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
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=346282
6
UPDATING
6
UPDATING
@ -31,6 +31,12 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 13.x IS SLOW:
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disable the most expensive debugging functionality run
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disable the most expensive debugging functionality run
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"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
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"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
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20190416:
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The loadable random module KPI has changed; the random_infra_init()
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routine now requires a 3rd function pointer for a bool (*)(void)
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method that returns true if the random device is seeded (and
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therefore unblocked).
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20190404:
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20190404:
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r345895 reverts r320698. This implies that an nfsuserd(8) daemon
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r345895 reverts r320698. This implies that an nfsuserd(8) daemon
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built from head sources between r320757 (July 6, 2017) and
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built from head sources between r320757 (July 6, 2017) and
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@ -1668,6 +1668,7 @@ MLINKS+=psignal.9 gsignal.9 \
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psignal.9 tdsignal.9
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psignal.9 tdsignal.9
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MLINKS+=random.9 arc4rand.9 \
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MLINKS+=random.9 arc4rand.9 \
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random.9 arc4random.9 \
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random.9 arc4random.9 \
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random.9 is_random_seeded.9 \
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random.9 read_random.9 \
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random.9 read_random.9 \
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random.9 read_random_uio.9 \
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random.9 read_random_uio.9 \
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random.9 srandom.9
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random.9 srandom.9
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@ -26,13 +26,14 @@
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.\"
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.\"
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.\" $FreeBSD$
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.\" $FreeBSD$
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.\" "
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.\" "
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.Dd April 15, 2019
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.Dd April 16, 2019
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.Dt RANDOM 9
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.Dt RANDOM 9
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.Os
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.Os
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.Sh NAME
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.Sh NAME
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.Nm arc4rand ,
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.Nm arc4rand ,
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.Nm arc4random ,
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.Nm arc4random ,
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.Nm arc4random_buf ,
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.Nm arc4random_buf ,
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.Nm is_random_seeded ,
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.Nm random ,
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.Nm random ,
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.Nm read_random ,
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.Nm read_random ,
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.Nm read_random_uio ,
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.Nm read_random_uio ,
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@ -48,6 +49,8 @@
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.Fn arc4rand "void *ptr" "u_int length" "int reseed"
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.Fn arc4rand "void *ptr" "u_int length" "int reseed"
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.Pp
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.Pp
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.In sys/random.h
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.In sys/random.h
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.Ft bool
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.Fn is_random_seeded "void"
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.Ft void
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.Ft void
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.Fn read_random "void *buffer" "int count"
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.Fn read_random "void *buffer" "int count"
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.Ft int
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.Ft int
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@ -108,6 +111,13 @@ instead, use the
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family of functions.
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family of functions.
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.Pp
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.Pp
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The
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The
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.Fn is_random_seeded
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function can be used to check in advance if
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.Fn read_random
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will block.
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(If random is seeded, it will not block.)
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.Pp
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The
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.Fn read_random_uio
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.Fn read_random_uio
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function behaves identically to
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function behaves identically to
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.Xr read 2
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.Xr read 2
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@ -63,12 +63,20 @@ null_read_random(void *dummy __unused, u_int dummy2 __unused)
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panic("%s: no random module is loaded", __func__);
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panic("%s: no random module is loaded", __func__);
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}
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}
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static bool
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null_is_random_seeded(void)
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{
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return (false);
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}
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struct random_readers {
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struct random_readers {
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int (*read_random_uio)(struct uio *, bool);
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int (*read_random_uio)(struct uio *, bool);
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void (*read_random)(void *, u_int);
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void (*read_random)(void *, u_int);
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bool (*is_random_seeded)(void);
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} random_reader_context = {
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} random_reader_context = {
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(int (*)(struct uio *, bool))nullop,
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(int (*)(struct uio *, bool))nullop,
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null_read_random,
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null_read_random,
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null_is_random_seeded,
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};
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};
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struct sx randomdev_config_lock;
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struct sx randomdev_config_lock;
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@ -82,12 +90,15 @@ random_infra_sysinit(void *dummy __unused)
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SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysinit, NULL);
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SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysinit, NULL);
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void
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void
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random_infra_init(int (*p_random_read_uio)(struct uio *, bool), void (*p_random_read)(void *, u_int))
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random_infra_init(int (*p_random_read_uio)(struct uio *, bool),
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void (*p_random_read)(void *, u_int),
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bool (*p_is_random_seeded)(void))
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{
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{
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RANDOM_CONFIG_X_LOCK();
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RANDOM_CONFIG_X_LOCK();
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random_reader_context.read_random_uio = p_random_read_uio;
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random_reader_context.read_random_uio = p_random_read_uio;
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random_reader_context.read_random = p_random_read;
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random_reader_context.read_random = p_random_read;
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random_reader_context.is_random_seeded = p_is_random_seeded;
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RANDOM_CONFIG_X_UNLOCK();
