fix: harden vcl lifecycle for varnish9 v4.3.3

Author: RamazanKara

.dockerignore

@@ -3,6 +3,11 @@
 **/vendor
 .libs
 .deps
+**/.libs
+**/.deps
+*.lo
+*.la
+*.o
 autom4te.cache
 aclocal.m4
 config.h

CHANGELOG.md

@@ -2,6 +2,27 @@
 
 All notable changes to vmod-wasm will be documented in this file.
 
+## [4.3.3] - 2026-05-24
+
+### Fixed
+- Isolated Wasm engines per loaded VCL so VCL reloads and discards no longer
+  tear down modules still owned by another active VCL.
+- Reordered engine shutdown so tick timers, store pools, warm instances, and
+  HTTP pools are destroyed before Wasmtime modules and the Wasmtime engine.
+- Hardened HTTP connection pooling by applying socket I/O timeouts and refusing
+  to reuse pooled sockets with unread stale data.
+- Initialized Proxy-Wasm warm lifecycle calls with a real host context, memory,
+  allocator, shared data, queue store, and metric store.
+- Copied Proxy-Wasm header and request-property mutations into Varnish
+  workspace before passing them to Varnish HTTP APIs.
+- Fixed Proxy-Wasm header-map size reporting for request and response pseudo
+  headers.
+- Rejected duplicate module names in a VCL-local engine and cleaned up failed
+  module loads more defensively.
+
+### Tests
+- Added VTC coverage for VCL reload lifecycle isolation.
+
 ## [4.3.2] - 2026-05-24
 
 ### Fixed

Makefile.am

@@ -79,6 +79,7 @@ EXTRA_DIST = \
 	tests/proxy_wasm_sdk.vtc \
 	tests/proxy_wasm_security.vtc \
 	tests/resource_config.vtc \
+	tests/vcl_reload_lifecycle.vtc \
 	tests/wasm/test_module.wasm
 
 # Unit tests cannot link standalone against the VMOD because Varnish internal

README.md

@@ -119,9 +119,9 @@ make install
 
 ### Release Bundles
 
-GitHub releases use Varnish-specific tags such as `varnish9-v4.3.2` so the
+GitHub releases use Varnish-specific tags such as `varnish9-v4.3.3` so the
 supported Varnish ABI line is visible before download. The package version
-remains semantic (`4.3.2`), while the release channel identifies Varnish 9.
+remains semantic (`4.3.3`), while the release channel identifies Varnish 9.
 
 Release assets include source and convenience binary bundles for Linux `amd64`
 and `arm64` on Varnish 9. Binary bundles include `libvmod_wasm.so`,

configure.ac

@@ -1,5 +1,5 @@
 AC_PREREQ([2.69])
-AC_INIT([vmod-wasm], [4.3.2], [https://github.com/RamazanKara/vmod-wasm/issues])
+AC_INIT([vmod-wasm], [4.3.3], [https://github.com/RamazanKara/vmod-wasm/issues])
 AC_CONFIG_SRCDIR([src/vmod_wasm.vcc])
 AC_CONFIG_MACRO_DIRS([m4])
 AC_CONFIG_HEADERS([config.h])

src/host_functions.c

@@ -583,6 +583,7 @@ wasi_fd_write(void *env, wasmtime_caller_t *caller,
 
 	(void)env;
 	(void)nargs;
+	(void)nresults;
 
 	ctx = wasmtime_caller_context(caller);
 	hctx = (struct vwasm_host_ctx *)wasmtime_context_get_data(ctx);
@@ -899,6 +900,7 @@ wasi_proc_exit(void *env, wasmtime_caller_t *caller,
 	(void)caller;
 	(void)args;
 	(void)nargs;
+	(void)results;
 	(void)nresults;
 	/* Trap instead of exiting the process */
 	return (wasmtime_trap_new("wasi proc_exit called", 21));

src/http_pool.c

@@ -19,6 +19,7 @@
 #include <poll.h>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <sys/time.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
@@ -61,15 +62,6 @@ make_cache_key(const char *method, const char *host, uint16_t port,
 	return (key);
 }
 
