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selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages

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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: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240308010812.89848-13-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2024-03-07 17:08:10 -08:00 committed by Andrii Nakryiko
parent 204c628730
commit 80a4129fcf
6 changed files with 227 additions and 2 deletions
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1
tools/testing/selftests/bpf/DENYLIST.aarch64
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@ -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

1
tools/testing/selftests/bpf/DENYLIST.s390x
View File

@ -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

70
tools/testing/selftests/bpf/bpf_arena_common.h Normal file
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@ -0,0 +1,70 @@
/* 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

2
tools/testing/selftests/bpf/prog_tests/verifier.c
View File

@ -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); }

146
tools/testing/selftests/bpf/progs/verifier_arena.c Normal file
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@ -0,0 +1,146 @@
// 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";

9
tools/testing/selftests/bpf/test_loader.c
View File

@ -501,7 +501,7 @@ static bool is_unpriv_capable_map(struct bpf_map *map)
}
}
static int do_prog_test_run(int fd_prog, int *retval)
static int do_prog_test_run(int fd_prog, int *retval, bool empty_opts)
{
__u8 tmp_out[TEST_DATA_LEN << 2] = {};
__u8 tmp_in[TEST_DATA_LEN] = {};
@ -514,6 +514,10 @@ static int do_prog_test_run(int fd_prog, int *retval)
.repeat = 1,
);
if (empty_opts) {
memset(&topts, 0, sizeof(struct bpf_test_run_opts));
topts.sz = sizeof(struct bpf_test_run_opts);
}
err = bpf_prog_test_run_opts(fd_prog, &topts);
saved_errno = errno;
@ -649,7 +653,8 @@ void run_subtest(struct test_loader *tester,
}
}
do_prog_test_run(bpf_program__fd(tprog), &retval);
do_prog_test_run(bpf_program__fd(tprog), &retval,
bpf_program__type(tprog) == BPF_PROG_TYPE_SYSCALL ? true : false);
if (retval != subspec->retval && subspec->retval != POINTER_VALUE) {
PRINT_FAIL("Unexpected retval: %d != %d\n", retval, subspec->retval);
goto tobj_cleanup;