Hello,
syzbot found the following issue on:
HEAD commit: cb231e2f67ec fs: more fsdata fixes
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14ef6401880000
kernel config: https://syzkaller.appspot.com/x/.config?x=dc6d7125db95a828
dashboard link: https://syzkaller.appspot.com/bug?extid=0e6ddb1ef80986bdfe64
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6eabbc575a06/disk-cb231e2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/01e99c04e1d7/vmlinux-cb231e2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/67893482166a/bzImage-cb231e2f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
=====================================================
BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x13ff/0x1a30 net/core/dev.c:4782
bpf_prog_run_generic_xdp+0x13ff/0x1a30 net/core/dev.c:4782
netif_receive_generic_xdp+0x639/0x910 net/core/dev.c:4845
do_xdp_generic net/core/dev.c:4904 [inline]
__netif_receive_skb_core+0x290f/0x6360 net/core/dev.c:5310
__netif_receive_skb_one_core net/core/dev.c:5487 [inline]
__netif_receive_skb+0xc8/0x5d0 net/core/dev.c:5603
process_backlog+0x45a/0x890 net/core/dev.c:5931
__napi_poll+0xe6/0x920 net/core/dev.c:6498
napi_poll net/core/dev.c:6565 [inline]
net_rx_action+0x9e8/0x1a20 net/core/dev.c:6676
__do_softirq+0x1c5/0x7b9 kernel/softirq.c:571
invoke_softirq+0x8f/0x100 kernel/softirq.c:445
__irq_exit_rcu+0x5a/0x110 kernel/softirq.c:650
irq_exit_rcu+0xe/0x10 kernel/softirq.c:662
sysvec_apic_timer_interrupt+0x9a/0xc0 arch/x86/kernel/apic/apic.c:1107
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:649
kmsan_get_shadow_origin_ptr+0x34/0xa0 mm/kmsan/shadow.c:97
get_shadow_origin_ptr mm/kmsan/instrumentation.c:36 [inline]
__msan_metadata_ptr_for_load_8+0x20/0x30 mm/kmsan/instrumentation.c:78
unwind_get_return_address_ptr+0x97/0xc0 arch/x86/kernel/unwind_frame.c:28
update_stack_state+0x177/0x1e0 arch/x86/kernel/unwind_frame.c:251
unwind_next_frame+0x119/0x360 arch/x86/kernel/unwind_frame.c:315
arch_stack_walk+0x1b9/0x280 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xb2/0x100 kernel/stacktrace.c:122
kmsan_save_stack_with_flags mm/kmsan/core.c:75 [inline]
kmsan_internal_poison_memory+0x45/0x90 mm/kmsan/core.c:60
kmsan_slab_free+0xcd/0x130 mm/kmsan/hooks.c:90
slab_free_hook mm/slub.c:1694 [inline]
slab_free_freelist_hook mm/slub.c:1750 [inline]
slab_free mm/slub.c:3661 [inline]
kmem_cache_free+0x365/0xdb0 mm/slub.c:3683
security_file_free+0x15d/0x1a0 security/security.c:1548
file_free fs/file_table.c:56 [inline]
__fput+0xbed/0xea0 fs/file_table.c:333
____fput+0x1a/0x20 fs/file_table.c:348
task_work_run+0x229/0x2c0 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0x2a9/0x320 kernel/entry/common.c:171
exit_to_user_mode_prepare+0x16e/0x220 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x23/0x40 kernel/entry/common.c:296
__do_fast_syscall_32+0xb1/0x100 arch/x86/entry/common.c:181
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82
Uninit was created at:
slab_post_alloc_hook mm/slab.h:742 [inline]
slab_alloc_node mm/slub.c:3398 [inline]
__kmem_cache_alloc_node+0x6ee/0xc90 mm/slub.c:3437
__do_kmalloc_node mm/slab_common.c:954 [inline]
__kmalloc_node_track_caller+0x117/0x3d0 mm/slab_common.c:975
kmalloc_reserve net/core/skbuff.c:437 [inline]
pskb_expand_head+0x23d/0x1970 net/core/skbuff.c:1832
netif_receive_generic_xdp+0x4c6/0x910 net/core/dev.c:4837
do_xdp_generic net/core/dev.c:4904 [inline]
__netif_receive_skb_core+0x290f/0x6360 net/core/dev.c:5310
__netif_receive_skb_one_core net/core/dev.c:5487 [inline]
__netif_receive_skb+0xc8/0x5d0 net/core/dev.c:5603
process_backlog+0x45a/0x890 net/core/dev.c:5931
__napi_poll+0xe6/0x920 net/core/dev.c:6498
napi_poll net/core/dev.c:6565 [inline]
net_rx_action+0x9e8/0x1a20 net/core/dev.c:6676
__do_softirq+0x1c5/0x7b9 kernel/softirq.c:571
CPU: 0 PID: 3506 Comm: syz-executor.2 Tainted: G W 6.1.0-rc4-syzkaller-62821-gcb231e2f67ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================
---
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Hello I reprudced this bug and comfirme triggered in the latest
net/bpf/bpf-next tree.