-static char *
-make_upstream_key(const char *host, uint16_t port)
-{
-	char key[280];
-
-	snprintf(key, sizeof(key), "%s:%u", host, port);
-	return (strdup(key));
-}
-
 static int
 set_nonblocking(int fd)
 {
@@ -111,12 +103,16 @@ conn_is_alive(int fd)
 		return (0);
 	if (ret == 0)
 		return (1);  /* No data pending = alive and idle */
+	if (pfd.revents & (POLLERR | POLLHUP | POLLNVAL))
+		return (0);
+	if (!(pfd.revents & POLLIN))
+		return (1);
 
-	/* Data pending: either response data (unlikely) or EOF */
+	/* Data pending means the connection is not cleanly idle. */
 	ret = (int)recv(fd, &buf, 1, MSG_PEEK | MSG_DONTWAIT);
 	if (ret <= 0)
 		return (0);  /* EOF or error: peer closed */
-	return (1);  /* Data available: might be stale response */
+	return (0);
 }
 
 int
@@ -197,6 +193,8 @@ vwasm_http_addr_is_private(const struct sockaddr *sa)
 /*
  * Connect to host:port with timeout.
  */
+static void set_io_timeouts(int fd, uint32_t timeout_ms);
+
 static int
 connect_with_timeout(const struct sockaddr_storage *addr, socklen_t addrlen,
     uint32_t timeout_ms)
@@ -221,6 +219,7 @@ connect_with_timeout(const struct sockaddr_storage *addr, socklen_t addrlen,
 	ret = connect(fd, (const struct sockaddr *)addr, addrlen);
 	if (ret == 0) {
 		set_blocking(fd);
+		set_io_timeouts(fd, timeout_ms);
 		return (fd);
 	}
 
@@ -249,9 +248,23 @@ connect_with_timeout(const struct sockaddr_storage *addr, socklen_t addrlen,
 	}
 
 	set_blocking(fd);
+	set_io_timeouts(fd, timeout_ms);
 	return (fd);
 }
 
+static void
+set_io_timeouts(int fd, uint32_t timeout_ms)
+{
+	struct timeval tv;
+
+	if (timeout_ms == 0)
+		timeout_ms = VWASM_HTTP_DEFAULT_TIMEOUT_MS;
+	tv.tv_sec = timeout_ms / 1000;
+	tv.tv_usec = (timeout_ms % 1000) * 1000;
+	(void)setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+	(void)setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+}
+
 /* ----------------------------------------------------------------
  * Pool Creation / Destruction
  * ---------------------------------------------------------------- */

src/proxy_wasm.c

@@ -1130,6 +1130,7 @@ pw_proxy_get_metric(void *env, wasmtime_caller_t *caller,
 	struct vwasm_metric_store *store;
 	uint32_t metric_id;
 	uint64_t value;
+	uint8_t *dst;
 
 	(void)env;
 	ctx = wasmtime_context_get_data(wasmtime_caller_context(caller));
@@ -1160,7 +1161,12 @@ pw_proxy_get_metric(void *env, wasmtime_caller_t *caller,
 		results[0].of.i32 = PROXY_BAD_ARGUMENT;
 		return (NULL);
 	}
-	memcpy(pw_mem_ptr(ctx, (uint32_t)args[1].of.i32), &value, 8);
+	dst = pw_mem_ptr(ctx, (uint32_t)args[1].of.i32);
+	if (dst == NULL) {
+		results[0].of.i32 = PROXY_BAD_ARGUMENT;
+		return (NULL);
+	}
+	memcpy(dst, &value, 8);
 
 	results[0].of.i32 = PROXY_OK;
 	return (NULL);

src/proxy_wasm_headers.c

@@ -365,6 +365,7 @@ pw_proxy_add_header_map_value(void *env, wasmtime_caller_t *caller,
 	struct vwasm_proxy_ctx *ctx;
 	struct http *hp;
 	char key_buf[256], val_buf[4096], hdr_line[4352];
+	const char *ws_hdr;
 	int32_t map_type;
 
