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rdkafka_ssl.c
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rdkafka_ssl.c
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/*
* librdkafka - The Apache Kafka C/C++ library
*
* Copyright (c) 2019 Magnus Edenhill
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @name OpenSSL integration
*
*/
#include "rdkafka_int.h"
#include "rdkafka_transport_int.h"
#include "rdkafka_cert.h"
#ifdef _WIN32
#include <wincrypt.h>
#pragma comment(lib, "crypt32.lib")
#pragma comment(lib, "libcrypto.lib")
#pragma comment(lib, "libssl.lib")
#endif
#include <openssl/x509.h>
#include <openssl/x509_vfy.h>
#include <ctype.h>
#if !_WIN32
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#endif
#if WITH_VALGRIND
/* OpenSSL relies on uninitialized memory, which Valgrind will whine about.
* We use in-code Valgrind macros to suppress those warnings. */
#include <valgrind/memcheck.h>
#else
#define VALGRIND_MAKE_MEM_DEFINED(A, B)
#endif
#if OPENSSL_VERSION_NUMBER < 0x10100000L
static mtx_t *rd_kafka_ssl_locks;
static int rd_kafka_ssl_locks_cnt;
#endif
/**
* @brief Close and destroy SSL session
*/
void rd_kafka_transport_ssl_close(rd_kafka_transport_t *rktrans) {
SSL_shutdown(rktrans->rktrans_ssl);
SSL_free(rktrans->rktrans_ssl);
rktrans->rktrans_ssl = NULL;
}
/**
* @brief Clear OpenSSL error queue to get a proper error reporting in case
* the next SSL_*() operation fails.
*/
static RD_INLINE void
rd_kafka_transport_ssl_clear_error(rd_kafka_transport_t *rktrans) {
ERR_clear_error();
#ifdef _WIN32
WSASetLastError(0);
#else
rd_set_errno(0);
#endif
}
/**
* @returns a thread-local single-invocation-use error string for
* the last thread-local error in OpenSSL, or an empty string
* if no error.
*/
const char *rd_kafka_ssl_last_error_str(void) {
static RD_TLS char errstr[256];
unsigned long l;
const char *file, *data;
int line, flags;
l = ERR_peek_last_error_line_data(&file, &line, &data, &flags);
if (!l)
return "";
rd_snprintf(errstr, sizeof(errstr), "%lu:%s:%s:%s:%d: %s", l,
ERR_lib_error_string(l), ERR_func_error_string(l), file,
line,
((flags & ERR_TXT_STRING) && data && *data)
? data
: ERR_reason_error_string(l));
return errstr;
}
/**
* Serves the entire OpenSSL error queue and logs each error.
* The last error is not logged but returned in 'errstr'.
*
* If 'rkb' is non-NULL broker-specific logging will be used,
* else it will fall back on global 'rk' debugging.
*/
static char *rd_kafka_ssl_error(rd_kafka_t *rk,
rd_kafka_broker_t *rkb,
char *errstr,
size_t errstr_size) {
unsigned long l;
const char *file, *data;
int line, flags;
int cnt = 0;
if (!rk) {
rd_assert(rkb);
rk = rkb->rkb_rk;
}
while ((l = ERR_get_error_line_data(&file, &line, &data, &flags)) !=
0) {
char buf[256];
if (cnt++ > 0) {
/* Log last message */
if (rkb)
rd_rkb_log(rkb, LOG_ERR, "SSL", "%s", errstr);
else
rd_kafka_log(rk, LOG_ERR, "SSL", "%s", errstr);
}
ERR_error_string_n(l, buf, sizeof(buf));
if (!(flags & ERR_TXT_STRING) || !data || !*data)
data = NULL;
/* Include openssl file:line if debugging is enabled */
if (rk->rk_conf.log_level >= LOG_DEBUG)
rd_snprintf(errstr, errstr_size, "%s:%d: %s%s%s", file,
line, buf, data ? ": " : "",
data ? data : "");
else
rd_snprintf(errstr, errstr_size, "%s%s%s", buf,
data ? ": " : "", data ? data : "");
}
if (cnt == 0)
rd_snprintf(errstr, errstr_size,
"No further error information available");
return errstr;
}
/**
* Set transport IO event polling based on SSL error.
