stream: non infinite default value for reassembly.depth

So that empty config have a safer default.

Ticket: 8290

doc/userguide/upgrade.rst

@@ -42,6 +42,8 @@ Major Changes
 - Encrypted quic traffic bypass is now independently controlled through
   ``app-layer.protocols.quic.encryption-handling`` setting. The setting can either
   be ``bypass``, ``track-only`` or ``full``.
+- Default value for ``stream.reassembly.depth`` when the value is not specified in
+  suricata.yaml is now 1 MiB instead of 0/unlimited.
 
 Logging Changes
 ~~~~~~~~~~~~~~~

src/stream-tcp.c

@@ -89,6 +89,8 @@
 #define STREAMTCP_DEFAULT_TOCLIENT_CHUNK_SIZE   2560
 #define STREAMTCP_DEFAULT_MAX_SYN_QUEUED        10
 #define STREAMTCP_DEFAULT_MAX_SYNACK_QUEUED     5
+// 1 MiB
+#define STREAM_DEPTH_DEFAULT 1024 * 1024
 
 /* Settings order as in the enum */
 // clang-format off
@@ -735,7 +737,7 @@ void StreamTcpInitConfig(bool quiet)
             exit(EXIT_FAILURE);
         }
     } else {
-        stream_config.reassembly_depth = 0;
+        stream_config.reassembly_depth = STREAM_DEPTH_DEFAULT;
     }
 
     if (!quiet) {

suricata.yaml.in

@@ -1670,8 +1670,9 @@ flow-timeouts:
 #     memcap-policy: ignore     # The exception policy value can be "drop-flow",
 #                               # "pass-flow", "bypass", "drop-packet", "pass-packet",
 #                               # "reject" or "ignore" default is "ignore"
-#     depth: 1 MiB               # Can be specified in KiB, MiB, GiB.  Just a number
+#     depth: 1 MiB              # Can be specified in KiB, MiB, GiB.  Just a number
 #                               # indicates it's in bytes.
+#                               # 1 MiB is the default when this value is not specified
 #     toserver-chunk-size: 2560 # inspect raw stream in chunks of at least
 #                               # this size.  Can be specified in KiB, MiB, GiB.
 #                               # Just a number indicates it's in bytes.
@@ -1717,7 +1718,7 @@ stream:
       oob-limit-policy: drop
     memcap: 256 MiB
     #memcap-policy: ignore
-    depth: 1 MiB                # reassemble 1 MiB into a stream
+    #depth: 1 MiB                # reassemble 1 MiB into a stream
     toserver-chunk-size: 2560
     toclient-chunk-size: 2560
     randomize-chunk-size: yes