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-rw-r--r--comm/third_party/libgcrypt/random/rndlinux.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/comm/third_party/libgcrypt/random/rndlinux.c b/comm/third_party/libgcrypt/random/rndlinux.c
new file mode 100644
index 0000000000..a7a78906d2
--- /dev/null
+++ b/comm/third_party/libgcrypt/random/rndlinux.c
@@ -0,0 +1,366 @@
+/* rndlinux.c - raw random number for OSes with /dev/random
+ * Copyright (C) 1998, 2001, 2002, 2003, 2007,
+ * 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt 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.
+ *
+ * Libgcrypt 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifdef HAVE_GETTIMEOFDAY
+# include <sys/times.h>
+#endif
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#if defined(__APPLE__) && defined(__MACH__)
+#include <Availability.h>
+#ifdef __MAC_10_11
+extern int getentropy (void *buf, size_t buflen) __attribute__ ((weak_import));
+#define HAVE_GETENTROPY
+#endif
+#endif
+#if defined(__linux__) || !defined(HAVE_GETENTROPY)
+#ifdef HAVE_SYSCALL
+# include <sys/syscall.h>
+# ifdef __NR_getrandom
+# define getentropy(buf,buflen) syscall (__NR_getrandom, buf, buflen, 0)
+# endif
+#endif
+#endif
+
+#include "types.h"
+#include "g10lib.h"
+#include "rand-internal.h"
+
+static int open_device (const char *name, int retry);
+
+
+static int
+set_cloexec_flag (int fd)
+{
+ int oldflags;
+
+ oldflags= fcntl (fd, F_GETFD, 0);
+ if (oldflags < 0)
+ return oldflags;
+ oldflags |= FD_CLOEXEC;
+ return fcntl (fd, F_SETFD, oldflags);
+}
+
+
+
+/*
+ * Used to open the /dev/random devices (Linux, xBSD, Solaris (if it
+ * exists)). If RETRY is true, the function does not terminate with
+ * a fatal error but retries until it is able to reopen the device.
+ */
+static int
+open_device (const char *name, int retry)
+{
+ int fd;
+
+ if (retry)
+ _gcry_random_progress ("open_dev_random", 'X', 1, 0);
+ again:
+ fd = open (name, O_RDONLY);
+ if (fd == -1 && retry)
+ {
+ struct timeval tv;
+
+ tv.tv_sec = 5;
+ tv.tv_usec = 0;
+ _gcry_random_progress ("wait_dev_random", 'X', 0, (int)tv.tv_sec);
+ select (0, NULL, NULL, NULL, &tv);
+ goto again;
+ }
+ if (fd == -1)
+ log_fatal ("can't open %s: %s\n", name, strerror(errno) );
+
+ if (set_cloexec_flag (fd))
+ log_error ("error setting FD_CLOEXEC on fd %d: %s\n",
+ fd, strerror (errno));
+
+ /* We used to do the following check, however it turned out that this
+ is not portable since more OSes provide a random device which is
+ sometimes implemented as another device type.
+
+ struct stat sb;
+
+ if( fstat( fd, &sb ) )
+ log_fatal("stat() off %s failed: %s\n", name, strerror(errno) );
+ if( (!S_ISCHR(sb.st_mode)) && (!S_ISFIFO(sb.st_mode)) )
+ log_fatal("invalid random device!\n" );
+ */
+ return fd;
+}
+
+
+/* Note that the caller needs to make sure that this function is only
+ * called by one thread at a time. The function returns 0 on success
+ * or true on failure (in which case the caller will signal a fatal
+ * error). This function should be entered only by one thread at a
+ * time. */
+int
+_gcry_rndlinux_gather_random (void (*add)(const void*, size_t,
+ enum random_origins),
+ enum random_origins origin,
+ size_t length, int level )
+{
+ static int fd_urandom = -1;
+ static int fd_random = -1;
+ static int only_urandom = -1;
+ static unsigned char ever_opened;
+ static volatile pid_t my_pid; /* The volatile is there to make sure
+ * the compiler does not optimize the
+ * code away in case the getpid
+ * function is badly attributed. */
+ volatile pid_t apid;
+ int fd;
+ int n;
+ byte buffer[768];
+ size_t n_hw;
+ size_t want = length;
+ size_t last_so_far = 0;
+ int any_need_entropy = 0;
+ int delay;
+
+ /* On the first call read the conf file to check whether we want to
+ * use only urandom. */
+ if (only_urandom == -1)
+ {
+ my_pid = getpid ();
+ if ((_gcry_random_read_conf () & RANDOM_CONF_ONLY_URANDOM))
+ only_urandom = 1;
+ else
+ only_urandom = 0;
+ }
+
+ if (!add)
+ {
+ /* Special mode to close the descriptors. */
+ if (fd_random != -1)
+ {
+ close (fd_random);
+ fd_random = -1;
+ }
+ if (fd_urandom != -1)
+ {
+ close (fd_urandom);
+ fd_urandom = -1;
+ }
+
+ _gcry_rndjent_fini ();
+ return 0;
+ }
+
+ /* Detect a fork and close the devices so that we don't use the old
+ * file descriptors. Note that open_device will be called in retry
+ * mode if the devices was opened by the parent process. */
+ apid = getpid ();
+ if (my_pid != apid)
+ {
+ if (fd_random != -1)
+ {
+ close (fd_random);
+ fd_random = -1;
+ }
+ if (fd_urandom != -1)
+ {
+ close (fd_urandom);
+ fd_urandom = -1;
+ }
+ my_pid = apid;
+ }
+
+
+ /* First read from a hardware source. Note that _gcry_rndhw_poll_slow lets
+ it account only for up to 50% (or 25% for RDRAND) of the requested
+ bytes. */
+ n_hw = _gcry_rndhw_poll_slow (add, origin, length);
+ if (length > 1)
+ length -= n_hw;
+
+ /* When using a blocking random generator try to get some entropy
+ * from the jitter based RNG. In this case we take up to 50% of the
+ * remaining requested bytes. */
+ if (level >= GCRY_VERY_STRONG_RANDOM)
+ {
+ n_hw = _gcry_rndjent_poll (add, origin, length/2);
+ if (n_hw > length/2)
+ n_hw = length/2;
+ if (length > 1)
+ length -= n_hw;
+ }
+
+
+ /* Open the requested device. The first time a device is to be
+ opened we fail with a fatal error if the device does not exists.