kernel: bpf-next fc3a5534e2a8855427403113cbeb54af5837bbe0
kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=4a65fa9f077ead01
with KMSAN enabled
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
=* repro.c =*
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/capability.h>
#include <linux/genetlink.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/if_tun.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/neighbour.h>
#include <linux/net.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/tcp.h>
#include <linux/veth.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.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/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#ifndef __NR_bpf
#define __NR_bpf 321
#endif
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 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 nlmsg {
char* pos;
int nesting;
struct nlattr* nested[8];
char buf[4096];
};
static void netlink_init(struct nlmsg* nlmsg, int typ, int flags,
const void* data, int size) {
memset(nlmsg, 0, sizeof(*nlmsg));
struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
hdr->nlmsg_type = typ;
hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
memcpy(hdr + 1, data, size);
nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
}
static void netlink_attr(struct nlmsg* nlmsg, int typ, const void* data,
int size) {
struct nlattr* attr = (struct nlattr*)nlmsg->pos;
attr->nla_len = sizeof(*attr) + size;
attr->nla_type = typ;
if (size > 0) memcpy(attr + 1, data, size);
nlmsg->pos += NLMSG_ALIGN(attr->nla_len);
}
static int netlink_send_ext(struct nlmsg* nlmsg, int sock, uint16_t reply_type,
int* reply_len, bool dofail) {
if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting) exit(1);
struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
hdr->nlmsg_len = nlmsg->pos - nlmsg->buf;
struct sockaddr_nl addr;
memset(&addr, 0, sizeof(addr));
addr.nl_family = AF_NETLINK;
ssize_t n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0,
(struct sockaddr*)&addr, sizeof(addr));
if (n != (ssize_t)hdr->nlmsg_len) {
if (dofail) exit(1);
return -1;
}
n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
if (reply_len) *reply_len = 0;
if (n < 0) {
if (dofail) exit(1);
return -1;
}
if (n < (ssize_t)sizeof(struct nlmsghdr)) {
errno = EINVAL;
if (dofail) exit(1);
return -1;
}
if (hdr->nlmsg_type == NLMSG_DONE) return 0;
if (reply_len && hdr->nlmsg_type == reply_type) {
*reply_len = n;
return 0;
}
if (n < (ssize_t)(sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))) {
errno = EINVAL;
if (dofail) exit(1);
return -1;
}
if (hdr->nlmsg_type != NLMSG_ERROR) {
errno = EINVAL;
if (dofail) exit(1);
return -1;
}
errno = -((struct nlmsgerr*)(hdr + 1))->error;
return -errno;
}
static int netlink_send(struct nlmsg* nlmsg, int sock) {
return netlink_send_ext(nlmsg, sock, 0, NULL, true);
}
static int netlink_query_family_id(struct nlmsg* nlmsg, int sock,
const char* family_name, bool dofail) {
struct genlmsghdr genlhdr;
memset(&genlhdr, 0, sizeof(genlhdr));
genlhdr.cmd = CTRL_CMD_GETFAMILY;
netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name,
strnlen(family_name, GENL_NAMSIZ - 1) + 1);
int n = 0;
int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n, dofail);
if (err < 0) {
return -1;
}
uint16_t id = 0;
struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN +
NLMSG_ALIGN(sizeof(genlhdr)));
