From e9ac27430c0c639c1f89b1f048a44f6cea0ec265 Mon Sep 17 00:00:00 2001 From: Conrad Meyer Date: Wed, 21 Mar 2018 01:15:45 +0000 Subject: [PATCH] Implement getrandom(2) and getentropy(3) The general idea here is to provide userspace programs with well-defined sources of entropy, in a fashion that doesn't require opening a new file descriptor (ulimits) or accessing paths (/dev/urandom may be restricted by chroot or capsicum). getrandom(2) is the more general API, and comes from the Linux world. Since our urandom and random devices are identical, the GRND_RANDOM flag is ignored. getentropy(3) is added as a compatibility shim for the OpenBSD API. truss(1) support is included. Tests for both system calls are provided. Coverage is believed to be at least as comprehensive as LTP getrandom(2) test coverage. Additionally, instructions for running the LTP tests directly against FreeBSD are provided in the "Test Plan" section of the Differential revision linked below. (They pass, of course.) PR: 194204 Reported by: David CARLIER Discussed with: cperciva, delphij, jhb, markj Relnotes: maybe Differential Revision: https://reviews.freebsd.org/D14500 --- include/unistd.h | 1 + lib/libc/gen/Makefile.inc | 2 + lib/libc/gen/Symbol.map | 1 + lib/libc/gen/getentropy.3 | 86 ++++++++++++++++++ lib/libc/gen/getentropy.c | 70 +++++++++++++++ lib/libc/sys/Makefile.inc | 1 + lib/libc/sys/Symbol.map | 3 + lib/libc/sys/getrandom.2 | 121 +++++++++++++++++++++++++ lib/libc/tests/gen/Makefile | 3 + lib/libc/tests/gen/getentropy_test.c | 84 +++++++++++++++++ sys/compat/freebsd32/syscalls.master | 2 + sys/conf/files | 1 + sys/kern/sys_getrandom.c | 97 ++++++++++++++++++++ sys/kern/syscalls.master | 2 + sys/sys/random.h | 8 +- tests/sys/kern/Makefile | 5 ++ tests/sys/kern/sys_getrandom.c | 130 +++++++++++++++++++++++++++ usr.bin/truss/syscalls.c | 2 + 18 files changed, 617 insertions(+), 2 deletions(-) create mode 100644 lib/libc/gen/getentropy.3 create mode 100644 lib/libc/gen/getentropy.c create mode 100644 lib/libc/sys/getrandom.2 create mode 100644 lib/libc/tests/gen/getentropy_test.c create mode 100644 sys/kern/sys_getrandom.c create mode 100644 tests/sys/kern/sys_getrandom.c diff --git a/include/unistd.h b/include/unistd.h index 1d6f474a1239..7e46f0e69712 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -506,6 +506,7 @@ int execvP(const char *, const char *, char * const *); int feature_present(const char *); char *fflagstostr(u_long); int getdomainname(char *, int); +int getentropy(void *, size_t); int getgrouplist(const char *, gid_t, gid_t *, int *); int getloginclass(char *, size_t); mode_t getmode(const void *, mode_t); diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc index d6e73ecaf087..c19655ec8a16 100644 --- a/lib/libc/gen/Makefile.inc +++ b/lib/libc/gen/Makefile.inc @@ -57,6 +57,7 @@ SRCS+= __getosreldate.c \ getcap.c \ getcwd.c \ getdomainname.c \ + getentropy.c \ getgrent.c \ getgrouplist.c \ gethostname.c \ @@ -220,6 +221,7 @@ MAN+= alarm.3 \ getcwd.3 \ getdiskbyname.3 \ getdomainname.3 \ + getentropy.3 \ getfsent.3 \ getgrent.3 \ getgrouplist.3 \ diff --git a/lib/libc/gen/Symbol.map b/lib/libc/gen/Symbol.map index 44fb85a4fabe..908206e18e94 100644 --- a/lib/libc/gen/Symbol.map +++ b/lib/libc/gen/Symbol.map @@ -408,6 +408,7 @@ FBSD_1.5 { fts_set; fts_set_clientptr; ftw; + getentropy; getmntinfo; glob; globfree; diff --git a/lib/libc/gen/getentropy.3 b/lib/libc/gen/getentropy.3 new file mode 100644 index 000000000000..dae17cc1b5c1 --- /dev/null +++ b/lib/libc/gen/getentropy.3 @@ -0,0 +1,86 @@ +.