Adding upstream version 1.21.3.upstream/1.21.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 345 insertions, 0 deletions

diff --git a/lib/tempname.c b/lib/tempname.c
new file mode 100644
index 0000000..5fc5efe
--- /dev/null
+++ b/lib/tempname.c
@@ -0,0 +1,345 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#if !_LIBC
+# include <libc-config.h>
+# include "tempname.h"
+#endif
+
+#include <sys/types.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#include <errno.h>
+
+#include <stdio.h>
+#ifndef P_tmpdir
+# define P_tmpdir "/tmp"
+#endif
+#ifndef TMP_MAX
+# define TMP_MAX 238328
+#endif
+#ifndef __GT_FILE
+# define __GT_FILE      0
+# define __GT_DIR       1
+# define __GT_NOCREATE  2
+#endif
+#if !_LIBC && (GT_FILE != __GT_FILE || GT_DIR != __GT_DIR       \
+               || GT_NOCREATE != __GT_NOCREATE)
+# error report this to bug-gnulib@gnu.org
+#endif
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <fcntl.h>
+#include <stdalign.h>
+#include <stdint.h>
+#include <sys/random.h>
+#include <sys/stat.h>
+#include <time.h>
+
+#if _LIBC
+# define struct_stat64 struct stat64
+# define __secure_getenv __libc_secure_getenv
+#else
+# define struct_stat64 struct stat
+# define __gen_tempname gen_tempname
+# define __mkdir mkdir
+# define __open open
+# define __lstat64(file, buf) lstat (file, buf)
+# define __stat64(file, buf) stat (file, buf)
+# define __getrandom getrandom
+# define __clock_gettime64 clock_gettime
+# define __timespec64 timespec
+#endif
+
+/* Use getrandom if it works, falling back on a 64-bit linear
+   congruential generator that starts with Var's value
+   mixed in with a clock's low-order bits if available.  */
+typedef uint_fast64_t random_value;
+#define RANDOM_VALUE_MAX UINT_FAST64_MAX
+#define BASE_62_DIGITS 10 /* 62**10 < UINT_FAST64_MAX */
+#define BASE_62_POWER (62LL * 62 * 62 * 62 * 62 * 62 * 62 * 62 * 62 * 62)
+
+static random_value
+random_bits (random_value var, bool use_getrandom)
+{
+  random_value r;
+  /* Without GRND_NONBLOCK it can be blocked for minutes on some systems.  */
+  if (use_getrandom && __getrandom (&r, sizeof r, GRND_NONBLOCK) == sizeof r)
+    return r;
+#if _LIBC || (defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME)
+  /* Add entropy if getrandom did not work.  */
+  struct __timespec64 tv;
+  __clock_gettime64 (CLOCK_MONOTONIC, &tv);
+  var ^= tv.tv_nsec;
+#endif
+  return 2862933555777941757 * var + 3037000493;
+}
+
+#if _LIBC
+/* Return nonzero if DIR is an existent directory.  */
+static int
+direxists (const char *dir)
+{
+  struct_stat64 buf;
+  return __stat64 (dir, &buf) == 0 && S_ISDIR (buf.st_mode);
+}
+
+/* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is
+   non-null and exists, uses it; otherwise uses the first of $TMPDIR,
+   P_tmpdir, /tmp that exists.  Copies into TMPL a template suitable
+   for use with mk[s]temp.  Will fail (-1) if DIR is non-null and
+   doesn't exist, none of the searched dirs exists, or there's not
+   enough space in TMPL. */
+int
+__path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
+               int try_tmpdir)
+{
+  const char *d;
+  size_t dlen, plen;
+
+  if (!pfx || !pfx[0])
+    {
+      pfx = "file";
+      plen = 4;
+    }
+  else
+    {
+      plen = strlen (pfx);
+      if (plen > 5)
+        plen = 5;
+    }
+
+  if (try_tmpdir)
+    {
+      d = __secure_getenv ("TMPDIR");
+      if (d != NULL && direxists (d))
+        dir = d;
+      else if (dir != NULL && direxists (dir))
+        /* nothing */ ;
+      else
+        dir = NULL;
+    }
+  if (dir == NULL)
+    {
+      if (direxists (P_tmpdir))
+        dir = P_tmpdir;
+      else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
+        dir = "/tmp";
+      else
+        {
+          __set_errno (ENOENT);
+          return -1;
+        }
+    }
+
+  dlen = strlen (dir);
+  while (dlen > 1 && dir[dlen - 1] == '/')
+    dlen--;                     /* remove trailing slashes */
+
+  /* check we have room for "${dir}/${pfx}XXXXXX\0" */
+  if (tmpl_len < dlen + 1 + plen + 6 + 1)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
+  return 0;
+}
+#endif /* _LIBC */
+
+#if _LIBC
+static int try_tempname_len (char *, int, void *, int (*) (char *, void *),
+                             size_t);
+#endif
+
+static int
+try_file (char *tmpl, void *flags)
+{
+  int *openflags = flags;
+  return __open (tmpl,
+                 (*openflags & ~O_ACCMODE)
+                 | O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+}
+
+static int
+try_dir (char *tmpl, _GL_UNUSED void *flags)
+{
+  return __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
+}
+
+static int
+try_nocreate (char *tmpl, _GL_UNUSED void *flags)
+{
+  struct_stat64 st;
+
+  if (__lstat64 (tmpl, &st) == 0 || errno == EOVERFLOW)
+    __set_errno (EEXIST);
+  return errno == ENOENT ? 0 : -1;
+}
+
+/* These are the characters used in temporary file names.  */
+static const char letters[] =
+"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+
+/* Generate a temporary file name based on TMPL.  TMPL must match the
+   rules for mk[s]temp (i.e., end in at least X_SUFFIX_LEN "X"s,
+   possibly with a suffix).
