Differential D17050 Diff 49363 head/lib/libc/gen/getentropy.c

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head/lib/libc/gen/getentropy.c

Show All 28 Lines
#include <sys/cdefs.h>		#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");		__FBSDID("$FreeBSD$");

#include <sys/param.h>		#include <sys/param.h>
#include <sys/random.h>		#include <sys/random.h>
#include <sys/sysctl.h>		#include <sys/sysctl.h>

#include <errno.h>		#include <errno.h>
		#include <signal.h>
#include <stdbool.h>		#include <stdbool.h>
#include <stdlib.h>		#include <stdlib.h>

#include "libc_private.h"		#include "libc_private.h"

/* First __FreeBSD_version bump after introduction of getrandom(2) (r331279) */		/* First __FreeBSD_version bump after introduction of getrandom(2) (r331279) */
#define GETRANDOM_FIRST 1200061		#define GETRANDOM_FIRST 1200061

extern int __sysctl(int , u_int, void , size_t , void , size_t);		extern int __sysctl(int , u_int, void , size_t , void , size_t);

		static inline void
		_getentropy_fail(void)
		{
		raise(SIGKILL);
		}

static size_t		static size_t
arnd_sysctl(u_char *buf, size_t size)		arnd_sysctl(u_char *buf, size_t size)
{		{
int mib[2];		int mib[2];
size_t len, done;		size_t len, done;

mib[0] = CTL_KERN;		mib[0] = CTL_KERN;
mib[1] = KERN_ARND;		mib[1] = KERN_ARND;
Show All 27 Lines	getentropy_fallback(void *buf, size_t buflen)
if (buf == NULL && buflen > 0) {		if (buf == NULL && buflen > 0) {
errno = EFAULT;		errno = EFAULT;
return (-1);		return (-1);
}		}
if (arnd_sysctl(buf, buflen) != buflen) {		if (arnd_sysctl(buf, buflen) != buflen) {
if (errno == EFAULT)		if (errno == EFAULT)
return (-1);		return (-1);
/*		/*
* This cannot happen. _arc4_sysctl() spins until the random		* This cannot happen. arnd_sysctl() spins until the random
* device is seeded and then repeatedly reads until the full		* device is seeded and then repeatedly reads until the full
* request is satisfied. The only way for this to return a zero		* request is satisfied. The only way for this to return a zero
* byte or short read is if sysctl(2) on the kern.arandom MIB		* byte or short read is if sysctl(2) on the kern.arandom MIB
* fails. In this case, exceping the user-provided-a-bogus-		* fails. In this case, excepting the user-provided-a-bogus-
* buffer EFAULT, give up (like for arc4random(3)'s arc4_stir).		* buffer EFAULT, give up (like for arc4random(3)'s arc4_stir).
*/		*/
abort();		_getentropy_fail();
}		}
return (0);		return (0);
}		}

int		int
getentropy(void *buf, size_t buflen)		getentropy(void *buf, size_t buflen)
{		{
ssize_t rd;		ssize_t rd;
Show All 18 Lines	if (have_getrandom) {
* caller is already in capability		* caller is already in capability
* mode, fallback to traditional		* mode, fallback to traditional
* method in this case.		* method in this case.
*/		*/
have_getrandom = false;		have_getrandom = false;
continue;		continue;
case EINTR:		case EINTR:
continue;		continue;
default:		case EFAULT:
return (-1);		return (-1);
		default:
		_getentropy_fail();
}		}
}		}
} else {		} else {
return (getentropy_fallback(buf, buflen));		return (getentropy_fallback(buf, buflen));
}		}

/* This cannot happen. */		/* This cannot happen. */
if (rd == 0)		if (rd == 0)
abort();		_getentropy_fail();

buf = (char *)buf + rd;		buf = (char *)buf + rd;
buflen -= rd;		buflen -= rd;
}		}

return (0);		return (0);
}		}