Use -Wshorten-64-to-32 if it's available, and fix warnings it shows.

Probably harmless, but do it to help catch some issues on LP64 (64-bit
UN*X) or LLP64 (64-bit Windows) platforms when compiling on macOS.

10 files changed, 133 insertions, 14 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 95a0f88a..497ef607 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1676,6 +1676,7 @@ if(EXISTS ${CMAKE_SOURCE_DIR}/.devel OR EXISTS ${CMAKE_BINARY_DIR}/.devel)
         check_and_add_compiler_option(-Wmissing-variable-declarations)
         check_and_add_compiler_option(-Wshadow)
         check_and_add_compiler_option(-Wsign-compare)
+        check_and_add_compiler_option(-Wshorten-64-to-32)
         check_and_add_compiler_option(-Wstrict-prototypes)
         check_and_add_compiler_option(-Wunreachable-code)
         check_and_add_compiler_option(-Wunused-parameter)
diff --git a/aclocal.m4 b/aclocal.m4
index af34a796..807e74b1 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -830,6 +830,7 @@ testme(unsigned short a)
 }
 		      ],
 		      [generates warnings from ntohs()])
+		    AC_LBL_CHECK_COMPILER_OPT($1, -Wshorten-64-to-32)
 	    fi
 	    AC_LBL_CHECK_DEPENDENCY_GENERATION_OPT()
 	    #
diff --git a/configure b/configure
index 5d6cd825..37575a49 100755
--- a/configure
+++ b/configure
@@ -9770,6 +9770,88 @@ $as_echo "no" >&6; }
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
+
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports the -Wshorten-64-to-32 option" >&5
+$as_echo_n "checking whether the compiler supports the -Wshorten-64-to-32 option... " >&6; }
+	save_CFLAGS="$CFLAGS"
+	if expr "x-Wshorten-64-to-32" : "x-W.*" >/dev/null
+	then
+	    CFLAGS="$CFLAGS $ac_lbl_unknown_warning_option_error -Wshorten-64-to-32"
+	elif expr "x-Wshorten-64-to-32" : "x-f.*" >/dev/null
+	then
+	    CFLAGS="$CFLAGS -Werror -Wshorten-64-to-32"
+	elif expr "x-Wshorten-64-to-32" : "x-m.*" >/dev/null
+	then
+	    CFLAGS="$CFLAGS -Werror -Wshorten-64-to-32"
+	else
+	    CFLAGS="$CFLAGS -Wshorten-64-to-32"
+	fi
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+return 0
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+		can_add_to_cflags=yes
+		#
+		# The compile supports this; do we have some C code for
+		# which the warning should *not* appear?
+		# We test the fourth argument because the third argument
+		# could contain quotes, breaking the test.
+		#
+		if test "x" != "x"
+		then
+		    CFLAGS="$CFLAGS $ac_lbl_cc_force_warning_errors"
+		    { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether -Wshorten-64-to-32 " >&5
+$as_echo_n "checking whether -Wshorten-64-to-32 ... " >&6; }
+		    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+			#
+			# Not a problem.
+			#
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+else
+
+			#
+			# A problem.
+			#
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+			can_add_to_cflags=no
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+		fi
+		CFLAGS="$save_CFLAGS"
+		if test x"$can_add_to_cflags" = "xyes"
+		then
+		    V_CCOPT="$V_CCOPT -Wshorten-64-to-32"
+		fi
+
+else
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+		CFLAGS="$save_CFLAGS"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
 	    fi
 
