fix(squid): run Squid container as non-root user

containers/squid/Dockerfile

@@ -1,19 +1,20 @@
 FROM ubuntu/squid:latest
 
 # Install additional tools for debugging, healthcheck, and SSL Bump
+# gosu is used to drop from root to proxy user after permission setup
 # Retry logic handles transient 404s when Ubuntu archive supersedes package versions mid-build
 RUN set -eux; \
-    PKGS="curl dnsutils net-tools netcat-openbsd openssl squid-openssl"; \
+    PKGS="curl dnsutils gosu net-tools netcat-openbsd openssl squid-openssl"; \
     apt-get update && \
     apt-get install -y --only-upgrade gpgv && \
     ( apt-get install -y --no-install-recommends $PKGS || \
       (rm -rf /var/lib/apt/lists/* && apt-get update && \
        apt-get install -y --no-install-recommends $PKGS) ) && \
     rm -rf /var/lib/apt/lists/*
 
-# Create log directory and SSL database directory
-RUN mkdir -p /var/log/squid && \
-    chown -R proxy:proxy /var/log/squid
+# Create log directory and SSL database directory, ensure proxy user owns them
+RUN mkdir -p /var/log/squid /var/spool/squid /var/run/squid && \
+    chown -R proxy:proxy /var/log/squid /var/spool/squid /var/run/squid /etc/squid
 
 # Copy entrypoint script
 COPY entrypoint.sh /usr/local/bin/entrypoint.sh

containers/squid/entrypoint.sh

@@ -19,5 +19,11 @@ if [ -d "/var/spool/squid_ssl_db" ]; then
   echo "[squid-entrypoint] SSL certificate database ready"
 fi
 
-# Start Squid
-exec squid -N -d 1
+# Ensure Squid config directory and run directory are writable by proxy
+chown -R proxy:proxy /etc/squid /var/run/squid /var/spool/squid 2>/dev/null || true
+
+# Ensure pid file is writable by proxy user (default: /run/squid.pid)
+touch /run/squid.pid && chown proxy:proxy /run/squid.pid
+
+# Drop to proxy user and start Squid
+exec gosu proxy squid -N -d 1

src/docker-manager.test.ts

@@ -2008,11 +2008,11 @@ describe('docker-manager', () => {
         // May fail after writing configs
       }
 
-      // Verify squid.conf has restricted permissions
+      // Verify squid.conf is readable by proxy user (0o644) for non-root Squid
       const squidConfPath = path.join(testDir, 'squid.conf');
       if (fs.existsSync(squidConfPath)) {
         const stats = fs.statSync(squidConfPath);
-        expect((stats.mode & 0o777).toString(8)).toBe('600');
+        expect((stats.mode & 0o777).toString(8)).toBe('644');
       }
 
       // Verify docker-compose.yml has restricted permissions

src/docker-manager.ts

@@ -1254,7 +1254,7 @@ export async function writeConfigs(config: WrapperConfig): Promise<void> {
     allowHostPorts: config.allowHostPorts,
   });
   const squidConfigPath = path.join(config.workDir, 'squid.conf');
-  fs.writeFileSync(squidConfigPath, squidConfig, { mode: 0o600 });
+  fs.writeFileSync(squidConfigPath, squidConfig, { mode: 0o644 });
   logger.debug(`Squid config written to: ${squidConfigPath}`);
 
   // Write Docker Compose config