linux-kernel/linux-7.2.3/tools/testing/selftests/bpf/progs/verifier_ld_ind.c

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

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

SEC("socket")
__description("ld_ind: check calling conv, r1")
__failure __msg("R1 !read_ok")
__failure_unpriv
__naked void ind_check_calling_conv_r1(void)
{
	asm volatile ("					\
	r6 = r1;					\
	r1 = 1;						\
	.8byte %[ld_ind];				\
	r0 = r1;					\
	exit;						\
"	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_1, -0x200000))
	: __clobber_all);
}

SEC("socket")
__description("ld_ind: check calling conv, r2")
__failure __msg("R2 !read_ok")
__failure_unpriv
__naked void ind_check_calling_conv_r2(void)
{
	asm volatile ("					\
	r6 = r1;					\
	r2 = 1;						\
	.8byte %[ld_ind];				\
	r0 = r2;					\
	exit;						\
"	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_2, -0x200000))
	: __clobber_all);
}

SEC("socket")
__description("ld_ind: check calling conv, r3")
__failure __msg("R3 !read_ok")
__failure_unpriv
__naked void ind_check_calling_conv_r3(void)
{
	asm volatile ("					\
	r6 = r1;					\
	r3 = 1;						\
	.8byte %[ld_ind];				\
	r0 = r3;					\
	exit;						\
"	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_3, -0x200000))
	: __clobber_all);
}

SEC("socket")
__description("ld_ind: check calling conv, r4")
__failure __msg("R4 !read_ok")
__failure_unpriv
__naked void ind_check_calling_conv_r4(void)
{
	asm volatile ("					\
	r6 = r1;					\
	r4 = 1;						\
	.8byte %[ld_ind];				\
	r0 = r4;					\
	exit;						\
"	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_4, -0x200000))
	: __clobber_all);
}

SEC("socket")
__description("ld_ind: check calling conv, r5")
__failure __msg("R5 !read_ok")
__failure_unpriv
__naked void ind_check_calling_conv_r5(void)
{
	asm volatile ("					\
	r6 = r1;					\
	r5 = 1;						\
	.8byte %[ld_ind];				\
	r0 = r5;					\
	exit;						\
"	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_5, -0x200000))
	: __clobber_all);
}

SEC("socket")
__description("ld_ind: check calling conv, r7")
__success __success_unpriv __retval(1)
__naked void ind_check_calling_conv_r7(void)
{
	asm volatile ("					\
	r6 = r1;					\
	r7 = 1;						\
	.8byte %[ld_ind];				\
	r0 = r7;					\
	exit;						\
"	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, -0x200000))
	: __clobber_all);
}

/*
 * ld_{abs,ind} subprog that always sets r0=1 on the success path.
 * bpf_gen_ld_abs() emits a hidden exit with r0=0 when the load helper
 * fails. The verifier must model this failure return so that callers
 * account for r0=0 as a possible return value.
 */
__naked __noinline __used
static int ldabs_subprog(void)
{
	asm volatile (
	"r6 = r1;"
	".8byte %[ld_abs];"
	"r0 = 1;"
	"exit;"
	:
	: __imm_insn(ld_abs, BPF_LD_ABS(BPF_W, 0))
	: __clobber_all);
}

__naked __noinline __used
static int ldind_subprog(void)
{
	asm volatile (
	"r6 = r1;"
	"r7 = 0;"
	".8byte %[ld_ind];"
	"r0 = 1;"
	"exit;"
	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, 0))
	: __clobber_all);
}

SEC("socket")
__description("ld_abs: subprog early exit on ld_abs failure")
__failure __msg("R9 !read_ok")
__naked void ld_abs_subprog_early_exit(void)
{
	asm volatile (
	"call ldabs_subprog;"
	"if r0 != 0 goto l_exit_%=;"
	"r0 = r9;"
	"l_exit_%=:"
	"r0 = 0;"
	"exit;"
	::: __clobber_all);
}

SEC("socket")
__description("ld_ind: subprog early exit on ld_ind failure")
__failure __msg("R9 !read_ok")
__naked void ld_ind_subprog_early_exit(void)
{
	asm volatile (
	"call ldind_subprog;"
	"if r0 != 0 goto l_exit_%=;"
	"r0 = r9;"
	"l_exit_%=:"
	"r0 = 0;"
	"exit;"
	::: __clobber_all);
}

SEC("socket")
__description("ld_abs: subprog with both paths safe")
__success
__naked void ld_abs_subprog_both_paths_safe(void)
{
	asm volatile (
	"call ldabs_subprog;"
	"r0 = 0;"
	"exit;"
	::: __clobber_all);
}

SEC("socket")
__description("ld_ind: subprog with both paths safe")
__success
__naked void ld_ind_subprog_both_paths_safe(void)
{
	asm volatile (
	"call ldind_subprog;"
	"r0 = 0;"
	"exit;"
	::: __clobber_all);
}

/*
 * ld_{abs,ind} in subprogs require scalar (int) return type in BTF.
 * A test with void return must be rejected.
 */
__naked __noinline __used
static void ldabs_void_subprog(void)
{
	asm volatile (
	"r6 = r1;"
	".8byte %[ld_abs];"
	"r0 = 1;"
	"exit;"
	:
	: __imm_insn(ld_abs, BPF_LD_ABS(BPF_W, 0))
	: __clobber_all);
}

SEC("socket")
__description("ld_abs: reject void return subprog")
__failure __msg("LD_ABS is only allowed in functions that return 'int'")
__naked void ld_abs_void_subprog_reject(void)
{
	asm volatile (
	"call ldabs_void_subprog;"
	"r0 = 0;"
	"exit;"
	::: __clobber_all);
}

__naked __noinline __used
static void ldind_void_subprog(void)
{
	asm volatile (
	"r6 = r1;"
	"r7 = 0;"
	".8byte %[ld_ind];"
	"r0 = 1;"
	"exit;"
	:
	: __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, 0))
	: __clobber_all);
}

SEC("socket")
__description("ld_ind: reject void return subprog")
__failure __msg("LD_ABS is only allowed in functions that return 'int'")
__naked void ld_ind_void_subprog_reject(void)
{
	asm volatile (
	"call ldind_void_subprog;"
	"r0 = 0;"
	"exit;"
	::: __clobber_all);
}

char _license[] SEC("license") = "GPL";