*
* Returns -1 on permanent errors.
*
* Locality: broker thread
*/
static RD_INLINE int
rd_kafka_transport_ssl_io_update(rd_kafka_transport_t *rktrans,
int ret,
char *errstr,
size_t errstr_size) {
int serr = SSL_get_error(rktrans->rktrans_ssl, ret);
int serr2;
switch (serr) {
case SSL_ERROR_WANT_READ:
rd_kafka_transport_poll_set(rktrans, POLLIN);
break;
case SSL_ERROR_WANT_WRITE:
rd_kafka_transport_set_blocked(rktrans, rd_true);
rd_kafka_transport_poll_set(rktrans, POLLOUT);
break;
case SSL_ERROR_SYSCALL:
serr2 = ERR_peek_error();
if (serr2)
rd_kafka_ssl_error(NULL, rktrans->rktrans_rkb, errstr,
errstr_size);
else if (!rd_socket_errno || rd_socket_errno == ECONNRESET)
rd_snprintf(errstr, errstr_size, "Disconnected");
else
rd_snprintf(errstr, errstr_size,
"SSL transport error: %s",
rd_strerror(rd_socket_errno));
return -1;
case SSL_ERROR_ZERO_RETURN:
rd_snprintf(errstr, errstr_size, "Disconnected");
return -1;
default:
rd_kafka_ssl_error(NULL, rktrans->rktrans_rkb, errstr,
errstr_size);
return -1;
}
return 0;
}
ssize_t rd_kafka_transport_ssl_send(rd_kafka_transport_t *rktrans,
rd_slice_t *slice,
char *errstr,
size_t errstr_size) {
ssize_t sum = 0;
const void *p;
size_t rlen;
rd_kafka_transport_ssl_clear_error(rktrans);
while ((rlen = rd_slice_peeker(slice, &p))) {
int r;
size_t r2;
r = SSL_write(rktrans->rktrans_ssl, p, (int)rlen);
if (unlikely(r <= 0)) {
if (rd_kafka_transport_ssl_io_update(rktrans, r, errstr,
errstr_size) == -1)
return -1;
else
return sum;
}
/* Update buffer read position */
r2 = rd_slice_read(slice, NULL, (size_t)r);
rd_assert((size_t)r == r2 &&
*"BUG: wrote more bytes than available in slice");
sum += r;
/* FIXME: remove this and try again immediately and let
* the next SSL_write() call fail instead? */
if ((size_t)r < rlen)
break;
}
return sum;
}
ssize_t rd_kafka_transport_ssl_recv(rd_kafka_transport_t *rktrans,
rd_buf_t *rbuf,
char *errstr,
size_t errstr_size) {
ssize_t sum = 0;
void *p;
size_t len;
while ((len = rd_buf_get_writable(rbuf, &p))) {
int r;
rd_kafka_transport_ssl_clear_error(rktrans);
r = SSL_read(rktrans->rktrans_ssl, p, (int)len);
if (unlikely(r <= 0)) {
if (rd_kafka_transport_ssl_io_update(rktrans, r, errstr,
errstr_size) == -1)
return -1;
else
return sum;
}
VALGRIND_MAKE_MEM_DEFINED(p, r);
/* Update buffer write position */
rd_buf_write(rbuf, NULL, (size_t)r);
sum += r;
/* FIXME: remove this and try again immediately and let
* the next SSL_read() call fail instead? */
if ((size_t)r < len)
break;
}
return sum;
}
/**
* OpenSSL password query callback
*
* Locality: application thread
*/
static int rd_kafka_transport_ssl_passwd_cb(char *buf,
int size,
int rwflag,
void *userdata) {
rd_kafka_t *rk = userdata;
int pwlen;
rd_kafka_dbg(rk, SECURITY, "SSLPASSWD",
"Private key requires password");
if (!rk->rk_conf.ssl.key_password) {
rd_kafka_log(rk, LOG_WARNING, "SSLPASSWD",
"Private key requires password but "
"no password configured (ssl.key.password)");
return -1;
}
pwlen = (int)strlen(rk->rk_conf.ssl.key_password);
memcpy(buf, rk->rk_conf.ssl.key_password, RD_MIN(pwlen, size));
return pwlen;
}
/**
* @brief OpenSSL callback to perform additional broker certificate
* verification and validation.
