KASAN: use-after-free Read in inode_cgwb_move_to_attached

repro.c

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

#define _GNU_SOURCE 

#include <endian.h>
#include <errno.h>
#include <fcntl.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/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>

#include <linux/loop.h>

#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif

static unsigned long long procid;

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;
}

uint64_t r[1] = {0xffffffffffffffff};

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);
				intptr_t res = 0;
memcpy((void*)0x200000c0, "vfat\000", 5);
memcpy((void*)0x20000080, "./file0\000", 8);
*(uint64_t*)0x20000140 = 0x20000000;
memcpy((void*)0x20000000, "\xeb\x3c\x90\x6d\x8d\x66\x73\xfd\xd2\x61\x74\x00\x02\x80\x01\x00\x02\x40\x00\x00\x04\xf8\x01", 23);
*(uint64_t*)0x20000148 = 0x17;
*(uint64_t*)0x20000150 = 0;
*(uint64_t*)0x20000158 = 0x20000400;
memcpy((void*)0x20000400, "\x57\x59\x5a\x4b\x41\x4c\x4c\x45\x52\x20\x20\x08\x5a\xc1\x9f\x69\xf2\xb2\xb1\xea\x1b\x8a\x0a\xc9\x13\x5e\xed\x1d\xf1\xd1\x00\x1c\xc2\xde\x85\x0f\x06\x00\x00\x00\x00\x00\x00\x00\xf7\xe7\x5e\xff\xac\x2a\xc4\xc1\x5e\x29\xfb\x3c\x18\xfa\xff\xf8\xd1\x98\xe3\x12\x47\x5f\xfa\x1d\x00\x00\x00\x00\x00\x00\xad\x25\x82\x2a\x17\xb1\x7f\x46\x3e\x10\x41\x79\xc1\x9c\x2a\xd2\xfb\xdd\xc0\x77\x7d\xf2\xec\x4f\x62\x82\x60\x86\x70\x4d\xc5\x75\xb6\x97\x06\xd1\x15\x47\x81\x27\xd9\xf0\xbe\x59\xcd\xc0\x76\x84\x48\x0b\xe4\xb8\x86\x93\x7d\x8f\xb4\xf0\xff\x94\xe3\xa7\x6e\xcb\xc6\x3c\x2a\xe0\xb3\x87\xef\x96\xd2\x06\x6a\x83\x2e\xb0\x74\x3d\x5b\x8d\x2d\xd7\x53\x1c\x1b\x63\xa8\xb2\x81\xdd\xaa\x3d\x1a\x5a\xb2\xe1\xe3\xed\x7a\xba\x34\x0e\xad\x25\x71\x05\xf3\x6c\xf4\x99\x31\x92\x41\x1d\x5a\xbb\x4c\x65\xf2\xe6\xc2\xb2\x8b\x69\xb9\x68\x1b\x56\xdb\xb1\x9b\x01\x1d\x41\xf6\x17\x3b\x1e\x9d\xe0\xae\x2d\x37\xcc\x0d\x67\x74\x57\xb0\x61\x22\x0e\x7a\xa9\x70\x46\x35\x16\xf0\x82\x4f\x1d\xf4\xdd\x9b\xbf\x16\x5f\xa3\xb0\xea\x49\xdc\xa4\x04\x73\x07\x74\x59\xda\xe8\xce\x5e\x07\x33\x2c\xa1\x1f\x60\xaa\x39\x88\x64\xd5\x2c\x56\x96\x0c\x7d\x5c\x65\xcf\x9f\xe7\xdf\x48\x48\x7d\xf8\x6c\x42\x22\xae\x62\x1f\x0c\x1e\xc0\xbc\x3c\xf7\x94\x3f\xa8\x31\x5d\x96\x31\x40\x0b\x5c\x16\x57\xd4\xfd\x72\x91\xfe\xbd\xc1\xf9\xe0\x04\x65\xfa\xac\x75\xf3\xd1\x60\x46\xef\x88\x84\xbe\xc8\x06\x7e\x1d\xe4\xd0\x6e\xcd\x94\x44\xd6\x3d\x34\x8e\xb2\x20\x9f\xbe\xbc\x00\xc1\xcf\x2a\x4a\x09\x6e\x52\xde\xe0\xdd\xd6\x81\xa9\xf8\xb9\x12\x55\xa8\xa5\xd4\xaf\xd8\x97\xa2\x39\xf4\xae\x53\x95\x97\x3e\xd6\x93\xfa\x0a\xcf\x68\x79\x7f\x73\xd1\xd5\xb7\x26\x90\xe6\x05\x63\xd9\x0d\x8b\x58\xde\x72\xaf\x8d\x1f\x7b\x7e\x9e\xe0\xa9\x39\xd1\x01\x8d\x95\xf0\xe4\x01\x37\x4c\x40\x10\x08\xa7\x0e\x5a\x4b\x32\x42\x3c\x70\xd2\xc6\x99\xeb\xdd\x13\x95\xf4\x00\x00\x00\x00\x00\x00\x00\x00", 450);
*(uint64_t*)0x20000160 = 0x1c2;
*(uint64_t*)0x20000168 = 0x100;
memcpy((void*)0x20000240, "\x69\x6f\x63\x68\x61\x72\x73\x65\x74\x3d\x63\x70\x38\x35\x32\x2c\x6e\x6f\x6e\x75\x6d\x74\x61\x69\x6c\x3d\x30\x2c\x66\x6c\x75\x73\x68\x2c\x73\x68\x6f\x72\x74\x6e\x61\x6d\x65\x3d\x6c\x6f\x77\x65\x72\x2c\x64\x65\x62\x75\x67\x2c\x75\x74\x66\x38\x3d\x31\x2c\x64\x69\x73\x63\x61\x72\x64\x2c\x73\x68\x6f\x72\x74\x6e\x61\x6d\x65\x3d\x6c\x6f\x77\x65\x72\x2c\x6e\x6f\x6e\x75\x6d\x74\x61\x69\x6c\x3d\x30\x2c\x75\x6e\x69\x5f\x78\x6c\x61\x74\x65\x3d\x31\x2c\x72\x6f\x64\x69\x72\x2c\x63\x6f\x64\x65\x70\x61\x67\x65\x3d\x39\x35\x30\x2c\x69\x6f\x63\x68\x61\x72\x73\x65\x74\x3d\x69\x73\x6f\x38\x38\x35\x39\x2d\x36\x2c\x75\x6e\x69\x5f\x78\x6c\x61\x74\x65\x3d\x31\x2c\x72\x6f\x64\x69\x72\x2c\x00\x39\xed\x94\x4f\x9d\x68\x77\xe1\x93\x46\x97\x0f\x21\xda\xcc\xbb\x5f\xde\xaf\x6b\xdb\x1e\x88\x5f\xd3\x81\x66\xbd\x55\x0c", 199);
syz_mount_image(0x200000c0, 0x20000080, 0x8000, 2, 0x20000140, 0x2010000, 0x20000240, 0);
memcpy((void*)0x20000140, "./file0\000", 8);
	syscall(__NR_chdir, 0x20000140ul);
memcpy((void*)0x20000040, "./bus\000", 6);
	res = syscall(__NR_creat, 0x20000040ul, 0ul);
	if (res != -1)
		r[0] = res;
memcpy((void*)0x20000100, "./bus\000", 6);
	syscall(__NR_unlink, 0x20000100ul);
memcpy((void*)0x20000180, "1000000\000", 8);
	syscall(__NR_write, r[0], 0x20000180ul, 8ul);
	return 0;
}