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports generating dependencies" >&5
diff --git a/gencode.c b/gencode.c
index 42c3bdcb..0f006411 100644
--- a/gencode.c
+++ b/gencode.c
@@ -6181,13 +6181,13 @@ gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
 			 */
 			b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS);
 			/* OSI in C-HDLC is stuffed with a fudge byte */
-			b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (long)v);
+			b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (bpf_int32)v);
 			gen_and(b0, b1);
 			return b1;
 
 		default:
 			b0 = gen_linktype(cstate, LLCSAP_ISONS);
-			b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (long)v);
+			b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (bpf_int32)v);
 			gen_and(b0, b1);
 			return b1;
 		}
@@ -6198,7 +6198,7 @@ gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
 		 * 4 is the offset of the PDU type relative to the IS-IS
 		 * header.
 		 */
-		b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (long)v);
+		b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (bpf_int32)v);
 		gen_and(b0, b1);
 		return b1;
 
diff --git a/pcap-bpf.c b/pcap-bpf.c
index 5e9f6899..8a8e8a15 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -974,7 +974,7 @@ pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 		} else
 #endif
 		{
-			cc = read(p->fd, p->buffer, p->bufsize);
+			cc = (int)read(p->fd, p->buffer, p->bufsize);
 		}
 		if (cc < 0) {
 			/* Don't choke when we get ptraced */
@@ -1076,7 +1076,7 @@ pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 		 */
 		if (p->break_loop) {
 			p->bp = bp;
-			p->cc = ep - bp;
+			p->cc = (int)(ep - bp);
 			/*
 			 * ep is set based on the return value of read(),
 			 * but read() from a BPF device doesn't necessarily
@@ -1166,7 +1166,7 @@ pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 			bp += BPF_WORDALIGN(caplen + hdrlen);
 			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 				p->bp = bp;
-				p->cc = ep - bp;
+				p->cc = (int)(ep - bp);
 				/*
 				 * See comment above about p->cc < 0.
 				 */
@@ -1189,7 +1189,17 @@ pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 static int
 pcap_inject_bpf(pcap_t *p, const void *buf, size_t size)
 {
-	int ret;
+	ssize_t ret;
+
+	/*
+	 * We return the number of bytes written, so the number of
+	 * bytes to write must fit in an int.
+	 */
+	if (size > INT_MAX) {
+		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+		    errno, "More than %d bytes cannot be injected", INT_MAX);
+		return (PCAP_ERROR);
+	}
 
 	ret = write(p->fd, buf, size);
 #ifdef __APPLE__
@@ -1231,7 +1241,7 @@ pcap_inject_bpf(pcap_t *p, const void *buf, size_t size)
 		    errno, "send");
 		return (PCAP_ERROR);
 	}
-	return (ret);
+	return ((int)ret);
 }
 
 #ifdef _AIX
diff --git a/pcap-rpcap.c b/pcap-rpcap.c
index 21d4a23e..a35eaf24 100644
--- a/pcap-rpcap.c
+++ b/pcap-rpcap.c
@@ -388,7 +388,7 @@ static int pcap_read_nocb_remote(pcap_t *p, struct pcap_pkthdr *pkt_header, u_ch
 	 * 'timeout', in pcap_t, is in milliseconds; we have to convert it into sec and microsec
 	 */
 	tv.tv_sec = p->opt.timeout / 1000;
-	tv.tv_usec = (p->opt.timeout - tv.tv_sec * 1000) * 1000;
+	tv.tv_usec = (suseconds_t)((p->opt.timeout - tv.tv_sec * 1000) * 1000);
 
 	/* Watch out sockdata to see if it has input */
 	FD_ZERO(&rfds);
diff --git a/rpcapd/daemon.c b/rpcapd/daemon.c
index e7cef199..27662fd5 100644
--- a/rpcapd/daemon.c
+++ b/rpcapd/daemon.c
@@ -39,6 +39,7 @@
 #include <errno.h>		// for the errno variable
 #include <stdlib.h>		// for malloc(), free(), ...
 #include <string.h>		// for strlen(), ...
+#include <limits.h>		// for INT_MAX
 
