svn commit: r346282 - in head: . share/man/man9 sys/dev/random sys/sys
Conrad Meyer
cem at FreeBSD.org
Tue Sep 3 14:07:07 UTC 2019
Author: cem
Date: Tue Apr 16 17:12:17 2019
New Revision: 346282
URL: https://svnweb.freebsd.org/changeset/base/346282
Log:
random(4): Add is_random_seeded(9) KPI
The imagined use is for early boot consumers of random to be able to make
decisions based on whether random is available yet or not. One such
consumer seems to be __stack_chk_init(), which runs immediately after random
is initialized. A follow-up patch will attempt to address that.
Reported by: many
Reviewed by: delphij (except man page)
Approved by: secteam(delphij)
Differential Revision: https://reviews.freebsd.org/D19926
Modified:
head/UPDATING
head/share/man/man9/Makefile
head/share/man/man9/random.9
head/sys/dev/random/random_infra.c
head/sys/dev/random/randomdev.c
head/sys/dev/random/randomdev.h
head/sys/sys/param.h
head/sys/sys/random.h
Modified: head/UPDATING
==============================================================================
--- head/UPDATING Tue Apr 16 16:49:34 2019 (r346281)
+++ head/UPDATING Tue Apr 16 17:12:17 2019 (r346282)
@@ -31,6 +31,12 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 13.x IS SLOW:
disable the most expensive debugging functionality run
"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
+20190416:
+ The loadable random module KPI has changed; the random_infra_init()
+ routine now requires a 3rd function pointer for a bool (*)(void)
+ method that returns true if the random device is seeded (and
+ therefore unblocked).
+
20190404:
r345895 reverts r320698. This implies that an nfsuserd(8) daemon
built from head sources between r320757 (July 6, 2017) and
Modified: head/share/man/man9/Makefile
==============================================================================
--- head/share/man/man9/Makefile Tue Apr 16 16:49:34 2019 (r346281)
+++ head/share/man/man9/Makefile Tue Apr 16 17:12:17 2019 (r346282)
@@ -1668,6 +1668,7 @@ MLINKS+=psignal.9 gsignal.9 \
psignal.9 tdsignal.9
MLINKS+=random.9 arc4rand.9 \
random.9 arc4random.9 \
+ random.9 is_random_seeded.9 \
random.9 read_random.9 \
random.9 read_random_uio.9 \
random.9 srandom.9
Modified: head/share/man/man9/random.9
==============================================================================
--- head/share/man/man9/random.9 Tue Apr 16 16:49:34 2019 (r346281)
+++ head/share/man/man9/random.9 Tue Apr 16 17:12:17 2019 (r346282)
@@ -26,13 +26,14 @@
.\"
.\" $FreeBSD$
.\" "
-.Dd April 15, 2019
+.Dd April 16, 2019
.Dt RANDOM 9
.Os
.Sh NAME
.Nm arc4rand ,
.Nm arc4random ,
.Nm arc4random_buf ,
+.Nm is_random_seeded ,
.Nm random ,
.Nm read_random ,
.Nm read_random_uio ,
@@ -48,6 +49,8 @@
.Fn arc4rand "void *ptr" "u_int length" "int reseed"
.Pp
.In sys/random.h
+.Ft bool
+.Fn is_random_seeded "void"
.Ft void
.Fn read_random "void *buffer" "int count"
.Ft int
@@ -106,6 +109,13 @@ is not used directly;
instead, use the
.Fn arc4rand
family of functions.
+.Pp
+The
+.Fn is_random_seeded
+function can be used to check in advance if
+.Fn read_random
+will block.
+(If random is seeded, it will not block.)
