189 lines
5.5 KiB
Bash
Executable File
189 lines
5.5 KiB
Bash
Executable File
#!/bin/sh
|
|
|
|
#
|
|
# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
|
|
#
|
|
# Copyright (c) 2020 Peter Holm
|
|
#
|
|
# 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.
|
|
#
|
|
|
|
# getrandom(2) DoS scenario.
|
|
|
|
# panic: pmap_growkernel: no memory to grow kernel
|
|
# cpuid = 8
|
|
# time = 1582102582
|
|
# KDB: stack backtrace:
|
|
# db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe03e6992450
|
|
# vpanic() at vpanic+0x185/frame 0xfffffe03e69924b0
|
|
# panic() at panic+0x43/frame 0xfffffe03e6992510
|
|
# pmap_growkernel() at pmap_growkernel+0x2d4/frame 0xfffffe03e6992550
|
|
# vm_map_insert() at vm_map_insert+0x296/frame 0xfffffe03e69925f0
|
|
# vm_map_find() at vm_map_find+0x617/frame 0xfffffe03e69926d0
|
|
# kva_import() at kva_import+0x3c/frame 0xfffffe03e6992710
|
|
# vmem_try_fetch() at vmem_try_fetch+0xde/frame 0xfffffe03e6992760
|
|
# vmem_xalloc() at vmem_xalloc+0x4bb/frame 0xfffffe03e69927e0
|
|
# kva_import_domain() at kva_import_domain+0x36/frame 0xfffffe03e6992810
|
|
# vmem_try_fetch() at vmem_try_fetch+0xde/frame 0xfffffe03e6992860
|
|
# vmem_xalloc() at vmem_xalloc+0x4bb/frame 0xfffffe03e69928e0
|
|
# vmem_alloc() at vmem_alloc+0x8a/frame 0xfffffe03e6992930
|
|
# kmem_malloc_domainset() at kmem_malloc_domainset+0x92/frame 0xfffffe03e69929a0
|
|
# malloc() at malloc+0x162/frame 0xfffffe03e69929f0
|
|
# read_random_uio() at read_random_uio+0xa5/frame 0xfffffe03e6992a40
|
|
# sys_getrandom() at sys_getrandom+0x7b/frame 0xfffffe03e6992ac0
|
|
# amd64_syscall() at amd64_syscall+0x183/frame 0xfffffe03e6992bf0
|
|
# fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe03e6992bf0
|
|
# --- syscall (563, FreeBSD ELF64, sys_getrandom), rip = 0x80041899a, rsp = 0x7ffffffc3cb8, rbp = 0x7ffffffc3cd0 ---
|
|
# KDB: enter: panic
|
|
# [ thread pid 12095 tid 186584 ]
|
|
# Stopped at kdb_enter+0x37: movq $0,0x1084916(%rip)
|
|
# db> x/s version
|
|
# version: FreeBSD 13.0-CURRENT #0 r358094: Wed Feb 19 06:25:16 CET 2020\012 pho@t2.osted.lan:/usr/src/sys/amd64/compile/PHO\012
|
|
# db>
|
|
|
|
. ../default.cfg
|
|
|
|
dir=/tmp
|
|
odir=`pwd`
|
|
cd $dir
|
|
sed '1,/^EOF/d' < $odir/$0 > $dir/getrandom2.c
|
|
mycc -o getrandom2 -Wall -Wextra -O0 -g getrandom2.c || exit 1
|
|
rm -f getrandom2.c
|
|
cd $odir
|
|
|
|
cd /tmp
|
|
$dir/getrandom2
|
|
s=$?
|
|
[ -f getrandom2.core -a $s -eq 0 ] &&
|
|
{ ls -l getrandom2.core; s=1; }
|
|
cd $odir
|
|
|
|
rm -rf $dir/getrandom2
|
|
exit $s
|
|
|
|
EOF
|
|
#include <sys/param.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/random.h>
|
|
#include <sys/resource.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/wait.h>
|
|
|
|
#include <err.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stdatomic.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
static size_t mx;
|
|
static _Atomic(int) *share;
|
|
static int parallel;
|
|
static char *bp;
|
|
|
|
#define PARALLEL 40000 /* Arbitrary cap */
|
|
#define SYNC 0
|
|
|
|
static void
|
|
test(void)
|
|
{
|
|
int i;
|
|
|
|
alarm(180);
|
|
(void)atomic_fetch_add(&share[SYNC], 1);
|
|
while (atomic_load(&share[SYNC]) != parallel)
|
|
usleep(200000);
|
|
for (i = 0; i < 10; i++)
|
|
getrandom(bp, mx, 0);
|
|
// close(66);
|
|
|
|
_exit(0);
|
|
}
|
|
|
|
int
|
|
main(void)
|
|
{
|
|
pid_t *pids;
|
|
struct rlimit rlp;
|
|
size_t len;
|
|
size_t f, vsz;
|
|
u_int pages;
|
|
int e, i, status;
|
|
|
|
e = 0;
|
|
len = PAGE_SIZE;
|
|
if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
|
|
err(1, "mmap");
|
|
|
|
if (getrlimit(RLIMIT_NPROC, &rlp) < 0)
|
|
err(1, "getrlimit");
|
|
parallel = rlp.rlim_cur / 100 * 80;
|
|
if (parallel > PARALLEL)
|
|
parallel = PARALLEL;
|
|
pids = calloc(parallel, sizeof(pid_t));
|
|
|
|
vsz = sizeof(pages);
|
|
if (sysctlbyname("vm.stats.vm.v_free_count", &pages, &vsz, NULL, 0) != 0)
|
|
err(1, "sysctl(vm.stats.vm.v_free_count)");
|
|
f = pages;
|
|
f *= PAGE_SIZE;
|
|
|
|
if (getrlimit(RLIMIT_DATA, &rlp) < 0)
|
|
err(1,"getrlimit");
|
|
mx = rlp.rlim_cur;
|
|
if (mx > f / parallel)
|
|
mx = f / parallel;
|
|
if ((bp = mmap(NULL, mx, PROT_READ | PROT_WRITE, MAP_ANON, -1,
|
|
0)) == MAP_FAILED)
|
|
err(1, "mmap");
|
|
for (;;) {
|
|
if (getrandom(bp, mx, 0) != -1)
|
|
break;
|
|
mx = mx / 2;
|
|
}
|
|
printf("Max getrandom() buffer size is %zu, %d threads\n", mx,
|
|
parallel);
|
|
for (i = 0; i < parallel; i++) {
|
|
if ((pids[i] = fork()) == 0)
|
|
test();
|
|
if (pids[i] == -1)
|
|
err(1, "fork()");
|
|
}
|
|
for (i = 0; i < parallel; i++) {
|
|
if (waitpid(pids[i], &status, 0) == -1)
|
|
err(1, "waitpid(%d)", pids[i]);
|
|
if (status != 0) {
|
|
if (WIFSIGNALED(status))
|
|
fprintf(stderr,
|
|
"pid %d exit signal %d\n",
|
|
pids[i], WTERMSIG(status));
|
|
}
|
|
e += status == 0 ? 0 : 1;
|
|
}
|
|
|
|
return (e);
|
|
}
|