgeTvCngvc1KZn92Y//EI7G9tPZtylj2b56sHtMftIoYJ9+ODM\n\
sccD5Piz/rejE3Ome8EOOceUSCYAhXn8b3qvxVI1ddd1pED6FHRhFvLrZxFvBEM9\n\
ERRMp5QqOaHJkM+Dxv8Cj6MqrCbfC4u+ZErxodzuusgDgvZiLF22uxMZbobFWyte\n\
OvOzKGtwcTqO/1wV5gKkzu1ZVswVUQd5Gg8lJicwqRWyyNRczDDoG9jVDxmogKTH\n\
AaqLulO7R8Ifa1SwF2DteSGVtgWEN8gDpN3RBmmPTDngyF2DHb5qmpnznwtFKdTL\n\
KWbuHn491xNO25CQWMtem80uKw+pTnisBRF/454n1Jnhub144YRBoN8CAQI=\n\
-----END DH PARAMETERS-----\n";
#endif
/* ------------------------------------------------------------ */
/* Procedures common to all secure sessions */
/* ------------------------------------------------------------ */
/*
* Initialize global context
*/
int
secure_initialize(void)
{
#ifdef USE_SSL
initialize_SSL();
#endif
return 0;
}
/*
* Indicate if we have loaded the root CA store to verify certificates
*/
bool
secure_loaded_verify_locations(void)
{
#ifdef USE_SSL
return ssl_loaded_verify_locations;
#endif
return false;
}
/*
* Attempt to negotiate secure session.
*/
int
secure_open_server(Port *port)
{
int r = 0;
#ifdef USE_SSL
r = open_server_SSL(port);
#endif
return r;
}
/*
* Close secure session.
*/
void
secure_close(Port *port)
{
#ifdef USE_SSL
if (port->ssl)
close_SSL(port);
#endif
}
/*
* Read data from a secure connection.
*/
ssize_t
secure_read(Port *port, void *ptr, size_t len)
{
ssize_t n;
#ifdef USE_SSL
if (port->ssl)
{
int err;
rloop:
errno = 0;
n = SSL_read(port->ssl, ptr, len);
err = SSL_get_error(port->ssl, n);
switch (err)
{
case SSL_ERROR_NONE:
port->count += n;
break;
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
if (port->noblock)
{
errno = EWOULDBLOCK;
n = -1;
break;
}
#ifdef WIN32
pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
(err == SSL_ERROR_WANT_READ) ?
FD_READ | FD_CLOSE : FD_WRITE | FD_CLOSE,
INFINITE);
#endif
goto rloop;
case SSL_ERROR_SYSCALL:
/* leave it to caller to ereport the value of errno */
if (n != -1)
{
errno = ECONNRESET;
n = -1;
}
break;
case SSL_ERROR_SSL:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL error: %s", SSLerrmessage())));
/* fall through */
case SSL_ERROR_ZERO_RETURN:
errno = ECONNRESET;
n = -1;
break;
default:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unrecognized SSL error code: %d",
err)));
n = -1;
break;
}
}
else
#endif
{
prepare_for_client_read();
n = recv(port->sock, ptr, len, 0);
client_read_ended();
}
return n;
}
/*
* Write data to a secure connection.
*/
ssize_t
secure_write(Port *port, void *ptr, size_t len)
{
ssize_t n;
#ifdef USE_SSL
if (port->ssl)
{
int err;
if (ssl_renegotiation_limit && port->count > ssl_renegotiation_limit * 1024L)
{
SSL_set_session_id_context(port->ssl, (void *) &SSL_context,
sizeof(SSL_context));
if (SSL_renegotiate(port->ssl) <= 0)
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL renegotiation failure")));
if (SSL_do_handshake(port->ssl) <= 0)
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL renegotiation failure")));
if (port->ssl->state != SSL_ST_OK)
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL failed to send renegotiation request")));
port->ssl->state |= SSL_ST_ACCEPT;
SSL_do_handshake(port->ssl);
if (port->ssl->state != SSL_ST_OK)
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL renegotiation failure")));
port->count = 0;
}
wloop:
errno = 0;
n = SSL_write(port->ssl, ptr, len);
err = SSL_get_error(port->ssl, n);
switch (err)
{
case SSL_ERROR_NONE:
port->count += n;
break;
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
#ifdef WIN32
pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
(err == SSL_ERROR_WANT_READ) ?
