TLDRVuln - Cybersecurity Vulnerabilities Made Simple

In the Linux kernel, the following vulnerability has been resolved:

net/sched: act_ife: avoid possible NULL deref

tcf_ife_encode() must make sure ife_encode() does not return NULL.

syzbot reported:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI

KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]

RIP: 0010:ife_tlv_meta_encode+0x41/0xa0 net/ife/ife.c:166

CPU: 3 UID: 0 PID: 8990 Comm: syz.0.696 Not tainted syzkaller #0 PREEMPT(full)

Call Trace:

<TASK>

ife_encode_meta_u32+0x153/0x180 net/sched/act_ife.c:101

tcf_ife_encode net/sched/act_ife.c:841 [inline]

tcf_ife_act+0x1022/0x1de0 net/sched/act_ife.c:877

tc_act include/net/tc_wrapper.h:130 [inline]

tcf_action_exec+0x1c0/0xa20 net/sched/act_api.c:1152

tcf_exts_exec include/net/pkt_cls.h:349 [inline]

mall_classify+0x1a0/0x2a0 net/sched/cls_matchall.c:42

tc_classify include/net/tc_wrapper.h:197 [inline]

__tcf_classify net/sched/cls_api.c:1764 [inline]

tcf_classify+0x7f2/0x1380 net/sched/cls_api.c:1860

multiq_classify net/sched/sch_multiq.c:39 [inline]

multiq_enqueue+0xe0/0x510 net/sched/sch_multiq.c:66

dev_qdisc_enqueue+0x45/0x250 net/core/dev.c:4147

__dev_xmit_skb net/core/dev.c:4262 [inline]

__dev_queue_xmit+0x2998/0x46c0 net/core/dev.c:4798