[syzbot] [netfilter?] KMSAN: uninit-value in __nla_validate_parse (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c1ca10ceffbb Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1120c23c180000
kernel config: https://syzkaller.appspot.com/x/.config?x=e3dd779fba027968
dashboard link: https://syzkaller.appspot.com/bug?extid=3f497b07aa3baf2fb4d0
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/83d019f0ac47/disk-c1ca10ce.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/49e05dd7a23d/vmlinux-c1ca10ce.xz
kernel image: https://storage.googleapis.com/syzbot-assets/68ec9fa2d33d/bzImage-c1ca10ce.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3f497b...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in nla_validate_range_unsigned lib/nlattr.c:222 [inline]
BUG: KMSAN: uninit-value in nla_validate_int_range lib/nlattr.c:336 [inline]
BUG: KMSAN: uninit-value in validate_nla lib/nlattr.c:575 [inline]
BUG: KMSAN: uninit-value in __nla_validate_parse+0x2e20/0x45c0 lib/nlattr.c:631
nla_validate_range_unsigned lib/nlattr.c:222 [inline]
nla_validate_int_range lib/nlattr.c:336 [inline]
validate_nla lib/nlattr.c:575 [inline]
__nla_validate_parse+0x2e20/0x45c0 lib/nlattr.c:631
__nla_parse+0x5f/0x70 lib/nlattr.c:728
nla_parse_deprecated include/net/netlink.h:703 [inline]
nfnetlink_rcv_msg+0x723/0xde0 net/netfilter/nfnetlink.c:275
netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2543
nfnetlink_rcv+0x372/0x4950 net/netfilter/nfnetlink.c:659
netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0xf49/0x1250 net/netlink/af_netlink.c:1367
netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 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+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook mm/slub.c:3819 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
kmem_cache_alloc_node+0x5cb/0xbc0 mm/slub.c:3903
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
__alloc_skb+0x352/0x790 net/core/skbuff.c:651
alloc_skb include/linux/skbuff.h:1296 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1213 [inline]
netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 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+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 6771 Comm: syz-executor.0 Not tainted 6.8.0-rc4-syzkaller-00331-gc1ca10ceffbb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================


---
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[xingwei lee]

Hello, I reproduced this bug in the syzbot dashboard and upstream linux.

If you fix this issue, please add the following tag to the commit:
Reported-by: xingwei lee <xrive...@gmail.com>

I use the same config with syzbot dashboard.
kernel version: c1ca10ceffbb289ed02feaf005bc9ee6095b4507
kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=e3dd779fba027968
with KMSAN enabled

compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

[ 254.423842][ T8047] =====================================================
[ 254.430576][ T8047] BUG: KMSAN: uninit-value in
__nla_validate_parse+0x3d62/0x4f90
[ 254.434357][ T8047] __nla_validate_parse+0x3d62/0x4f90
[ 254.437054][ T8047] __nla_parse+0x6a/0x80
[ 254.439556][ T8047] nfnetlink_rcv_msg+0x74c/0xed0
[ 254.444928][ T8047] netlink_rcv_skb+0x58f/0x6d0
[ 254.447359][ T8047] nfnetlink_rcv+0x3e8/0x4d10
[ 254.449893][ T8047] netlink_unicast+0x107c/0x13e0
[ 254.452371][ T8047] netlink_sendmsg+0x132c/0x1540
[ 254.454791][ T8047] ____sys_sendmsg+0xa5b/0xe70
[ 254.456975][ T8047] ___sys_sendmsg+0x2a7/0x3f0
[ 254.459423][ T8047] __x64_sys_sendmsg+0x342/0x510
[ 254.461514][ T8047] do_syscall_64+0xcf/0x1e0
[ 254.463345][ T8047] entry_SYSCALL_64_after_hwframe+0x63/0x6b
[ 254.465643][ T8047]
[ 254.466539][ T8047] Uninit was created at:
[ 254.468194][ T8047] kmem_cache_alloc_node+0x5cb/0xbc0
[ 254.470272][ T8047] kmalloc_reserve+0x14d/0x500
[ 254.471882][ T8047] __alloc_skb+0x385/0x820
[ 254.473385][ T8047] netlink_sendmsg+0xbd6/0x1540
[ 254.475011][ T8047] ____sys_sendmsg+0xa5b/0xe70
[ 254.476534][ T8047] ___sys_sendmsg+0x2a7/0x3f0
[ 254.478039][ T8047] __x64_sys_sendmsg+0x342/0x510
[ 254.479628][ T8047] do_syscall_64+0xcf/0x1e0
[ 254.480995][ T8047] entry_SYSCALL_64_after_hwframe+0x63/0x6b
[ 254.482719][ T8047]


=* repro.c =*
#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 <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>

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;
}

#define BITMASK(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off))
#define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len) \
*(type*)(addr) = \
htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) | \
(((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len))))

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");
}

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[1] = {0xffffffffffffffff};

void execute_one(void) {
intptr_t res = 0;
res = syscall(__NR_socket, /*domain=*/0x10ul, /*type=*/3ul, /*proto=*/0xc);
if (res != -1)
r[0] = res;
*(uint64_t*)0x20000080 = 0;
*(uint32_t*)0x20000088 = 0;
*(uint64_t*)0x20000090 = 0x20000040;
*(uint64_t*)0x20000040 = 0x20000100;
*(uint32_t*)0x20000100 = 0x18;
*(uint8_t*)0x20000104 = 0;
*(uint8_t*)0x20000105 = 0xb;
*(uint16_t*)0x20000106 = 0x401;
*(uint32_t*)0x20000108 = 0;
*(uint32_t*)0x2000010c = 0;
*(uint8_t*)0x20000110 = 0;
*(uint8_t*)0x20000111 = 0;
*(uint16_t*)0x20000112 = htobe16(0);
*(uint16_t*)0x20000114 = 4;
STORE_BY_BITMASK(uint16_t, , 0x20000116, 2, 0, 14);
STORE_BY_BITMASK(uint16_t, , 0x20000117, 0, 6, 1);
STORE_BY_BITMASK(uint16_t, , 0x20000117, 1, 7, 1);
*(uint64_t*)0x20000048 = 0x18;
*(uint64_t*)0x20000098 = 1;
*(uint64_t*)0x200000a0 = 0;
*(uint64_t*)0x200000a8 = 0;
*(uint32_t*)0x200000b0 = 0;
syscall(__NR_sendmsg, /*fd=*/r[0], /*msg=*/0x20000080ul, /*f=*/0ul);
}
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;
}

=* repro.txt =*
r0 = socket$nl_netfilter(0x10, 0x3, 0xc)
sendmsg$IPCTNL_MSG_CT_NEW(r0, &(0x7f0000000080)={0x0, 0x0,
&(0x7f0000000040)={&(0x7f0000000100)={0x18, 0x0, 0xb, 0x401, 0x0, 0x0,
{}, [@CTA_TUPLE_REPLY={0x4}]}, 0x18}}, 0x0)


and see also in
https://gist.github.com/xrivendell7/fe97316e8a66f8d81109a158a3225bc0

I hope it helps.
Best regards!
xingwei Lee