FD_READ | FD_CLOSE : FD_WRITE | FD_CLOSE,
INFINITE);
#endif
goto wloop;
case SSL_ERROR_SYSCALL:
/* leave it to caller to ereport the value of errno */
if (n != -1)
{
errno = ECONNRESET;
n = -1;
}
break;
case SSL_ERROR_SSL:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL error: %s", SSLerrmessage())));
/* fall through */
case SSL_ERROR_ZERO_RETURN:
errno = ECONNRESET;
n = -1;
break;
default:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unrecognized SSL error code: %d",
err)));
n = -1;
break;
}
}
else
#endif
n = send(port->sock, ptr, len, 0);
return n;
}
/* ------------------------------------------------------------ */
/* SSL specific code */
/* ------------------------------------------------------------ */
#ifdef USE_SSL
/*
* Private substitute BIO: this does the sending and receiving using send() and
* recv() instead. This is so that we can enable and disable interrupts
* just while calling recv(). We cannot have interrupts occurring while
* the bulk of openssl runs, because it uses malloc() and possibly other
* non-reentrant libc facilities. We also need to call send() and recv()
* directly so it gets passed through the socket/signals layer on Win32.
*
* They are closely modelled on the original socket implementations in OpenSSL.
*/
static bool my_bio_initialized = false;
static BIO_METHOD my_bio_methods;
static int
my_sock_read(BIO *h, char *buf, int size)
{
int res = 0;
prepare_for_client_read();
if (buf != NULL)
{
res = recv(h->num, buf, size, 0);
BIO_clear_retry_flags(h);
if (res <= 0)
{
/* If we were interrupted, tell caller to retry */
if (errno == EINTR)
{
BIO_set_retry_read(h);
}
}
}
client_read_ended();
return res;
}
static int
my_sock_write(BIO *h, const char *buf, int size)
{
int res = 0;
res = send(h->num, buf, size, 0);
if (res <= 0)
{
if (errno == EINTR)
{
BIO_set_retry_write(h);
}
}
return res;
}
static BIO_METHOD *
my_BIO_s_socket(void)
{
if (!my_bio_initialized)
{
memcpy(&my_bio_methods, BIO_s_socket(), sizeof(BIO_METHOD));
my_bio_methods.bread = my_sock_read;
my_bio_methods.bwrite = my_sock_write;
my_bio_initialized = true;
}
return &my_bio_methods;
}
/* This should exactly match openssl's SSL_set_fd except for using my BIO */
static int
my_SSL_set_fd(SSL *s, int fd)
{
int ret = 0;
BIO *bio = NULL;
bio = BIO_new(my_BIO_s_socket());
if (bio == NULL)
{
SSLerr(SSL_F_SSL_SET_FD, ERR_R_BUF_LIB);
goto err;
}
BIO_set_fd(bio, fd, BIO_NOCLOSE);
SSL_set_bio(s, bio, bio);
ret = 1;
err:
return ret;
}
/*
* Load precomputed DH parameters.
*
* To prevent "downgrade" attacks, we perform a number of checks
* to verify that the DBA-generated DH parameters file contains
* what we expect it to contain.
*/
static DH *
load_dh_file(int keylength)
{
FILE *fp;
char fnbuf[MAXPGPATH];
DH *dh = NULL;
int codes;
/* attempt to open file. It's not an error if it doesn't exist. */
snprintf(fnbuf, sizeof(fnbuf), "dh%d.pem", keylength);
if ((fp = fopen(fnbuf, "r")) == NULL)
return NULL;
/* flock(fileno(fp), LOCK_SH); */
dh = PEM_read_DHparams(fp, NULL, NULL, NULL);
/* flock(fileno(fp), LOCK_UN); */
fclose(fp);
/* is the prime the correct size? */
if (dh != NULL && 8 * DH_size(dh) < keylength)
{
elog(LOG, "DH errors (%s): %d bits expected, %d bits found",
fnbuf, keylength, 8 * DH_size(dh));
dh = NULL;
}
/* make sure the DH parameters are usable */
if (dh != NULL)
{
if (DH_check(dh, &codes) == 0)
{
elog(LOG, "DH_check error (%s): %s", fnbuf, SSLerrmessage());
return NULL;
}
if (codes & DH_CHECK_P_NOT_PRIME)
{
elog(LOG, "DH error (%s): p is not prime", fnbuf);
return NULL;
}
if ((codes & DH_NOT_SUITABLE_GENERATOR) &&
(codes & DH_CHECK_P_NOT_SAFE_PRIME))
{
elog(LOG,
"DH error (%s): neither suitable generator or safe prime",
fnbuf);
return NULL;
}
}
return dh;
}
/*
* Load hardcoded DH parameters.
