Handle very large -f files by rejecting them.

_read(), on Windows, has a 32-bit size argument and a 32-bit return
value, so reject -f files that have more than 2^31-1 characters.

Add some #defines so that, on Windows, we use _fstati64 to get the size
of that file, to handle large files.

Don't assume that our definition for ssize_t is the same size as size_t;
by the time we want to print the return value of the read, we know it'll
fit into an int, so just cast it to int and print it with %d.

netdissect-stdinc.h

@@ -166,11 +166,17 @@
   #define stat _stat
   #define strdup _strdup
   #define open _open
-  #define fstat _fstat
   #define read _read
   #define close _close
   #define O_RDONLY _O_RDONLY
 
+  /*
+   * We define our_fstat64 as _fstati64, and define our_statb as
+   * struct _stati64, so we get 64-bit file sizes.
+   */
+  #define our_fstat _fstati64
+  #define our_statb struct _stati64
+
   /*
    * If <crtdbg.h> has been included, and _DEBUG is defined, and
    * __STDC__ is zero, <crtdbg.h> will define strdup() to call
@@ -232,6 +238,13 @@ typedef char* caddr_t;
 
 #include <arpa/inet.h>
 
+/*
+ * We should have large file support enabled, if it's available,
+ * so just use fstat as our_fstat and struct stat as our_statb.
+ */
+#define our_fstat fstat
+#define our_statb struct stat
+
 /*
  * Assume all UN*Xes have strtoll(), and use it for strtoint64_t().
  */
@@ -241,7 +254,6 @@ typedef char* caddr_t;
  * Assume LL works.
  */
 #define INT64_T_CONSTANT(constant)	(constant##LL)
-
 #endif /* _WIN32 */
 
 /*

tcpdump.c

@@ -151,6 +151,7 @@ The Regents of the University of California.  All rights reserved.\n";
 #include <sys/sysctl.h>
 #endif /* __FreeBSD__ */
 
+#include "netdissect-stdinc.h"
 #include "netdissect.h"
 #include "interface.h"
 #include "addrtoname.h"
@@ -1065,15 +1066,22 @@ read_infile(char *fname)
 	int i, fd;
 	ssize_t cc;
 	char *cp;
-	struct stat buf;
+	our_statb buf;
 
 	fd = open(fname, O_RDONLY|O_BINARY);
 	if (fd < 0)
 		error("can't open %s: %s", fname, pcap_strerror(errno));
 
-	if (fstat(fd, &buf) < 0)
+	if (our_fstat(fd, &buf) < 0)
 		error("can't stat %s: %s", fname, pcap_strerror(errno));
 
+	/*
+	 * Reject files whose size doesn't fit into an int; a filter
+	 * *that* large will probably be too big.
+	 */
+	if (buf.st_size > INT_MAX)
+		error("%s is too large", fname);
+
 	cp = malloc((u_int)buf.st_size + 1);
 	if (cp == NULL)
 		error("malloc(%d) for %s: %s", (u_int)buf.st_size + 1,
@@ -1082,7 +1090,8 @@ read_infile(char *fname)
 	if (cc < 0)
 		error("read %s: %s", fname, pcap_strerror(errno));
 	if (cc != buf.st_size)
-		error("short read %s (%zd != %d)", fname, cc, (int)buf.st_size);
+		error("short read %s (%d != %d)", fname, (int) cc,
+		    (int)buf.st_size);
 
 	close(fd);
 	/* replace "# comment" with spaces */