--- bzip2/bzip2recover.c

+++ bzip2/bzip2recover.c

@@ -24,10 +24,20 @@

 #include <config.h>

 #endif

+#define BZ_UNIX      1

+#if defined(_WIN32) && !defined(__CYGWIN__)

+# undef  BZ_UNIX

+# define BZ_UNIX 0

+#endif

+

 #include <stdio.h>

 #include <errno.h>

 #include <stdlib.h>

 #include <string.h>

+#if BZ_UNIX

+# include <unistd.h>

+# include <fcntl.h>

+#endif

 /* This program records bit locations in the file to be recovered.

@@ -274,6 +284,33 @@ static Bool endsInBz2 ( Char* name )

 }

+/*---------------------------------------------*/

+/* Open an output file safely with O_EXCL and good permissions.

+   This avoids a race condition in older versions, in which

+   the file was first opened and then had its interim permissions

+   set safely.  We instead use open() to create the file with

+   the interim permissions required (rw-------).

+

+   For non-Unix platforms, if we are not worrying about

+   security issues, this simply behaves like fopen.

+*/

+static

+FILE* fopen_output_safely ( Char* name, const char* mode )

+{

+#if BZ_UNIX

+   FILE* fp;

+   int fh;

+   fh = open(name, O_WRONLY|O_CREAT|O_EXCL, S_IWUSR|S_IRUSR);

+   if (fh == -1) return NULL;

+   fp = fdopen(fh, mode);

+   if (fp == NULL) close(fh);

+   return fp;

+#else

+   return fopen(name, mode);

+#endif

+}

+

+

 /*---------------------------------------------------*/

 /*---                                             ---*/

 /*---------------------------------------------------*/

@@ -490,7 +527,7 @@ Int32 main ( Int32 argc, Char** argv )

          fprintf ( stderr, "   writing block %d to `%s' ...\n",

                            wrBlock+1, outFileName );

-         outFile = fopen ( outFileName, "wb" );

+         outFile = fopen_output_safely ( outFileName, "wb" );

          if (outFile == NULL) {

             fprintf ( stderr, "%s: can't write `%s'\n",

                       progName, outFileName );