KFENCE: invalid read in leaf_paste_entries

repro.c

// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE 

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.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/loop.h>

#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif

static unsigned long long procid;

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 use_temporary_dir(void)
{
	char tmpdir_template[] = "./syzkaller.XXXXXX";
	char* tmpdir = mkdtemp(tmpdir_template);
	if (!tmpdir)
	exit(1);
	if (chmod(tmpdir, 0777))
	exit(1);
	if (chdir(tmpdir))
	exit(1);
}

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;
}

struct fs_image_segment {
	void* data;
	uintptr_t size;
	uintptr_t offset;
};
static int setup_loop_device(long unsigned size, long unsigned nsegs, struct fs_image_segment* segs, const char* loopname, int* memfd_p, int* loopfd_p)
{
	int err = 0, loopfd = -1;
	int memfd = syscall(__NR_memfd_create, "syzkaller", 0);
	if (memfd == -1) {
		err = errno;
		goto error;
	}
	if (ftruncate(memfd, size)) {
		err = errno;
		goto error_close_memfd;
	}
	for (size_t i = 0; i < nsegs; i++) {
		if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) {
		}
	}
	loopfd = open(loopname, O_RDWR);
	if (loopfd == -1) {
		err = errno;
		goto error_close_memfd;
	}
	if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
		if (errno != EBUSY) {
			err = errno;
			goto error_close_loop;
		}
		ioctl(loopfd, LOOP_CLR_FD, 0);
		usleep(1000);
		if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
			err = errno;
			goto error_close_loop;
		}
	}
	*memfd_p = memfd;
	*loopfd_p = loopfd;
	return 0;

error_close_loop:
	close(loopfd);
error_close_memfd:
	close(memfd);
error:
	errno = err;
	return -1;
}

static long syz_mount_image(volatile long fsarg, volatile long dir, volatile unsigned long size, volatile unsigned long nsegs, volatile long segments, volatile long flags, volatile long optsarg, volatile long change_dir)
{
	struct fs_image_segment* segs = (struct fs_image_segment*)segments;
	int res = -1, err = 0, loopfd = -1, memfd = -1, need_loop_device = !!segs;
	char* mount_opts = (char*)optsarg;
	char* target = (char*)dir;
	char* fs = (char*)fsarg;
	char* source = NULL;
	char loopname[64];
	if (need_loop_device) {
		memset(loopname, 0, sizeof(loopname));
		snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid);
		if (setup_loop_device(size, nsegs, segs, loopname, &memfd, &loopfd) == -1)
			return -1;
		source = loopname;
	}
	mkdir(target, 0777);
	char opts[256];
	memset(opts, 0, sizeof(opts));
	if (strlen(mount_opts) > (sizeof(opts) - 32)) {
	}
	strncpy(opts, mount_opts, sizeof(opts) - 32);
	if (strcmp(fs, "iso9660") == 0) {
		flags |= MS_RDONLY;
	} else if (strncmp(fs, "ext", 3) == 0) {
		if (strstr(opts, "errors=panic") || strstr(opts, "errors=remount-ro") == 0)
			strcat(opts, ",errors=continue");
	} else if (strcmp(fs, "xfs") == 0) {
		strcat(opts, ",nouuid");
	}
	res = mount(source, target, fs, flags, opts);
	if (res == -1) {
		err = errno;
		goto error_clear_loop;
	}
	res = open(target, O_RDONLY | O_DIRECTORY);
	if (res == -1) {
		err = errno;
		goto error_clear_loop;
	}
	if (change_dir) {
		res = chdir(target);
		if (res == -1) {
			err = errno;
		}
	}

error_clear_loop:
	if (need_loop_device) {
		ioctl(loopfd, LOOP_CLR_FD, 0);
		close(loopfd);
		close(memfd);
	}
	errno = err;
	return res;
}

#define FS_IOC_SETFLAGS _IOW('f', 2, long)
static void remove_dir(const char* dir)
{
	int iter = 0;
	DIR* dp = 0;
retry:
		while (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) {
		}
	dp = opendir(dir);
	if (dp == NULL) {
		if (errno == EMFILE) {
	exit(1);
		}
	exit(1);
	}
	struct dirent* ep = 0;
	while ((ep = readdir(dp))) {
		if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
			continue;
		char filename[FILENAME_MAX];
		snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
			while (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) {
			}
		struct stat st;
		if (lstat(filename, &st))
	exit(1);
		if (S_ISDIR(st.st_mode)) {
			remove_dir(filename);
			continue;
		}
		int i;
		for (i = 0;; i++) {
			if (unlink(filename) == 0)
				break;
			if (errno == EPERM) {
				int fd = open(filename, O_RDONLY);
				if (fd != -1) {
					long flags = 0;
					if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
					}
					close(fd);
					continue;
				}
			}
			if (errno == EROFS) {
				break;
			}
			if (errno != EBUSY || i > 100)
	exit(1);
				if (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW))
	exit(1);
		}
	}
	closedir(dp);
	for (int i = 0;; i++) {
		if (rmdir(dir) == 0)
			break;
		if (i < 100) {
			if (errno == EPERM) {
				int fd = open(dir, O_RDONLY);
				if (fd != -1) {
					long flags = 0;
					if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
					}
					close(fd);
					continue;
				}
			}
			if (errno == EROFS) {
				break;
			}
			if (errno == EBUSY) {
					if (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW))
	exit(1);
				continue;
			}
			if (errno == ENOTEMPTY) {
				if (iter < 100) {
					iter++;
					goto retry;
				}
			}
		}
	exit(1);
	}
}