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RANDOM_CONFIG_X_UNLOCK();
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}
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}
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@ -98,6 +109,7 @@ random_infra_uninit(void)
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RANDOM_CONFIG_X_LOCK();
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RANDOM_CONFIG_X_LOCK();
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random_reader_context.read_random_uio = (int (*)(struct uio *, bool))nullop;
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random_reader_context.read_random_uio = (int (*)(struct uio *, bool))nullop;
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random_reader_context.read_random = null_read_random;
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random_reader_context.read_random = null_read_random;
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random_reader_context.is_random_seeded = null_is_random_seeded;
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RANDOM_CONFIG_X_UNLOCK();
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RANDOM_CONFIG_X_UNLOCK();
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}
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}
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@ -129,4 +141,13 @@ read_random(void *buf, u_int len)
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RANDOM_CONFIG_S_UNLOCK();
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RANDOM_CONFIG_S_UNLOCK();
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}
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}
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bool
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is_random_seeded(void)
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{
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RANDOM_CONFIG_S_LOCK();
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random_reader_context.is_random_seeded();
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RANDOM_CONFIG_S_UNLOCK();
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}
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#endif /* defined(RANDOM_LOADABLE) */
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#endif /* defined(RANDOM_LOADABLE) */
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@ -62,11 +62,14 @@ __FBSDID("$FreeBSD$");
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#if defined(RANDOM_LOADABLE)
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#if defined(RANDOM_LOADABLE)
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#define READ_RANDOM_UIO _read_random_uio
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#define READ_RANDOM_UIO _read_random_uio
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#define READ_RANDOM _read_random
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#define READ_RANDOM _read_random
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#define IS_RANDOM_SEEDED _is_random_seeded
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static int READ_RANDOM_UIO(struct uio *, bool);
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static int READ_RANDOM_UIO(struct uio *, bool);
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static void READ_RANDOM(void *, u_int);
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static void READ_RANDOM(void *, u_int);
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static bool IS_RANDOM_SEEDED(void);
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#else
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#else
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#define READ_RANDOM_UIO read_random_uio
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#define READ_RANDOM_UIO read_random_uio
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#define READ_RANDOM read_random
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#define READ_RANDOM read_random
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#define IS_RANDOM_SEEDED is_random_seeded
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#endif
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#endif
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static d_read_t randomdev_read;
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static d_read_t randomdev_read;
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@ -93,7 +96,7 @@ random_alg_context_ra_init_alg(void *data)
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p_random_alg_context = &random_alg_context;
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p_random_alg_context = &random_alg_context;
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p_random_alg_context->ra_init_alg(data);
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p_random_alg_context->ra_init_alg(data);
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#if defined(RANDOM_LOADABLE)
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#if defined(RANDOM_LOADABLE)
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random_infra_init(READ_RANDOM_UIO, READ_RANDOM);
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random_infra_init(READ_RANDOM_UIO, READ_RANDOM, IS_RANDOM_SEEDED);
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#endif
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#endif
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}
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}
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@ -271,6 +274,12 @@ READ_RANDOM(void *random_buf, u_int len)
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}
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}
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}
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}
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bool
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IS_RANDOM_SEEDED(void)
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{
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return (p_random_alg_context->ra_seeded());
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}
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static __inline void
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static __inline void
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randomdev_accumulate(uint8_t *buf, u_int count)
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randomdev_accumulate(uint8_t *buf, u_int count)
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{
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{
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#define RANDOM_CONFIG_S_LOCK(x) sx_slock(&randomdev_config_lock)
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#define RANDOM_CONFIG_S_LOCK(x) sx_slock(&randomdev_config_lock)
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#define RANDOM_CONFIG_S_UNLOCK(x) sx_sunlock(&randomdev_config_lock)
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#define RANDOM_CONFIG_S_UNLOCK(x) sx_sunlock(&randomdev_config_lock)
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#define RANDOM_CONFIG_DEINIT_LOCK(x) sx_destroy(&randomdev_config_lock)
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#define RANDOM_CONFIG_DEINIT_LOCK(x) sx_destroy(&randomdev_config_lock)
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void random_infra_init(int (*)(struct uio *, bool), void (*)(void *, u_int));
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void random_infra_init(int (*)(struct uio *, bool), void (*)(void *, u_int),
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bool (*)(void));
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void random_infra_uninit(void);
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void random_infra_uninit(void);
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#endif
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#endif
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@ -60,7 +60,7 @@
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* in the range 5 to 9.
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* in the range 5 to 9.
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*/
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*/
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#undef __FreeBSD_version
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#undef __FreeBSD_version
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#define __FreeBSD_version 1300018 /* Master, propagated to newvers */
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#define __FreeBSD_version 1300019 /* Master, propagated to newvers */
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/*
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/*
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* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
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* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
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#if defined(DEV_RANDOM)
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#if defined(DEV_RANDOM)
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void read_random(void *, u_int);
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void read_random(void *, u_int);
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int read_random_uio(struct uio *, bool);
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int read_random_uio(struct uio *, bool);
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bool is_random_seeded(void);
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#else
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#else
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static __inline int
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static __inline int
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read_random_uio(void *a __unused, u_int b __unused)
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read_random_uio(void *a __unused, u_int b __unused)
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@ -50,6 +51,11 @@ static __inline void
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read_random(void *a __unused, u_int b __unused)
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read_random(void *a __unused, u_int b __unused)
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{
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{
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}
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}
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static __inline bool
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is_random_seeded(void)
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{
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return (false);
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}
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#endif
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#endif
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/*
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/*
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