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4fe5a00ec7
syzbot reported that tcf_get_base_ptr() can be called while transport
header is not set [1].
Instead of returning a dangling pointer, return NULL.
Fix tcf_get_base_ptr() callers to handle this NULL value.
[1]
WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 skb_transport_header include/linux/skbuff.h:3071 [inline]
WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 tcf_get_base_ptr include/net/pkt_cls.h:539 [inline]
WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 em_nbyte_match+0x2d8/0x3f0 net/sched/em_nbyte.c:43
Modules linked in:
CPU: 1 UID: 0 PID: 6019 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Call Trace:
<TASK>
tcf_em_match net/sched/ematch.c:494 [inline]
__tcf_em_tree_match+0x1ac/0x770 net/sched/ematch.c:520
tcf_em_tree_match include/net/pkt_cls.h:512 [inline]
basic_classify+0x115/0x2d0 net/sched/cls_basic.c:50
tc_classify include/net/tc_wrapper.h:197 [inline]
__tcf_classify net/sched/cls_api.c:1764 [inline]
tcf_classify+0x4cf/0x1140 net/sched/cls_api.c:1860
multiq_classify net/sched/sch_multiq.c:39 [inline]
multiq_enqueue+0xfd/0x4c0 net/sched/sch_multiq.c:66
dev_qdisc_enqueue+0x4e/0x260 net/core/dev.c:4118
__dev_xmit_skb net/core/dev.c:4214 [inline]
__dev_queue_xmit+0xe83/0x3b50 net/core/dev.c:4729
packet_snd net/packet/af_packet.c:3076 [inline]
packet_sendmsg+0x3e33/0x5080 net/packet/af_packet.c:3108
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
____sys_sendmsg+0x505/0x830 net/socket.c:2630
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+f3a497f02c389d86ef16@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6920855a.a70a0220.2ea503.0058.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20251121154100.1616228-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
100 lines
2.0 KiB
C
100 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/em_cmp.c Simple packet data comparison ematch
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/tc_ematch/tc_em_cmp.h>
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#include <linux/unaligned.h>
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#include <net/pkt_cls.h>
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static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
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{
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return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
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}
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static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,
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struct tcf_pkt_info *info)
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{
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struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;
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unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer);
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u32 val = 0;
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if (!ptr)
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return 0;
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ptr += cmp->off;
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if (!tcf_valid_offset(skb, ptr, cmp->align))
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return 0;
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switch (cmp->align) {
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case TCF_EM_ALIGN_U8:
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val = *ptr;
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break;
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case TCF_EM_ALIGN_U16:
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val = get_unaligned_be16(ptr);
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if (cmp_needs_transformation(cmp))
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val = be16_to_cpu(val);
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break;
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case TCF_EM_ALIGN_U32:
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/* Worth checking boundaries? The branching seems
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* to get worse. Visit again.
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*/
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val = get_unaligned_be32(ptr);
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if (cmp_needs_transformation(cmp))
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val = be32_to_cpu(val);
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break;
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default:
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return 0;
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}
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if (cmp->mask)
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val &= cmp->mask;
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switch (cmp->opnd) {
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case TCF_EM_OPND_EQ:
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return val == cmp->val;
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case TCF_EM_OPND_LT:
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return val < cmp->val;
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case TCF_EM_OPND_GT:
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return val > cmp->val;
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}
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return 0;
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}
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static struct tcf_ematch_ops em_cmp_ops = {
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.kind = TCF_EM_CMP,
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.datalen = sizeof(struct tcf_em_cmp),
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.match = em_cmp_match,
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.owner = THIS_MODULE,
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.link = LIST_HEAD_INIT(em_cmp_ops.link)
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};
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static int __init init_em_cmp(void)
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{
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return tcf_em_register(&em_cmp_ops);
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}
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static void __exit exit_em_cmp(void)
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{
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tcf_em_unregister(&em_cmp_ops);
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}
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MODULE_DESCRIPTION("ematch classifier for basic data types(8/16/32 bit) against skb data");
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MODULE_LICENSE("GPL");
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module_init(init_em_cmp);
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module_exit(exit_em_cmp);
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MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);
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