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 reset_loop()
{
	char buf[64];
	snprintf(buf, sizeof(buf), "/dev/loop%llu", procid);
	int loopfd = open(buf, O_RDWR);
	if (loopfd != -1) {
		ioctl(loopfd, LOOP_CLR_FD, 0);
		close(loopfd);
	}
}

static void setup_test()
{
	prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
	setpgrp();
	write_file("/proc/self/oom_score_adj", "1000");
	if (symlink("/dev/binderfs", "./binderfs")) {
	}
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
	int iter = 0;
	for (;; iter++) {
		char cwdbuf[32];
		sprintf(cwdbuf, "./%d", iter);
		if (mkdir(cwdbuf, 0777))
	exit(1);
		reset_loop();
		int pid = fork();
		if (pid < 0)
	exit(1);
		if (pid == 0) {
			if (chdir(cwdbuf))
	exit(1);
			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;
		}
		remove_dir(cwdbuf);
	}
}

void execute_one(void)
{
memcpy((void*)0x20000000, "reiserfs\000", 9);
memcpy((void*)0x20000100, "./file0\000", 8);
*(uint64_t*)0x20000200 = 0x20010000;
memcpy((void*)0x20010000, "\x00\x40\x00\x00\x68\x02\x00\x00\x97\x3d\x00\x00\x12\x00\x00\x00\x00\x00\x00\x00\x84\x3d\x00\x00\x00\x04\x00\x00\x73\x56\x4d\x38\x84\x03\x00\x00\x1e\x00\x00\x00\x00\x00\x00\x00\x00\x10\xcc\x03\x02\x00\x01\x00\x52\x65\x49\x73\x45\x72\x33\x46\x73\x00\x00\x00\x01\x00\x00\x00\x02\x00\x01\x00\x02\x00\x85\x3d\x00\x00\x00\x00\x01\x00\x00\x00\x12\x31\x23\x12\x12\x33\x12\x33\x12\x31\x12\x34\x13\x41\x24\x12\x73\x79\x7a\x6b\x61\x6c\x6c\x65\x72\x00\x00\x00\x00\x00\x00\x00\x01\x00\x1e\x00\x3b\xc1\x65\x5f\x00\x4e\xed\x00", 128);
*(uint64_t*)0x20000208 = 0x80;
*(uint64_t*)0x20000210 = 0x10000;
*(uint64_t*)0x20000218 = 0x20010100;
memcpy((void*)0x20010100, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 32);
*(uint64_t*)0x20000220 = 0x20;
*(uint64_t*)0x20000228 = 0x100c0;
*(uint64_t*)0x20000230 = 0x20011200;
memcpy((void*)0x20011200, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x12\x00\x00\x00\x00\x00\x00\x00\x84\x3d\x00\x00\x00\x04\x00\x00\x73\x56\x4d\x38\x84\x03\x00\x00\x1e\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 64);
*(uint64_t*)0x20000238 = 0x40;
*(uint64_t*)0x20000240 = 0x3d96000;
*(uint64_t*)0x20000248 = 0x20011300;
memcpy((void*)0x20011300, "\x01\x00\x02\x00\x5c\x0f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x2c\x00\xd4\x0f\x01\x00\x01\x00\x00\x00\x02\x00\x00\x00\x01\x00\x00\x00\xf4\x01\x00\x00\x02\x00\x30\x00\xa4\x0f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 96);
*(uint64_t*)0x20000250 = 0x60;
*(uint64_t*)0x20000258 = 0x3d97000;
*(uint64_t*)0x20000260 = 0x20000080;
memcpy((void*)0x20000080, "\x00\x00\x00\x00\x01\x00\x00\x00\x01\x0e\x00\x00\x02\x00\x00\x00\x28\x00\x04\x00\x02\x00\x00\x00\x00\x00\x8c\xee\x00\x00\x00\x00\x00\x00\x04\x00\x2e\x2e\x00\x00\x00\x00\x00\x00\x2e\x00\x00\x00\x00\x00\x00\x00\xed\x41\x00\x00\x03\x00\x00\x00\x30\x00\x00\x00\x00\x00\x00\x00\x5c\xf9\x01\x00\x53\x5f\x01\x00\x3b\xc1\x65\xf3\x54\xdf\xfa\x32\xec\x94\xed\x23\xbb\x55\x68\xcf\xa0\x5f\x3b\xc1\x65\x5f\x3b\xc1\x65\x5f\x01\x00\x00\x29\x00\x00\x00\x00\x00", 111);
*(uint64_t*)0x20000268 = 0x6f;
*(uint64_t*)0x20000270 = 0x3d97fa0;
syz_mount_image(0x20000000, 0x20000100, 0x4000000, 5, 0x20000200, 0, 0x200003c0, 0);

}
int main(void)
{
		syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
	syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
	syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
			use_temporary_dir();
			loop();
	return 0;
}