\" $OpenBSD: getentropy.2,v 1.8 2015/01/31 00:20:12 schwarze Exp $ +.\" +.\" Copyright (c) 2018 Conrad Meyer +.\" Copyright (c) 2014 Theo de Raadt +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.\" $FreeBSD$ +.\" +.Dd February 24, 2018 +.Dt GETENTROPY 3 +.Os +.Sh NAME +.Nm getentropy +.Nd get entropy +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In unistd.h +.Ft int +.Fn getentropy "void *buf" "size_t buflen" +.Sh DESCRIPTION +.Fn getentropy +fills a buffer with high-quality random data. +.Pp +The maximum +.Fa buflen +permitted is 256 bytes. +.Pp +If it does not produce an error, +.Fn getentropy +always provides the requested number of bytes of random data. +.Pp +Similar to reading from +.Pa /dev/urandom +just after boot, +.Fn getentropy +may block until the system has collected enough entropy to seed the CSPRNG. +.Sh IMPLEMENTATION NOTES +The +.Fn getentropy +function is implemented using +.Xr getrandom 2 . +.Sh RETURN VALUES +.Rv -std +.Sh ERRORS +.Fn getentropy +will succeed unless: +.Bl -tag -width Er +.It Bq Er EFAULT +The +.Fa buf +parameter points to an +invalid address. +.It Bq Er EIO +Too many bytes requested, or some other fatal error occurred. +.El +.Sh SEE ALSO +.Xr arc4random 3 , +.Xr getrandom 2 , +.Xr random 4 +.Sh STANDARDS +.Fn getentropy +is non-standard. +It is present on +.Ox +and Linux. +.Sh HISTORY +The +.Fn getentropy +function appeared in +.Ox 5.6 . +The +.Fx +libc compatibility shim first appeared in +.Fx 12.0 . diff --git a/lib/libc/gen/getentropy.c b/lib/libc/gen/getentropy.c new file mode 100644 index 000000000000..8484570ba78d --- /dev/null +++ b/lib/libc/gen/getentropy.c @@ -0,0 +1,70 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2018 Conrad Meyer + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +__FBSDID("$FreeBSD$"); + +#include +#include + +#include +#include + +#include "libc_private.h" + +int +getentropy(void *buf, size_t buflen) +{ + ssize_t rd; + + if (buflen > 256) { + errno = EIO; + return (-1); + } + + while (buflen > 0) { + rd = getrandom(buf, buflen, 0); + if (rd == -1) { + if (errno == EINTR) + continue; + else if (errno == ENOSYS) + abort(); + else + return (-1); + } + + /* This cannot happen. */ + if (rd == 0) + abort(); + + buf = (char *)buf + rd; + buflen -= rd; + } + + return (0); +} diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc index c1237cdab68f..39e1974375c7 100644 --- a/lib/libc/sys/Makefile.inc +++ b/lib/libc/sys/Makefile.inc @@ -197,6 +197,7 @@ MAN+= abort2.2 \ getpgrp.2 \ getpid.2 \ getpriority.2 \ + getrandom.2 \ getrlimit.2 \ getrusage.2 \ getsid.2 \ diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map index ae58d4cd481d..1a711c99ba8a 100644 --- a/lib/libc/sys/Symbol.map +++ b/lib/libc/sys/Symbol.map @@ -392,6 +392,7 @@ FBSD_1.5 { getdents; getdirentries; getfsstat; + getrandom; kevent; lstat; mknod; @@ -627,6 +628,8 @@ FBSDprivate_1.0 { __sys_getppid; _getpriority; __sys_getpriority; + _getrandom; + __sys_getrandom; _getresgid; __sys_getresgid; _getresuid; diff --git a/lib/libc/sys/getrandom.2 b/lib/libc/sys/getrandom.2 new file mode 100644 index 000000000000..7f2144709beb --- /dev/null +++ b/lib/libc/sys/getrandom.2 @@ -0,0 +1,121 @@ +.\" Copyright (c) 2018 Conrad Meyer +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd February 24, 2018 +.Dt GETRANDOM 2 +.Os +.Sh NAME +.Nm getrandom +.Nd get random data +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/random.h +.Ft ssize_t +.Fn getrandom "void *buf" "size_t buflen" "unsigned int flags" +.Sh DESCRIPTION +.Fn getrandom +fills +.Fa buf +with up to +.Fa buflen +bytes of random data. +.Pp +The +.Fa flags +argument may include zero or more of the following: +.Bl -tag -width _GRND_NONBLOCK_ +.It Ql GRND_NONBLOCK +Return +.Er EAGAIN +instead of blocking, if the +.Xr random 4 +device has not yet been seeded. +By default, +.Fn getrandom +will block until the device is seeded. +.It Ql GRND_RANDOM +This flag does nothing on +.Fx . +.Pa /dev/random +and +.Pa /dev/urandom +are identical. +.El +.Pp +If the +.Xr random 4 +device has been seeded, reads of up to 256 bytes will always return as many +bytes as requested and will not be interrupted by signals. +.Pp +.Sh RETURN VALUES +Upon successful completion, the number of bytes which were actually read is +returned. +For requests larger than 256 bytes, this can be fewer bytes than were +requested. +Otherwise, -1 is returned and the global variable +.Va errno +is set to indicate the error. +.Sh ERRORS +The +.Fn getrandom +operation returns the following errors: +.Bl -tag -width Er +.It Bq Er EAGAIN +The +.Ql GRND_NONBLOCK +flag was set and the +.Xr random 4 +device was not yet seeded. +.It Bq Er EFAULT +The +.Fa buf +parameter points to an invalid address. +.It Bq Er EINTR +The sleep was interrupted by a signal. +.It Bq Er EINVAL +An invalid +.Fa flags +was specified. +.It Bq Er EINVAL +The requested +.Fa buflen +was larger than +.Dv IOSIZE_MAX . +.El +.Sh SEE ALSO +.Xr arc4random 3 , +.Xr getentropy 3 , +.Xr random 4 +.Sh STANDARDS +.Fn getentropy +is non-standard. +It is present in Linux. +.Sh HISTORY +The +.Fn getrandom +system call first appeared in +.Fx 12.0 . diff --git a/lib/libc/tests/gen/Makefile b/lib/libc/tests/gen/Makefile index 0087a7069575..80bec69bbcaa 100644 --- a/lib/libc/tests/gen/Makefile +++ b/lib/libc/tests/gen/Makefile @@ -10,6 +10,7 @@ ATF_TESTS_C+= fmtmsg_test ATF_TESTS_C+= fnmatch2_test ATF_TESTS_C+= fpclassify2_test ATF_TESTS_C+= ftw_test +ATF_TESTS_C+= getentropy_test ATF_TESTS_C+= getmntinfo_test ATF_TESTS_C+= glob2_test ATF_TESTS_C+= makecontext_test @@ -61,6 +62,8 @@ NETBSD_ATF_TESTS_C+= vis_test .include "../Makefile.netbsd-tests" +CFLAGS.getentropy_test+= -I${SRCTOP}/include +LIBADD.getentropy_test+= c LIBADD.humanize_number_test+= util LIBADD.fpclassify_test+=m diff --git a/lib/libc/tests/gen/getentropy_test.c