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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#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, int);
__type(value, long long);
} map SEC(".maps");
SEC("socket")
__log_level(2)
__msg("(0) frame 0 insn 2 +written -8")
__msg("(0) frame 0 insn 1 +live -24")
__msg("(0) frame 0 insn 1 +written -8")
__msg("(0) frame 0 insn 0 +live -8,-24")
__msg("(0) frame 0 insn 0 +written -8")
__msg("(0) live stack update done in 2 iterations")
__naked void simple_read_simple_write(void)
{
asm volatile (
"r1 = *(u64 *)(r10 - 8);"
"r2 = *(u64 *)(r10 - 24);"
"*(u64 *)(r10 - 8) = r1;"
"r0 = 0;"
"exit;"
::: __clobber_all);
}
SEC("socket")
__log_level(2)
__msg("(0) frame 0 insn 1 +live -8")
__not_msg("(0) frame 0 insn 1 +written")
__msg("(0) live stack update done in 2 iterations")
__msg("(0) frame 0 insn 1 +live -16")
__msg("(0) frame 0 insn 1 +written -32")
__msg("(0) live stack update done in 2 iterations")
__naked void read_write_join(void)
{
asm volatile (
"call %[bpf_get_prandom_u32];"
"if r0 > 42 goto 1f;"
"r0 = *(u64 *)(r10 - 8);"
"*(u64 *)(r10 - 32) = r0;"
"*(u64 *)(r10 - 40) = r0;"
"exit;"
"1:"
"r0 = *(u64 *)(r10 - 16);"
"*(u64 *)(r10 - 32) = r0;"
"exit;"
:: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("socket")
__log_level(2)
__msg("2: (25) if r0 > 0x2a goto pc+1")
__msg("7: (95) exit")
__msg("(0) frame 0 insn 2 +written -16")
__msg("(0) live stack update done in 2 iterations")
__msg("7: (95) exit")
__not_msg("(0) frame 0 insn 2")
__msg("(0) live stack update done in 1 iterations")
__naked void must_write_not_same_slot(void)
{
asm volatile (
"call %[bpf_get_prandom_u32];"
"r1 = -8;"
"if r0 > 42 goto 1f;"
"r1 = -16;"
"1:"
"r2 = r10;"
"r2 += r1;"
"*(u64 *)(r2 + 0) = r0;"
"exit;"
:: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
SEC("socket")
__log_level(2)
__msg("(0) frame 0 insn 0 +written -8,-16")
__msg("(0) live stack update done in 2 iterations")
__msg("(0) frame 0 insn 0 +written -8")
__msg("(0) live stack update done in 2 iterations")
__naked void must_write_not_same_type(void)
{
asm volatile (
"*(u64*)(r10 - 8) = 0;"
"r2 = r10;"
"r2 += -8;"
"r1 = %[map] ll;"
"call %[bpf_map_lookup_elem];"
"if r0 != 0 goto 1f;"
"r0 = r10;"
"r0 += -16;"
"1:"
"*(u64 *)(r0 + 0) = 42;"
"exit;"
:
: __imm(bpf_get_prandom_u32),
__imm(bpf_map_lookup_elem),
__imm_addr(map)
: __clobber_all);
}
SEC("socket")
__log_level(2)
__msg("(2,4) frame 0 insn 4 +written -8")
__msg("(2,4) live stack update done in 2 iterations")
__msg("(0) frame 0 insn 2 +written -8")
__msg("(0) live stack update done in 2 iterations")
__naked void caller_stack_write(void)
{
asm volatile (
"r1 = r10;"
"r1 += -8;"
"call write_first_param;"
"exit;"
::: __clobber_all);
}
static __used __naked void write_first_param(void)
{
asm volatile (
"*(u64 *)(r1 + 0) = 7;"
"r0 = 0;"
"exit;"
::: __clobber_all);
}
SEC("socket")
__log_level(2)
/* caller_stack_read() function */
__msg("2: .12345.... (85) call pc+4")
__msg("5: .12345.... (85) call pc+1")
__msg("6: 0......... (95) exit")
/* read_first_param() function */
__msg("7: .1........ (79) r0 = *(u64 *)(r1 +0)")
__msg("8: 0......... (95) exit")
/* update for callsite at (2) */
