Add a 'max_send_frag' option to configure maximum size of send fragments

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3141)

4 files changed, 64 insertions, 11 deletions

diff --git a/apps/s_client.c b/apps/s_client.c
index d018268fbf..d7a3a80e2b 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -540,13 +540,12 @@ typedef enum OPTION_choice {
     OPT_SSL3, OPT_SSL_CONFIG,
     OPT_TLS1_3, OPT_TLS1_2, OPT_TLS1_1, OPT_TLS1, OPT_DTLS, OPT_DTLS1,
     OPT_DTLS1_2, OPT_SCTP, OPT_TIMEOUT, OPT_MTU, OPT_KEYFORM, OPT_PASS,
-    OPT_CERT_CHAIN, OPT_CAPATH, OPT_NOCAPATH, OPT_CHAINCAPATH,
-        OPT_VERIFYCAPATH,
+    OPT_CERT_CHAIN, OPT_CAPATH, OPT_NOCAPATH, OPT_CHAINCAPATH, OPT_VERIFYCAPATH,
     OPT_KEY, OPT_RECONNECT, OPT_BUILD_CHAIN, OPT_CAFILE, OPT_NOCAFILE,
     OPT_CHAINCAFILE, OPT_VERIFYCAFILE, OPT_NEXTPROTONEG, OPT_ALPN,
-    OPT_SERVERINFO, OPT_STARTTLS, OPT_SERVERNAME, OPT_NOSERVERNAME,
+    OPT_SERVERINFO, OPT_STARTTLS, OPT_SERVERNAME, OPT_NOSERVERNAME, OPT_ASYNC,
     OPT_USE_SRTP, OPT_KEYMATEXPORT, OPT_KEYMATEXPORTLEN, OPT_SMTPHOST,
-    OPT_ASYNC, OPT_SPLIT_SEND_FRAG, OPT_MAX_PIPELINES, OPT_READ_BUF,
+    OPT_MAX_SEND_FRAG, OPT_SPLIT_SEND_FRAG, OPT_MAX_PIPELINES, OPT_READ_BUF,
     OPT_KEYLOG_FILE, OPT_EARLY_DATA, OPT_REQCAFILE,
     OPT_V_ENUM,
     OPT_X_ENUM,
@@ -665,6 +664,7 @@ const OPTIONS s_client_options[] = {
      "Enable ALPN extension, considering named protocols supported (comma-separated list)"},
     {"async", OPT_ASYNC, '-', "Support asynchronous operation"},
     {"ssl_config", OPT_SSL_CONFIG, 's', "Use specified configuration file"},
+    {"max_send_frag", OPT_MAX_SEND_FRAG, 'p', "Maximum Size of send frames "},
     {"split_send_frag", OPT_SPLIT_SEND_FRAG, 'n',
      "Size used to split data for encrypt pipelines"},
     {"max_pipelines", OPT_MAX_PIPELINES, 'n',
@@ -895,8 +895,8 @@ int s_client_main(int argc, char **argv)
 #endif
     int min_version = 0, max_version = 0, prot_opt = 0, no_prot_opt = 0;
     int async = 0;
-    unsigned int split_send_fragment = 0;
-    unsigned int max_pipelines = 0;
+    unsigned int max_send_fragment = 0;
+    unsigned int split_send_fragment = 0,  max_pipelines = 0;
     enum { use_inet, use_unix, use_unknown } connect_type = use_unknown;
     int count4or6 = 0;
     int c_nbio = 0, c_msg = 0, c_ign_eof = 0, c_brief = 0;
@@ -1379,6 +1379,16 @@ int s_client_main(int argc, char **argv)
         case OPT_ASYNC:
             async = 1;
             break;
+        case OPT_MAX_SEND_FRAG:
+            max_send_fragment = atoi(opt_arg());
+            if (max_send_fragment == 0) {
+                /*
+                 * Not allowed - set to a deliberately bad value so we get an
+                 * error message below
+                 */
+                max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH + 1;
+            }
+            break;
         case OPT_SPLIT_SEND_FRAG:
             split_send_fragment = atoi(opt_arg());
             if (split_send_fragment == 0) {
@@ -1476,6 +1486,10 @@ int s_client_main(int argc, char **argv)
         socket_type = SOCK_STREAM;
     }
 #endif
+    if (max_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
+        BIO_printf(bio_err, "Bad max send fragment size\n");
+        goto end;
+    }
 
