glibc/patches/glibc-2.11.1-mktemp_urandom.patch

   1 Submitted By: Robert Connolly <robert at linuxfromscratch dot org> (ashes)
   2 Date: 2010-02-19
   3 Initial Package Version: 2.11.1
   4 Upstream Status: Not Submitted
   5 Origin: Based on http://www.uclibc.org/cgi-bin/viewcvs.cgi/trunk/uClibc/libc/
   6         misc/internals/tempname.c?rev=8887&r1=5747&r2=8887
   7 Description:
   8 Use /dev/urandom exclusively with __gen_tempname(), for the mktemp/tmpnam
   9 family, instead of hp-timing, gettimeofday(), or getpid(). return -1 if
  10 /dev/urandom does not open.
  11
  12 diff -Naur glibc-2.11.1.orig/sysdeps/posix/tempname.c glibc-2.11.1/sysdeps/posix/tempname.c
  13 --- glibc-2.11.1.orig/sysdeps/posix/tempname.c  2009-12-08 20:10:20.000000000 +0000
  14 +++ glibc-2.11.1/sysdeps/posix/tempname.c       2010-02-19 17:36:44.000000000 +0000
  15 @@ -51,10 +51,6 @@
  16  # include <fcntl.h>
  17  #endif
  18
  19 -#if HAVE_SYS_TIME_H || _LIBC
  20 -# include <sys/time.h>
  21 -#endif
  22 -
  23  #if HAVE_STDINT_H || _LIBC
  24  # include <stdint.h>
  25  #endif
  26 @@ -93,11 +89,11 @@
  27  # define struct_stat64 struct stat64
  28  #else
  29  # define struct_stat64 struct stat
  30 -# define __getpid getpid
  31 -# define __gettimeofday gettimeofday
  32  # define __mkdir mkdir
  33  # define __open open
  34  # define __open64 open
  35 +# define __close close
  36 +# define __read read
  37  # define __lxstat64(version, path, buf) lstat (path, buf)
  38  # define __xstat64(version, path, buf) stat (path, buf)
  39  #endif
  40 @@ -106,25 +102,6 @@
  41  # define __secure_getenv getenv
  42  #endif
  43
  44 -#ifdef _LIBC
  45 -# include <hp-timing.h>
  46 -# if HP_TIMING_AVAIL
  47 -#  define RANDOM_BITS(Var) \
  48 -  if (__builtin_expect (value == UINT64_C (0), 0))                           \
  49 -    {                                                                        \
  50 -      /* If this is the first time this function is used initialize          \
  51 -        the variable we accumulate the value in to some somewhat             \
  52 -        random value.  If we'd not do this programs at startup time          \
  53 -        might have a reduced set of possible names, at least on slow         \
  54 -        machines.  */                                                        \
  55 -      struct timeval tv;                                                     \
  56 -      __gettimeofday (&tv, NULL);                                            \
  57 -      value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;                     \
  58 -    }                                                                        \
  59 -  HP_TIMING_NOW (Var)
  60 -# endif
  61 -#endif
  62 -
  63  /* Use the widest available unsigned type if uint64_t is not
  64     available.  The algorithm below extracts a number less than 62**6
  65     (approximately 2**35.725) from uint64_t, so ancient hosts where
  66 @@ -209,6 +186,19 @@
  67  static const char letters[] =
  68  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  69
  70 +static unsigned int fillrand(unsigned char *buf, unsigned int len)
  71 +{
  72 +    int fd;
  73 +    unsigned int result = -1;
  74 +    fd = __open("/dev/urandom", O_RDONLY|O_NONBLOCK|O_NOCTTY);
  75 +    if (fd >= 0)
  76 +      {
  77 +        result = __read(fd, buf, len);
  78 +        __close(fd);
  79 +      }
  80 +    return result;
  81 +}
  82 +
  83  /* Generate a temporary file name based on TMPL.  TMPL must match the
  84     rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
  85     The name constructed does not exist at the time of the call to
  86 @@ -219,13 +209,12 @@
  87                         at the time of the call.
  88     __GT_FILE:          create the file using open(O_CREAT|O_EXCL)
  89                         and return a read-write fd.  The file is mode 0600.
  90 -   __GT_DIR:           create a directory, which will be mode 0700.
  91 +   __GT_DIR:           create a directory, which will be mode 0700. */
  92
  93 -   We use a clever algorithm to get hard-to-predict names. */
  94  int
  95  __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
  96  {
  97 -  int len;
  98 +  int len, i;
  99    char *XXXXXX;
 100    static uint64_t value;
 101    uint64_t random_time_bits;
 102 @@ -233,6 +222,8 @@
 103    int fd = -1;
 104    int save_errno = errno;
 105    struct_stat64 st;
 106 +  unsigned char randomness[6];
 107 +  unsigned int k;
 108
 109    /* A lower bound on the number of temporary files to attempt to
 110       generate.  The maximum total number of temporary file names that
 111 @@ -260,39 +251,20 @@
 112    /* This is where the Xs start.  */
 113    XXXXXX = &tmpl[len - 6 - suffixlen];
 114
 115 -  /* Get some more or less random data.  */
 116 -#ifdef RANDOM_BITS
 117 -  RANDOM_BITS (random_time_bits);
 118 -#else
 119 -# if HAVE_GETTIMEOFDAY || _LIBC
 120 -  {
 121 -    struct timeval tv;
 122 -    __gettimeofday (&tv, NULL);
 123 -    random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
 124 -  }
 125 -# else
 126 -  random_time_bits = time (NULL);
 127 -# endif
 128 -#endif
 129 -  value += random_time_bits ^ __getpid ();
 130 +  /* Get some random data, and die otherwise.  */
 131 +  if (fillrand(randomness,  sizeof(randomness)) != sizeof(randomness))
 132 +    {
 133 +      __set_errno (ENODEV);
 134 +      return -1;
 135 +    }
 136 +  for (i = 0 ; i < sizeof(randomness) ; i++)
 137 +    {
 138 +      k = ((randomness[i]) % 62);
 139 +      XXXXXX[i] = letters[k];
 140 +    }
 141
 142    for (count = 0; count < attempts; value += 7777, ++count)
 143      {
 144 -      uint64_t v = value;
 145 -
 146 -      /* Fill in the random bits.  */
 147 -      XXXXXX[0] = letters[v % 62];
 148 -      v /= 62;
 149 -      XXXXXX[1] = letters[v % 62];
 150 -      v /= 62;
 151 -      XXXXXX[2] = letters[v % 62];
 152 -      v /= 62;
 153 -      XXXXXX[3] = letters[v % 62];
 154 -      v /= 62;
 155 -      XXXXXX[4] = letters[v % 62];
 156 -      v /= 62;
 157 -      XXXXXX[5] = letters[v % 62];
 158 -
 159        switch (kind)
 160         {
 161         case __GT_FILE: