1#!/bin/sh 2 3# panic: Assertion *buflen >= 2 failed at ../../../kern/vfs_cache.c:2837 4# cpuid = 21 5# time = 1598296274 6# KDB: stack backtrace: 7# db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0149a9e860 8# vpanic() at vpanic+0x182/frame 0xfffffe0149a9e8b0 9# panic() at panic+0x43/frame 0xfffffe0149a9e910 10# vn_fullpath_any_smr() at vn_fullpath_any_smr+0x4df/frame 0xfffffe0149a9e980 11# sys___realpathat() at sys___realpathat+0x20b/frame 0xfffffe0149a9ead0 12# amd64_syscall() at amd64_syscall+0x159/frame 0xfffffe0149a9ebf0 13# fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe0149a9ebf0 14# --- syscall (0, FreeBSD ELF64, nosys), rip = 0x8004294ea, rsp = 0x7fffffffe548, rbp = 0x7fffffffe580 --- 15# KDB: enter: panic 16# [ thread pid 2831 tid 100306 ] 17# Stopped at kdb_enter+0x37: movq $0,0x10b4246(%rip) 18# db> x/s version 19# version: FreeBSD 13.0-CURRENT #0 r364722: Mon Aug 24 21:04:09 CEST 2020 20# pho@t2.osted.lan:/usr/src/sys/amd64/compile/PHO\012 21# db> 22 23[ `uname -p` != "amd64" ] && exit 0 24 25# Obtained from markj (syzkaller). 26# Fixed by r364723. 27 28. ../default.cfg 29kldstat -v | grep -q sctp || kldload sctp.ko 30cat > /tmp/syzkaller22.c <<EOF 31// autogenerated by syzkaller (https://github.com/google/syzkaller) 32 33#define _GNU_SOURCE 34 35#include <pwd.h> 36#include <stdarg.h> 37#include <stdbool.h> 38#include <stdint.h> 39#include <stdio.h> 40#include <stdlib.h> 41#include <string.h> 42#include <sys/endian.h> 43#include <sys/syscall.h> 44#include <unistd.h> 45 46uint64_t r[1] = {0xffffffffffffffff}; 47 48int main(void) 49{ 50 syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x1012ul, -1, 0ul); 51 intptr_t res = 0; 52 memcpy((void*)0x20000000, "./file0\000", 8); 53 syscall(SYS_open, 0x20000000ul, 0x200645ul, 0ul); 54 memcpy((void*)0x20000000, ".\000", 2); 55 res = syscall(SYS_open, 0x20000000ul, 0ul, 0ul); 56 if (res != -1) 57 r[0] = res; 58 memcpy((void*)0x20000240, "./file0\000", 8); 59 syscall(SYS___realpathat, r[0], 0x20000240ul, 0x20000280ul, 8ul, 0ul); 60 return 0; 61} 62EOF 63mycc -o /tmp/syzkaller22 -Wall -Wextra -O0 /tmp/syzkaller22.c || 64 exit 1 65 66(cd /tmp; timeout 1m ./syzkaller22) 67 68rm -f /tmp/syzkaller22 /tmp/syzkaller22.c /tmp/syzkaller22.core /tmp/file0 69exit 0 70