*
* To prevent problems if the DH parameters files don't even
* exist, we can load DH parameters hardcoded into this file.
*/
static DH *
load_dh_buffer(const char *buffer, size_t len)
{
BIO *bio;
DH *dh = NULL;
bio = BIO_new_mem_buf((char *) buffer, len);
if (bio == NULL)
return NULL;
dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
if (dh == NULL)
ereport(DEBUG2,
(errmsg_internal("DH load buffer: %s",
SSLerrmessage())));
BIO_free(bio);
return dh;
}
/*
* Generate an ephemeral DH key. Because this can take a long
* time to compute, we can use precomputed parameters of the
* common key sizes.
*
* Since few sites will bother to precompute these parameter
* files, we also provide a fallback to the parameters provided
* by the OpenSSL project.
*
* These values can be static (once loaded or computed) since
* the OpenSSL library can efficiently generate random keys from
* the information provided.
*/
static DH *
tmp_dh_cb(SSL *s, int is_export, int keylength)
{
DH *r = NULL;
static DH *dh = NULL;
static DH *dh512 = NULL;
static DH *dh1024 = NULL;
static DH *dh2048 = NULL;
static DH *dh4096 = NULL;
switch (keylength)
{
case 512:
if (dh512 == NULL)
dh512 = load_dh_file(keylength);
if (dh512 == NULL)
dh512 = load_dh_buffer(file_dh512, sizeof file_dh512);
r = dh512;
break;
case 1024:
if (dh1024 == NULL)
dh1024 = load_dh_file(keylength);
if (dh1024 == NULL)
dh1024 = load_dh_buffer(file_dh1024, sizeof file_dh1024);
r = dh1024;
break;
case 2048:
if (dh2048 == NULL)
dh2048 = load_dh_file(keylength);
if (dh2048 == NULL)
dh2048 = load_dh_buffer(file_dh2048, sizeof file_dh2048);
r = dh2048;
break;
case 4096:
if (dh4096 == NULL)
dh4096 = load_dh_file(keylength);
if (dh4096 == NULL)
dh4096 = load_dh_buffer(file_dh4096, sizeof file_dh4096);
r = dh4096;
break;
default:
if (dh == NULL)
dh = load_dh_file(keylength);
r = dh;
}
/* this may take a long time, but it may be necessary... */
if (r == NULL || 8 * DH_size(r) < keylength)
{
ereport(DEBUG2,
(errmsg_internal("DH: generating parameters (%d bits)....",
keylength)));
r = DH_generate_parameters(keylength, DH_GENERATOR_2, NULL, NULL);
}
return r;
}
/*
* Certificate verification callback
*
* This callback allows us to log intermediate problems during
* verification, but for now we'll see if the final error message
* contains enough information.
*
* 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;
}
/*
* This callback is used to copy SSL information messages
* into the PostgreSQL log.
*/
static void
info_cb(const SSL *ssl, int type, int args)
{
switch (type)
{
case SSL_CB_HANDSHAKE_START:
ereport(DEBUG4,
(errmsg_internal("SSL: handshake start")));
break;
case SSL_CB_HANDSHAKE_DONE:
ereport(DEBUG4,
(errmsg_internal("SSL: handshake done")));
break;
case SSL_CB_ACCEPT_LOOP:
ereport(DEBUG4,
(errmsg_internal("SSL: accept loop")));
break;
case SSL_CB_ACCEPT_EXIT:
ereport(DEBUG4,
(errmsg_internal("SSL: accept exit (%d)", args)));
break;
case SSL_CB_CONNECT_LOOP:
ereport(DEBUG4,
(errmsg_internal("SSL: connect loop")));
break;
case SSL_CB_CONNECT_EXIT:
ereport(DEBUG4,
(errmsg_internal("SSL: connect exit (%d)", args)));
break;
case SSL_CB_READ_ALERT:
ereport(DEBUG4,
(errmsg_internal("SSL: read alert (0x%04x)", args)));
break;
case SSL_CB_WRITE_ALERT:
ereport(DEBUG4,
(errmsg_internal("SSL: write alert (0x%04x)", args)));
break;
}
}
/*
* Initialize global SSL context.
