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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
#include <errno.h>
#include <string.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
char _license[] SEC("license") = "GPL";
#define ITER_HELPERS \
__imm(bpf_iter_num_new), \
__imm(bpf_iter_num_next), \
__imm(bpf_iter_num_destroy)
SEC("?raw_tp")
__success
int force_clang_to_emit_btf_for_externs(void *ctx)
{
/* we need this as a workaround to enforce compiler emitting BTF
* information for bpf_iter_num_{new,next,destroy}() kfuncs,
* as, apparently, it doesn't emit it for symbols only referenced from
* assembly (or cleanup attribute, for that matter, as well)
*/
bpf_repeat(0);
return 0;
}
SEC("?raw_tp")
__success
int consume_first_item_only(void *ctx)
{
struct bpf_iter_num iter;
asm volatile (
/* create iterator */
"r1 = %[iter];"
"r2 = 0;"
"r3 = 1000;"
"call %[bpf_iter_num_new];"
/* consume first item */
"r1 = %[iter];"
"call %[bpf_iter_num_next];"
"if r0 == 0 goto +1;"
"r0 = *(u32 *)(r0 + 0);"
/* destroy iterator */
"r1 = %[iter];"
"call %[bpf_iter_num_destroy];"
:
: __imm_ptr(iter), ITER_HELPERS
: __clobber_common
);
return 0;
}
SEC("?raw_tp")
__failure __msg("R0 invalid mem access 'scalar'")
int missing_null_check_fail(void *ctx)
{
struct bpf_iter_num iter;
asm volatile (
/* create iterator */
"r1 = %[iter];"
"r2 = 0;"
"r3 = 1000;"
"call %[bpf_iter_num_new];"
/* consume first element */
"r1 = %[iter];"
"call %[bpf_iter_num_next];"
/* FAIL: deref with no NULL check */
"r1 = *(u32 *)(r0 + 0);"
/* destroy iterator */
"r1 = %[iter];"
"call %[bpf_iter_num_destroy];"
:
: __imm_ptr(iter), ITER_HELPERS
: __clobber_common
);
return 0;
}
SEC("?raw_tp")
__failure
__msg("invalid access to memory, mem_size=4 off=0 size=8")
__msg("R0 min value is outside of the allowed memory range")
int wrong_sized_read_fail(void *ctx)
{
struct bpf_iter_num iter;
asm volatile (
/* create iterator */
"r1 = %[iter];"
"r2 = 0;"
"r3 = 1000;"
"call %[bpf_iter_num_new];"
/* consume first element */
"r1 = %[iter];"
"call %[bpf_iter_num_next];"
"if r0 == 0 goto +1;"
/* FAIL: deref more than available 4 bytes */
"r0 = *(u64 *)(r0 + 0);"
/* destroy iterator */
"r1 = %[iter];"
"call %[bpf_iter_num_destroy];"
:
: __imm_ptr(iter), ITER_HELPERS
: __clobber_common
);
return 0;
}
SEC("?raw_tp")
__success __log_level(2)
__flag(BPF_F_TEST_STATE_FREQ)
int simplest_loop(void *ctx)
{
struct bpf_iter_num iter;
asm volatile (
"r6 = 0;" /* init sum */
/* create iterator */
"r1 = %[iter];"
"r2 = 0;"
"r3 = 10;"
"call %[bpf_iter_num_new];"
"1:"
/* consume next item */
"r1 = %[iter];"
"call %[bpf_iter_num_next];"
"if r0 == 0 goto 2f;"
"r0 = *(u32 *)(r0 + 0);"
"r6 += r0;" /* accumulate sum */
"goto 1b;"
"2:"
/* destroy iterator */
"r1 = %[iter];"
"call %[bpf_iter_num_destroy];"
:
: __imm_ptr(iter), ITER_HELPERS
: __clobber_common, "r6"
);
return 0;
}
__used
static void iterator_with_diff_stack_depth(int x)
{
struct bpf_iter_num iter;
asm volatile (
"if r1 == 42 goto 0f;"
"*(u64 *)(r10 - 128) = 0;"
"0:"
/* create iterator */
"r1 = %[iter];"
"r2 = 0;"
"r3 = 10;"
"call %[bpf_iter_num_new];"
"1:"
/* consume next item */
"r1 = %[iter];"
"call %[bpf_iter_num_next];"
"if r0 == 0 goto 2f;"
"goto 1b;"
"2:"
/* destroy iterator */
"r1 = %[iter];"
"call %[bpf_iter_num_destroy];"
:
: __imm_ptr(iter), ITER_HELPERS
: __clobber_common, "r6"
);
}
SEC("socket")
__success
__naked int widening_stack_size_bug(void *ctx)
{
/*
* Depending on iterator_with_diff_stack_depth() parameter value,
* subprogram stack depth is either 8 or 128 bytes. Arrange values so
* that it is 128 on a first call and 8 on a second. This triggered a
* bug in verifier's widen_imprecise_scalars() logic.
*/
asm volatile (
"r6 = 0;"
"r1 = 0;"
"1:"
"call iterator_with_diff_stack_depth;"
"r1 = 42;"
"r6 += 1;"
"if r6 < 2 goto 1b;"
"r0 = 0;"
"exit;"
::: __clobber_all);
}
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