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

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

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/verifier_bounds.c
Extension
.c
Size
60054 bytes
Lines
2298
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/bounds.c */

#include <linux/bpf.h>
#include <../../../include/linux/filter.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("socket")
__description("subtraction bounds (map value) variant 1")
__failure __msg("R0 max value is outside of the allowed memory range")
__failure_unpriv
__naked void bounds_map_value_variant_1(void)
{
	asm volatile ("					\
	r1 = 0;						\
	*(u64*)(r10 - 8) = r1;				\
	r2 = r10;					\
	r2 += -8;					\
	r1 = %[map_hash_8b] ll;				\
	call %[bpf_map_lookup_elem];			\
	if r0 == 0 goto l0_%=;				\
	r1 = *(u8*)(r0 + 0);				\
	if r1 > 0xff goto l0_%=;			\
	r3 = *(u8*)(r0 + 1);				\
	if r3 > 0xff goto l0_%=;			\
	r1 -= r3;					\
	r1 >>= 56;					\
	r0 += r1;					\
	r0 = *(u8*)(r0 + 0);				\
	exit;						\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b)
	: __clobber_all);
}

SEC("socket")
__description("subtraction bounds (map value) variant 2")
__failure
__msg("R0 min value is negative, either use unsigned index or do a if (index >=0) check.")
__msg_unpriv("R1 has unknown scalar with mixed signed bounds")
__naked void bounds_map_value_variant_2(void)
{
	asm volatile ("					\
	r1 = 0;						\
	*(u64*)(r10 - 8) = r1;				\
	r2 = r10;					\
	r2 += -8;					\
	r1 = %[map_hash_8b] ll;				\
	call %[bpf_map_lookup_elem];			\
	if r0 == 0 goto l0_%=;				\
	r1 = *(u8*)(r0 + 0);				\
	if r1 > 0xff goto l0_%=;			\
	r3 = *(u8*)(r0 + 1);				\
	if r3 > 0xff goto l0_%=;			\
	r1 -= r3;					\
	r0 += r1;					\
	r0 = *(u8*)(r0 + 0);				\
	exit;						\
l0_%=:	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm_addr(map_hash_8b)
	: __clobber_all);
}

SEC("socket")
__description("check subtraction on pointers for unpriv")
__success __failure_unpriv __msg_unpriv("R9 pointer -= pointer prohibited")
__retval(0)
__naked void subtraction_on_pointers_for_unpriv(void)
{
	asm volatile ("					\
	r0 = 0;						\
	r1 = %[map_hash_8b] ll;				\
	r2 = r10;					\
	r2 += -8;					\
	r6 = 9;						\
	*(u64*)(r2 + 0) = r6;				\

Annotation

Implementation Notes