b/lib/libc/tests/gen/getentropy_test.c new file mode 100644 index 000000000000..731bed775263 --- /dev/null +++ b/lib/libc/tests/gen/getentropy_test.c @@ -0,0 +1,84 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2018 Conrad Meyer + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +__FBSDID("$FreeBSD$"); + +#include +#include +#include + +#include + +ATF_TC_WITHOUT_HEAD(getentropy_count); +ATF_TC_BODY(getentropy_count, tc) +{ + char buf[2]; + int ret; + + /* getentropy(2) does not modify buf past the requested length */ + buf[1] = 0x7C; + ret = getentropy(buf, 1); + ATF_REQUIRE_EQ(ret, 0); + ATF_REQUIRE_EQ(buf[1], 0x7C); +} + +ATF_TC_WITHOUT_HEAD(getentropy_fault); +ATF_TC_BODY(getentropy_fault, tc) +{ + int ret; + + ret = getentropy(NULL, 1); + ATF_REQUIRE_EQ(ret, -1); + ATF_REQUIRE_EQ(errno, EFAULT); +} + +ATF_TC_WITHOUT_HEAD(getentropy_sizes); +ATF_TC_BODY(getentropy_sizes, tc) +{ + char buf[512]; + + ATF_REQUIRE_EQ(getentropy(buf, sizeof(buf)), -1); + ATF_REQUIRE_EQ(errno, EIO); + ATF_REQUIRE_EQ(getentropy(buf, 257), -1); + ATF_REQUIRE_EQ(errno, EIO); + + /* Smaller sizes always succeed: */ + ATF_REQUIRE_EQ(getentropy(buf, 256), 0); + ATF_REQUIRE_EQ(getentropy(buf, 128), 0); + ATF_REQUIRE_EQ(getentropy(buf, 0), 0); +} + +ATF_TP_ADD_TCS(tp) +{ + + ATF_TP_ADD_TC(tp, getentropy_count); + ATF_TP_ADD_TC(tp, getentropy_fault); + ATF_TP_ADD_TC(tp, getentropy_sizes); + return (atf_no_error()); +} diff --git a/sys/compat/freebsd32/syscalls.master b/sys/compat/freebsd32/syscalls.master index 50613d037ca8..6e9a3a63d61f 100644 --- a/sys/compat/freebsd32/syscalls.master +++ b/sys/compat/freebsd32/syscalls.master @@ -1116,5 +1116,7 @@ cpuwhich_t which, uint32_t id1, uint32_t id2, \ size_t domainsetsize, domainset_t *mask, \ int policy); } +563 AUE_NULL NOPROTO { int getrandom(void *buf, size_t buflen, \ + unsigned int flags); } ; vim: syntax=off diff --git a/sys/conf/files b/sys/conf/files index 99b9c87734bb..92f39e6b1443 100644 --- a/sys/conf/files +++ b/sys/conf/files @@ -3895,6 +3895,7 @@ kern/subr_vmem.c standard kern/subr_witness.c optional witness kern/sys_capability.c standard kern/sys_generic.c standard +kern/sys_getrandom.c standard kern/sys_pipe.c standard kern/sys_procdesc.c standard kern/sys_process.c standard diff --git a/sys/kern/sys_getrandom.c b/sys/kern/sys_getrandom.c new file mode 100644 index 000000000000..34916df79be7 --- /dev/null +++ b/sys/kern/sys_getrandom.c @@ -0,0 +1,97 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2018 Conrad Meyer + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +__FBSDID("$FreeBSD$"); + +#include "opt_compat.h" + +#include +#include +#include +#include +#include +#include +#include + +#define GRND_VALIDFLAGS (GRND_NONBLOCK | GRND_RANDOM) + +/* + * random_read_uio(9) returns EWOULDBLOCK if a nonblocking request would block, + * but the Linux API name is EAGAIN. On FreeBSD, they have the same numeric + * value for now. + */ +CTASSERT(EWOULDBLOCK == EAGAIN); + +static int +kern_getrandom(struct thread *td, void *user_buf, size_t buflen, + unsigned int flags) +{ + struct uio auio; + struct iovec aiov; + int error; + + if ((flags & ~GRND_VALIDFLAGS) != 0) + return (EINVAL); + if (buflen > IOSIZE_MAX) + return (EINVAL); + + if (buflen == 0) { + td->td_retval[0] = 0; + return (0); + } + + aiov.iov_base = user_buf; + aiov.iov_len = buflen; + auio.uio_iov = &aiov; + auio.uio_iovcnt = 1; + auio.uio_offset = 0; + auio.uio_resid = buflen; + auio.uio_segflg = UIO_USERSPACE; + auio.uio_rw = UIO_READ; + auio.uio_td = td; + + error = read_random_uio(&auio, (flags & GRND_NONBLOCK) != 0); + if (error == 0) + td->td_retval[0] = buflen - auio.uio_resid; + return (error); +} + +#ifndef _SYS_SYSPROTO_H_ +struct getrandom_args { + void *buf; + size_t buflen; + unsigned int flags; +}; +#endif + +int +sys_getrandom(struct thread *td, struct getrandom_args *uap) +{ + return (kern_getrandom(td, uap->buf, uap->buflen, uap->flags)); +} diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master index 00d47533c4e5..871d379034c6 100644 --- a/sys/kern/syscalls.master +++ b/sys/kern/syscalls.master @@ -1021,6 +1021,8 @@ cpuwhich_t which, id_t id, \ size_t domainsetsize, domainset_t *mask, \ int policy); } +563 AUE_NULL STD { int getrandom(void *buf, size_t buflen, \ + unsigned int flags); } ; Please copy any additions and changes to the following compatability tables: ; sys/compat/freebsd32/syscalls.master diff --git a/sys/sys/random.h b/sys/sys/random.h index cf8e663d8f9e..ed71f34b3386 100644 --- a/sys/sys/random.h +++ b/sys/sys/random.h @@ -31,10 +31,10 @@ #ifndef _SYS_RANDOM_H_ #define _SYS_RANDOM_H_ -#ifdef _KERNEL - #include +#ifdef _KERNEL + #if !defined(KLD_MODULE) #if defined(RANDOM_LOADABLE) && defined(RANDOM_YARROW) #error "Cannot define both RANDOM_LOADABLE and RANDOM_YARROW" @@ -127,4 +127,8 @@ void random_harvest_deregister_source(enum random_entropy_source); #endif /* _KERNEL */ +#define GRND_NONBLOCK 0x1 +#define GRND_RANDOM 0x2 +ssize_t getrandom(void *buf, size_t buflen, unsigned int flags); + #endif /* _SYS_RANDOM_H_ */ diff --git a/tests/sys/kern/Makefile b/tests/sys/kern/Makefile index d053ecccd940..3a0dbcbce25c 100644 --- a/tests/sys/kern/Makefile +++ b/tests/sys/kern/Makefile @@ -11,6 +11,7 @@ ATF_TESTS_C+= ptrace_test TEST_METADATA.ptrace_test+= timeout="15" ATF_TESTS_C+= reaper PLAIN_TESTS_C+= subr_unit_test +ATF_TESTS_C+= sys_getrandom ATF_TESTS_C+= unix_seqpacket_test ATF_TESTS_C+= unix_passfd_test TEST_METADATA.unix_seqpacket_test+= timeout="15" @@ -21,6 +22,10 @@ ATF_TESTS_SH+= coredump_phnum_test BINDIR= ${TESTSDIR} PROGS+= coredump_phnum_helper +CFLAGS.sys_getrandom+= -I${SRCTOP}/sys/contrib/zstd/lib +LIBADD.sys_getrandom+= zstd +LIBADD.sys_getrandom+= c +LIBADD.sys_getrandom+= pthread LIBADD.ptrace_test+= pthread LIBADD.unix_seqpacket_test+= pthread diff --git a/tests/sys/kern/sys_getrandom.c b/tests/sys/kern/sys_getrandom.c new file mode 100644 index 000000000000..d75e54003261 --- /dev/null +++ b/tests/sys/kern/sys_getrandom.c @@ -0,0 +1,130 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2018 Conrad Meyer + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +__FBSDID("$FreeBSD$"); + +#include +#include +#include + +#include + +#include + +const static unsigned valid_flags[] = { 