Sorry for the resend some mail servers rejected the mime type. Hi, I've been getting more into Kernel stuff lately and forged ahead with some syzkaller bug finding. I played with reducing it further as you can see from the attached c code but am moving on and hope to get better about this process moving forward as I'm still building out my test systems/debugging tools. Attached is the report and C repro that still triggers on a fresh git pull as of a few minutes ago, if you need anything else please let me know. Esme Linux syzkaller 5.0.0-rc1+ #5 SMP Tue Jan 8 20:39:33 EST 2019 x86_64 GNU/Linux GNU C 6.3.0 Binutils 2.28 Util-linux 2.29.2 Mount 2.29.2 Module-init-tools 23 E2fsprogs 1.43.4 Linux C Library 2.24 Dynamic linker (ldd) 2.24 Linux C++ Library 6.0.22 Procps 3.3.12 Sh-utils 8.26 Udev 232
// autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include <dirent.h> #include <endian.h> #include <errno.h> #include <fcntl.h> #include <setjmp.h> #include <signal.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/ioctl.h> #include <sys/prctl.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/types.h> #include <sys/wait.h> #include <time.h> #include <unistd.h> #include <linux/genetlink.h> #include <linux/netlink.h> unsigned long long procid; static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) { _longjmp(segv_env, 1); } exit(sig); } static void install_segv_handler(void) { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = SIG_IGN; syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); memset(&sa, 0, sizeof(sa)); sa.sa_sigaction = segv_handler; sa.sa_flags = SA_NODEFER | SA_SIGINFO; sigaction(SIGSEGV, &sa, NULL); sigaction(SIGBUS, &sa, NULL); } #define NONFAILING(...) { __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); if (_setjmp(segv_env) == 0) { __VA_ARGS__; } __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); } static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } static uint64_t current_time_ms(void) { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static long syz_open_dev(long a0, long a1, long a2) { if (a0 == 0xc || a0 == 0xb) { char buf[128]; sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2); return open(buf, O_RDWR, 0); } else { char buf[1024]; char* hash; NONFAILING(strncpy(buf, (char*)a0, sizeof(buf) - 1)); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(a1 % 10); a1 /= 10; } return open(buf, a2, 0); } } static long syz_open_pts(long a0, long a1) { int ptyno = 0; if (ioctl(a0, TIOCGPTN, &ptyno)) return -1; char buf[128]; sprintf(buf, "/dev/pts/%d", ptyno); return open(buf, a1, 0); } static long syz_genetlink_get_family_id(long name) { char buf[512] = {0}; struct nlmsghdr* hdr = (struct nlmsghdr*)buf; struct genlmsghdr* genlhdr = (struct genlmsghdr*)NLMSG_DATA(hdr); struct nlattr* attr = (struct nlattr*)(genlhdr + 1); hdr->nlmsg_len = sizeof(*hdr) + sizeof(*genlhdr) + sizeof(*attr) + GENL_NAMSIZ; hdr->nlmsg_type = GENL_ID_CTRL; hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; genlhdr->cmd = CTRL_CMD_GETFAMILY; attr->nla_type = CTRL_ATTR_FAMILY_NAME; attr->nla_len = sizeof(*attr) + GENL_NAMSIZ; NONFAILING(strncpy((char*)(attr + 1), (char*)name, GENL_NAMSIZ)); struct iovec iov = {hdr, hdr->nlmsg_len}; struct sockaddr_nl addr = {0}; addr.nl_family = AF_NETLINK; int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC); if (fd == -1) { return -1; } struct msghdr msg = {&addr, sizeof(addr), &iov, 1, NULL, 0, 0}; if (sendmsg(fd, &msg, 0) == -1) { close(fd); return -1; } ssize_t n = recv(fd, buf, sizeof(buf), 0); close(fd); if (n <= 0) { return -1; } if (hdr->nlmsg_type != GENL_ID_CTRL) { return -1; } for (; (char*)attr < buf + n; attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) { if (attr->nla_type == CTRL_ATTR_FAMILY_ID) return *(uint16_t*)(attr + 1); } return -1; } static void kill_and_wait(int pid, int* status) { kill(-pid, SIGKILL); kill(pid, SIGKILL); int i; for (i = 0; i < 100; i++) { if (waitpid(-1, status, WNOHANG | __WALL) == pid) return; usleep(1000); } DIR* dir = opendir("/sys/fs/fuse/connections"); if (dir) { for (;;) { struct dirent* ent = readdir(dir); if (!ent) break; if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue; char abort[300]; snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort", ent->d_name); int fd = open(abort, O_WRONLY); if (fd == -1) { continue; } if (write(fd, abort, 