Use a single set of FDs for all random plugin RNG instances
authorMartin Willi <martin@revosec.ch>
Tue, 21 Feb 2012 09:22:48 +0000 (10:22 +0100)
committerMartin Willi <martin@revosec.ch>
Tue, 20 Mar 2012 16:31:40 +0000 (17:31 +0100)
src/libstrongswan/plugins/random/random_plugin.c
src/libstrongswan/plugins/random/random_plugin.h
src/libstrongswan/plugins/random/random_rng.c

index 7f81e26..418eeae 100644 (file)
 
 #include "random_plugin.h"
 
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
 #include <library.h>
+#include <debug.h>
 #include "random_rng.h"
 
+#ifndef DEV_RANDOM
+# define DEV_RANDOM "/dev/random"
+#endif
+
+#ifndef DEV_URANDOM
+# define DEV_URANDOM "/dev/urandom"
+#endif
+
 typedef struct private_random_plugin_t private_random_plugin_t;
 
 /**
@@ -31,6 +46,41 @@ struct private_random_plugin_t {
        random_plugin_t public;
 };
 
+/** /dev/random file descriptor */
+static int dev_random = -1;
+/** /dev/urandom file descriptor */
+static int dev_urandom = -1;
+
+/**
+ * See header.
+ */
+int random_plugin_get_dev_random()
+{
+       return dev_random;
+}
+
+/**
+ * See header.
+ */
+int random_plugin_get_dev_urandom()
+{
+       return dev_urandom;
+}
+
+/**
+ * Open a random device file
+ */
+static bool open_dev(char *file, int *fd)
+{
+       *fd = open(file, O_RDONLY);
+       if (*fd == -1)
+       {
+               DBG1(DBG_LIB, "opening \"%s\" failed: %s", file, strerror(errno));
+               return FALSE;
+       }
+       return TRUE;
+}
+
 METHOD(plugin_t, get_name, char*,
        private_random_plugin_t *this)
 {
@@ -52,6 +102,14 @@ METHOD(plugin_t, get_features, int,
 METHOD(plugin_t, destroy, void,
        private_random_plugin_t *this)
 {
+       if (dev_random != -1)
+       {
+               close(dev_random);
+       }
+       if (dev_urandom != -1)
+       {
+               close(dev_urandom);
+       }
        free(this);
 }
 
@@ -72,6 +130,13 @@ plugin_t *random_plugin_create()
                },
        );
 
+       if (!open_dev(DEV_URANDOM, &dev_urandom) ||
+               !open_dev(DEV_RANDOM, &dev_random))
+       {
+               destroy(this);
+               return NULL;
+       }
+
        return &this->public.plugin;
 }
 
index 7e22c3e..c34fa81 100644 (file)
@@ -39,4 +39,14 @@ struct random_plugin_t {
        plugin_t plugin;
 };
 
+/**
+ * Get the /dev/random file descriptor
+ */
+int random_plugin_get_dev_random();
+
+/**
+ * Get the /dev/urandom file descriptor
+ */
+int random_plugin_get_dev_urandom();
+
 #endif /** RANDOM_PLUGIN_H_ @}*/
index 1d99a63..42eddbb 100644 (file)
  */
 
 #include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
 #include <debug.h>
 
 #include "random_rng.h"
-
-#ifndef DEV_RANDOM
-# define DEV_RANDOM "/dev/random"
-#endif
-
-#ifndef DEV_URANDOM
-# define DEV_URANDOM "/dev/urandom"
-#endif
+#include "random_plugin.h"
 
 typedef struct private_random_rng_t private_random_rng_t;
 
@@ -47,12 +37,7 @@ struct private_random_rng_t {
        /**
         * random device, depends on quality
         */
-       int dev;
-
-       /**
-        * file we read random bytes from
-        */
-       char *file;
+       int fd;
 };
 
 METHOD(rng_t, get_bytes, void,
@@ -65,14 +50,12 @@ METHOD(rng_t, get_bytes, void,
 
        while (done < bytes)
        {
-               got = read(this->dev, buffer + done, bytes - done);
+               got = read(this->fd, buffer + done, bytes - done);
                if (got <= 0)
                {
-                       DBG1(DBG_LIB, "reading from \"%s\" failed: %s, retrying...",
-                                this->file, strerror(errno));
-                       close(this->dev);
+                       DBG1(DBG_LIB, "reading from random FD %d failed: %s, retrying...",
+                                this->fd, strerror(errno));
                        sleep(1);
-                       this->dev = open(this->file, 0);
                }
                done += got;
        }
@@ -88,7 +71,6 @@ METHOD(rng_t, allocate_bytes, void,
 METHOD(rng_t, destroy, void,
        private_random_rng_t *this)
 {
-       close(this->dev);
        free(this);
 }
 
@@ -109,22 +91,18 @@ random_rng_t *random_rng_create(rng_quality_t quality)
                },
        );
 
-       if (quality == RNG_TRUE)
+       switch (quality)
        {
-               this->file = DEV_RANDOM;
-       }
-       else
-       {
-               this->file = DEV_URANDOM;
+               case RNG_TRUE:
+                       this->fd = random_plugin_get_dev_random();
+                       break;
+               case RNG_STRONG:
+               case RNG_WEAK:
+               default:
+                       this->fd = random_plugin_get_dev_urandom();
+                       break;
        }
 
-       this->dev = open(this->file, 0);
-       if (this->dev < 0)
-       {
-               DBG1(DBG_LIB, "opening \"%s\" failed: %s", this->file, strerror(errno));
-               free(this);
-               return NULL;
-       }
        return &this->public;
 }