Commit 80a4129f authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages 



Add unit tests for bpf_arena_alloc/free_pages() functionality
and bpf_arena_common.h with a set of common helpers and macros that
is used in this test and the following patches.

Also modify test_loader that didn't support running bpf_prog_type_syscall
programs.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240308010812.89848-13-alexei.starovoitov@gmail.com
parent 204c6287

tools/testing/selftests/bpf/DENYLIST.aarch64

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ fill_link_info/kprobe_multi_link_info # bpf_program__attach_kprobe_mu 
fill_link_info/kretprobe_multi_link_info         # bpf_program__attach_kprobe_multi_opts unexpected error: -95

fill_link_info/kprobe_multi_invalid_ubuff        # bpf_program__attach_kprobe_multi_opts unexpected error: -95

missed/kprobe_recursion                          # missed_kprobe_recursion__attach unexpected error: -95 (errno 95)

verifier_arena                                   # JIT does not support arena

tools/testing/selftests/bpf/DENYLIST.s390x

+1 −0
Original line number Diff line number Diff line
@@ -4,3 +4,4 @@ exceptions # JIT does not support calling kfunc bpf_throw (excepti 
get_stack_raw_tp                         # user_stack corrupted user stack                                             (no backchain userspace)

stacktrace_build_id                      # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2                   (?)

verifier_iterating_callbacks

verifier_arena                           # JIT does not support arena

tools/testing/selftests/bpf/bpf_arena_common.h

0 → 100644
+70 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */

/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */

#pragma once



#ifndef WRITE_ONCE

#define WRITE_ONCE(x, val) ((*(volatile typeof(x) *) &(x)) = (val))

#endif



#ifndef NUMA_NO_NODE

#define	NUMA_NO_NODE	(-1)

#endif



#ifndef arena_container_of

#define arena_container_of(ptr, type, member)			\

	({							\

		void __arena *__mptr = (void __arena *)(ptr);	\

		((type *)(__mptr - offsetof(type, member)));	\

	})

#endif



#ifdef __BPF__ /* when compiled as bpf program */



#ifndef PAGE_SIZE

#define PAGE_SIZE __PAGE_SIZE

/*

 * for older kernels try sizeof(struct genradix_node)

 * or flexible:

 * static inline long __bpf_page_size(void) {

 *   return bpf_core_enum_value(enum page_size_enum___l, __PAGE_SIZE___l) ?: sizeof(struct genradix_node);

 * }

 * but generated code is not great.

 */

#endif



#if defined(__BPF_FEATURE_ARENA_CAST) && !defined(BPF_ARENA_FORCE_ASM)

#define __arena __attribute__((address_space(1)))

#define cast_kern(ptr) /* nop for bpf prog. emitted by LLVM */

#define cast_user(ptr) /* nop for bpf prog. emitted by LLVM */

#else

#define __arena

#define cast_kern(ptr) bpf_addr_space_cast(ptr, 0, 1)

#define cast_user(ptr) bpf_addr_space_cast(ptr, 1, 0)

#endif



void __arena* bpf_arena_alloc_pages(void *map, void __arena *addr, __u32 page_cnt,

				    int node_id, __u64 flags) __ksym __weak;

void bpf_arena_free_pages(void *map, void __arena *ptr, __u32 page_cnt) __ksym __weak;



#else /* when compiled as user space code */



#define __arena

#define __arg_arena

#define cast_kern(ptr) /* nop for user space */

#define cast_user(ptr) /* nop for user space */

__weak char arena[1];



#ifndef offsetof

#define offsetof(type, member)  ((unsigned long)&((type *)0)->member)

#endif



static inline void __arena* bpf_arena_alloc_pages(void *map, void *addr, __u32 page_cnt,

						  int node_id, __u64 flags)

{

	return NULL;

}

static inline void bpf_arena_free_pages(void *map, void __arena *ptr, __u32 page_cnt)

{

}



#endif

tools/testing/selftests/bpf/prog_tests/verifier.c

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


#include "cap_helpers.h"

#include "verifier_and.skel.h"

#include "verifier_arena.skel.h"

#include "verifier_array_access.skel.h"

#include "verifier_basic_stack.skel.h"

