FreeBSD Mail Archives

Date:      Tue, 17 Feb 2015 17:46:13 +0000
From:      Mark R V Murray <mark@grondar.org>
To:        John-Mark Gurney <jmg@FreeBSD.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r278907 - head/sys/dev/random
Message-ID:  <30B45F07-482F-44D2-B871-468709C5B3F3@grondar.org>
In-Reply-To: <201502171737.t1HHb1Gq035943@svn.freebsd.org>
References:  <201502171737.t1HHb1Gq035943@svn.freebsd.org>


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Hi

Thanks John-Mark!

M

> On 17 Feb 2015, at 17:37, John-Mark Gurney <jmg@FreeBSD.org> wrote:
>=20
> Author: jmg
> Date: Tue Feb 17 17:37:00 2015
> New Revision: 278907
> URL: https://svnweb.freebsd.org/changeset/base/278907
>=20
> Log:
>  When the new random adaptor code was brought it in r273872, a call to
>  randomdev_init_reader to change read_random over to the newly =
installed
>  adaptor was missed.  This means both read_random and arc4random =
(seeded
>  from read_random) were not returning very random data.  This also
>  effects userland arc4random as it is seeded from kernel arc4random.
>=20
>  The random devices are uneffected and have returned good randomness
>  since the change.
>=20
>  All keys generated with a kernel of r273872 must be regenerated with
>  a kernel with this patch.  Keys generated may be predictable.
>=20
>  Remove the warning as log is too early to print anything, and it =
would
>  always get printed due to early use of arc4random...
>=20
>  Reviewed by:	delphij, markm
>  Approved by:    so (delphij)
>=20
> Modified:
>  head/sys/dev/random/dummy_rng.c
>  head/sys/dev/random/random_adaptors.c
>  head/sys/dev/random/randomdev.c
>  head/sys/dev/random/randomdev.h
>=20
> Modified: head/sys/dev/random/dummy_rng.c
> =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D
> --- head/sys/dev/random/dummy_rng.c	Tue Feb 17 17:34:45 2015	=
(r278906)
> +++ head/sys/dev/random/dummy_rng.c	Tue Feb 17 17:37:00 2015	=
(r278907)
> @@ -82,19 +82,13 @@ dummy_random_init(void)
>  *
>  * Caveat Emptor.
>  */
> -u_int
> +void
> dummy_random_read_phony(uint8_t *buf, u_int count)
> {
> 	/* If no entropy device is loaded, don't spam the console with =
warnings */
> -	static int warned =3D 0;
> 	u_long randval;
> 	size_t size, i;
>=20
> -	if (!warned) {
> -		log(LOG_WARNING, "random device not loaded/active; using =
insecure pseudo-random number generator\n");
> -		warned =3D 1;
> -	}
> -
> 	/* srandom() is called in kern/init_main.c:proc0_post() */
>=20
> 	/* Fill buf[] with random(9) output */
> @@ -103,8 +97,6 @@ dummy_random_read_phony(uint8_t *buf, u_
> 		size =3D MIN(count - i, sizeof(randval));
> 		memcpy(buf + i, &randval, (size_t)size);
> 	}
> -
> -	return (count);
> }
>=20
> struct random_adaptor randomdev_dummy =3D {
>=20
> Modified: head/sys/dev/random/random_adaptors.c
> =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D
> --- head/sys/dev/random/random_adaptors.c	Tue Feb 17 17:34:45 2015	=
(r278906)
> +++ head/sys/dev/random/random_adaptors.c	Tue Feb 17 17:37:00 2015	=
(r278907)
> @@ -149,10 +149,14 @@ random_adaptor_choose(void)
> 		    (random_adaptor_previous =3D=3D NULL ? "NULL" : =
random_adaptor_previous->ra_ident),
> 		    random_adaptor->ra_ident);
> #endif
> -		if (random_adaptor_previous !=3D NULL)
> +		if (random_adaptor_previous !=3D NULL) {
> +			randomdev_deinit_reader();
> 			(random_adaptor_previous->ra_deinit)();
> +		}
> 		(random_adaptor->ra_init)();
> 	}
> +
> +	randomdev_init_reader(random_adaptor->ra_read);
> }
>=20
>=20
>=20
> Modified: head/sys/dev/random/randomdev.c
> =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D
> --- head/sys/dev/random/randomdev.c	Tue Feb 17 17:34:45 2015	=
(r278906)
> +++ head/sys/dev/random/randomdev.c	Tue Feb 17 17:37:00 2015	=
(r278907)
> @@ -214,11 +214,11 @@ random_harvest(const void *entropy, u_in
>  */
>=20
> /* Hold the address of the routine which is actually called */
> -static u_int (*read_func)(uint8_t *, u_int) =3D =
dummy_random_read_phony;
> +static void (*read_func)(uint8_t *, u_int) =3D =
dummy_random_read_phony;
>=20
> /* Initialise the reader when/if it is loaded */
> void
> -randomdev_init_reader(u_int (*reader)(uint8_t *, u_int))
> +randomdev_init_reader(void (*reader)(uint8_t *, u_int))
> {
>=20
> 	read_func =3D reader;
> @@ -240,5 +240,10 @@ int
> read_random(void *buf, int count)
> {
>=20
> -	return ((int)(*read_func)(buf, (u_int)count));
> +	if (count < 0)
> +		return 0;
> +
> +	read_func(buf, count);
> +
> +	return count;
> }
>=20
> Modified: head/sys/dev/random/randomdev.h
> =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D
> --- head/sys/dev/random/randomdev.h	Tue Feb 17 17:34:45 2015	=
(r278906)
> +++ head/sys/dev/random/randomdev.h	Tue Feb 17 17:37:00 2015	=
(r278907)
> @@ -37,12 +37,12 @@ typedef void random_init_func_t(void);
> typedef void random_deinit_func_t(void);
>=20
> void randomdev_init_harvester(void (*)(const void *, u_int, u_int, =
enum random_entropy_source));
> -void randomdev_init_reader(u_int (*)(uint8_t *, u_int));
> +void randomdev_init_reader(void (*)(uint8_t *, u_int));
> void randomdev_deinit_harvester(void);
> void randomdev_deinit_reader(void);
>=20
> /* Stub/fake routines for when no entropy processor is loaded */
> -extern u_int dummy_random_read_phony(uint8_t *, u_int);
> +extern void dummy_random_read_phony(uint8_t *, u_int);
>=20
> /* kern.random sysctls */
> #ifdef SYSCTL_DECL	/* from sysctl.h */
>=20

--
Mark R V Murray


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