Commit 3bb5e5b0 authored by Matt Caswell's avatar Matt Caswell
Browse files

Add the ability to configure anti-replay via SSL_CONF



This also adds the ability to control this through s_server

Reviewed-by: default avatarViktor Dukhovni <viktor@openssl.org>
Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6469)
parent 5a421415
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+5 −0
Original line number Diff line number Diff line
@@ -749,6 +749,7 @@ typedef enum OPTION_choice {
    OPT_CERT2, OPT_KEY2, OPT_NEXTPROTONEG, OPT_ALPN,
    OPT_SRTP_PROFILES, OPT_KEYMATEXPORT, OPT_KEYMATEXPORTLEN,
    OPT_KEYLOG_FILE, OPT_MAX_EARLY, OPT_EARLY_DATA, OPT_S_NUM_TICKETS,
    OPT_ANTI_REPLAY, OPT_NO_ANTI_REPLAY,
    OPT_R_ENUM,
    OPT_S_ENUM,
    OPT_V_ENUM,
@@ -958,6 +959,8 @@ const OPTIONS s_server_options[] = {
    {"early_data", OPT_EARLY_DATA, '-', "Attempt to read early data"},
    {"num_tickets", OPT_S_NUM_TICKETS, 'n',
     "The number of TLSv1.3 session tickets that a server will automatically  issue" },
    {"anti_replay", OPT_ANTI_REPLAY, '-', "Switch on anti-replay protection (default)"},
    {"no_anti_replay", OPT_NO_ANTI_REPLAY, '-', "Switch off anti-replay protection"},
    {NULL, OPT_EOF, 0, NULL}
};

@@ -1258,6 +1261,8 @@ int s_server_main(int argc, char *argv[])
            break;
        case OPT_S_CASES:
        case OPT_S_NUM_TICKETS:
        case OPT_ANTI_REPLAY:
        case OPT_NO_ANTI_REPLAY:
            if (ssl_args == NULL)
                ssl_args = sk_OPENSSL_STRING_new_null();
            if (ssl_args == NULL
+11 −0
Original line number Diff line number Diff line
@@ -180,6 +180,8 @@ B<openssl> B<s_server>
[B<-keylogfile outfile>]
[B<-max_early_data int>]
[B<-early_data>]
[B<-anti_replay>]
[B<-no_anti_replay>]

=head1 DESCRIPTION

@@ -709,6 +711,15 @@ greater than or equal to 0.

Accept early data where possible.

=item B<-anti_replay>, B<-no_anti_replay>

Switches replay protection on or off, respectively. Replay protection is on by
default unless overridden by a configuration file. When it is on, OpenSSL will
automatically detect if a session ticket has been used more than once, TLSv1.3
has been negotiated, and early data is enabled on the server. A full handshake
is forced if a session ticket is used a second or subsequent time. Any early
data that was sent will be rejected.

=back

=head1 CONNECTED COMMANDS
+21 −0
Original line number Diff line number Diff line
@@ -211,6 +211,18 @@ that there will be no forward secrecy for the resumed session.
enables strict mode protocol handling. Equivalent to setting
B<SSL_CERT_FLAG_TLS_STRICT>.

=item B<-anti_replay>, B<-no_anti_replay>

Switches replay protection, on or off respectively. With replay protection on,
OpenSSL will automatically detect if a session ticket has been used more than
once, TLSv1.3 has been negotiated, and early data is enabled on the server. A
full handshake is forced if a session ticket is used a second or subsequent
time. Anti-Replay is on by default unless overridden by a configuration file and
is only used by servers. Anti-replay measures are required for compliance with
the TLSv1.3 specification. Some applications may be able to mitigate the replay
risks in other ways and in such cases the built-in OpenSSL functionality is not
required. Switching off anti-replay is equivalent to B<SSL_OP_NO_ANTI_REPLAY>.

=back

=head1 SUPPORTED CONFIGURATION FILE COMMANDS
@@ -441,6 +453,15 @@ middleboxes that do not understand TLSv1.3 will not drop the connection. This
option is set by default. A future version of OpenSSL may not set this by
default. Equivalent to B<SSL_OP_ENABLE_MIDDLEBOX_COMPAT>.

B<AntiReplay>: If set then OpenSSL will automatically detect if a session ticket
has been used more than once, TLSv1.3 has been negotiated, and early data is
enabled on the server. A full handshake is forced if a session ticket is used a
second or subsequent time. This option is set by default and is only used by
servers. Anti-replay measures are required to comply with the TLSv1.3
specification. Some applications may be able to mitigate the replay risks in
other ways and in such cases the built-in OpenSSL functionality is not required.
Disabling anti-replay is equivalent to setting B<SSL_OP_NO_ANTI_REPLAY>.