__msg("(2,7) frame 0 insn 7 +live -8")
__msg("(2,7) live stack update done in 2 iterations")
__msg("(0) frame 0 insn 2 +live -8")
__msg("(0) live stack update done in 2 iterations")
/* update for callsite at (5) */
__msg("(5,7) frame 0 insn 7 +live -16")
__msg("(5,7) live stack update done in 2 iterations")
__msg("(0) frame 0 insn 5 +live -16")
__msg("(0) live stack update done in 2 iterations")
__naked void caller_stack_read(void)
{
asm volatile (
"r1 = r10;"
"r1 += -8;"
"call read_first_param;"
"r1 = r10;"
"r1 += -16;"
"call read_first_param;"
"exit;"
::: __clobber_all);
}
static __used __naked void read_first_param(void)
{
asm volatile (
"r0 = *(u64 *)(r1 + 0);"
"exit;"
::: __clobber_all);
}
SEC("socket")
__flag(BPF_F_TEST_STATE_FREQ)
__log_level(2)
/* read_first_param2() function */
__msg(" 9: .1........ (79) r0 = *(u64 *)(r1 +0)")
__msg("10: .......... (b7) r0 = 0")
__msg("11: 0......... (05) goto pc+0")
__msg("12: 0......... (95) exit")
/*
* The purpose of the test is to check that checkpoint in
* read_first_param2() stops path traversal. This will only happen if
* verifier understands that fp[0]-8 at insn (12) is not alive.
*/
__msg("12: safe")
__msg("processed 20 insns")
__naked void caller_stack_pruning(void)
{
asm volatile (
"call %[bpf_get_prandom_u32];"
"if r0 == 42 goto 1f;"
"r0 = %[map] ll;"
"1:"
"*(u64 *)(r10 - 8) = r0;"
"r1 = r10;"
"r1 += -8;"
/*
* fp[0]-8 is either pointer to map or a scalar,
* preventing state pruning at checkpoint created for call.
*/
"call read_first_param2;"
"exit;"
:
: __imm(bpf_get_prandom_u32),
__imm_addr(map)
: __clobber_all);
}
static __used __naked void read_first_param2(void)
{
asm volatile (
"r0 = *(u64 *)(r1 + 0);"
"r0 = 0;"
/*
* Checkpoint at goto +0 should fire,
* as caller stack fp[0]-8 is not alive at this point.
*/
"goto +0;"
"exit;"
::: __clobber_all);
}
SEC("socket")
__flag(BPF_F_TEST_STATE_FREQ)
__failure
__msg("R1 type=scalar expected=map_ptr")
__naked void caller_stack_pruning_callback(void)
{
asm volatile (
"r0 = %[map] ll;"
"*(u64 *)(r10 - 8) = r0;"
"r1 = 2;"
"r2 = loop_cb ll;"
"r3 = r10;"
"r3 += -8;"
"r4 = 0;"
/*
* fp[0]-8 is either pointer to map or a scalar,
* preventing state pruning at checkpoint created for call.
*/
"call %[bpf_loop];"
"r0 = 42;"
"exit;"
:
: __imm(bpf_get_prandom_u32),
__imm(bpf_loop),
__imm_addr(map)
: __clobber_all);
}
static __used __naked void loop_cb(void)
{
asm volatile (
/*
* Checkpoint at function entry should not fire, as caller
* stack fp[0]-8 is alive at this point.
*/
"r6 = r2;"
"r1 = *(u64 *)(r6 + 0);"
"*(u64*)(r10 - 8) = 7;"
"r2 = r10;"
"r2 += -8;"
"call %[bpf_map_lookup_elem];"
/*
* This should stop verifier on a second loop iteration,
* but only if verifier correctly maintains that fp[0]-8
* is still alive.
*/
"*(u64 *)(r6 + 0) = 0;"
"r0 = 0;"
"exit;"
:
: __imm(bpf_map_lookup_elem),
__imm(bpf_get_prandom_u32)
: __clobber_all);
}
/*
* Because of a bug in verifier.c:compute_postorder()
* the program below overflowed traversal queue in that function.
*/
SEC("socket")
__naked void syzbot_postorder_bug1(void)
{
asm volatile (
"r0 = 0;"
"if r0 != 0 goto -1;"
"exit;"
::: __clobber_all);
}
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