*/
static void
initialize_SSL(void)
{
struct stat buf;
STACK_OF(X509_NAME) *root_cert_list = NULL;
if (!SSL_context)
{
#if SSLEAY_VERSION_NUMBER >= 0x0907000L
OPENSSL_config(NULL);
#endif
SSL_library_init();
SSL_load_error_strings();
SSL_context = SSL_CTX_new(SSLv23_method());
if (!SSL_context)
ereport(FATAL,
(errmsg("could not create SSL context: %s",
SSLerrmessage())));
/*
* Load and verify server's certificate and private key
*/
if (SSL_CTX_use_certificate_chain_file(SSL_context,
SERVER_CERT_FILE) != 1)
ereport(FATAL,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("could not load server certificate file \"%s\": %s",
SERVER_CERT_FILE, SSLerrmessage())));
if (stat(SERVER_PRIVATE_KEY_FILE, &buf) != 0)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not access private key file \"%s\": %m",
SERVER_PRIVATE_KEY_FILE)));
/*
* Require no public access to key file.
*
* XXX temporarily suppress check when on Windows, because there may
* not be proper support for Unix-y file permissions. Need to think
* of a reasonable check to apply on Windows. (See also the data
* directory permission check in postmaster.c)
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
if (!S_ISREG(buf.st_mode) || buf.st_mode & (S_IRWXG | S_IRWXO))
ereport(FATAL,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" has group or world access",
SERVER_PRIVATE_KEY_FILE),
errdetail("Permissions should be u=rw (0600) or less.")));
#endif
if (SSL_CTX_use_PrivateKey_file(SSL_context,
SERVER_PRIVATE_KEY_FILE,
SSL_FILETYPE_PEM) != 1)
ereport(FATAL,
(errmsg("could not load private key file \"%s\": %s",
SERVER_PRIVATE_KEY_FILE, SSLerrmessage())));
if (SSL_CTX_check_private_key(SSL_context) != 1)
ereport(FATAL,
(errmsg("check of private key failed: %s",
SSLerrmessage())));
}
/* set up ephemeral DH keys, and disallow SSL v2 while at it */
SSL_CTX_set_tmp_dh_callback(SSL_context, tmp_dh_cb);
SSL_CTX_set_options(SSL_context, SSL_OP_SINGLE_DH_USE | SSL_OP_NO_SSLv2);
/* set up the allowed cipher list */
if (SSL_CTX_set_cipher_list(SSL_context, SSLCipherSuites) != 1)
elog(FATAL, "could not set the cipher list (no valid ciphers available)");
/*
* Attempt to load CA store, so we can verify client certificates if
* needed.
*/
ssl_loaded_verify_locations = false;
if (access(ROOT_CERT_FILE, R_OK) != 0)
{
/*
* If root certificate file simply not found, don't log an error here,
* because it's quite likely the user isn't planning on using client
* certificates. If we can't access it for other reasons, it is an
* error.
*/
if (errno != ENOENT)
ereport(FATAL,
(errmsg("could not access root certificate file \"%s\": %m",
ROOT_CERT_FILE)));
}
else if (SSL_CTX_load_verify_locations(SSL_context, ROOT_CERT_FILE, NULL) != 1 ||
(root_cert_list = SSL_load_client_CA_file(ROOT_CERT_FILE)) == NULL)
{
/*
* File was there, but we could not load it. This means the file is
* somehow broken, and we cannot do verification at all - so fail.
*/
ereport(FATAL,
(errmsg("could not load root certificate file \"%s\": %s",
ROOT_CERT_FILE, SSLerrmessage())));
}
else
{
/*----------
* Load the Certificate Revocation List (CRL) if file exists.
* http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci803160,00.html
*----------
*/
X509_STORE *cvstore = SSL_CTX_get_cert_store(SSL_context);
if (cvstore)
{
/* Set the flags to check against the complete CRL chain */
if (X509_STORE_load_locations(cvstore, ROOT_CRL_FILE, 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
ereport(LOG,
(errmsg("SSL certificate revocation list file \"%s\" ignored",
ROOT_CRL_FILE),
errdetail("SSL library does not support certificate revocation lists.")));
#endif
}
else
{
/* Not fatal - we do not require CRL */
ereport(LOG,
(errmsg("SSL certificate revocation list file \"%s\" not found, skipping: %s",
ROOT_CRL_FILE, SSLerrmessage()),
errdetail("Certificates will not be checked against revocation list.")));
}
/*
* Always ask for SSL client cert, but don't fail if it's not
* presented. We might fail such connections later, depending on
* what we find in pg_hba.conf.
