Commit 2188de4f authored by unknown's avatar unknown
Browse files

Bug#26233 very suspect code in mf_tempfile.c, in function create_temp_file() 

 - Rework the windows implementation in 'create_temp_file' to be
   thread safe by using GetTempFileName instad of fiddling
   with "environ"


mysys/mf_tempfile.c:
  - Update windows implementation  of 'create_temp_file' to use
    GetTempFileName in favor of fiddeling with "environ" in an unsafe way
  - Remove the implementation that is supposed to be used if not
    windows, not mkstemp or tmpnam exists as it not longer compiles it
    can't be used anywhere.
  - Update function comment for 'create_temp_file'
mysys/my_static.c:
  Remove unused variable
mysys/my_static.h:
  Remove unused variable
parent d6bd171f

mysys/mf_tempfile.c

+61 −84
Original line number Diff line number Diff line
@@ -22,15 +22,36 @@ 
#include <paths.h>

#endif



#ifdef HAVE_TEMPNAM

#if !defined(MSDOS) && !defined(OS2) && !defined(__NETWARE__)

extern char **environ;

#endif

#endif





/*

  Create a temporary file in a given directory

  This function should be used instead of my_tempnam() !

  @brief

  Create a temporary file with unique name in a given directory



  @details

  create_temp_file

    to             pointer to buffer where temporary filename will be stored

    dir            directory where to create the file

    prefix         prefix the filename with this

    mode           Flags to use for my_create/my_open

    MyFlags        Magic flags



  @return

    File descriptor of opened file if success

    -1 and sets errno if fails.



  @note

    The behaviour of this function differs a lot between

    implementation, it's main use is to generate a file with

    a name that does not already exist.



    When passing O_TEMPORARY flag in "mode" the file should

    be automatically deleted



    The implementation using mkstemp should be considered the

    reference implementation when adding a new or modifying an

    existing one



*/



File create_temp_file(char *to, const char *dir, const char *prefix,
@@ -38,41 +59,33 @@ File create_temp_file(char *to, const char *dir, const char *prefix, 
		      myf MyFlags __attribute__((unused)))

{

  File file= -1;



  DBUG_ENTER("create_temp_file");

#if defined(_MSC_VER)

  {

    char temp[FN_REFLEN],*end,*res,**old_env,*temp_env[1];

    old_env=environ;

    if (dir)

    {

      end=strend(dir)-1;

      if (!dir[0])

      {				/* Change empty string to current dir */

	to[0]= FN_CURLIB;

	to[1]= 0;

	dir=to;

      }

      else if (*end == FN_DEVCHAR)

      {				/* Get current dir for drive */

	_fullpath(temp,dir,FN_REFLEN);

	dir=to;

      }

      else if (*end == FN_LIBCHAR && dir < end && end[-1] != FN_DEVCHAR)

      {

	strmake(to,dir,(uint) (end-dir));	/* Copy and remove last '\' */

	dir=to;

      }

      environ=temp_env;		/* Force use of dir (dir not checked) */

      temp_env[0]=0;

    }

    if ((res=tempnam((char*) dir,(char *) prefix)))

  DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir, prefix));

#if defined (__WIN__)



   /*

     Use GetTempFileName to generate a unique filename, create

     the file and release it's handle

      - uses up to the first three letters from prefix

   */

  if (GetTempFileName(dir, prefix, 0, to) == 0)

    DBUG_RETURN(-1);



  DBUG_PRINT("info", ("name: %s", to));



  /*

    Open the file without the "open only if file doesn't already exist"

    since the file has already been created by GetTempFileName

  */

  if ((file= my_open(to,  (mode & ~O_EXCL), MyFlags)) < 0)

  {

      strmake(to,res,FN_REFLEN-1);

      (*free)(res);

      file=my_create(to,0, mode | O_EXCL | O_NOFOLLOW, MyFlags);

    }

    environ=old_env;

    /* Open failed, remove the file created by GetTempFileName */

    int tmp= my_errno;

    (void) my_delete(to, MYF(0));

    my_errno= tmp;

  }



#elif defined(_ZTC__)

  if (!dir)

    dir=getenv("TMPDIR");
@@ -101,6 +114,8 @@ File create_temp_file(char *to, const char *dir, const char *prefix, 
    }

    strmov(convert_dirname(to,dir,NullS),prefix_buff);

    org_file=mkstemp(to);

    if (mode & O_TEMPORARY)