*
* @return 1 on success when the broker certificate
* is valid and 0 when the certificate is not valid.
*
* @sa SSL_CTX_set_verify()
*/
static int rd_kafka_transport_ssl_cert_verify_cb(int preverify_ok,
X509_STORE_CTX *x509_ctx) {
rd_kafka_transport_t *rktrans = rd_kafka_curr_transport;
rd_kafka_broker_t *rkb;
rd_kafka_t *rk;
X509 *cert;
char *buf = NULL;
int buf_size;
int depth;
int x509_orig_error, x509_error;
char errstr[512];
int ok;
rd_assert(rktrans != NULL);
rkb = rktrans->rktrans_rkb;
rk = rkb->rkb_rk;
cert = X509_STORE_CTX_get_current_cert(x509_ctx);
if (!cert) {
rd_rkb_log(rkb, LOG_ERR, "SSLCERTVRFY",
"Failed to get current certificate to verify");
return 0;
}
depth = X509_STORE_CTX_get_error_depth(x509_ctx);
x509_orig_error = x509_error = X509_STORE_CTX_get_error(x509_ctx);
buf_size = i2d_X509(cert, (unsigned char **)&buf);
if (buf_size < 0 || !buf) {
rd_rkb_log(rkb, LOG_ERR, "SSLCERTVRFY",
"Unable to convert certificate to X509 format");
return 0;
}
*errstr = '\0';
/* Call application's verification callback. */
ok = rk->rk_conf.ssl.cert_verify_cb(
rk, rkb->rkb_nodename, rkb->rkb_nodeid, &x509_error, depth, buf,
(size_t)buf_size, errstr, sizeof(errstr), rk->rk_conf.opaque);
OPENSSL_free(buf);
if (!ok) {
char subject[128];
char issuer[128];
X509_NAME_oneline(X509_get_subject_name(cert), subject,
sizeof(subject));
X509_NAME_oneline(X509_get_issuer_name(cert), issuer,
sizeof(issuer));
rd_rkb_log(rkb, LOG_ERR, "SSLCERTVRFY",
"Certificate (subject=%s, issuer=%s) verification "
"callback failed: %s",
subject, issuer, errstr);
X509_STORE_CTX_set_error(x509_ctx, x509_error);
return 0; /* verification failed */
}
/* Clear error */
if (x509_orig_error != 0 && x509_error == 0)
X509_STORE_CTX_set_error(x509_ctx, 0);
return 1; /* verification successful */
}
/**
* @brief Set TLSEXT hostname for SNI and optionally enable
* SSL endpoint identification verification.
*
* @returns 0 on success or -1 on error.
*/
static int rd_kafka_transport_ssl_set_endpoint_id(rd_kafka_transport_t *rktrans,
char *errstr,
size_t errstr_size) {
char name[RD_KAFKA_NODENAME_SIZE];
char *t;
rd_kafka_broker_lock(rktrans->rktrans_rkb);
rd_snprintf(name, sizeof(name), "%s",
rktrans->rktrans_rkb->rkb_nodename);
rd_kafka_broker_unlock(rktrans->rktrans_rkb);
/* Remove ":9092" port suffix from nodename */
if ((t = strrchr(name, ':')))
*t = '\0';
#if (OPENSSL_VERSION_NUMBER >= 0x0090806fL) && !defined(OPENSSL_NO_TLSEXT)
/* If non-numerical hostname, send it for SNI */
if (!(/*ipv6*/ (strchr(name, ':') &&
strspn(name, "0123456789abcdefABCDEF:.[]%") ==
strlen(name)) ||
/*ipv4*/ strspn(name, "0123456789.") == strlen(name)) &&
!SSL_set_tlsext_host_name(rktrans->rktrans_ssl, name))
goto fail;
#endif
if (rktrans->rktrans_rkb->rkb_rk->rk_conf.ssl.endpoint_identification ==
RD_KAFKA_SSL_ENDPOINT_ID_NONE)
return 0;
#if OPENSSL_VERSION_NUMBER >= 0x10100000
if (!SSL_set1_host(rktrans->rktrans_ssl, name))
goto fail;
#elif OPENSSL_VERSION_NUMBER >= 0x1000200fL /* 1.0.2 */
{
X509_VERIFY_PARAM *param;
param = SSL_get0_param(rktrans->rktrans_ssl);
if (!X509_VERIFY_PARAM_set1_host(param, name, 0))
goto fail;
}
#else
rd_snprintf(errstr, errstr_size,
"Endpoint identification not supported on this "
"OpenSSL version (0x%lx)",
OPENSSL_VERSION_NUMBER);
return -1;
#endif
rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "ENDPOINT",
"Enabled endpoint identification using hostname %s", name);
return 0;
fail:
rd_kafka_ssl_error(NULL, rktrans->rktrans_rkb, errstr, errstr_size);
return -1;
}
/**
* @brief Set up SSL for a newly connected connection
*
* @returns -1 on failure, else 0.