+   The name constructed does not exist at the time of the call to
+   this function.  TMPL is overwritten with the result.
+
+   KIND may be one of:
+   __GT_NOCREATE:       simply verify that the name does not exist
+                        at the time of the call.
+   __GT_FILE:           create the file using open(O_CREAT|O_EXCL)
+                        and return a read-write fd.  The file is mode 0600.
+   __GT_DIR:            create a directory, which will be mode 0700.
+
+   We use a clever algorithm to get hard-to-predict names. */
+#ifdef _LIBC
+static
+#endif
+int
+gen_tempname_len (char *tmpl, int suffixlen, int flags, int kind,
+                  size_t x_suffix_len)
+{
+  static int (*const tryfunc[]) (char *, void *) =
+    {
+      [__GT_FILE] = try_file,
+      [__GT_DIR] = try_dir,
+      [__GT_NOCREATE] = try_nocreate
+    };
+  return try_tempname_len (tmpl, suffixlen, &flags, tryfunc[kind],
+                           x_suffix_len);
+}
+
+#ifdef _LIBC
+static
+#endif
+int
+try_tempname_len (char *tmpl, int suffixlen, void *args,
+                  int (*tryfunc) (char *, void *), size_t x_suffix_len)
+{
+  size_t len;
+  char *XXXXXX;
+  unsigned int count;
+  int fd = -1;
+  int save_errno = errno;
+
+  /* A lower bound on the number of temporary files to attempt to
+     generate.  The maximum total number of temporary file names that
+     can exist for a given template is 62**6.  It should never be
+     necessary to try all of these combinations.  Instead if a reasonable
+     number of names is tried (we define reasonable as 62**3) fail to
+     give the system administrator the chance to remove the problems.
+     This value requires that X_SUFFIX_LEN be at least 3.  */
+#define ATTEMPTS_MIN (62 * 62 * 62)
+
+  /* The number of times to attempt to generate a temporary file.  To
+     conform to POSIX, this must be no smaller than TMP_MAX.  */
+#if ATTEMPTS_MIN < TMP_MAX
+  unsigned int attempts = TMP_MAX;
+#else
+  unsigned int attempts = ATTEMPTS_MIN;
+#endif
+
+  /* A random variable.  The initial value is used only the for fallback path
+     on 'random_bits' on 'getrandom' failure.  Its initial value tries to use
+     some entropy from the ASLR and ignore possible bits from the stack
+     alignment.  */
+  random_value v = ((uintptr_t) &v) / alignof (max_align_t);
+
+  /* How many random base-62 digits can currently be extracted from V.  */
+  int vdigits = 0;
+
+  /* Whether to consume entropy when acquiring random bits.  On the
+     first try it's worth the entropy cost with __GT_NOCREATE, which
+     is inherently insecure and can use the entropy to make it a bit
+     less secure.  On the (rare) second and later attempts it might
+     help against DoS attacks.  */
+  bool use_getrandom = tryfunc == try_nocreate;
+
+  /* Least unfair value for V.  If V is less than this, V can generate
+     BASE_62_DIGITS digits fairly.  Otherwise it might be biased.  */
+  random_value const unfair_min
+    = RANDOM_VALUE_MAX - RANDOM_VALUE_MAX % BASE_62_POWER;
+
+  len = strlen (tmpl);
+  if (len < x_suffix_len + suffixlen
+      || strspn (&tmpl[len - x_suffix_len - suffixlen], "X") < x_suffix_len)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  /* This is where the Xs start.  */
+  XXXXXX = &tmpl[len - x_suffix_len - suffixlen];
+
+  for (count = 0; count < attempts; ++count)
+    {
+      for (size_t i = 0; i < x_suffix_len; i++)
+        {
+          if (vdigits == 0)
+            {
+              do
+                {
+                  v = random_bits (v, use_getrandom);
+                  use_getrandom = true;
+                }
+              while (unfair_min <= v);
+
+              vdigits = BASE_62_DIGITS;
+            }
+
+          XXXXXX[i] = letters[v % 62];
+          v /= 62;
+          vdigits--;
+        }
+
+      fd = tryfunc (tmpl, args);
+      if (fd >= 0)
+        {
+          __set_errno (save_errno);
+          return fd;
+        }
+      else if (errno != EEXIST)
+        return -1;
+    }
+
+  /* We got out of the loop because we ran out of combinations to try.  */
+  __set_errno (EEXIST);
+  return -1;
+}
+
+int
+__gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
+{
+  return gen_tempname_len (tmpl, suffixlen, flags, kind, 6);
+}
+
+#if !_LIBC
+int
+try_tempname (char *tmpl, int suffixlen, void *args,
+              int (*tryfunc) (char *, void *))
+{
+  return try_tempname_len (tmpl, suffixlen, args, tryfunc, 6);
+}
+#endif