     if (split_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
         BIO_printf(bio_err, "Bad split send fragment size\n");
@@ -1608,6 +1622,10 @@ int s_client_main(int argc, char **argv)
     if (async) {
         SSL_CTX_set_mode(ctx, SSL_MODE_ASYNC);
     }
+
+    if (max_send_fragment > 0)
+        SSL_CTX_set_max_send_fragment(ctx, max_send_fragment);
+
     if (split_send_fragment > 0) {
         SSL_CTX_set_split_send_fragment(ctx, split_send_fragment);
     }
diff --git a/apps/s_server.c b/apps/s_server.c
index 46316630be..5faeb21a8b 100644
--- a/apps/s_server.c
+++ b/apps/s_server.c
@@ -717,7 +717,8 @@ typedef enum OPTION_choice {
     OPT_CRLF, OPT_QUIET, OPT_BRIEF, OPT_NO_DHE,
     OPT_NO_RESUME_EPHEMERAL, OPT_PSK_HINT, OPT_PSK, OPT_SRPVFILE,
     OPT_SRPUSERSEED, OPT_REV, OPT_WWW, OPT_UPPER_WWW, OPT_HTTP, OPT_ASYNC,
-    OPT_SSL_CONFIG, OPT_SPLIT_SEND_FRAG, OPT_MAX_PIPELINES, OPT_READ_BUF,
+    OPT_SSL_CONFIG, 
+    OPT_MAX_SEND_FRAG, OPT_SPLIT_SEND_FRAG, OPT_MAX_PIPELINES, OPT_READ_BUF,
     OPT_SSL3, OPT_TLS1_3, OPT_TLS1_2, OPT_TLS1_1, OPT_TLS1, OPT_DTLS, OPT_DTLS1,
     OPT_DTLS1_2, OPT_SCTP, OPT_TIMEOUT, OPT_MTU, OPT_LISTEN,
     OPT_ID_PREFIX, OPT_RAND, OPT_SERVERNAME, OPT_SERVERNAME_FATAL,
@@ -856,6 +857,7 @@ const OPTIONS s_server_options[] = {
     {"async", OPT_ASYNC, '-', "Operate in asynchronous mode"},
     {"ssl_config", OPT_SSL_CONFIG, 's',
      "Configure SSL_CTX using the configuration 'val'"},
+    {"max_send_frag", OPT_MAX_SEND_FRAG, 'p', "Maximum Size of send frames "},
     {"split_send_frag", OPT_SPLIT_SEND_FRAG, 'n',
      "Size used to split data for encrypt pipelines"},
     {"max_pipelines", OPT_MAX_PIPELINES, 'n',
@@ -999,6 +1001,7 @@ int s_server_main(int argc, char *argv[])
     int s_tlsextstatus = 0;
 #endif
     int no_resume_ephemeral = 0;
+    unsigned int max_send_fragment = 0;
     unsigned int split_send_fragment = 0, max_pipelines = 0;
     const char *s_serverinfo_file = NULL;
     const char *keylog_file = NULL;
@@ -1497,6 +1500,16 @@ int s_server_main(int argc, char *argv[])
         case OPT_ASYNC:
             async = 1;
             break;
+        case OPT_MAX_SEND_FRAG:
+            max_send_fragment = atoi(opt_arg());
+            if (max_send_fragment == 0) {
+                /*
+                 * Not allowed - set to a deliberately bad value so we get an
+                 * error message below
+                 */
+                max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH + 1;
+            }
+            break;
         case OPT_SPLIT_SEND_FRAG:
             split_send_fragment = atoi(opt_arg());
             if (split_send_fragment == 0) {
@@ -1561,6 +1574,10 @@ int s_server_main(int argc, char *argv[])
         socket_type = SOCK_STREAM;
     }
 #endif
+    if (max_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
+        BIO_printf(bio_err, "Bad max send fragment size\n");
+        goto end;
+    }
 
