Under several circumstances, overly large filenames (or overly long command
line arguments) cause buffer overflows due to the lack of bounds checking in
the original xv source code. This patch is a first pass attempt at fixing that.

Signed-off-by: Gabriel Somlo <somlo@cmu.edu>

diff -NarU5 a/xv.c b/xv.c
--- a/xv.c	2013-03-28 12:59:56.364082302 -0400
+++ b/xv.c	2013-03-28 13:22:10.312576922 -0400
@@ -62,11 +62,11 @@
 static double vexpand = 1.0;    /* '-expand' argument */
 static const char *maingeom = NULL;
 static const char *icongeom = NULL;
 static Atom   __SWM_VROOT = None;
 
-static char   basefname[128];   /* just the current fname, no path */
+static char   basefname[NAME_MAX+1];   /* just the current fname, no path */
 
 #ifdef TV_L10N
 #  ifndef TV_FONTSET
 #    define TV_FONTSET "-*-fixed-medium-r-normal--%d-*"
 #  endif
@@ -2167,15 +2167,17 @@
   else if (filenum == PADDED) {
     /* need fullfname (used for window/icon name),
        basefname(compute from fullfname) */
 
     i = LoadPad(&pinfo, fullfname);
+    if (!i) goto FAILED;   /* shouldn't happen */
+
     fullname = fullfname;
     strcpy(filename, fullfname);
+    if (strlen(BaseName(fullfname)) > NAME_MAX) goto FAILED;
     strcpy(basefname, BaseName(fullfname));
 
-    if (!i) goto FAILED;   /* shouldn't happen */
 
     if (killpage) {      /* kill old page files, if any */
       KillPageFiles(pageBaseName, numPages);
       pageBaseName[0] = '\0';
       numPages = 1;
@@ -2236,10 +2238,11 @@
 #else
   else fullname = namelist[filenum];
 #endif
 
   strcpy(fullfname, fullname);
+  if (strlen(BaseName(fullfname)) > NAME_MAX) goto FAILED;
   strcpy(basefname, BaseName(fullname));
 
 
   /* chop off trailing ".Z", ".z", or ".gz" from displayed basefname, if any */
   if (strlen(basefname)>2 && strcmp(basefname+strlen(basefname)-2,".Z")==0)
@@ -3998,11 +4001,11 @@
 
 /***********************************/
 static void setWinIconNames(name)
      const char *name;
 {
-  char winname[256], iconname[256];
+  char winname[NAME_MAX+sizeof("xv : ")+sizeof(VERSTR)+sizeof(" <unregistered>")+1], iconname[NAME_MAX+1];
 
   if (winTitle) {
     strcpy(winname, winTitle);
     strcpy(iconname, winTitle);
   }
diff -NarU5 a/xvtext.c b/xvtext.c
--- a/xvtext.c	2013-03-28 12:59:56.400084367 -0400
+++ b/xvtext.c	2013-03-28 13:02:26.056666623 -0400
@@ -51,11 +51,11 @@
 #  define TV_MSCODE   7
 
 #  define TV_J_NBUTTS 8
 #endif
 
-#define TITLELEN 128
+#define TITLELEN (NAME_MAX+sizeof("File: ''")+1)
 
 #ifdef TV_MULTILINGUAL
 struct coding_spec {
     struct coding_system coding_system;
     char *(*converter)PARM((char *, int, int *));