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Message-ID: <CABOYnLyY40dS4p2beHyEnXqSm4K_NuXAvsozOvz=cX9TnxXsYA@mail.gmail.com>
Date: Wed, 22 Nov 2023 14:13:36 +0800
From: xingwei lee <xrivendell7@...il.com>
To: "syzbot+50ef815ba3bcce06d409@...kaller.appspotmail.com"
<syzbot+50ef815ba3bcce06d409@...kaller.appspotmail.com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"luto@...nel.org" <luto@...nel.org>,
"peterz@...radead.org" <peterz@...radead.org>,
"syzkaller-bugs@...glegroups.com" <syzkaller-bugs@...glegroups.com>,
"tglx@...utronix.de" <tglx@...utronix.de>
Subject: Re: [syzbot] [kernel?] KASAN: slab-use-after-free Read in kill_orphaned_pgrp
Hi! I reproduce this bug.
Without analyzing deeply, I find the other bug titled "KASAN:
slab-use-after-free read in do_acct_process" or titled "KASAN:
slab-use-after-free in release_task" may also be the same because with
the same reproducer.
repro.txt
r0 = creat(&(0x7f0000000280)='./file0\x00', 0xecf86c37d53049cc)
write$binfmt_elf32(r0, &(0x7f0000000440)={{0x7f, 0x45, 0x4c, 0x46,
0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x3e, 0x0, 0x0, 0x38, 0x0, 0x0, 0xeb0,
0x20, 0x2}, [{}], "", ['\x00', '\x00', '\x00', '\x00', '\x00', '\x00',
'\x00']}, 0x758)
close(r0)
r1 = openat$vnet(0xffffffffffffff9c, &(0x7f0000000000), 0x2, 0x0)
ioctl$int_in(r1, 0x40000000af01, 0x0)
execve(&(0x7f0000000400)='./file0\x00', 0x0, 0x0)
repro.c
#define _GNU_SOURCE
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.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/futex.h>
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 void thread_start(void* (*fn)(void*), void* arg)
{
pthread_t th;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setstacksize(&attr, 128 << 10);
int i = 0;
for (; i < 100; i++) {
if (pthread_create(&th, &attr, fn, arg) == 0) {
pthread_attr_destroy(&attr);
return;
}
if (errno == EAGAIN) {
usleep(50);
continue;
}
break;
}
exit(1);
}
typedef struct {
int state;
} event_t;
static void event_init(event_t* ev)
{
ev->state = 0;
}
static void event_reset(event_t* ev)
{
ev->state = 0;
}
static void event_set(event_t* ev)
{
if (ev->state)
exit(1);
__atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
syscall(SYS_futex, &ev->state, FUTEX_WAKE |
FUTEX_PRIVATE_FLAG, 1000000);
}
static void event_wait(event_t* ev)
{
while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
syscall(SYS_futex, &ev->state, FUTEX_WAIT |
FUTEX_PRIVATE_FLAG, 0, 0);
}
static int event_isset(event_t* ev)
{
return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE);
}
static int event_timedwait(event_t* ev, uint64_t timeout)
{
uint64_t start = current_time_ms();
uint64_t now = start;
for (;;) {
uint64_t remain = timeout - (now - start);
struct timespec ts;
ts.tv_sec = remain / 1000;
ts.tv_nsec = (remain % 1000) * 1000 * 1000;
syscall(SYS_futex, &ev->state, FUTEX_WAIT |
FUTEX_PRIVATE_FLAG, 0, &ts);
if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
return 1;
now = current_time_ms();
if (now - start > timeout)
return 0;
}
}
static bool write_file(const char* file, const char* what, ...)
