From: Philippe Antoine <pantoine@oisf.net>
Date: Mon, 28 Apr 2025 08:11:13 +0000 (+0200)
Subject: websocket: limit allocation for small sizes
X-Git-Tag: suricata-8.0.0-rc1~409
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6436a5cebed11ee3d36a73c4f96c0a2814706375;p=thirdparty%2Fsuricata.git

websocket: limit allocation for small sizes

Fixes: 16f74c68aaa9 ("websocket: use max window bits of 15")

We do not need to allocate 8kbytes for a small message
---

diff --git a/rust/src/websocket/websocket.rs b/rust/src/websocket/websocket.rs
index f86101743d..c1b6bbfa53 100644
--- a/rust/src/websocket/websocket.rs
+++ b/rust/src/websocket/websocket.rs
@@ -239,7 +239,12 @@ impl WebSocketState {
                         buf.compress = false;
                         // cf RFC 7692 section-7.2.2
                         tx.pdu.payload.extend_from_slice(&[0, 0, 0xFF, 0xFF]);
-                        let mut v = Vec::with_capacity(WEBSOCKET_DECOMPRESS_BUF_SIZE);
+                        let mut v = Vec::with_capacity(std::cmp::min(
+                            WEBSOCKET_DECOMPRESS_BUF_SIZE,
+                            // Do not allocate 8kbytes for a small size.
+                            // Numbers here may be optimized.
+                            256 + 16 * tx.pdu.payload.len(),
+                        ));
                         if let Some(dec) = dec {
                             let expect = dec.total_in() + tx.pdu.payload.len() as u64;
                             let start = dec.total_in();