      (void) my_delete(to, MYF(MY_WME | ME_NOINPUT));

    file=my_register_filename(org_file, to, FILE_BY_MKSTEMP,

			      EE_CANTCREATEFILE, MyFlags);

    /* If we didn't manage to register the name, remove the temp file */
@@ -113,6 +128,10 @@ File create_temp_file(char *to, const char *dir, const char *prefix, 
  }

#elif defined(HAVE_TEMPNAM)

  {

#if !defined(__NETWARE__)

    extern char **environ;

#endif



    char *res,**old_env,*temp_env[1];

    if (dir && !dir[0])

    {				/* Change empty string to current dir */
@@ -120,16 +139,7 @@ File create_temp_file(char *to, const char *dir, const char *prefix, 
      to[1]= 0;

      dir=to;

    }

#ifdef OS2

    /* changing environ variable doesn't work with VACPP */

    char  buffer[256], *end;

    buffer[sizeof(buffer)-1]= 0;

    end= strxnmov(buffer, sizeof(buffer)-1, (char*) "TMP=", dir, NullS);

    /* remove ending backslash */

    if (end[-1] == '\\')

      end[-1]= 0;

    putenv(buffer);

#elif !defined(__NETWARE__)

#if !defined(__NETWARE__)

    old_env= (char**) environ;

    if (dir)

    {				/* Don't use TMPDIR if dir is given */
@@ -151,45 +161,12 @@ File create_temp_file(char *to, const char *dir, const char *prefix, 
    {

      DBUG_PRINT("error",("Got error: %d from tempnam",errno));

    }

#if !defined(OS2) && !defined(__NETWARE__)

#if !defined(__NETWARE__)

    environ=(const char**) old_env;

#endif

  }

#else

  {

    register long uniq;

    register int length;

    my_string pos,end_pos;

    /* Make an unique number */

    pthread_mutex_lock(&THR_LOCK_open);

    uniq= ((long) getpid() << 20) + (long) _my_tempnam_used++ ;

    pthread_mutex_unlock(&THR_LOCK_open);

    if (!dir && !(dir=getenv("TMPDIR")))	/* Use this if possibly */

      dir=P_tmpdir;			/* Use system default */

    length=strlen(dir)+strlen(pfx)+1;



    DBUG_PRINT("test",("mallocing %d byte",length+8+sizeof(TMP_EXT)+1));

    if (length+8+sizeof(TMP_EXT)+1 > FN_REFLENGTH)

      errno=my_errno= ENAMETOOLONG;

    else

    {

      end_pos=strmov(to,dir);

      if (end_pos != to && end_pos[-1] != FN_LIBCHAR)

	*end_pos++=FN_LIBCHAR;

      end_pos=strmov(end_pos,pfx);



      for (length=0 ; length < 8 && uniq ; length++)

      {

	*end_pos++= _dig_vec_upper[(int) (uniq & 31)];

	uniq >>= 5;

      }

      (void) strmov(end_pos,TMP_EXT);

      file=my_create(to,0,

		     (int) (O_RDWR | O_BINARY | O_TRUNC | O_EXCL | O_NOFOLLOW |

			    O_TEMPORARY | O_SHORT_LIVED),

		     MYF(MY_WME));

    }

  }

#error No implementation found for create_temp_file

#endif

  if (file >= 0)

    thread_safe_increment(my_tmp_file_created,&THR_LOCK_open);

mysys/my_static.c

+0 −5
Original line number Diff line number Diff line
@@ -67,11 +67,6 @@ uint my_once_extra=ONCE_ALLOC_INIT; /* Memory to alloc / block */ 
#ifdef HAVE_LARGE_PAGES

my_bool my_use_large_pages= 0;

uint    my_large_page_size= 0;

#endif



	/* from my_tempnam */

#if !defined(HAVE_TEMPNAM) || defined(HPUX11)

int _my_tempnam_used=0;

#endif



	/* from safe_malloc */

mysys/my_static.h

+0 −4
Original line number Diff line number Diff line
@@ -60,10 +60,6 @@ extern const char *soundex_map; 
extern USED_MEM* my_once_root_block;

extern uint	 my_once_extra;



#if !defined(HAVE_TEMPNAM) || defined(HPUX11)

extern int	_my_tempnam_used;

#endif



extern byte	*sf_min_adress,*sf_max_adress;

extern uint	sf_malloc_count;

extern struct st_irem *sf_malloc_root;