.Pp
The
.Fn read_random_uio
Modified: head/sys/dev/random/random_infra.c
==============================================================================
--- head/sys/dev/random/random_infra.c Tue Apr 16 16:49:34 2019 (r346281)
+++ head/sys/dev/random/random_infra.c Tue Apr 16 17:12:17 2019 (r346282)
@@ -63,12 +63,20 @@ null_read_random(void *dummy __unused, u_int dummy2 __
panic("%s: no random module is loaded", __func__);
}
+static bool
+null_is_random_seeded(void)
+{
+ return (false);
+}
+
struct random_readers {
int (*read_random_uio)(struct uio *, bool);
void (*read_random)(void *, u_int);
+ bool (*is_random_seeded)(void);
} random_reader_context = {
(int (*)(struct uio *, bool))nullop,
null_read_random,
+ null_is_random_seeded,
};
struct sx randomdev_config_lock;
@@ -82,12 +90,15 @@ random_infra_sysinit(void *dummy __unused)
SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysinit, NULL);
void
-random_infra_init(int (*p_random_read_uio)(struct uio *, bool), void (*p_random_read)(void *, u_int))
+random_infra_init(int (*p_random_read_uio)(struct uio *, bool),
+ void (*p_random_read)(void *, u_int),
+ bool (*p_is_random_seeded)(void))
{
RANDOM_CONFIG_X_LOCK();
random_reader_context.read_random_uio = p_random_read_uio;
random_reader_context.read_random = p_random_read;
+ random_reader_context.is_random_seeded = p_is_random_seeded;
RANDOM_CONFIG_X_UNLOCK();
}
@@ -98,6 +109,7 @@ random_infra_uninit(void)
RANDOM_CONFIG_X_LOCK();
random_reader_context.read_random_uio = (int (*)(struct uio *, bool))nullop;
random_reader_context.read_random = null_read_random;
+ random_reader_context.is_random_seeded = null_is_random_seeded;
RANDOM_CONFIG_X_UNLOCK();
}
@@ -128,5 +140,14 @@ read_random(void *buf, u_int len)
random_reader_context.read_random(buf, len);
RANDOM_CONFIG_S_UNLOCK();
}
+
+bool
+is_random_seeded(void)
+{
+ RANDOM_CONFIG_S_LOCK();
+ random_reader_context.is_random_seeded();
+ RANDOM_CONFIG_S_UNLOCK();
+}
+
#endif /* defined(RANDOM_LOADABLE) */
Modified: head/sys/dev/random/randomdev.c
==============================================================================
--- head/sys/dev/random/randomdev.c Tue Apr 16 16:49:34 2019 (r346281)
+++ head/sys/dev/random/randomdev.c Tue Apr 16 17:12:17 2019 (r346282)
@@ -62,11 +62,14 @@ __FBSDID("$FreeBSD$");
#if defined(RANDOM_LOADABLE)
#define READ_RANDOM_UIO _read_random_uio
#define READ_RANDOM _read_random
+#define IS_RANDOM_SEEDED _is_random_seeded
static int READ_RANDOM_UIO(struct uio *, bool);
static void READ_RANDOM(void *, u_int);
+static bool IS_RANDOM_SEEDED(void);
#else
#define READ_RANDOM_UIO read_random_uio
#define READ_RANDOM read_random
+#define IS_RANDOM_SEEDED is_random_seeded
#endif
static d_read_t randomdev_read;
@@ -93,7 +96,7 @@ random_alg_context_ra_init_alg(void *data)
p_random_alg_context = &random_alg_context;
p_random_alg_context->ra_init_alg(data);
#if defined(RANDOM_LOADABLE)
- random_infra_init(READ_RANDOM_UIO, READ_RANDOM);
+ random_infra_init(READ_RANDOM_UIO, READ_RANDOM, IS_RANDOM_SEEDED);
#endif
}
@@ -269,6 +272,12 @@ READ_RANDOM(void *random_buf, u_int len)
explicit_bzero(remainder_buf, sizeof(remainder_buf));
}
+}
+
+bool
+IS_RANDOM_SEEDED(void)
+{
+ return (p_random_alg_context->ra_seeded());
}
static __inline void
Modified: head/sys/dev/random/randomdev.h
==============================================================================
--- head/sys/dev/random/randomdev.h Tue Apr 16 16:49:34 2019 (r346281)
+++ head/sys/dev/random/randomdev.h Tue Apr 16 17:12:17 2019 (r346282)
@@ -118,7 +118,8 @@ extern struct sx randomdev_config_lock;
#define RANDOM_CONFIG_S_LOCK(x) sx_slock(&randomdev_config_lock)
#define RANDOM_CONFIG_S_UNLOCK(x) sx_sunlock(&randomdev_config_lock)
#define RANDOM_CONFIG_DEINIT_LOCK(x) sx_destroy(&randomdev_config_lock)
-void random_infra_init(int (*)(struct uio *, bool), void (*)(void *, u_int));
+void random_infra_init(int (*)(struct uio *, bool), void (*)(void *, u_int),
+ bool (*)(void));
void random_infra_uninit(void);
#endif
Modified: head/sys/sys/param.h
==============================================================================
--- head/sys/sys/param.h Tue Apr 16 16:49:34 2019 (r346281)
+++ head/sys/sys/param.h Tue Apr 16 17:12:17 2019 (r346282)
@@ -60,7 +60,7 @@
* in the range 5 to 9.
*/
#undef __FreeBSD_version
-#define __FreeBSD_version 1300018 /* Master, propagated to newvers */
+#define __FreeBSD_version 1300019 /* Master, propagated to newvers */
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
Modified: head/sys/sys/random.h
==============================================================================
--- head/sys/sys/random.h Tue Apr 16 16:49:34 2019 (r346281)
+++ head/sys/sys/random.h Tue Apr 16 17:12:17 2019 (r346282)
@@ -40,6 +40,7 @@ struct uio;
#if defined(DEV_RANDOM)
void read_random(void *, u_int);
int read_random_uio(struct uio *, bool);
+bool is_random_seeded(void);
#else
static __inline int
read_random_uio(void *a __unused, u_int b __unused)
@@ -49,6 +50,11 @@ read_random_uio(void *a __unused, u_int b __unused)
static __inline void
read_random(void *a __unused, u_int b __unused)
{
+}
+static __inline bool
+is_random_seeded(void)
+{
+ return (false);
}
#endif
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