+ In case the device has ever been closed, further open requests
+ will however retry indefinitely. The rationale for this behaviour is
+ that we always require the device to be existent but want a more
+ graceful behaviour if the rarely needed close operation has been
+ used and the device needs to be re-opened later. */
+ if (level >= GCRY_VERY_STRONG_RANDOM && !only_urandom)
+ {
+ if (fd_random == -1)
+ {
+ fd_random = open_device (NAME_OF_DEV_RANDOM, (ever_opened & 1));
+ ever_opened |= 1;
+ }
+ fd = fd_random;
+ }
+ else
+ {
+ if (fd_urandom == -1)
+ {
+ fd_urandom = open_device (NAME_OF_DEV_URANDOM, (ever_opened & 2));
+ ever_opened |= 2;
+ }
+ fd = fd_urandom;
+ }
+
+ /* Enter the read loop. */
+ delay = 0; /* Start with 0 seconds so that we do no block on the
+ first iteration and in turn call the progress function
+ before blocking. To give the OS a better chance to
+ return with something we will actually use 100ms. */
+ while (length)
+ {
+ fd_set rfds;
+ struct timeval tv;
+ int rc;
+
+ /* If we have a modern operating system, we first try to use the new
+ * getentropy function. That call guarantees that the kernel's
+ * RNG has been properly seeded before returning any data. This
+ * is different from /dev/urandom which may, due to its
+ * non-blocking semantics, return data even if the kernel has
+ * not been properly seeded. And it differs from /dev/random by never
+ * blocking once the kernel is seeded. */
+#if defined(HAVE_GETENTROPY) || defined(__NR_getrandom)
+#if defined(__APPLE__) && defined(__MACH__)
+ if (&getentropy != NULL)
+#endif
+ {
+ long ret;
+ size_t nbytes;
+
+ do
+ {
+ nbytes = length < sizeof(buffer)? length : sizeof(buffer);
+ if (nbytes > 256)
+ nbytes = 256;
+ _gcry_pre_syscall ();
+ ret = getentropy (buffer, nbytes);
+ _gcry_post_syscall ();
+ }
+ while (ret == -1 && errno == EINTR);
+ if (ret == -1 && errno == ENOSYS)
+ ; /* getentropy is not supported - fallback to pulling from fd. */
+ else
+ { /* getentropy is supported. Some sanity checks. */
+ if (ret == -1)
+ log_fatal ("unexpected error from getentropy: %s\n",
+ strerror (errno));
+#ifdef __NR_getrandom
+ else if (ret != nbytes)
+ log_fatal ("getentropy returned only"
+ " %ld of %zu requested bytes\n", ret, nbytes);
+#endif
+
+ (*add)(buffer, nbytes, origin);
+ length -= nbytes;
+ continue; /* until LENGTH is zero. */
+ }
+ }
+#endif
+
+ /* If we collected some bytes update the progress indicator. We
+ do this always and not just if the select timed out because
+ often just a few bytes are gathered within the timeout
+ period. */
+ if (any_need_entropy || last_so_far != (want - length) )
+ {
+ last_so_far = want - length;
+ _gcry_random_progress ("need_entropy", 'X',
+ (int)last_so_far, (int)want);
+ any_need_entropy = 1;
+ }
+
+ /* If the system has no limit on the number of file descriptors
+ and we encounter an fd which is larger than the fd_set size,
+ we don't use the select at all. The select code is only used
+ to emit progress messages. A better solution would be to
+ fall back to poll() if available. */
+#ifdef FD_SETSIZE
+ if (fd < FD_SETSIZE)
+#endif
+ {
+ FD_ZERO(&rfds);
+ FD_SET(fd, &rfds);
+ tv.tv_sec = delay;
+ tv.tv_usec = delay? 0 : 100000;
+ _gcry_pre_syscall ();
+ rc = select (fd+1, &rfds, NULL, NULL, &tv);
+ _gcry_post_syscall ();
+ if (!rc)
+ {
+ any_need_entropy = 1;
+ delay = 3; /* Use 3 seconds henceforth. */
+ continue;
+ }
+ else if( rc == -1 )
+ {
+ log_error ("select() error: %s\n", strerror(errno));
+ if (!delay)
+ delay = 1; /* Use 1 second if we encounter an error before
+ we have ever blocked. */
+ continue;
+ }
+ }
+
+ do
+ {
+ size_t nbytes;
+
+ nbytes = length < sizeof(buffer)? length : sizeof(buffer);
+ n = read (fd, buffer, nbytes);
+ if (n >= 0 && n > nbytes)
+ {
+ log_error("bogus read from random device (n=%d)\n", n );
+ n = nbytes;
+ }
+ }
+ while (n == -1 && errno == EINTR);
+ if (n == -1)
+ log_fatal("read error on random device: %s\n", strerror(errno));
+ (*add)(buffer, n, origin);
+ length -= n;
+ }
+ wipememory (buffer, sizeof buffer);
+
+ if (any_need_entropy)
+ _gcry_random_progress ("need_entropy", 'X', (int)want, (int)want);
+
+ return 0; /* success */
+}
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