From 64cc4714abd0d616327bfacdfc1b0fb45bff096e Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Sun, 17 Jan 2021 20:42:10 +0000
Subject: [PATCH] malware: use sendfile for ClamAV TCP

---
 src/src/malware.c | 47 +++++++++++++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/src/src/malware.c b/src/src/malware.c
index abe627ded..7c134d759 100644
--- a/src/src/malware.c
+++ b/src/src/malware.c
@@ -1559,10 +1559,7 @@ badseek:  err = errno;
       if (!use_scan_command)
 	{ cmd_str.data = US"zINSTREAM"; cmd_str.len = 10; }
       else
-	{
-	cmd_str.data = string_sprintf("SCAN %s\n", eml_filename);
-	cmd_str.len = Ustrlen(cmd_str.data);
-	}
+	cmd_str.data = string_sprintf("SCAN %s\n%n", eml_filename, &cmd_str.len);
 
       /* We have some network servers specified */
       if (num_servers)
@@ -1583,13 +1580,14 @@ badseek:  err = errno;
 	  on both connections (as one host could resolve to multiple ips) */
 	  for (;;)
 	    {
-	    /*XXX we trust that the cmd_str is ideempotent */
+	    /*XXX we trust that the cmd_str is idempotent */
 	    if ((malware_daemon_ctx.sock = m_tcpsocket(cd->hostspec, cd->tcp_port,
-				    &connhost, &errstr, &cmd_str)) >= 0)
+				    &connhost, &errstr,
+				    use_scan_command ? &cmd_str : NULL)) >= 0)
 	      {
 	      /* Connection successfully established with a server */
 	      hostname = cd->hostspec;
-	      cmd_str.len = 0;
+	      if (use_scan_command) cmd_str.len = 0;
 	      break;
 	      }
 	    if (cd->retry <= 0) break;
@@ -1630,17 +1628,21 @@ badseek:  err = errno;
       if (!use_scan_command)
 	{
 	struct stat st;
-#ifdef EXIM_TCP_CORK
+#if defined(EXIM_TCP_CORK) && !defined(OS_SENDFILE)
 	BOOL corked = TRUE;
 #endif
 	/* New protocol: "zINSTREAM\n" followed by a sequence of <length><data>
 	chunks, <n> a 4-byte number (network order), terminated by a zero-length
-	chunk. */
+	chunk. We only send one chunk. */
 
 	DEBUG(D_acl) debug_printf_indent(
 	    "Malware scan: issuing %s new-style remote scan (zINSTREAM)\n",
 	    scanner_name);
 
+#if defined(EXIM_TCP_CORK)
+	(void) setsockopt(malware_daemon_ctx.sock, IPPROTO_TCP, EXIM_TCP_CORK,
+			  US &on, sizeof(on));
+#endif
 	/* Pass the string to ClamAV (10 = "zINSTREAM\0"), if not already sent */
 	if (cmd_str.len)
 	  if (send(malware_daemon_ctx.sock, cmd_str.data, cmd_str.len, 0) < 0)
@@ -1676,10 +1678,6 @@ badseek:  err = errno;
 	  }
 
 	/* send file size */
-#ifdef EXIM_TCP_CORK
-	(void) setsockopt(malware_daemon_ctx.sock, IPPROTO_TCP, EXIM_TCP_CORK,
-			  US &on, sizeof(on));
-#endif
 	send_size = htonl(fsize_uint);
 	if (send(malware_daemon_ctx.sock, &send_size, sizeof(send_size), 0) < 0)
 	  return m_panic_defer_3(scanent, NULL,
@@ -1687,10 +1685,17 @@ badseek:  err = errno;
 	    malware_daemon_ctx.sock);
 
 	/* send file body */
-	/*XXX sendfile? */
 	while (fsize_uint)
 	  {
-	  unsigned n = MIN(fsize_uint, big_buffer_size);
+#ifdef OS_SENDFILE
+	  int n = os_sendfile(malware_daemon_ctx.sock, clam_fd, NULL, (size_t)fsize_uint);
+	  if (n < 0)
+	    return m_panic_defer_3(scanent, NULL,
+	      string_sprintf("unable to send file body to socket (%s): %s", hostname, strerror(errno)),
+	      malware_daemon_ctx.sock);
+	  fsize_uint -= n;
+#else
+	  int n = MIN(fsize_uint, big_buffer_size);
 	  if ((n = read(clam_fd, big_buffer, n)) < 0)
 	    return m_panic_defer_3(scanent, NULL,
 	      string_sprintf("can't read spool file %s: %s",
@@ -1701,14 +1706,16 @@ badseek:  err = errno;
 	      string_sprintf("unable to send file body to socket (%s): %s", hostname, strerror(errno)),
 	      malware_daemon_ctx.sock);
 	  fsize_uint -= n;
-#ifdef EXIM_TCP_CORK
+# ifdef EXIM_TCP_CORK
 	  if (corked)
 	    {
 	    corked = FALSE;
 	    (void) setsockopt(malware_daemon_ctx.sock, IPPROTO_TCP, EXIM_TCP_CORK,
 			      US &off, sizeof(off));
 	    }
-#endif
+# endif
+#endif	/*!OS_SENDFILE*/
+
 	  }
 
 	send_final_zeroblock = 0;
@@ -1716,11 +1723,15 @@ badseek:  err = errno;
 	  return m_panic_defer_3(scanent, NULL,
 	    string_sprintf("unable to send file terminator to socket (%s)", hostname),
 	    malware_daemon_ctx.sock);
+#ifdef OS_SENDFILE
+	(void) setsockopt(malware_daemon_ctx.sock, IPPROTO_TCP, EXIM_TCP_CORK,
+			  US &off, sizeof(off));
+#endif
 	}
       else
 	{ /* use scan command */
 	/* Send a SCAN command pointing to a filename; then in the then in the
-	 * scan-method-neutral part, read the response back */
+	scan-method-neutral part, read the response back */
 
 /* ================================================================= */
 
-- 
2.30.2