=item B<VerifyMode>

The B<value> argument is a comma separated list of flags to set.
+9 −2
Original line number Diff line number Diff line
@@ -383,7 +383,8 @@ static int cmd_Options(SSL_CONF_CTX *cctx, const char *value)
        SSL_FLAG_TBL("NoRenegotiation", SSL_OP_NO_RENEGOTIATION),
        SSL_FLAG_TBL("AllowNoDHEKEX", SSL_OP_ALLOW_NO_DHE_KEX),
        SSL_FLAG_TBL("PrioritizeChaCha", SSL_OP_PRIORITIZE_CHACHA),
        SSL_FLAG_TBL("MiddleboxCompat", SSL_OP_ENABLE_MIDDLEBOX_COMPAT)
        SSL_FLAG_TBL("MiddleboxCompat", SSL_OP_ENABLE_MIDDLEBOX_COMPAT),
        SSL_FLAG_TBL_INV("AntiReplay", SSL_OP_NO_ANTI_REPLAY)
    };
    if (value == NULL)
        return -3;
@@ -626,6 +627,8 @@ static const ssl_conf_cmd_tbl ssl_conf_cmds[] = {
    SSL_CONF_CMD_SWITCH("prioritize_chacha", SSL_CONF_FLAG_SERVER),
    SSL_CONF_CMD_SWITCH("strict", 0),
    SSL_CONF_CMD_SWITCH("no_middlebox", 0),
    SSL_CONF_CMD_SWITCH("anti_replay", SSL_CONF_FLAG_SERVER),
    SSL_CONF_CMD_SWITCH("no_anti_replay", SSL_CONF_FLAG_SERVER),
    SSL_CONF_CMD_STRING(SignatureAlgorithms, "sigalgs", 0),
    SSL_CONF_CMD_STRING(ClientSignatureAlgorithms, "client_sigalgs", 0),
    SSL_CONF_CMD_STRING(Curves, "curves", 0),
@@ -671,7 +674,7 @@ static const ssl_conf_cmd_tbl ssl_conf_cmds[] = {
                 SSL_CONF_TYPE_FILE),
#endif
    SSL_CONF_CMD_STRING(RecordPadding, "record_padding", 0),
    SSL_CONF_CMD_STRING(NumTickets, "num_tickets", SSL_CONF_FLAG_SERVER)
    SSL_CONF_CMD_STRING(NumTickets, "num_tickets", SSL_CONF_FLAG_SERVER),
};

/* Supported switches: must match order of switches in ssl_conf_cmds */
@@ -704,6 +707,10 @@ static const ssl_switch_tbl ssl_cmd_switches[] = {
    {SSL_CERT_FLAG_TLS_STRICT, SSL_TFLAG_CERT}, /* strict */
    /* no_middlebox */
    {SSL_OP_ENABLE_MIDDLEBOX_COMPAT, SSL_TFLAG_INV},
    /* anti_replay */
    {SSL_OP_NO_ANTI_REPLAY, SSL_TFLAG_INV},
    /* no_anti_replay */
    {SSL_OP_NO_ANTI_REPLAY, 0},
};

static int ssl_conf_cmd_skip_prefix(SSL_CONF_CTX *cctx, const char **pcmd)
+25 −6
Original line number Diff line number Diff line
@@ -2179,8 +2179,10 @@ static int allow_early_data_cb(SSL *s, void *arg)
 * usecb == 0: Don't use a custom early data callback
 * usecb == 1: Use a custom early data callback and reject the early data
 * usecb == 2: Use a custom early data callback and accept the early data
 * confopt == 0: Configure anti-replay directly
 * confopt == 1: Configure anti-replay using SSL_CONF
 */
static int test_early_data_replay_int(int idx, int usecb)
static int test_early_data_replay_int(int idx, int usecb, int confopt)
{
    SSL_CTX *cctx = NULL, *sctx = NULL;
    SSL *clientssl = NULL, *serverssl = NULL;
@@ -2197,7 +2199,23 @@ static int test_early_data_replay_int(int idx, int usecb)
        return 0;

    if (usecb > 0) {
        if (confopt == 0) {
            SSL_CTX_set_options(sctx, SSL_OP_NO_ANTI_REPLAY);
        } else {
            SSL_CONF_CTX *confctx = SSL_CONF_CTX_new();

            if (!TEST_ptr(confctx))
                goto end;
            SSL_CONF_CTX_set_flags(confctx, SSL_CONF_FLAG_FILE
                                            | SSL_CONF_FLAG_SERVER);
            SSL_CONF_CTX_set_ssl_ctx(confctx, sctx);
            if (!TEST_int_eq(SSL_CONF_cmd(confctx, "Options", "-AntiReplay"),
                             2)) {
                SSL_CONF_CTX_free(confctx);
                goto end;
            }
            SSL_CONF_CTX_free(confctx);
        }
        SSL_CTX_set_allow_early_data_cb(sctx, allow_early_data_cb, &usecb);
    }

@@ -2282,11 +2300,12 @@ static int test_early_data_replay_int(int idx, int usecb)

static int test_early_data_replay(int idx)
{
    int ret;
    int ret = 1, usecb, confopt;

    ret = test_early_data_replay_int(idx, 0);
    ret &= test_early_data_replay_int(idx, 1);
    ret &= test_early_data_replay_int(idx, 2);
    for (usecb = 0; usecb < 3; usecb++) {
        for (confopt = 0; confopt < 2; confopt++)
            ret &= test_early_data_replay_int(idx, usecb, confopt);
    }

    return ret;
}