diff options
| author | Dmitry Antipov <dmantipov@yandex.ru> | 2024-11-21 09:55:42 +0300 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2024-11-28 13:14:24 +0100 |
| commit | 04317f4eb2aad312ad85c1a17ad81fe75f1f9bc7 (patch) | |
| tree | 56b00a318aa3622a2f524ee44cc6e16f4d3f47b9 /net | |
| parent | 146b6f1112eb30a19776d6c323c994e9d67790db (diff) | |
netfilter: x_tables: fix LED ID check in led_tg_check()
Syzbot has reported the following BUG detected by KASAN:
BUG: KASAN: slab-out-of-bounds in strlen+0x58/0x70
Read of size 1 at addr ffff8881022da0c8 by task repro/5879
...
Call Trace:
<TASK>
dump_stack_lvl+0x241/0x360
? __pfx_dump_stack_lvl+0x10/0x10
? __pfx__printk+0x10/0x10
? _printk+0xd5/0x120
? __virt_addr_valid+0x183/0x530
? __virt_addr_valid+0x183/0x530
print_report+0x169/0x550
? __virt_addr_valid+0x183/0x530
? __virt_addr_valid+0x183/0x530
? __virt_addr_valid+0x45f/0x530
? __phys_addr+0xba/0x170
? strlen+0x58/0x70
kasan_report+0x143/0x180
? strlen+0x58/0x70
strlen+0x58/0x70
kstrdup+0x20/0x80
led_tg_check+0x18b/0x3c0
xt_check_target+0x3bb/0xa40
? __pfx_xt_check_target+0x10/0x10
? stack_depot_save_flags+0x6e4/0x830
? nft_target_init+0x174/0xc30
nft_target_init+0x82d/0xc30
? __pfx_nft_target_init+0x10/0x10
? nf_tables_newrule+0x1609/0x2980
? nf_tables_newrule+0x1609/0x2980
? rcu_is_watching+0x15/0xb0
? nf_tables_newrule+0x1609/0x2980
? nf_tables_newrule+0x1609/0x2980
? __kmalloc_noprof+0x21a/0x400
nf_tables_newrule+0x1860/0x2980
? __pfx_nf_tables_newrule+0x10/0x10
? __nla_parse+0x40/0x60
nfnetlink_rcv+0x14e5/0x2ab0
? __pfx_validate_chain+0x10/0x10
? __pfx_nfnetlink_rcv+0x10/0x10
? __lock_acquire+0x1384/0x2050
? netlink_deliver_tap+0x2e/0x1b0
? __pfx_lock_release+0x10/0x10
? netlink_deliver_tap+0x2e/0x1b0
netlink_unicast+0x7f8/0x990
? __pfx_netlink_unicast+0x10/0x10
? __virt_addr_valid+0x183/0x530
? __check_object_size+0x48e/0x900
netlink_sendmsg+0x8e4/0xcb0
? __pfx_netlink_sendmsg+0x10/0x10
? aa_sock_msg_perm+0x91/0x160
? __pfx_netlink_sendmsg+0x10/0x10
__sock_sendmsg+0x223/0x270
____sys_sendmsg+0x52a/0x7e0
? __pfx_____sys_sendmsg+0x10/0x10
__sys_sendmsg+0x292/0x380
? __pfx___sys_sendmsg+0x10/0x10
? lockdep_hardirqs_on_prepare+0x43d/0x780
? __pfx_lockdep_hardirqs_on_prepare+0x10/0x10
? exc_page_fault+0x590/0x8c0
? do_syscall_64+0xb6/0x230
do_syscall_64+0xf3/0x230
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
</TASK>
Since an invalid (without '\0' byte at all) byte sequence may be passed
from userspace, add an extra check to ensure that such a sequence is
rejected as possible ID and so never passed to 'kstrdup()' and further.
Reported-by: syzbot+6c8215822f35fdb35667@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6c8215822f35fdb35667
Fixes: 268cb38e1802 ("netfilter: x_tables: add LED trigger target")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/xt_LED.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c index f7b0286d106a..8a80fd76fe45 100644 --- a/net/netfilter/xt_LED.c +++ b/net/netfilter/xt_LED.c @@ -96,7 +96,9 @@ static int led_tg_check(const struct xt_tgchk_param *par) struct xt_led_info_internal *ledinternal; int err; - if (ledinfo->id[0] == '\0') + /* Bail out if empty string or not a string at all. */ + if (ledinfo->id[0] == '\0' || + !memchr(ledinfo->id, '\0', sizeof(ledinfo->id))) return -EINVAL; mutex_lock(&xt_led_mutex); |