 #ifdef _WIN32
   #include <process.h>		// for threads
@@ -2270,7 +2271,21 @@ daemon_thrdatamain(void *ptr)
 	//
 	// So we don't need to make sure that sendbufsize will overflow.
 	//
+	// However, we *do* need to make sure its value fits in an int,
+	// because sock_send() can't send more than INT_MAX bytes (it could
+	// do so on 64-bit UN*Xes, but can't do so on Windows, not even
+	// 64-bit Windows, as the send() buffer size argument is an int
+	// in Winsock).
+	//
 	sendbufsize = sizeof(struct rpcap_header) + sizeof(struct rpcap_pkthdr) + pcap_snapshot(session->fp);
+	if (sendbufsize > INT_MAX)
+	{
+		rpcapd_log(LOGPRIO_ERROR,
+		    "Buffer size for this child thread would be larger than %d",
+		    INT_MAX);
+		sendbuf = NULL;	// we haven't allocated a buffer, so nothing to free
+		goto error;
+	}
 	sendbuf = (char *) malloc (sendbufsize);
 	if (sendbuf == NULL)
 	{
@@ -2311,7 +2326,7 @@ daemon_thrdatamain(void *ptr)
 
 		// Bufferize the general header
 		if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
-		    &sendbufidx, sendbufsize, SOCKBUF_CHECKONLY, errbuf,
+		    &sendbufidx, (int)sendbufsize, SOCKBUF_CHECKONLY, errbuf,
 		    PCAP_ERRBUF_SIZE) == -1)
 		{
 			rpcapd_log(LOGPRIO_ERROR,
@@ -2328,7 +2343,7 @@ daemon_thrdatamain(void *ptr)
 
 		// Bufferize the pkt header
 		if (sock_bufferize(NULL, sizeof(struct rpcap_pkthdr), NULL,
-		    &sendbufidx, sendbufsize, SOCKBUF_CHECKONLY, errbuf,
+		    &sendbufidx, (int)sendbufsize, SOCKBUF_CHECKONLY, errbuf,
 		    PCAP_ERRBUF_SIZE) == -1)
 		{
 			rpcapd_log(LOGPRIO_ERROR,
@@ -2345,7 +2360,7 @@ daemon_thrdatamain(void *ptr)
 
 		// Bufferize the pkt data
 		if (sock_bufferize((char *) pkt_data, pkt_header->caplen,
-		    sendbuf, &sendbufidx, sendbufsize, SOCKBUF_BUFFERIZE,
+		    sendbuf, &sendbufidx, (int)sendbufsize, SOCKBUF_BUFFERIZE,
 		    errbuf, PCAP_ERRBUF_SIZE) == -1)
 		{
 			rpcapd_log(LOGPRIO_ERROR,
diff --git a/rpcapd/fileconf.c b/rpcapd/fileconf.c
index ab1e9dd3..5b896086 100644
--- a/rpcapd/fileconf.c
+++ b/rpcapd/fileconf.c
@@ -202,7 +202,7 @@ static int strrem(char *string, char chr)
 {
 	char *pos;
 	int num = 0;
-	int len, i;
+	size_t len, i;
 
 	while ((pos = strchr(string, chr)) != NULL)
 	{
diff --git a/sf-pcap.c b/sf-pcap.c
index b3260f9d..9e52a8bb 100644
--- a/sf-pcap.c
+++ b/sf-pcap.c
@@ -731,7 +731,11 @@ pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 	struct pcap_sf_pkthdr sf_hdr;
 
 	f = (FILE *)user;
-	sf_hdr.ts.tv_sec  = h->ts.tv_sec;
+	/*
+	 * Better not try writing pcap files after
+	 * 2038-01-19 03:14:07 UTC; switch to pcapng.
+	 */
+	sf_hdr.ts.tv_sec  = (bpf_int32)h->ts.tv_sec;
 	sf_hdr.ts.tv_usec = h->ts.tv_usec;
 	sf_hdr.caplen     = h->caplen;
 	sf_hdr.len        = h->len;
diff --git a/sockutils.h b/sockutils.h
index 1df1ef7b..d3299eaf 100644
--- a/sockutils.h
+++ b/sockutils.h
@@ -53,6 +53,12 @@
    * don't have it, either?
    */
   typedef int socklen_t;
+
+  /*
+   * Winsock doesn't have this POSIX type; it's used for the
+   * tv_usec value of struct timeval.
+   */
+  typedef long suseconds_t;
 #else
   /* UN*X */
   #include <stdio.h>