*/
int rd_kafka_transport_ssl_connect(rd_kafka_broker_t *rkb,
rd_kafka_transport_t *rktrans,
char *errstr,
size_t errstr_size) {
int r;
rktrans->rktrans_ssl = SSL_new(rkb->rkb_rk->rk_conf.ssl.ctx);
if (!rktrans->rktrans_ssl)
goto fail;
if (!SSL_set_fd(rktrans->rktrans_ssl, (int)rktrans->rktrans_s))
goto fail;
if (rd_kafka_transport_ssl_set_endpoint_id(rktrans, errstr,
errstr_size) == -1)
return -1;
rd_kafka_transport_ssl_clear_error(rktrans);
r = SSL_connect(rktrans->rktrans_ssl);
if (r == 1) {
/* Connected, highly unlikely since this is a
* non-blocking operation. */
rd_kafka_transport_connect_done(rktrans, NULL);
return 0;
}
if (rd_kafka_transport_ssl_io_update(rktrans, r, errstr, errstr_size) ==
-1)
return -1;
return 0;
fail:
rd_kafka_ssl_error(NULL, rkb, errstr, errstr_size);
return -1;
}
static RD_UNUSED int
rd_kafka_transport_ssl_io_event(rd_kafka_transport_t *rktrans, int events) {
int r;
char errstr[512];
if (events & POLLOUT) {
rd_kafka_transport_ssl_clear_error(rktrans);
r = SSL_write(rktrans->rktrans_ssl, NULL, 0);
if (rd_kafka_transport_ssl_io_update(rktrans, r, errstr,
sizeof(errstr)) == -1)
goto fail;
}
return 0;
fail:
/* Permanent error */
rd_kafka_broker_fail(rktrans->rktrans_rkb, LOG_ERR,
RD_KAFKA_RESP_ERR__TRANSPORT, "%s", errstr);
return -1;
}
/**
* @brief Verify SSL handshake was valid.
*/
static int rd_kafka_transport_ssl_verify(rd_kafka_transport_t *rktrans) {
long int rl;
X509 *cert;
if (!rktrans->rktrans_rkb->rkb_rk->rk_conf.ssl.enable_verify)
return 0;
cert = SSL_get_peer_certificate(rktrans->rktrans_ssl);
X509_free(cert);
if (!cert) {
rd_kafka_broker_fail(rktrans->rktrans_rkb, LOG_ERR,
RD_KAFKA_RESP_ERR__SSL,
"Broker did not provide a certificate");
return -1;
}
if ((rl = SSL_get_verify_result(rktrans->rktrans_ssl)) != X509_V_OK) {
rd_kafka_broker_fail(rktrans->rktrans_rkb, LOG_ERR,
RD_KAFKA_RESP_ERR__SSL,
"Failed to verify broker certificate: %s",
X509_verify_cert_error_string(rl));
return -1;
}
rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "SSLVERIFY",
"Broker SSL certificate verified");
return 0;
}
/**
* @brief SSL handshake handling.
* Call repeatedly (based on IO events) until handshake is done.
