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// SPDX-License-Identifier: GPL-2.0
#include <vmlinux.h>
#include "bpf_experimental.h"
#include "bpf_qdisc_common.h"
#include "bpf_misc.h"
char _license[] SEC("license") = "GPL";
SEC("struct_ops")
__failure __msg("only read is supported")
int BPF_PROG(untrusted_write, struct sk_buff *skb, struct Qdisc *sch,
struct bpf_sk_buff_ptr *to_free)
{
struct Qdisc *next = sch->next_sched;
/*
* sch is trusted, but the walk of next_sched yields a plain
* PTR_TO_BTF_ID which may fault on a dereference. A store through
* it does not get an exception table entry, there is no probed
* store to rewrite it into, hence it has to be rejected before
* bpf_qdisc_btf_struct_access() gets to allow the write to limit.
*/
next->limit = 1000;
bpf_qdisc_skb_drop(skb, to_free);
return NET_XMIT_DROP;
}
SEC("struct_ops")
__auxiliary
struct sk_buff *BPF_PROG(bpf_qdisc_test_dequeue, struct Qdisc *sch)
{
return NULL;
}
SEC("struct_ops")
__auxiliary
int BPF_PROG(bpf_qdisc_test_init, struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
return 0;
}
SEC("struct_ops")
__auxiliary
void BPF_PROG(bpf_qdisc_test_reset, struct Qdisc *sch)
{
}
SEC("struct_ops")
__auxiliary
void BPF_PROG(bpf_qdisc_test_destroy, struct Qdisc *sch)
{
}
SEC(".struct_ops")
struct Qdisc_ops test = {
.enqueue = (void *)untrusted_write,
.dequeue = (void *)bpf_qdisc_test_dequeue,
.init = (void *)bpf_qdisc_test_init,
.reset = (void *)bpf_qdisc_test_reset,
.destroy = (void *)bpf_qdisc_test_destroy,
.id = "bpf_qdisc_test",
};
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