patch for graphics/gif2png

[Jona Joachim]

Little patch for graphics/gif2png, prodded by
http://article.gmane.org/gmane.comp.security.full-disclosure/70757


Best regards,
Jona

-- 
Worse is better
    Richard P. Gabriel

$OpenBSD$
--- gif2png.c.orig      Fri May 10 16:06:02 2002
+++ gif2png.c   Sun Dec 13 20:33:25 2009
@@ -697,24 +697,24 @@ int processfile(char *fname, FILE *fp)
 
     /* create output filename */
 
-    strcpy(outname, fname);
+    strlcpy(outname, fname, sizeof(outname));
 
     file_ext = outname+strlen(outname)-4;
     if (strcmp(file_ext, ".gif") != 0 && strcmp(file_ext, ".GIF") != 0 &&
-       strcmp(file_ext, "_gif") != 0 && strcmp(file_ext, "_GIF") != 0) {
-       /* try to derive basename */
-       file_ext = outname+strlen(outname);
-       while(file_ext >= outname) {
-           if (*file_ext == '.' || *file_ext == '/' || *file_ext == '\\') 
break;
-           file_ext--;
-       }
-       if (file_ext<outname || *file_ext != '.') {
-           /* as a last resort, just add .png to the filename */
-           file_ext = outname+strlen(outname);
-       }
+    strcmp(file_ext, "_gif") != 0 && strcmp(file_ext, "_GIF") != 0) {
+    /* try to derive basename */
+    file_ext = outname+strlen(outname);
+    while(file_ext >= outname) {
+        if (*file_ext == '.' || *file_ext == '/' || *file_ext == '\\') break;
+        file_ext--;
     }
+    if (file_ext<outname || *file_ext != '.') {
+        /* as a last resort, just add .png to the filename */
+        file_ext = outname+strlen(outname);
+    }
+    }
 
-    strcpy(file_ext, ".png"); /* images are named .png, .p01, .p02, ... */
+    strlcpy(file_ext, ".png", outname - file_ext); /* images are named .png, 
.p01, .p02, ... */
 
     start = NULL;
 
@@ -732,7 +732,7 @@ int processfile(char *fname, FILE *fp)
                fclose(fp);
                ++numpngs;
                start = NULL;
-               sprintf(file_ext, ".p%02d", i);
+               snprintf(file_ext, outname - file_ext,".p%02d", i);
            }
        }
     }
@@ -898,10 +898,10 @@ int main(int argc, char *argv[])
        }
     } else {
        for (i = ac;i<argc; i++) {
-           strcpy(name, argv[i]);
+           strlcpy(name, argv[i], sizeof(name));
            if ((fp = fopen(name, "rb")) == NULL) {
                /* retry with .gif appended */
-               strcat(name, ".gif");
+               strlcat(name, ".gif", sizeof(name));
                fp = fopen(name,"rb");
            }
            if (fp == NULL) {