tools/testing/selftests/bpf/progs/verifier_helper_packet_access.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/verifier_helper_packet_access.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/verifier_helper_packet_access.c
Extension
.c
Size
14531 bytes
Lines
551
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/* Converted from tools/testing/selftests/bpf/verifier/helper_packet_access.c */

#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, 1);
	__type(key, long long);
	__type(value, long long);
} map_hash_8b SEC(".maps");

SEC("xdp")
__description("helper access to packet: test1, valid packet_ptr range")
__success __retval(0)
__naked void test1_valid_packet_ptr_range(void)
{
	asm volatile ("					\
	r2 = *(u32*)(r1 + %[xdp_md_data]);		\
	r3 = *(u32*)(r1 + %[xdp_md_data_end]);		\
	r1 = r2;					\
	r1 += 8;					\
	if r1 > r3 goto l0_%=;				\
	r1 = %[map_hash_8b] ll;				\
	r3 = r2;					\
	r4 = 0;						\
	call %[bpf_map_update_elem];			\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_update_elem),
	  __imm_addr(map_hash_8b),
	  __imm_const(xdp_md_data, offsetof(struct xdp_md, data)),
	  __imm_const(xdp_md_data_end, offsetof(struct xdp_md, data_end))
	: __clobber_all);
}

SEC("xdp")
__description("helper access to packet: test2, unchecked packet_ptr")
__failure __msg("invalid access to packet")
__naked void packet_test2_unchecked_packet_ptr(void)
{
	asm volatile ("					\
	r2 = *(u32*)(r1 + %[xdp_md_data]);		\
	r1 = %[map_hash_8b] ll;				\
	call %[bpf_map_lookup_elem];			\
	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b),
	  __imm_const(xdp_md_data, offsetof(struct xdp_md, data))
	: __clobber_all);
}

SEC("xdp")
__description("helper access to packet: test3, variable add")
__success __retval(0)
__naked void to_packet_test3_variable_add(void)
{
	asm volatile ("					\
	r2 = *(u32*)(r1 + %[xdp_md_data]);		\
	r3 = *(u32*)(r1 + %[xdp_md_data_end]);		\
	r4 = r2;					\
	r4 += 8;					\
	if r4 > r3 goto l0_%=;				\
	r5 = *(u8*)(r2 + 0);				\
	r4 = r2;					\
	r4 += r5;					\
	r5 = r4;					\
	r5 += 8;					\
	if r5 > r3 goto l0_%=;				\
	r1 = %[map_hash_8b] ll;				\
	r2 = r4;					\
	call %[bpf_map_lookup_elem];			\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b),
	  __imm_const(xdp_md_data, offsetof(struct xdp_md, data)),
	  __imm_const(xdp_md_data_end, offsetof(struct xdp_md, data_end))
	: __clobber_all);
}

SEC("xdp")
__description("helper access to packet: test4, packet_ptr with bad range")
__failure __msg("invalid access to packet")

Annotation

Implementation Notes