 	(void)env;
@@ -407,8 +408,13 @@ pw_proxy_add_header_map_value(void *env, wasmtime_caller_t *caller,
 	}
 
 	snprintf(hdr_line, sizeof(hdr_line), "%s: %s", key_buf, val_buf);
-	http_SetHeader(hp,
-	    WS_Copy(ctx->vrt_ctx->ws, hdr_line, (int)(strlen(hdr_line) + 1)));
+	ws_hdr = WS_Copy(ctx->vrt_ctx->ws, hdr_line,
+	    (int)(strlen(hdr_line) + 1));
+	if (ws_hdr == NULL) {
+		results[0].of.i32 = PROXY_INTERNAL;
+		return (NULL);
+	}
+	http_SetHeader(hp, ws_hdr);
 
 	results[0].of.i32 = PROXY_OK;
 	return (NULL);
@@ -426,6 +432,7 @@ pw_proxy_replace_header_map_value(void *env, wasmtime_caller_t *caller,
 	struct vwasm_proxy_ctx *ctx;
 	struct http *hp;
 	char key_buf[256], val_buf[4096], hdr_search[260], hdr_line[4352];
+	const char *ws_hdr;
 	int i;
 	int32_t map_type;
 
@@ -473,8 +480,13 @@ pw_proxy_replace_header_map_value(void *env, wasmtime_caller_t *caller,
 	}
 
 	snprintf(hdr_line, sizeof(hdr_line), "%s: %s", key_buf, val_buf);
-	http_SetHeader(hp,
-	    WS_Copy(ctx->vrt_ctx->ws, hdr_line, (int)(strlen(hdr_line) + 1)));
+	ws_hdr = WS_Copy(ctx->vrt_ctx->ws, hdr_line,
+	    (int)(strlen(hdr_line) + 1));
+	if (ws_hdr == NULL) {
+		results[0].of.i32 = PROXY_INTERNAL;
+		return (NULL);
+	}
+	http_SetHeader(hp, ws_hdr);
 
 	results[0].of.i32 = PROXY_OK;
 	return (NULL);
@@ -783,7 +795,7 @@ pw_proxy_get_header_map_pairs(void *env, wasmtime_caller_t *caller,
 				break;
 			}
 		}
-	} else if (map_type == 1) {
+	} else if (map_type == PROXY_MAP_HTTP_RESPONSE_HEADERS) {
 		if (hp->hd[HTTP_HDR_STATUS].b != NULL) {
 			pseudo_keys[num_pseudo] = ":status";
 			pseudo_vals[num_pseudo] = hp->hd[HTTP_HDR_STATUS].b;
@@ -951,6 +963,7 @@ pw_proxy_set_header_map_pairs(void *env, wasmtime_caller_t *caller,
 	uint32_t map_type, data_ptr, data_size;
 	uint32_t num_pairs, i, offset;
 	char hdr_line[4352];
+	const char *ws_hdr;
 
 	(void)env;
 	(void)nargs;
@@ -1050,7 +1063,13 @@ pw_proxy_set_header_map_pairs(void *env, wasmtime_caller_t *caller,
 		if (key_size > 0 && key_size < 256 && val_size < 4096) {
 			snprintf(hdr_line, sizeof(hdr_line), "%.*s: %.*s",
 			    (int)key_size, key, (int)val_size, val);
-			http_SetHeader(hp, hdr_line);
+			ws_hdr = WS_Copy(ctx->vrt_ctx->ws, hdr_line,
+			    (int)(strlen(hdr_line) + 1));
+			if (ws_hdr == NULL) {
+				results[0].of.i32 = PROXY_INTERNAL;
+				return (NULL);
+			}
+			http_SetHeader(hp, ws_hdr);
 		}
 	}
 
@@ -1072,6 +1091,7 @@ pw_proxy_get_header_map_size(void *env, wasmtime_caller_t *caller,
 	struct vwasm_proxy_ctx *ctx;
 	int32_t map_type;
 	uint32_t count = 0;
+	uint32_t i;
 