for (; (char*)attr < nlmsg->buf + n;
attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
id = *(uint16_t*)(attr + 1);
break;
}
}
if (!id) {
errno = EINVAL;
return -1;
}
recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
return id;
}
static void netlink_device_change(struct nlmsg* nlmsg, int sock,
const char* name, bool up, const char* master,
const void* mac, int macsize,
const char* new_name) {
struct ifinfomsg hdr;
memset(&hdr, 0, sizeof(hdr));
if (up) hdr.ifi_flags = hdr.ifi_change = IFF_UP;
hdr.ifi_index = if_nametoindex(name);
netlink_init(nlmsg, RTM_NEWLINK, 0, &hdr, sizeof(hdr));
if (new_name) netlink_attr(nlmsg, IFLA_IFNAME, new_name, strlen(new_name));
if (master) {
int ifindex = if_nametoindex(master);
netlink_attr(nlmsg, IFLA_MASTER, &ifindex, sizeof(ifindex));
}
if (macsize) netlink_attr(nlmsg, IFLA_ADDRESS, mac, macsize);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}
static int netlink_add_addr(struct nlmsg* nlmsg, int sock, const char* dev,
const void* addr, int addrsize) {
struct ifaddrmsg hdr;
memset(&hdr, 0, sizeof(hdr));
hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6;
hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120;
hdr.ifa_scope = RT_SCOPE_UNIVERSE;
hdr.ifa_index = if_nametoindex(dev);
netlink_init(nlmsg, RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr,
sizeof(hdr));
netlink_attr(nlmsg, IFA_LOCAL, addr, addrsize);
netlink_attr(nlmsg, IFA_ADDRESS, addr, addrsize);
return netlink_send(nlmsg, sock);
}
static void netlink_add_addr4(struct nlmsg* nlmsg, int sock, const char* dev,
const char* addr) {
struct in_addr in_addr;
inet_pton(AF_INET, addr, &in_addr);
int err = netlink_add_addr(nlmsg, sock, dev, &in_addr, sizeof(in_addr));
if (err < 0) {
}
}
static void netlink_add_addr6(struct nlmsg* nlmsg, int sock, const char* dev,
const char* addr) {
struct in6_addr in6_addr;
inet_pton(AF_INET6, addr, &in6_addr);
int err = netlink_add_addr(nlmsg, sock, dev, &in6_addr, sizeof(in6_addr));
if (err < 0) {
}
}
static void netlink_add_neigh(struct nlmsg* nlmsg, int sock, const char* name,
const void* addr, int addrsize, const void* mac,
int macsize) {
struct ndmsg hdr;
memset(&hdr, 0, sizeof(hdr));
hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6;
hdr.ndm_ifindex = if_nametoindex(name);
hdr.ndm_state = NUD_PERMANENT;
netlink_init(nlmsg, RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr,
sizeof(hdr));
netlink_attr(nlmsg, NDA_DST, addr, addrsize);
netlink_attr(nlmsg, NDA_LLADDR, mac, macsize);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}
static struct nlmsg nlmsg;
static int tunfd = -1;
#define TUN_IFACE "syz_tun"
#define LOCAL_MAC 0xaaaaaaaaaaaa
#define REMOTE_MAC 0xaaaaaaaaaabb
#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"
#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"
#define IFF_NAPI 0x0010
static void initialize_tun(void) {
tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
if (tunfd == -1) {
printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
printf("otherwise fuzzing or reproducing might not work as intended\n");
return;
}
const int kTunFd = 200;
if (dup2(tunfd, kTunFd) < 0) exit(1);
close(tunfd);
tunfd = kTunFd;
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
exit(1);
}
char sysctl[64];
sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE);
write_file(sysctl, "0");
sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE);
write_file(sysctl, "0");
int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock == -1) exit(1);
netlink_add_addr4(&nlmsg, sock, TUN_IFACE, LOCAL_IPV4);
netlink_add_addr6(&nlmsg, sock, TUN_IFACE, LOCAL_IPV6);
uint64_t macaddr = REMOTE_MAC;
struct in_addr in_addr;
inet_pton(AF_INET, REMOTE_IPV4, &in_addr);
netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in_addr, sizeof(in_addr),
&macaddr, ETH_ALEN);
struct in6_addr in6_addr;
inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr);
netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in6_addr, sizeof(in6_addr),
&macaddr, ETH_ALEN);
macaddr = LOCAL_MAC;
netlink_device_change(&nlmsg, sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN,
NULL);
close(sock);
}
static int read_tun(char* data, int size) {
if (tunfd < 0) return -1;
int rv = read(tunfd, data, size);
if (rv < 0) {
if (errno == EAGAIN || errno == EBADFD) return -1;
exit(1);
}
return rv;
}
static long syz_emit_ethernet(volatile long a0, volatile long a1,
volatile long a2) {
if (tunfd < 0) return (uintptr_t)-1;
uint32_t length = a0;
char* data = (char*)a1;
return write(tunfd, data, length);
}
static void flush_tun() {
char data[1000];
while (read_tun(&data[0], sizeof(data)) != -1) {
}
}
#define MAX_FDS 30
static void setup_common() {
if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
}
}
static void setup_binderfs() {
if (mkdir("/dev/binderfs", 0777)) {
}
if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
}
if (symlink("/dev/binderfs", "./binderfs")) {
}
}
static void loop();
static void sandbox_common() {
prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
setsid();
struct rlimit rlim;
rlim.rlim_cur = rlim.rlim_max = (200 << 20);
setrlimit(RLIMIT_AS, &rlim);
rlim.rlim_cur = rlim.rlim_max = 32 << 20;
setrlimit(RLIMIT_MEMLOCK, &rlim);
rlim.rlim_cur = rlim.rlim_max = 136 << 20;
setrlimit(RLIMIT_FSIZE, &rlim);
rlim.rlim_cur = rlim.rlim_max = 1 << 20;
setrlimit(RLIMIT_STACK, &rlim);
rlim.rlim_cur = rlim.rlim_max = 128 << 20;
setrlimit(RLIMIT_CORE, &rlim);
rlim.rlim_cur = rlim.rlim_max = 256;
setrlimit(RLIMIT_NOFILE, &rlim);
if (unshare(CLONE_NEWNS)) {
}
if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
}
if (unshare(CLONE_NEWIPC)) {
}
if (unshare(0x02000000)) {
}
if (unshare(CLONE_NEWUTS)) {
}
if (unshare(CLONE_SYSVSEM)) {
}
typedef struct {
const char* name;
const char* value;
} sysctl_t;
static const sysctl_t sysctls[] = {
{"/proc/sys/kernel/shmmax", "16777216"},
{"/proc/sys/kernel/shmall", "536870912"},
{"/proc/sys/kernel/shmmni", "1024"},
{"/proc/sys/kernel/msgmax", "8192"},
{"/proc/sys/kernel/msgmni", "1024"},
{"/proc/sys/kernel/msgmnb", "1024"},
{"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
};
unsigned i;
for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
write_file(sysctls[i].name, sysctls[i].value);
}
static int wait_for_loop(int pid) {
if (pid < 0) exit(1);
int status = 0;
while (waitpid(-1, &status, __WALL) != pid) {
}
return WEXITSTATUS(status);
}
static void drop_caps(void) {
struct __user_cap_header_struct cap_hdr = {};
struct __user_cap_data_struct cap_data[2] = {};
cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
cap_hdr.pid = getpid();
if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1);
const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
cap_data[0].effective &= ~drop;
cap_data[0].permitted &= ~drop;
