Differential D22839 Diff 78092 head/lib/libc/gen/arc4random.c

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head/lib/libc/gen/arc4random.c

Show All 21 Lines
/*		/*
* ChaCha based random number generator for OpenBSD.		* ChaCha based random number generator for OpenBSD.
*/		*/

#include <sys/cdefs.h>		#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");		__FBSDID("$FreeBSD$");

#include "namespace.h"		#include "namespace.h"
		#if defined(__FreeBSD__)
		#include <assert.h>
		#endif
#include <fcntl.h>		#include <fcntl.h>
#include <limits.h>		#include <limits.h>
#include <pthread.h>		#include <pthread.h>
#include <signal.h>		#include <signal.h>
#include <stdint.h>		#include <stdint.h>
#include <stdlib.h>		#include <stdlib.h>
#include <string.h>		#include <string.h>
#include <unistd.h>		#include <unistd.h>
Show All 25 Lines	static struct _rs {
size_t rs_have; /* valid bytes at end of rs_buf */		size_t rs_have; /* valid bytes at end of rs_buf */
size_t rs_count; /* bytes till reseed */		size_t rs_count; /* bytes till reseed */
} *rs;		} *rs;

/* Maybe be preserved in fork children, if _rs_allocate() decides. */		/* Maybe be preserved in fork children, if _rs_allocate() decides. */
static struct _rsx {		static struct _rsx {
chacha_ctx rs_chacha; /* chacha context for random keystream */		chacha_ctx rs_chacha; /* chacha context for random keystream */
u_char rs_buf[RSBUFSZ]; /* keystream blocks */		u_char rs_buf[RSBUFSZ]; /* keystream blocks */
		#ifdef __FreeBSD__
		uint32_t rs_seed_generation; /* 32-bit userspace RNG version */
		#endif
} *rsx;		} *rsx;

static inline int _rs_allocate(struct _rs , struct _rsx );		static inline int _rs_allocate(struct _rs , struct _rsx );
static inline void _rs_forkdetect(void);		static inline void _rs_forkdetect(void);
#include "arc4random.h"		#include "arc4random.h"

static inline void _rs_rekey(u_char *dat, size_t datlen);		static inline void _rs_rekey(u_char *dat, size_t datlen);

Show All 12 Lines	_rs_init(u_char *buf, size_t n)
chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ, NULL);		chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ, NULL);
}		}

static void		static void
_rs_stir(void)		_rs_stir(void)
{		{
u_char rnd[KEYSZ + IVSZ];		u_char rnd[KEYSZ + IVSZ];

		#if defined(__FreeBSD__)
		bool need_init;

		/*
		* De-couple allocation (which locates the vdso_fxrngp pointer in
		* auxinfo) from initialization. This allows us to read the root seed
		* version before we fetch system entropy, maintaining the invariant
		* that the PRF was seeded with entropy from rs_seed_generation or a
		* later generation. But never seeded from an earlier generation.
		* This invariant prevents us from missing a root reseed event.
		*/
		need_init = false;
		if (rs == NULL) {
		if (_rs_allocate(&rs, &rsx) == -1)
		abort();
		need_init = true;
		}
		/*
		* Transition period: new userspace on old kernel. This should become
		* a hard error at some point, if the scheme is adopted.
		*/
		if (vdso_fxrngp != NULL)
		rsx->rs_seed_generation =
		fxrng_load_acq_generation(&vdso_fxrngp->fx_generation32);
		#endif

if (getentropy(rnd, sizeof rnd) == -1)		if (getentropy(rnd, sizeof rnd) == -1)
_getentropy_fail();		_getentropy_fail();

		#if !defined(__FreeBSD__)
if (!rs)		if (!rs)
_rs_init(rnd, sizeof(rnd));		_rs_init(rnd, sizeof(rnd));
		#else /* __FreeBSD__ */
		assert(rs != NULL);
		if (need_init)
		_rs_init(rnd, sizeof(rnd));
		#endif
else		else
_rs_rekey(rnd, sizeof(rnd));		_rs_rekey(rnd, sizeof(rnd));
explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */		explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */

/* invalidate rs_buf */		/* invalidate rs_buf */
rs->rs_have = 0;		rs->rs_have = 0;
memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));		memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));

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