     if (split_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
         BIO_printf(bio_err, "Bad split send fragment size\n");
@@ -1760,6 +1777,10 @@ int s_server_main(int argc, char *argv[])
     if (async) {
         SSL_CTX_set_mode(ctx, SSL_MODE_ASYNC);
     }
+
+    if (max_send_fragment > 0)
+        SSL_CTX_set_max_send_fragment(ctx, max_send_fragment);
+
     if (split_send_fragment > 0) {
         SSL_CTX_set_split_send_fragment(ctx, split_send_fragment);
     }
diff --git a/doc/man1/s_client.pod b/doc/man1/s_client.pod
index 16538567bc..96df8a4101 100644
--- a/doc/man1/s_client.pod
+++ b/doc/man1/s_client.pod
@@ -86,6 +86,7 @@ B<openssl> B<s_client>
 [B<-sctp>]
 [B<-fallback_scsv>]
 [B<-async>]
+[B<-max_send_frag>]
 [B<-split_send_frag>]
 [B<-max_pipelines>]
 [B<-read_buf>]
@@ -416,6 +417,11 @@ asynchronously. This will only have an effect if an asynchronous capable engine
 is also used via the B<-engine> option. For test purposes the dummy async engine
 (dasync) can be used (if available).
 
+=item B<-max_send_frag int>
+
+The maximum size of data fragment to send.
+See L<SSL_CTX_set_max_send_fragment(3)> for further information.
+
 =item B<-split_send_frag int>
 
 The size used to split data for encrypt pipelines. If more data is written in
@@ -643,8 +649,9 @@ information whenever a session is renegotiated.
 
 =head1 SEE ALSO
 
-L<SSL_CONF_cmd(3)>,
-L<sess_id(1)>, L<s_server(1)>, L<ciphers(1)>
+L<SSL_CONF_cmd(3)>, L<sess_id(1)>, L<s_server(1)>, L<ciphers(1)>,
+L<SSL_CTX_set_max_send_fragment(3)>, L<SSL_CTX_set_split_send_fragment(3)>
+L<SSL_CTX_set_max_pipelines(3)> 
 
 =head1 HISTORY
 
diff --git a/doc/man1/s_server.pod b/doc/man1/s_server.pod
index d2fbb84973..c3e763f4e0 100644
--- a/doc/man1/s_server.pod
+++ b/doc/man1/s_server.pod
@@ -86,6 +86,7 @@ B<openssl> B<s_server>
 [B<-sctp>]
 [B<-listen>]
 [B<-async>]
+[B<-max_send_frag>]
 [B<-split_send_frag>]
 [B<-max_pipelines>]
 [B<-read_buf>]
@@ -376,6 +377,11 @@ asynchronously. This will only have an effect if an asynchronous capable engine
 is also used via the B<-engine> option. For test purposes the dummy async engine
 (dasync) can be used (if available).
 
+=item B<-max_send_frag int>
+
+The maximum size of data fragment to send.
+See L<SSL_CTX_set_max_send_fragment(3)> for further information.
+
 =item B<-split_send_frag int>
 
 The size used to split data for encrypt pipelines. If more data is written in
@@ -638,8 +644,9 @@ unknown cipher suites a client says it supports.
 
 =head1 SEE ALSO
 
-L<SSL_CONF_cmd(3)>,
-L<sess_id(1)>, L<s_client(1)>, L<ciphers(1)>
+L<SSL_CONF_cmd(3)>, L<sess_id(1)>, L<s_client(1)>, L<ciphers(1)>
+L<SSL_CTX_set_max_send_fragment(3)>, L<SSL_CTX_set_split_send_fragment(3)>
+L<SSL_CTX_set_max_pipelines(3)> 
 
 =head1 HISTORY