1 /* 2 * This file and its contents are supplied under the terms of the 3 * Common Development and Distribution License ("CDDL"), version 1.0. 4 * You may only use this file in accordance with the terms of version 5 * 1.0 of the CDDL. 6 * 7 * A full copy of the text of the CDDL should have accompanied this 8 * source. A copy of the CDDL is also available via the Internet at 9 * http://www.illumos.org/license/CDDL. 10 */ 11 12 /* 13 * Copyright (c) 2018, Joyent, Inc. 14 */ 15 16 /* 17 * getrandom system call implementation 18 */ 19 20 #include <sys/types.h> 21 #include <sys/errno.h> 22 #include <sys/systm.h> 23 #include <sys/random.h> 24 #include <sys/ddi.h> 25 #include <sys/sunddi.h> 26 #include <sys/sysmacros.h> 27 28 #include <sys/random.h> 29 30 /* 31 * Impose a maximum upper bound on the number of bytes that we'll read in one 32 * go, ala a read of /dev/random. For /dev/urandom, we clamp it based on our 33 * return value, because the system call returns an int, we can't handle more 34 * than INT_MAX. 35 */ 36 #define MAXRANDBYTES 1024 37 #define MAXURANDBYTES INT_MAX 38 39 ssize_t 40 getrandom(void *bufp, size_t buflen, unsigned int flags) 41 { 42 int out = 0; 43 uint8_t rbytes[128]; 44 uint8_t *buf = bufp; 45 46 if (flags & ~(GRND_NONBLOCK | GRND_RANDOM)) 47 return (set_errno(EINVAL)); 48 49 if ((flags & GRND_RANDOM) && buflen > MAXRANDBYTES) { 50 buflen = MAXRANDBYTES; 51 } else if (buflen > MAXURANDBYTES) { 52 buflen = MAXURANDBYTES; 53 } 54 55 while (out < buflen) { 56 int err; 57 size_t len = MIN(sizeof (rbytes), buflen - out); 58 59 if (flags & GRND_RANDOM) { 60 if (flags & GRND_NONBLOCK) 61 err = random_get_bytes(rbytes, len); 62 else 63 err = random_get_blocking_bytes(rbytes, len); 64 } else { 65 err = random_get_pseudo_bytes(rbytes, len); 66 } 67 68 if (err == 0) { 69 if (ddi_copyout(rbytes, buf + out, len, 0) != 0) 70 return (set_errno(EFAULT)); 71 out += len; 72 } else if (err == EAGAIN && out > 0) { 73 break; 74 } else { 75 return (set_errno(err)); 76 } 77 } 78 79 return (out); 80 } 81