*
* @returns -1 on error, 0 if handshake is still in progress,
* or 1 on completion.
*/
int rd_kafka_transport_ssl_handshake(rd_kafka_transport_t *rktrans) {
rd_kafka_broker_t *rkb = rktrans->rktrans_rkb;
char errstr[512];
int r;
r = SSL_do_handshake(rktrans->rktrans_ssl);
if (r == 1) {
/* SSL handshake done. Verify. */
if (rd_kafka_transport_ssl_verify(rktrans) == -1)
return -1;
rd_kafka_transport_connect_done(rktrans, NULL);
return 1;
} else if (rd_kafka_transport_ssl_io_update(rktrans, r, errstr,
sizeof(errstr)) == -1) {
const char *extra = "";
rd_kafka_resp_err_t err = RD_KAFKA_RESP_ERR__SSL;
if (strstr(errstr, "unexpected message"))
extra =
": client SSL authentication might be "
"required (see ssl.key.location and "
"ssl.certificate.location and consult the "
"broker logs for more information)";
else if (strstr(errstr,
"tls_process_server_certificate:"
"certificate verify failed") ||
strstr(errstr,
"get_server_certificate:"
"certificate verify failed"))
extra =
": broker certificate could not be verified, "
"verify that ssl.ca.location is correctly "
"configured or root CA certificates are "
"installed"
#ifdef __APPLE__
" (brew install openssl)"
#elif defined(_WIN32)
" (add broker's CA certificate to the Windows "
"Root certificate store)"
#else
" (install ca-certificates package)"
#endif
;
else if (!strcmp(errstr, "Disconnected")) {
extra = ": connecting to a PLAINTEXT broker listener?";
/* Disconnects during handshake are most likely
* not due to SSL, but rather at the transport level */
err = RD_KAFKA_RESP_ERR__TRANSPORT;
}
rd_kafka_broker_fail(rkb, LOG_ERR, err,
"SSL handshake failed: %s%s", errstr,
extra);
return -1;
}
return 0;
}
/**
* @brief Parse a PEM-formatted string into an EVP_PKEY (PrivateKey) object.
*
* @param str Input PEM string, nul-terminated
*
* @remark This method does not provide automatic addition of PEM
* headers and footers.
*
* @returns a new EVP_PKEY on success or NULL on error.
*/
static EVP_PKEY *rd_kafka_ssl_PKEY_from_string(rd_kafka_t *rk,
const char *str) {
BIO *bio = BIO_new_mem_buf((void *)str, -1);
EVP_PKEY *pkey;
pkey = PEM_read_bio_PrivateKey(bio, NULL,
rd_kafka_transport_ssl_passwd_cb, rk);
BIO_free(bio);
return pkey;
}
/**
* @brief Parse a PEM-formatted string into an X509 object.
*
* @param str Input PEM string, nul-terminated
*
* @returns a new X509 on success or NULL on error.
*/
static X509 *rd_kafka_ssl_X509_from_string(rd_kafka_t *rk, const char *str) {
BIO *bio = BIO_new_mem_buf((void *)str, -1);
X509 *x509;
x509 =
PEM_read_bio_X509(bio, NULL, rd_kafka_transport_ssl_passwd_cb, rk);
BIO_free(bio);
return x509;
}
#ifdef _WIN32
/**
* @brief Attempt load CA certificates from a Windows Certificate store.