 	(void)env;
 	(void)nargs;
@@ -1089,8 +1109,26 @@ pw_proxy_get_header_map_size(void *env, wasmtime_caller_t *caller,
 			count = tm->count;
 	} else {
 		const struct http *hp = pw_get_header_map(ctx, map_type);
-		if (hp != NULL)
+		if (hp != NULL) {
 			count = (uint32_t)(hp->nhd - HTTP_HDR_FIRST);
+			if (map_type == PROXY_MAP_HTTP_REQUEST_HEADERS) {
+				if (hp->hd[HTTP_HDR_METHOD].b != NULL)
+					count++;
+				if (hp->hd[HTTP_HDR_URL].b != NULL)
+					count++;
+				for (i = HTTP_HDR_FIRST; i < hp->nhd; i++) {
+					if (hp->hd[i].b != NULL &&
+					    strncasecmp(hp->hd[i].b, "Host:",
+					    5) == 0) {
+						count++;
+						break;
+					}
+				}
+			} else if (map_type == PROXY_MAP_HTTP_RESPONSE_HEADERS &&
+			    hp->hd[HTTP_HDR_STATUS].b != NULL) {
+				count++;
+			}
+		}
 	}
 
 	if (pw_write_u32(ctx, (uint32_t)args[1].of.i32, count) != 0) {

src/proxy_wasm_properties.c

@@ -176,6 +176,7 @@ pw_proxy_set_property(void *env, wasmtime_caller_t *caller,
 	char path_buf[512], value_buf[4096];
 	uint32_t path_size, value_size;
 	struct http *hp;
+	const char *ws_value;
 
 	(void)env;
 	(void)nargs;
@@ -219,8 +220,13 @@ pw_proxy_set_property(void *env, wasmtime_caller_t *caller,
 			results[0].of.i32 = PROXY_BAD_ARGUMENT;
 			return (NULL);
 		}
-		http_SetH(hp, HTTP_HDR_URL, WS_Copy(vctx->ws,
-		    value_buf, (int)(value_size + 1)));
+		ws_value = WS_Copy(vctx->ws, value_buf,
+		    (int)(value_size + 1));
+		if (ws_value == NULL) {
+			results[0].of.i32 = PROXY_INTERNAL;
+			return (NULL);
+		}
+		http_SetH(hp, HTTP_HDR_URL, ws_value);
 		results[0].of.i32 = PROXY_OK;
 		return (NULL);
 	}
@@ -232,8 +238,13 @@ pw_proxy_set_property(void *env, wasmtime_caller_t *caller,
 			results[0].of.i32 = PROXY_BAD_ARGUMENT;
 			return (NULL);
 		}
-		http_SetH(hp, HTTP_HDR_METHOD, WS_Copy(vctx->ws,
-		    value_buf, (int)(value_size + 1)));
+		ws_value = WS_Copy(vctx->ws, value_buf,
+		    (int)(value_size + 1));
+		if (ws_value == NULL) {
+			results[0].of.i32 = PROXY_INTERNAL;
+			return (NULL);
+		}
+		http_SetH(hp, HTTP_HDR_METHOD, ws_value);
 		results[0].of.i32 = PROXY_OK;
 		return (NULL);
 	}
@@ -249,8 +260,13 @@ pw_proxy_set_property(void *env, wasmtime_caller_t *caller,
 		snprintf(hdr_line, sizeof(hdr_line), "Host: %.*s",
 		    (int)value_size, value_buf);
 		http_Unset(hp, (hdr_t)"\005Host:");
-		http_SetHeader(hp, WS_Copy(vctx->ws,
-		    hdr_line, (int)(strlen(hdr_line) + 1)));
+		ws_value = WS_Copy(vctx->ws, hdr_line,
+		    (int)(strlen(hdr_line) + 1));
+		if (ws_value == NULL) {
+			results[0].of.i32 = PROXY_INTERNAL;
+			return (NULL);
+		}
+		http_SetHeader(hp, ws_value);
 		results[0].of.i32 = PROXY_OK;
 		return (NULL);
 	}