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

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

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/verifier_xdp_direct_packet_access.c
Extension
.c
Size
49723 bytes
Lines
1723
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/xdp_direct_packet_access.c */

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

SEC("xdp")
__description("XDP pkt read, pkt_end mangling, bad access 1")
__failure __msg("R3 pointer arithmetic on pkt_end")
__naked void end_mangling_bad_access_1(void)
{
	asm volatile ("					\
	r2 = *(u32*)(r1 + %[xdp_md_data]);		\
	r3 = *(u32*)(r1 + %[xdp_md_data_end]);		\
	r1 = r2;					\
	r1 += 8;					\
	r3 += 8;					\
	if r1 > r3 goto l0_%=;				\
	r0 = *(u64*)(r1 - 8);				\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __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("XDP pkt read, pkt_end mangling, bad access 2")
__failure __msg("R3 pointer arithmetic on pkt_end")
__naked void end_mangling_bad_access_2(void)
{
	asm volatile ("					\
	r2 = *(u32*)(r1 + %[xdp_md_data]);		\
	r3 = *(u32*)(r1 + %[xdp_md_data_end]);		\
	r1 = r2;					\
	r1 += 8;					\
	r3 -= 8;					\
	if r1 > r3 goto l0_%=;				\
	r0 = *(u64*)(r1 - 8);				\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __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("XDP pkt read, pkt_data' > pkt_end, corner case, good access")
__success __retval(0) __flag(BPF_F_ANY_ALIGNMENT)
__naked void end_corner_case_good_access_1(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_%=;				\
	r0 = *(u64*)(r1 - 8);				\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __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("XDP pkt read, pkt_data' > pkt_end, bad access 1")
__failure __msg("R1 {{min|max}} value is outside of the allowed memory range")
__flag(BPF_F_ANY_ALIGNMENT)
__naked void pkt_end_bad_access_1_1(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_%=;				\
	r0 = *(u64*)(r1 - 4);				\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __imm_const(xdp_md_data, offsetof(struct xdp_md, data)),
	  __imm_const(xdp_md_data_end, offsetof(struct xdp_md, data_end))
	: __clobber_all);
}

Annotation

Implementation Notes