*/
static int rd_kafka_ssl_win_load_cert_store(rd_kafka_t *rk,
SSL_CTX *ctx,
const char *store_name) {
HCERTSTORE w_store;
PCCERT_CONTEXT w_cctx = NULL;
X509_STORE *store;
int fail_cnt = 0, cnt = 0;
char errstr[256];
wchar_t *wstore_name;
size_t wsize = 0;
errno_t werr;
/* Convert store_name to wide-char */
werr = mbstowcs_s(&wsize, NULL, 0, store_name, strlen(store_name));
if (werr || wsize < 2 || wsize > 1000) {
rd_kafka_log(rk, LOG_ERR, "CERTSTORE",
"Invalid Windows certificate store name: %.*s%s",
30, store_name,
wsize < 2 ? " (empty)" : " (truncated)");
return -1;
}
wstore_name = rd_alloca(sizeof(*wstore_name) * wsize);
werr = mbstowcs_s(NULL, wstore_name, wsize, store_name,
strlen(store_name));
rd_assert(!werr);
w_store = CertOpenStore(CERT_STORE_PROV_SYSTEM, 0, 0,
CERT_SYSTEM_STORE_CURRENT_USER |
CERT_STORE_READONLY_FLAG |
CERT_STORE_OPEN_EXISTING_FLAG,
wstore_name);
if (!w_store) {
rd_kafka_log(
rk, LOG_ERR, "CERTSTORE",
"Failed to open Windows certificate "
"%s store: %s",
store_name,
rd_strerror_w32(GetLastError(), errstr, sizeof(errstr)));
return -1;
}
/* Get the OpenSSL trust store */
store = SSL_CTX_get_cert_store(ctx);
/* Enumerate the Windows certs */
while ((w_cctx = CertEnumCertificatesInStore(w_store, w_cctx))) {
X509 *x509;
/* Parse Windows cert: DER -> X.509 */
x509 = d2i_X509(NULL,
(const unsigned char **)&w_cctx->pbCertEncoded,
(long)w_cctx->cbCertEncoded);
if (!x509) {
fail_cnt++;
continue;
}
/* Add cert to OpenSSL's trust store */
if (!X509_STORE_add_cert(store, x509))
fail_cnt++;
else
cnt++;
X509_free(x509);
}
if (w_cctx)
CertFreeCertificateContext(w_cctx);
CertCloseStore(w_store, 0);
rd_kafka_dbg(rk, SECURITY, "CERTSTORE",
"%d certificate(s) successfully added from "
"Windows Certificate %s store, %d failed",
cnt, store_name, fail_cnt);
if (cnt == 0 && fail_cnt > 0)
return -1;
return cnt;
}
/**
* @brief Load certs from the configured CSV list of Windows Cert stores.
*
* @returns the number of successfully loaded certificates, or -1 on error.
*/
static int rd_kafka_ssl_win_load_cert_stores(rd_kafka_t *rk,
SSL_CTX *ctx,
const char *store_names) {
char *s;
int cert_cnt = 0, fail_cnt = 0;
if (!store_names || !*store_names)
return 0;
rd_strdupa(&s, store_names);
/* Parse CSV list ("Root,CA, , ,Something") and load
* each store in order. */
while (*s) {
char *t;
const char *store_name;
int r;
while (isspace((int)*s) || *s == ',')
s++;
if (!*s)
break;
store_name = s;
t = strchr(s, (int)',');
if (t) {
*t = '\0';
s = t + 1;
for (; t >= store_name && isspace((int)*t); t--)
*t = '\0';
} else {
s = "";
}
r = rd_kafka_ssl_win_load_cert_store(rk, ctx, store_name);
if (r != -1)
cert_cnt += r;
else
fail_cnt++;
}
if (cert_cnt == 0 && fail_cnt > 0)
return -1;
return cert_cnt;
}
#endif /* MSC_VER */
/**
* @brief Probe for the system's CA certificate location and if found set it
* on the \p CTX.
*
* @returns 0 if CA location was set, else -1.