cap_data[0].inheritable &= ~drop;
if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1);
}
static int do_sandbox_none(void) {
if (unshare(CLONE_NEWPID)) {
}
int pid = fork();
if (pid != 0) return wait_for_loop(pid);
setup_common();
sandbox_common();
drop_caps();
if (unshare(CLONE_NEWNET)) {
}
write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
initialize_tun();
setup_binderfs();
loop();
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 setup_test() {
prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
setpgrp();
write_file("/proc/self/oom_score_adj", "1000");
flush_tun();
}
static void close_fds() {
for (int fd = 3; fd < MAX_FDS; fd++) close(fd);
}
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();
close_fds();
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[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0x0};
void execute_one(void) {
intptr_t res = 0;
res = syscall(__NR_socket, /*domain=*/2ul, /*type=*/1ul, /*proto=*/0);
if (res != -1) r[0] = res;
*(uint32_t*)0x20000100 = 6;
*(uint32_t*)0x20000104 = 4;
*(uint64_t*)0x20000108 = 0x20000200;
memcpy((void*)0x20000200,
"\x18\x02\x00\x00\xfd\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x85"
"\x00\x00\x00\x2c\x00\x00\x00\x95",
25);
*(uint64_t*)0x20000110 = 0x20000040;
memcpy((void*)0x20000040, "GPL\000", 4);
*(uint32_t*)0x20000118 = 0;
*(uint32_t*)0x2000011c = 0;
*(uint64_t*)0x20000120 = 0;
*(uint32_t*)0x20000128 = 0;
*(uint32_t*)0x2000012c = 0;
memset((void*)0x20000130, 0, 16);
*(uint32_t*)0x20000140 = 0;
*(uint32_t*)0x20000144 = 0;
*(uint32_t*)0x20000148 = -1;
*(uint32_t*)0x2000014c = 8;
*(uint64_t*)0x20000150 = 0;
*(uint32_t*)0x20000158 = 0;
*(uint32_t*)0x2000015c = 0x10;
*(uint64_t*)0x20000160 = 0;
*(uint32_t*)0x20000168 = 0;
*(uint32_t*)0x2000016c = 0;
*(uint32_t*)0x20000170 = 0;
*(uint32_t*)0x20000174 = 0;
*(uint64_t*)0x20000178 = 0;
*(uint64_t*)0x20000180 = 0;
*(uint32_t*)0x20000188 = 0x10;
*(uint32_t*)0x2000018c = 0;
res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x20000100ul, /*size=*/0x90ul);
if (res != -1) r[1] = res;
memcpy((void*)0x20000180, "syz_tun\000\000\000\000\000\000\000\000\000", 16);
res = syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0x8933, /*arg=*/0x20000180ul);
if (res != -1) r[2] = *(uint32_t*)0x20000190;
*(uint32_t*)0x20000000 = r[1];
*(uint32_t*)0x20000004 = r[2];
*(uint32_t*)0x20000008 = 0x25;
*(uint32_t*)0x2000000c = 0;
*(uint32_t*)0x20000010 = 0;
syscall(__NR_bpf, /*cmd=*/0x1cul, /*arg=*/0x20000000ul, /*size=*/0x10ul);
memset((void*)0x20000f00, 170, 5);
*(uint8_t*)0x20000f05 = 0xaa;
memset((void*)0x20000f06, 0, 6);
*(uint16_t*)0x20000f0c = htobe16(0);
syz_emit_ethernet(/*len=*/0xfdef, /*packet=*/0x20000f00, /*frags=*/0);
}
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);
do_sandbox_none();
return 0;
}
=* repro.txt =*
r0 = socket$inet_tcp(0x2, 0x1, 0x0)
r1 = bpf$BPF_PROG_RAW_TRACEPOINT_LOAD(0x5, &(0x7f0000000100)={0x6,
0x4, &(0x7f0000000200)=ANY=[@ANYBLOB="18020000fdffffff0000000000000000850000002c00000095"],
&(0x7f0000000040)='GPL\x00'}, 0x90)
ioctl$sock_SIOCGIFINDEX(r0, 0x8933, &(0x7f0000000180)={'syz_tun\x00', <r2=>0x0})
bpf$BPF_LINK_CREATE_XDP(0x1c, &(0x7f0000000000)={r1, r2}, 0x10)
syz_emit_ethernet(0xfdef, &(0x7f0000000f00)={@local, @empty, @void}, 0x0)
See aslo https://gist.github.com/xrivendell7/c971ada013151e3b5a5f3f69f8f9ce63
I hope it helps.
