svn commit: r238118 - head/lib/libc/gen

[Pawel Jakub Dawidek]

Author: pjd
Date: Wed Jul  4 19:51:25 2012
New Revision: 238118
URL: http://svn.freebsd.org/changeset/base/238118

Log:
  Prefer sysctl to open/read/close for obtaining random data.
  This method is more sandbox-friendly and also should be faster as only
  one syscall is needed instead of three.
  In case of an error fall back to the old method.
  
  Reviewed by:  simon, gleb
  MFC after:    2 weeks

Modified:
  head/lib/libc/gen/arc4random.c

Modified: head/lib/libc/gen/arc4random.c
==============================================================================
--- head/lib/libc/gen/arc4random.c      Wed Jul  4 17:59:26 2012        
(r238117)
+++ head/lib/libc/gen/arc4random.c      Wed Jul  4 19:51:25 2012        
(r238118)
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/param.h>
+#include <sys/sysctl.h>
 #include <sys/time.h>
 #include <pthread.h>
 
@@ -78,6 +79,9 @@ static struct arc4_stream rs;
 static pid_t arc4_stir_pid;
 static int arc4_count;
 
+extern int __sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
+    void *newp, size_t newlen);
+
 static inline u_int8_t arc4_getbyte(void);
 static void arc4_stir(void);
 
@@ -109,6 +113,28 @@ arc4_addrandom(u_char *dat, int datlen)
        rs.j = rs.i;
 }
 
+static size_t
+arc4_sysctl(u_char *buf, size_t size)
+{
+       int mib[2];
+       size_t len, done;
+
+       mib[0] = CTL_KERN;
+       mib[1] = KERN_ARND;
+       done = 0;
+
+       do {
+               len = size;
+               if (__sysctl(mib, 2, buf, &len, NULL, 0) == -1)
+                       return (done);
+               done += len;
+               buf += len;
+               size -= len;
+       } while (size > 0);
+
+       return (done);
+}
+
 static void
 arc4_stir(void)
 {
@@ -123,12 +149,16 @@ arc4_stir(void)
                arc4_init();
                rs_initialized = 1;
        }
-       fd = _open(RANDOMDEV, O_RDONLY, 0);
        done = 0;
-       if (fd >= 0) {
-               if (_read(fd, &rdat, KEYSIZE) == KEYSIZE)
-                       done = 1;
-               (void)_close(fd);
+       if (arc4_sysctl((u_char *)&rdat, KEYSIZE) == KEYSIZE)
+               done = 1;
+       if (!done) {
+               fd = _open(RANDOMDEV, O_RDONLY, 0);
+               if (fd >= 0) {
+                       if (_read(fd, &rdat, KEYSIZE) == KEYSIZE)
+                               done = 1;
+                       (void)_close(fd);
+               }
        }
        if (!done) {
                (void)gettimeofday(&rdat.tv, NULL);
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"