1 files changed, 126 insertions, 0 deletions

diff --git a/unzcrash.c b/unzcrash.c
new file mode 100644
index 0000000..f0f17fc
--- /dev/null
+++ b/unzcrash.c
@@ -0,0 +1,126 @@
+
+/* A test program written to test robustness to decompression of
+   corrupted data.  Usage is 
+       unzcrash filename
+   and the program will read the specified file, compress it (in memory),
+   and then repeatedly decompress it, each time with a different bit of
+   the compressed data inverted, so as to test all possible one-bit errors.
+   This should not cause any invalid memory accesses.  If it does, 
+   I want to know about it!
+
+   p.s.  As you can see from the above description, the process is
+   incredibly slow.  A file of size eg 5KB will cause it to run for
+   many hours.
+*/
+
+#include <stdio.h>
+#include <assert.h>
+#include "bzlib.h"
+
+#define M_BLOCK 1000000
+
+typedef unsigned char uchar;
+
+#define M_BLOCK_OUT (M_BLOCK + 1000000)
+uchar inbuf[M_BLOCK];
+uchar outbuf[M_BLOCK_OUT];
+uchar zbuf[M_BLOCK + 600 + (M_BLOCK / 100)];
+
+int nIn, nOut, nZ;
+
+static char *bzerrorstrings[] = {
+       "OK"
+      ,"SEQUENCE_ERROR"
+      ,"PARAM_ERROR"
+      ,"MEM_ERROR"
+      ,"DATA_ERROR"
+      ,"DATA_ERROR_MAGIC"
+      ,"IO_ERROR"
+      ,"UNEXPECTED_EOF"
+      ,"OUTBUFF_FULL"
+      ,"???"   /* for future */
+      ,"???"   /* for future */
+      ,"???"   /* for future */
+      ,"???"   /* for future */
+      ,"???"   /* for future */
+      ,"???"   /* for future */
+};
+
+void flip_bit ( int bit )
+{
+   int byteno = bit / 8;
+   int bitno  = bit % 8;
+   uchar mask = 1 << bitno;
+   //fprintf ( stderr, "(byte %d  bit %d  mask %d)",
+   //          byteno, bitno, (int)mask );
+   zbuf[byteno] ^= mask;
+}
+
+int main ( int argc, char** argv )
+{
+   FILE* f;
+   int   r;
+   int   bit;
+   int   i;
+
+   if (argc != 2) {
+      fprintf ( stderr, "usage: unzcrash filename\n" );
+      return 1;
+   }
+
+   f = fopen ( argv[1], "r" );
+   if (!f) {
+      fprintf ( stderr, "unzcrash: can't open %s\n", argv[1] );
+      return 1;
+   }
+
+   nIn = fread ( inbuf, 1, M_BLOCK, f );
+   fprintf ( stderr, "%d bytes read\n", nIn );
+
+   nZ = M_BLOCK;
+   r = BZ2_bzBuffToBuffCompress (
+         zbuf, &nZ, inbuf, nIn, 9, 0, 30 );
+
+   assert (r == BZ_OK);
+   fprintf ( stderr, "%d after compression\n", nZ );
+
+   for (bit = 0; bit < nZ*8; bit++) {
+      fprintf ( stderr, "bit %d  ", bit );
+      flip_bit ( bit );
+      nOut = M_BLOCK_OUT;
+      r = BZ2_bzBuffToBuffDecompress (
+            outbuf, &nOut, zbuf, nZ, 0, 0 );
+      fprintf ( stderr, " %d  %s ", r, bzerrorstrings[-r] );
+
+      if (r != BZ_OK) {
+         fprintf ( stderr, "\n" );
+      } else {
+         if (nOut != nIn) {
+           fprintf(stderr, "nIn/nOut mismatch %d %d\n", nIn, nOut );
+           return 1;
+         } else {
+           for (i = 0; i < nOut; i++)
+             if (inbuf[i] != outbuf[i]) { 
+                fprintf(stderr, "mismatch at %d\n", i ); 
+                return 1; 
+           }
+           if (i == nOut) fprintf(stderr, "really ok!\n" );
+         }
+      }
+
+      flip_bit ( bit );
+   }
+
+#if 0
+   assert (nOut == nIn);
+   for (i = 0; i < nOut; i++) {
+     if (inbuf[i] != outbuf[i]) {
+        fprintf ( stderr, "difference at %d !\n", i );
+        return 1;
+     }
+   }
+#endif
+
+   fprintf ( stderr, "all ok\n" );
+   return 0;
+}