Best regards.
xingwei Lee
syzbot has found a reproducer for the following issue on:
HEAD commit: 66a27abac311 Merge tag 'powerpc-6.9-1' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14285ac9180000
kernel config: https://syzkaller.appspot.com/x/.config?x=48bb382b96e7eda7
dashboard link: https://syzkaller.appspot.com/bug?extid=0e6ddb1ef80986bdfe64
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17ab51c9180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=127d21f1180000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/37968fa0451e/disk-66a27aba.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5b288c5c3088/vmlinux-66a27aba.xz
kernel image: https://storage.googleapis.com/syzbot-assets/792ddbf8146d/bzImage-66a27aba.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
=====================================================
BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x13a0/0x1ee0 net/core/dev.c:4876
bpf_prog_run_generic_xdp+0x13a0/0x1ee0 net/core/dev.c:4876
netif_receive_generic_xdp net/core/dev.c:4958 [inline]
do_xdp_generic+0xb68/0x1440 net/core/dev.c:5017
__netif_receive_skb_core+0x2533/0x6190 net/core/dev.c:5358
__netif_receive_skb_one_core net/core/dev.c:5536 [inline]
__netif_receive_skb+0xca/0xa00 net/core/dev.c:5652
process_backlog+0x480/0x8b0 net/core/dev.c:5981
__napi_poll+0xe7/0x980 net/core/dev.c:6632
napi_poll net/core/dev.c:6701 [inline]
net_rx_action+0x89d/0x1820 net/core/dev.c:6813
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:633 [inline]
irq_exit_rcu+0x6a/0x130 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x83/0x90 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:702
__preempt_count_dec_and_test arch/x86/include/asm/preempt.h:94 [inline]
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x33/0x60 kernel/locking/spinlock.c:194
unlock_hrtimer_base kernel/time/hrtimer.c:1021 [inline]
hrtimer_start_range_ns+0x112c/0x11a0 kernel/time/hrtimer.c:1308
hrtimer_start include/linux/hrtimer.h:275 [inline]
j1939_tp_schedule_txtimer+0xc2/0x100 net/can/j1939/transport.c:702
j1939_sk_send_loop net/can/j1939/socket.c:1164 [inline]
j1939_sk_sendmsg+0x1a0e/0x2730 net/can/j1939/socket.c:1277
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x30f/0x380 net/socket.c:745
____sys_sendmsg+0x877/0xb60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2674
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
Uninit was stored to memory at:
pskb_expand_head+0x30f/0x19d0 net/core/skbuff.c:2253
netif_skb_check_for_xdp net/core/dev.c:4921 [inline]
netif_receive_generic_xdp net/core/dev.c:4952 [inline]
do_xdp_generic+0x931/0x1440 net/core/dev.c:5017
__netif_receive_skb_core+0x2533/0x6190 net/core/dev.c:5358
__netif_receive_skb_one_core net/core/dev.c:5536 [inline]
__netif_receive_skb+0xca/0xa00 net/core/dev.c:5652
process_backlog+0x480/0x8b0 net/core/dev.c:5981
__napi_poll+0xe7/0x980 net/core/dev.c:6632
napi_poll net/core/dev.c:6701 [inline]
net_rx_action+0x89d/0x1820 net/core/dev.c:6813
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554
Uninit was created at:
slab_post_alloc_hook mm/slub.c:3804 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
__alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668
alloc_skb include/linux/skbuff.h:1318 [inline]
alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504
sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795
sock_alloc_send_skb include/net/sock.h:1835 [inline]
j1939_sk_alloc_skb net/can/j1939/socket.c:878 [inline]
j1939_sk_send_loop net/can/j1939/socket.c:1142 [inline]
j1939_sk_sendmsg+0xc0a/0x2730 net/can/j1939/socket.c:1277
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x30f/0x380 net/socket.c:745
____sys_sendmsg+0x877/0xb60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2674
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
CPU: 0 PID: 5044 Comm: syz-executor640 Not tainted 6.8.0-syzkaller-11136-g66a27abac311 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================
---
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#syz test: git://repo/address.git branch-or-commit-hash
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