{
char buf[1024];
va_list args;
va_start(args, what);
vsnprintf(buf, sizeof(buf), what, args);
va_end(args);
buf[sizeof(buf) - 1] = 0;
int len = strlen(buf);
int fd = open(file, O_WRONLY | O_CLOEXEC);
if (fd == -1)
return false;
if (write(fd, buf, len) != len) {
int err = errno;
close(fd);
errno = err;
return false;
}
close(fd);
return true;
}
static void kill_and_wait(int pid, int* status)
{
kill(-pid, SIGKILL);
kill(pid, SIGKILL);
for (int 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) {
}
}
static void setup_test()
{
prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
setpgrp();
write_file("/proc/self/oom_score_adj", "1000");
}
struct thread_t {
int created, call;
event_t ready, done;
};
static struct thread_t threads[16];
static void execute_call(int call);
static int running;
static void* thr(void* arg)
{
struct thread_t* th = (struct thread_t*)arg;
for (;;) {
event_wait(&th->ready);
event_reset(&th->ready);
execute_call(th->call);
__atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
event_set(&th->done);
}
return 0;
}
static void execute_one(void)
{
int i, call, thread;
for (call = 0; call < 6; call++) {
for (thread = 0; thread < (int)(sizeof(threads) /
sizeof(threads[0])); thread++) {
struct thread_t* th = &threads[thread];
if (!th->created) {
th->created = 1;
event_init(&th->ready);
event_init(&th->done);
event_set(&th->done);
thread_start(thr, th);
}
if (!event_isset(&th->done))
continue;
event_reset(&th->done);
th->call = call;
__atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
event_set(&th->ready);
event_timedwait(&th->done, 50);
break;
}
}
for (i = 0; i < 100 && __atomic_load_n(&running,
__ATOMIC_RELAXED); i++)
sleep_ms(1);
}
static void execute_one(void);
#define WAIT_FLAGS __WALL
static void loop(void)
{
int iter = 0;
for (;; iter++) {
int pid = fork();
if (pid < 0)
exit(1);
if (pid == 0) {
setup_test();
execute_one();
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 < 5000)
continue;
kill_and_wait(pid, &status);
break;
}
}
}
uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};
void execute_call(int call)
{
intptr_t res = 0;
switch (call) {
case 0:
memcpy((void*)0x20000280, "./file0\000", 8);
res = syscall(__NR_creat, /*file=*/0x20000280ul,
/*mode=*/0xecf86c37d53049ccul);
if (res != -1)
r[0] = res;
break;
case 1:
*(uint8_t*)0x20000440 = 0x7f;
*(uint8_t*)0x20000441 = 0x45;
*(uint8_t*)0x20000442 = 0x4c;
*(uint8_t*)0x20000443 = 0x46;
*(uint8_t*)0x20000444 = 0;
*(uint8_t*)0x20000445 = 0;
*(uint8_t*)0x20000446 = 0;
*(uint8_t*)0x20000447 = 0;
*(uint64_t*)0x20000448 = 0;
*(uint16_t*)0x20000450 = 2;
*(uint16_t*)0x20000452 = 0x3e;
*(uint32_t*)0x20000454 = 0;
*(uint32_t*)0x20000458 = 0;
*(uint32_t*)0x2000045c = 0x38;
*(uint32_t*)0x20000460 = 0;
*(uint32_t*)0x20000464 = 0;
*(uint16_t*)0x20000468 = 0xeb0;
*(uint16_t*)0x2000046a = 0x20;
*(uint16_t*)0x2000046c = 2;
*(uint16_t*)0x2000046e = 0;
*(uint16_t*)0x20000470 = 0;
*(uint16_t*)0x20000472 = 0;
*(uint32_t*)0x20000478 = 0;
*(uint32_t*)0x2000047c = 0;
*(uint32_t*)0x20000480 = 0;
*(uint32_t*)0x20000484 = 0;
*(uint32_t*)0x20000488 = 0;
*(uint32_t*)0x2000048c = 0;
*(uint32_t*)0x20000490 = 0;
*(uint32_t*)0x20000494 = 0;
memset((void*)0x20000498, 0, 256);
memset((void*)0x20000598, 0, 256);
memset((void*)0x20000698, 0, 256);
memset((void*)0x20000798, 0, 256);
memset((void*)0x20000898, 0, 256);
memset((void*)0x20000998, 0, 256);
memset((void*)0x20000a98, 0, 256);
syscall(__NR_write, /*fd=*/r[0],
/*data=*/0x20000440ul, /*len=*/0x758ul);
break;
case 2:
syscall(__NR_close, /*fd=*/r[0]);
break;
case 3:
memcpy((void*)0x20000000, "/dev/vhost-net\000", 15);
res = syscall(__NR_openat,
/*fd=*/0xffffffffffffff9cul, /*file=*/0x20000000ul, /*flags=*/2ul,
/*mode=*/0ul);
if (res != -1)
r[1] = res;
break;
case 4:
syscall(__NR_ioctl, /*fd=*/r[1], /*cmd=*/0xaf01, /*v=*/0ul);
break;
case 5:
memcpy((void*)0x20000400, "./file0\000", 8);
syscall(__NR_execve, /*file=*/0x20000400ul,
/*argv=*/0ul, /*envp=*/0ul);
break;
}
}
int main(void)
{
syscall(__NR_mmap, /*addr=*/0x1ffff000ul,
/*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1,
/*offset=*/0ul);
syscall(__NR_mmap, /*addr=*/0x20000000ul,
/*len=*/0x1000000ul, /*prot=*/7ul, /*flags=*/0x32ul, /*fd=*/-1,
/*offset=*/0ul);
syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul,
/*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
loop();
return 0;
}
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