added check if input is not binary

include/pcp/z85.h

@@ -23,6 +23,8 @@
 /*  from https://github.com/tlinden/curve-keygen/ */
 #ifndef _HAVE_PCP_Z85_H
 
+#include <ctype.h>
+
 #include "defines.h"
 #include "zmq_z85.h"
 #include "mem.h"
@@ -44,4 +46,6 @@ char *pcp_z85_encode(unsigned char *raw, size_t srclen, size_t *dstlen);
 char *pcp_readz85file(FILE *infile);
 char *pcp_readz85string(unsigned char *input, size_t bufsize);
 
+size_t _buffer_is_binary(unsigned char *buf, size_t len);
+
 #endif /*  _HAVE_PCP_Z85_H */

libpcp/z85.c

@@ -22,6 +22,20 @@
 
 #include "z85.h"
 
+size_t _buffer_is_binary(unsigned char *buf, size_t len) {
+  size_t pos;
+  for (pos=0; pos<len; ++pos) {
+    if(buf[pos] == '\0' || (buf[pos] != '\r' && buf[pos] != '\n' && isprint(buf[pos]) == 0)) {
+      break;
+    }
+  }
+  if(pos < len)
+    return pos;
+  else
+    return 0;
+}
+
+
 unsigned char *pcp_padfour(unsigned char *src, size_t srclen, size_t *dstlen) {
   size_t outlen, zerolen;
   unsigned char *dst;
@@ -145,6 +159,16 @@ char *pcp_readz85string(unsigned char *input, size_t bufsize) {
   int i;
   size_t MAXLINE = 1024;
 
+  if(bufsize == 0) {
+    fatal("Input file is empty!\n");
+    return NULL;
+  }
+
+  if(_buffer_is_binary(input, bufsize) > 0) {
+    fatal("input is not z85 encoded and contains pure binary data");
+    return NULL;
+  }
+
   Buffer *z = buffer_new(MAXLINE, "z");
   Buffer *line = buffer_new(MAXLINE, "line");
   char *oneline;