0, GRND_NONBLOCK, GRND_RANDOM, + GRND_NONBLOCK | GRND_RANDOM }; + +ATF_TC_WITHOUT_HEAD(getrandom_randomness); +ATF_TC_BODY(getrandom_randomness, tc) +{ + char randomb[4096], compressed[5000]; + ssize_t ret; + size_t i, j, c; + unsigned mode; + + for (i = 0; i < nitems(valid_flags); i++) { + mode = valid_flags[i]; + + /* Get new random data, filling randomb. */ + + memset(randomb, 0, sizeof(randomb)); + + for (j = 0; j < sizeof(randomb);) { + ret = getrandom(&randomb[j], sizeof(randomb) - j, mode); + if (ret < 0 && (mode & GRND_NONBLOCK) != 0 && + errno == EAGAIN) + continue; + + ATF_REQUIRE_MSG(ret >= 0, "other error: %d", errno); + ATF_REQUIRE_MSG(ret > 0, "bogus zero return"); + + j += (size_t)ret; + } + + /* Perform compressibility test */ + c = ZSTD_compress(compressed, sizeof(compressed), randomb, + sizeof(randomb), ZSTD_maxCLevel()); + ATF_REQUIRE_MSG(!ZSTD_isError(c), "zstd compress: %s", + ZSTD_getErrorName(c)); + + /* + * If the output is very compressible, it's probably not random + */ + ATF_REQUIRE_MSG(c > (sizeof(randomb) * 4 / 5), + "purportedly random data was compressible: %zu/%zu or %f%%", + c, sizeof(randomb), (double)c / (double)sizeof(randomb)); + } +} + +ATF_TC_WITHOUT_HEAD(getrandom_fault); +ATF_TC_BODY(getrandom_fault, tc) +{ + ssize_t ret; + + ret = getrandom(NULL, 1, 0); + ATF_REQUIRE_EQ(ret, -1); + ATF_REQUIRE_EQ(errno, EFAULT); +} + +ATF_TC_WITHOUT_HEAD(getrandom_count); +ATF_TC_BODY(getrandom_count, tc) +{ + char buf[4096], reference[4096]; + ssize_t ret; + + /* getrandom(2) does not modify buf past the requested length */ + _Static_assert(sizeof(reference) == sizeof(buf), "must match"); + memset(reference, 0x7C, sizeof(reference)); + + memset(buf, 0x7C, sizeof(buf)); + ret = getrandom(buf, 1, 0); + ATF_REQUIRE_EQ(ret, 1); + ATF_REQUIRE_EQ(memcmp(&buf[1], reference, sizeof(reference) - 1), 0); + + memset(buf, 0x7C, sizeof(buf)); + ATF_REQUIRE_EQ(getrandom(buf, 15, 0), 15); + ATF_REQUIRE_EQ(memcmp(&buf[15], reference, sizeof(reference) - 15), 0); + + memset(buf, 0x7C, sizeof(buf)); + ATF_REQUIRE_EQ(getrandom(buf, 255, 0), 255); + ATF_REQUIRE_EQ(memcmp(&buf[255], reference, sizeof(reference) - 255), 0); + + memset(buf, 0x7C, sizeof(buf)); + ATF_REQUIRE_EQ(getrandom(buf, 4095, 0), 4095); + ATF_REQUIRE_EQ(memcmp(&buf[4095], reference, sizeof(reference) - 4095), 0); +} + +ATF_TP_ADD_TCS(tp) +{ + + ATF_TP_ADD_TC(tp, getrandom_count); + ATF_TP_ADD_TC(tp, getrandom_fault); + ATF_TP_ADD_TC(tp, getrandom_randomness); + return (atf_no_error()); +} diff --git a/usr.bin/truss/syscalls.c b/usr.bin/truss/syscalls.c index 685291ebc56e..f92bc7485957 100644 --- a/usr.bin/truss/syscalls.c +++ b/usr.bin/truss/syscalls.c @@ -259,6 +259,8 @@ static struct syscall decoded_syscalls[] = { .args = { { Int, 0 } } }, { .name = "getpriority", .ret_type = 1, .nargs = 2, .args = { { Priowhich, 0 }, { Int, 1 } } }, + { .name = "getrandom", .ret_type = 1, .nargs = 3, + .args = { { BinString | OUT, 0 }, { Sizet, 1 }, { UInt, 2 } } }, { .name = "getrlimit", .ret_type = 1, .nargs = 2, .args = { { Resource, 0 }, { Rlimit | OUT, 1 } } }, { .name = "getrusage", .ret_type = 1, .nargs = 2,