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OpenSSL: SSLKEYLOGFILE capability to allow Wireshark TLS decoding

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A port of the trivial patch I wrote for FreeRADIUS to allow TLS decoding
in Wireshark for hostapd/wpa_supplicant:

df0eb0a884

Signed-off-by: Alexander Clouter <alex@coremem.com>
This commit is contained in:
Alexander Clouter 2022-04-28 23:07:35 +01:00 • committed by Jouni Malinen
parent 3890fa5031
commit a8d058c939
1 changed files with 68 additions and 0 deletions
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68
src/crypto/tls_openssl.c
View file

@ -7,6 +7,9 @@
*/
#include "includes.h"
#ifdef CONFIG_TESTING_OPTIONS
#include <fcntl.h>
#endif /* CONFIG_TESTING_OPTIONS */
#ifndef CONFIG_SMARTCARD
#ifndef OPENSSL_NO_ENGINE
@ -1578,6 +1581,63 @@ static void tls_msg_cb(int write_p, int version, int content_type,
}
#ifdef CONFIG_TESTING_OPTIONS
#if OPENSSL_VERSION_NUMBER >= 0x10101000L && !defined(LIBRESSL_VERSION_NUMBER)
/*
* By setting the environment variable SSLKEYLOGFILE to a filename keying
* material will be exported that you may use with Wireshark to decode any
* TLS flows. Please see the following for more details:
*
* https://gitlab.com/wireshark/wireshark/-/wikis/TLS#tls-decryption
*
* Example logging sessions are (you should delete the file on each run):
*
* rm -f /tmp/sslkey.log
* env SSLKEYLOGFILE=/tmp/sslkey.log hostapd ...
*
* rm -f /tmp/sslkey.log
* env SSLKEYLOGFILE=/tmp/sslkey.log wpa_supplicant ...
*
* rm -f /tmp/sslkey.log
* env SSLKEYLOGFILE=/tmp/sslkey.log eapol_test ...
*/
static void tls_keylog_cb(const SSL *ssl, const char *line)
{
int fd;
const char *filename;
struct iovec iov[2];
filename = getenv("SSLKEYLOGFILE");
if (!filename)
return;
fd = open(filename, O_WRONLY | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
if (fd < 0) {
wpa_printf(MSG_ERROR,
"OpenSSL: Failed to open keylog file %s: %s",
filename, strerror(errno));
return;
}
/* Assume less than _POSIX_PIPE_BUF (512) where writes are guaranteed
* to be atomic for O_APPEND. */
iov[0].iov_base = (void *) line;
iov[0].iov_len = os_strlen(line);
iov[1].iov_base = "\n";
iov[1].iov_len = 1;
if (writev(fd, iov, ARRAY_SIZE(iov)) < 01) {
wpa_printf(MSG_DEBUG,
"OpenSSL: Failed to write to keylog file %s: %s",
filename, strerror(errno));
}
close(fd);
}
#endif
#endif /* CONFIG_TESTING_OPTIONS */
struct tls_connection * tls_connection_init(void *ssl_ctx)
{
struct tls_data *data = ssl_ctx;
@ -1635,6 +1695,14 @@ struct tls_connection * tls_connection_init(void *ssl_ctx)
SSL_clear_options(conn->ssl, SSL_OP_ENABLE_MIDDLEBOX_COMPAT);
#endif
#ifdef CONFIG_TESTING_OPTIONS
#if OPENSSL_VERSION_NUMBER >= 0x10101000L && !defined(LIBRESSL_VERSION_NUMBER)
/* Set the keylog file if the admin requested it. */
if (getenv("SSLKEYLOGFILE"))
SSL_CTX_set_keylog_callback(conn->ssl_ctx, tls_keylog_cb);
#endif
#endif /* CONFIG_TESTING_OPTIONS */
conn->ssl_in = BIO_new(BIO_s_mem());
if (!conn->ssl_in) {
tls_show_errors(MSG_INFO, __func__,