*/
static int rd_kafka_ssl_probe_and_set_default_ca_location(rd_kafka_t *rk,
SSL_CTX *ctx) {
#if _WIN32
/* No standard location on Windows, CA certs are in the ROOT store. */
return -1;
#else
/* The probe paths are based on:
* https://www.happyassassin.net/posts/2015/01/12/a-note-about-ssltls-trusted-certificate-stores-and-platforms/
* Golang's crypto probing paths:
* https://golang.org/search?q=certFiles and certDirectories
*/
static const char *paths[] = {
"/etc/pki/tls/certs/ca-bundle.crt",
"/etc/ssl/certs/ca-bundle.crt",
"/etc/pki/tls/certs/ca-bundle.trust.crt",
"/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem",
"/etc/ssl/ca-bundle.pem",
"/etc/pki/tls/cacert.pem",
"/etc/ssl/cert.pem",
"/etc/ssl/cacert.pem",
"/etc/certs/ca-certificates.crt",
"/etc/ssl/certs/ca-certificates.crt",
"/etc/ssl/certs",
"/usr/local/etc/ssl/cert.pem",
"/usr/local/etc/ssl/cacert.pem",
"/usr/local/etc/ssl/certs/cert.pem",
"/usr/local/etc/ssl/certs/cacert.pem",
/* BSD */
"/usr/local/share/certs/ca-root-nss.crt",
"/etc/openssl/certs/ca-certificates.crt",
#ifdef __APPLE__
"/private/etc/ssl/cert.pem",
"/private/etc/ssl/certs",
"/usr/local/etc/openssl@1.1/cert.pem",
"/usr/local/etc/openssl@1.0/cert.pem",
"/usr/local/etc/openssl/certs",
"/System/Library/OpenSSL",
#endif
#ifdef _AIX
"/var/ssl/certs/ca-bundle.crt",
#endif
NULL,
};
const char *path = NULL;
int i;
for (i = 0; (path = paths[i]); i++) {
struct stat st;
rd_bool_t is_dir;
int r;
if (stat(path, &st) != 0)
continue;
is_dir = S_ISDIR(st.st_mode);
if (is_dir && rd_kafka_dir_is_empty(path))
continue;
rd_kafka_dbg(rk, SECURITY, "CACERTS",
"Setting default CA certificate location "
"to %s, override with ssl.ca.location",
path);
r = SSL_CTX_load_verify_locations(ctx, is_dir ? NULL : path,
is_dir ? path : NULL);
if (r != 1) {
char errstr[512];
/* Read error and clear the error stack */
rd_kafka_ssl_error(rk, NULL, errstr, sizeof(errstr));
rd_kafka_dbg(rk, SECURITY, "CACERTS",
"Failed to set default CA certificate "
"location to %s %s: %s: skipping",
is_dir ? "directory" : "file", path,
errstr);
continue;
}
return 0;
}
rd_kafka_dbg(rk, SECURITY, "CACERTS",
"Unable to find any standard CA certificate"
"paths: is the ca-certificates package installed?");
return -1;
#endif
}
/**
* @brief Registers certificates, keys, etc, on the SSL_CTX
*
* @returns -1 on error, or 0 on success.
*/
static int rd_kafka_ssl_set_certs(rd_kafka_t *rk,
SSL_CTX *ctx,
char *errstr,
size_t errstr_size) {
rd_bool_t ca_probe = rd_true;
rd_bool_t check_pkey = rd_false;
int r;
/*
* ssl_ca, ssl.ca.location, or Windows cert root store,
* or default paths.
*/
if (rk->rk_conf.ssl.ca) {
/* CA certificate chain set with conf_set_ssl_cert() */
rd_kafka_dbg(rk, SECURITY, "SSL",
"Loading CA certificate(s) from memory");
SSL_CTX_set_cert_store(ctx, rk->rk_conf.ssl.ca->store);
/* OpenSSL takes ownership of the store */
rk->rk_conf.ssl.ca->store = NULL;
ca_probe = rd_false;
} else {
if (rk->rk_conf.ssl.ca_location &&
strcmp(rk->rk_conf.ssl.ca_location, "probe")) {
/* CA certificate location, either file or directory. */
int is_dir =
rd_kafka_path_is_dir(rk->rk_conf.ssl.ca_location);
rd_kafka_dbg(rk, SECURITY, "SSL",
"Loading CA certificate(s) from %s %s",
is_dir ? "directory" : "file",
rk->rk_conf.ssl.ca_location);
r = SSL_CTX_load_verify_locations(
ctx, !is_dir ? rk->rk_conf.ssl.ca_location : NULL,
is_dir ? rk->rk_conf.ssl.ca_location : NULL);
if (r != 1) {
rd_snprintf(errstr, errstr_size,
"ssl.ca.location failed: ");
return -1;
}
ca_probe = rd_false;
}
if (rk->rk_conf.ssl.ca_pem) {
/* CA as PEM string */
X509 *x509;
X509_STORE *store;
/* Get the OpenSSL trust store */