*/
SSL_CTX_set_verify(SSL_context,
(SSL_VERIFY_PEER |
SSL_VERIFY_CLIENT_ONCE),
verify_cb);
/* Set flag to remember CA store is successfully loaded */
ssl_loaded_verify_locations = true;
}
/*
* Tell OpenSSL to send the list of root certs we trust to clients in
* CertificateRequests. This lets a client with a keystore select the
* appropriate client certificate to send to us.
*/
SSL_CTX_set_client_CA_list(SSL_context, root_cert_list);
}
}
/*
* Attempt to negotiate SSL connection.
*/
static int
open_server_SSL(Port *port)
{
int r;
int err;
Assert(!port->ssl);
Assert(!port->peer);
if (!(port->ssl = SSL_new(SSL_context)))
{
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not initialize SSL connection: %s",
SSLerrmessage())));
close_SSL(port);
return -1;
}
if (!my_SSL_set_fd(port->ssl, port->sock))
{
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not set SSL socket: %s",
SSLerrmessage())));
close_SSL(port);
return -1;
}
aloop:
r = SSL_accept(port->ssl);
if (r <= 0)
{
err = SSL_get_error(port->ssl, r);
switch (err)
{
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
#ifdef WIN32
pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
(err == SSL_ERROR_WANT_READ) ?
FD_READ | FD_CLOSE | FD_ACCEPT : FD_WRITE | FD_CLOSE,
INFINITE);
#endif
goto aloop;
case SSL_ERROR_SYSCALL:
if (r < 0)
ereport(COMMERROR,
(errcode_for_socket_access(),
errmsg("could not accept SSL connection: %m")));
else
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not accept SSL connection: EOF detected")));
break;
case SSL_ERROR_SSL:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not accept SSL connection: %s",
SSLerrmessage())));
break;
case SSL_ERROR_ZERO_RETURN:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not accept SSL connection: EOF detected")));
break;
default:
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unrecognized SSL error code: %d",
err)));
break;
}
close_SSL(port);
return -1;
}
port->count = 0;
/* get client certificate, if available. */
port->peer = SSL_get_peer_certificate(port->ssl);
if (port->peer == NULL)
{
strlcpy(port->peer_dn, "(anonymous)", sizeof(port->peer_dn));
strlcpy(port->peer_cn, "(anonymous)", sizeof(port->peer_cn));
}
else
{
X509_NAME_oneline(X509_get_subject_name(port->peer),
port->peer_dn, sizeof(port->peer_dn));
port->peer_dn[sizeof(port->peer_dn) - 1] = '\0';
r = X509_NAME_get_text_by_NID(X509_get_subject_name(port->peer),
NID_commonName, port->peer_cn, sizeof(port->peer_cn));
port->peer_cn[sizeof(port->peer_cn) - 1] = '\0';
if (r == -1)
{
/* Unable to get the CN, set it to blank so it can't be used */
port->peer_cn[0] = '\0';
}
else
{
/*
* Reject embedded NULLs in certificate common name to prevent
* attacks like CVE-2009-4034.
*/
if (r != strlen(port->peer_cn))
{
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("SSL certificate's common name contains embedded null")));
close_SSL(port);
return -1;
}
}
}
ereport(DEBUG2,
(errmsg("SSL connection from \"%s\"", port->peer_cn)));
/* set up debugging/info callback */
SSL_CTX_set_info_callback(SSL_context, info_cb);
return 0;
}
/*
* Close SSL connection.
*/
static void
close_SSL(Port *port)
{
if (port->ssl)
{
SSL_shutdown(port->ssl);
SSL_free(port->ssl);
port->ssl = NULL;
}
if (port->peer)
{
X509_free(port->peer);
port->peer = NULL;
}
}
/*
* Obtain reason string for last SSL error
*
* 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 const char *
SSLerrmessage(void)
{
unsigned long errcode;
const char *errreason;
static char errbuf[32];
errcode = ERR_get_error();
if (errcode == 0)
return _("no SSL error reported");
errreason = ERR_reason_error_string(errcode);
if (errreason != NULL)
return errreason;
snprintf(errbuf, sizeof(errbuf), _("SSL error code %lu"), errcode);
return errbuf;
}
#endif /* USE_SSL */
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