1) < 0) { } close(fd); } closedir(dir); } else { } while (waitpid(-1, status, __WALL) != pid) { } } #define SYZ_HAVE_SETUP_TEST 1 static void setup_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); } #define SYZ_HAVE_RESET_TEST 1 static void reset_test() { int fd; for (fd = 3; fd < 30; fd++) close(fd); } static void execute_one(void); #define WAIT_FLAGS __WALL static void loop(void) { int iter; for (iter = 0;; iter++) { int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { setup_test(); execute_one(); reset_test(); exit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; sleep_ms(1); if (current_time_ms() - start < 5 * 1000) continue; kill_and_wait(pid, &status); break; } } } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; void execute_one(void) { long res = 0; NONFAILING(memcpy((void*)0x20000080, "/dev/sg#\x00", 9)); res = syz_open_dev(0x20000080, 0, 0); if (res != -1) r[0] = res; syscall(__NR_socket, 0xc, 0x800, 0x88); syscall(__NR_ioctl, 0xffffff9c, 0x8933, 0); NONFAILING(*(uint32_t*)0x200000c0 = 1); NONFAILING(*(uint32_t*)0x200000c4 = 0); NONFAILING(*(uint32_t*)0x200000c8 = 8); NONFAILING(memcpy((void*)0x200000cc, "\x86", 1)); syscall(__NR_ioctl, r[0], 1, 0x200000c0); syscall(__NR_openat, -1, 0, 0x88400, 0x100); syscall(__NR_socket, 0x11, 2, 0x300); syscall(__NR_write, -1, 0, 0); syscall(__NR_getsockopt, -1, 0x29, 0x39, 0, 0); syscall(__NR_read, -1, 0, 0); syscall(__NR_ioctl, -1, 0x5437, 0); syz_genetlink_get_family_id(0); syscall(__NR_getpid); NONFAILING(memcpy((void*)0x20000000, "/dev/loop#\x00", 11)); syz_open_dev(0x20000000, 0, 0); syz_open_dev(0, 2, 0x100); syscall(__NR_socket, 0x11, 3, 0x300); /* NONFAILING(*(uint64_t*)0x200003c0 = 0x200002c0); NONFAILING(*(uint16_t*)0x200002c0 = 0x10); NONFAILING(*(uint16_t*)0x200002c2 = 0); NONFAILING(*(uint32_t*)0x200002c4 = 0); NONFAILING(*(uint32_t*)0x200002c8 = 2); NONFAILING(*(uint32_t*)0x200003c8 = 0xc); NONFAILING(*(uint64_t*)0x200003d0 = 0x20000380); NONFAILING(*(uint64_t*)0x20000380 = 0); NONFAILING(*(uint64_t*)0x20000388 = 0); NONFAILING(*(uint64_t*)0x200003d8 = 1); NONFAILING(*(uint64_t*)0x200003e0 = 0); NONFAILING(*(uint64_t*)0x200003e8 = 0); NONFAILING(*(uint32_t*)0x200003f0 = 1); syscall(__NR_sendmsg, -1, 0x200003c0, 0x40040); syscall(__NR_openat, 0xffffffffffffff9c, 0, 0, 0); res = syscall(__NR_dup, -1); if (res != -1) r[1] = res; syscall(__NR_ioctl, r[1], 0x8903, 0); syscall(__NR_fdatasync, -1); syscall(__NR_shmctl, 0, 3, 0); syscall(__NR_openat, 0xffffffffffffff9c, 0, 0x20000, 0); syscall(__NR_creat, 0, 0); syscall(__NR_fcntl, -1, 4, 0x40003); syscall(__NR_write, -1, 0, 0); syscall(__NR_setitimer, 1, 0, 0); syscall(__NR_inotify_add_watch, -1, 0, 0x24000004); syscall(__NR_unlink, 0); NONFAILING(*(uint32_t*)0x20000180 = 0); NONFAILING(*(uint32_t*)0x20000184 = 0); NONFAILING(*(uint32_t*)0x20000188 = 0); NONFAILING(*(uint32_t*)0x2000018c = 0); NONFAILING(*(uint32_t*)0x20000190 = 0); NONFAILING(*(uint32_t*)0x20000194 = 0); syscall(__NR_capset, 0, 0x20000180); NONFAILING(*(uint64_t*)0x20000100 = 0); NONFAILING(*(uint64_t*)0x20000108 = 0); syscall(__NR_vmsplice, -1, 0x20000100, 1, 0); syscall(__NR_ioctl, -1, 0x89e0, 0); syscall(__NR_socket, 0xa, 2, 0); syscall(__NR_pipe2, 0, 0x84800); syscall(__NR_pipe, 0); */ syz_open_pts(0xffffff9c, 0x80000); syscall(__NR_socket, 0xa, 3, 0x3a); syscall(__NR_getsockopt, 0xffffff9c, 0x29, 0x22, 0, 0); syscall(__NR_readv, -1, 0, 0); syscall(__NR_creat, 0, 0); syscall(__NR_connect, -1, 0, 0); syscall(__NR_setsockopt, -1, 1, 0x19, 0, 0); syscall(__NR_sendmsg, -1, 0, 0x10); syscall(__NR_socket, 0x10, 3, 0x10); syscall(__NR_socket, 0x10, 3, 6); syscall(__NR_openat, 0xffffffffffffff9c, 0, 0x440040, 0); syscall(__NR_openat, 0xffffffffffffff9c, 0, 0x8000, 0); syscall(__NR_mmap, 0x20ff7000, 0x9000, 0, 0x5811, -1, 0); syscall(__NR_fstat, -1, 0); syscall(__NR_ioctl, -1, 0x40247007, 0); syscall(__NR_openat, 0xffffffffffffff9c, 0, 0x801, 0); syscall(__NR_ioctl, -1, 0x891b, 0); syscall(__NR_ioctl, -1, 0x541c, 0); syscall(__NR_openat, 0xffffffffffffff9c, 0, 0x200002, 0); syscall(__NR_socket, 2, 2, 0x88); syscall(__NR_readv, -1, 0, 0); syscall(__NR_pipe2, 0x20000000, 0); } int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); install_segv_handler(); for (procid = 0; procid < 8; procid++) { if (fork() == 0) { loop(); } } sleep(1000000); return 0; }
Attachment:
repro.report
Description: Binary data