#include "verifier_bitfield_write.skel.h"
@@ -118,6 +119,7 @@ static void run_tests_aux(const char *skel_name, 
#define RUN(skel) run_tests_aux(#skel, skel##__elf_bytes, NULL)



void test_verifier_and(void)                  { RUN(verifier_and); }

void test_verifier_arena(void)                { RUN(verifier_arena); }

void test_verifier_basic_stack(void)          { RUN(verifier_basic_stack); }

void test_verifier_bitfield_write(void)       { RUN(verifier_bitfield_write); }

void test_verifier_bounds(void)               { RUN(verifier_bounds); }

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

0 → 100644
+146 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */



#include <vmlinux.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"

#include "bpf_experimental.h"

#include "bpf_arena_common.h"



struct {

	__uint(type, BPF_MAP_TYPE_ARENA);

	__uint(map_flags, BPF_F_MMAPABLE);

	__uint(max_entries, 2); /* arena of two pages close to 32-bit boundary*/

	__ulong(map_extra, (1ull << 44) | (~0u - __PAGE_SIZE * 2 + 1)); /* start of mmap() region */

} arena SEC(".maps");



SEC("syscall")

__success __retval(0)

int basic_alloc1(void *ctx)

{

#if defined(__BPF_FEATURE_ARENA_CAST)

	volatile int __arena *page1, *page2, *no_page, *page3;



	page1 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);

	if (!page1)

		return 1;

	*page1 = 1;

	page2 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);

	if (!page2)

		return 2;

	*page2 = 2;

	no_page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);

	if (no_page)

		return 3;

	if (*page1 != 1)

		return 4;

	if (*page2 != 2)

		return 5;

	bpf_arena_free_pages(&arena, (void __arena *)page2, 1);

	if (*page1 != 1)

		return 6;

	if (*page2 != 0) /* use-after-free should return 0 */

		return 7;

	page3 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);

	if (!page3)

		return 8;

	*page3 = 3;

	if (page2 != page3)

		return 9;

	if (*page1 != 1)

		return 10;

#endif

	return 0;

}



SEC("syscall")

__success __retval(0)

int basic_alloc2(void *ctx)

{

#if defined(__BPF_FEATURE_ARENA_CAST)

	volatile char __arena *page1, *page2, *page3, *page4;



	page1 = bpf_arena_alloc_pages(&arena, NULL, 2, NUMA_NO_NODE, 0);

	if (!page1)

		return 1;

	page2 = page1 + __PAGE_SIZE;

	page3 = page1 + __PAGE_SIZE * 2;

	page4 = page1 - __PAGE_SIZE;

	*page1 = 1;

	*page2 = 2;

	*page3 = 3;

	*page4 = 4;

	if (*page1 != 1)

		return 1;

	if (*page2 != 2)

		return 2;

	if (*page3 != 0)

		return 3;

	if (*page4 != 0)

		return 4;

	bpf_arena_free_pages(&arena, (void __arena *)page1, 2);

	if (*page1 != 0)

		return 5;

	if (*page2 != 0)

		return 6;

	if (*page3 != 0)

		return 7;

	if (*page4 != 0)

		return 8;

#endif

	return 0;

}



struct bpf_arena___l {

        struct bpf_map map;

} __attribute__((preserve_access_index));



SEC("syscall")

__success __retval(0) __log_level(2)

int basic_alloc3(void *ctx)

{

	struct bpf_arena___l *ar = (struct bpf_arena___l *)&arena;

	volatile char __arena *pages;



	pages = bpf_arena_alloc_pages(&ar->map, NULL, ar->map.max_entries, NUMA_NO_NODE, 0);

	if (!pages)

		return 1;

	return 0;

}



SEC("iter.s/bpf_map")

__success __log_level(2)

int iter_maps1(struct bpf_iter__bpf_map *ctx)

{

	struct bpf_map *map = ctx->map;



	if (!map)

		return 0;

	bpf_arena_alloc_pages(map, NULL, map->max_entries, 0, 0);

	return 0;

}



SEC("iter.s/bpf_map")

__failure __msg("expected pointer to STRUCT bpf_map")

int iter_maps2(struct bpf_iter__bpf_map *ctx)

{

	struct seq_file *seq = ctx->meta->seq;



	bpf_arena_alloc_pages((void *)seq, NULL, 1, 0, 0);

	return 0;

}



SEC("iter.s/bpf_map")

__failure __msg("untrusted_ptr_bpf_map")

int iter_maps3(struct bpf_iter__bpf_map *ctx)

{

	struct bpf_map *map = ctx->map;



	if (!map)

		return 0;

	bpf_arena_alloc_pages(map->inner_map_meta, NULL, map->max_entries, 0, 0);

	return 0;

}



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