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selftests/bpf: test for malformed BPF_CORE_TYPE_ID_LOCAL relocation

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Check that verifier rejects BPF program containing relocation
pointing to non-existent BTF type.

To force relocation resolution on kernel side test case uses
bpf_attr->core_relos field. This field is not exposed by libbpf,
so directly do BPF system call in the test.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240822080124.2995724-3-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Eduard Zingerman 2024-08-22 01:01:24 -07:00 committed by Alexei Starovoitov
parent 3d2786d65a
commit 110bbd3a2e
1 changed files with 125 additions and 0 deletions
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125
tools/testing/selftests/bpf/prog_tests/core_reloc_raw.c Normal file
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// SPDX-License-Identifier: GPL-2.0
/* Test cases that can't load programs using libbpf and need direct
* BPF syscall access
*/
#include <sys/syscall.h>
#include <bpf/libbpf.h>
#include <bpf/btf.h>
#include "test_progs.h"
#include "test_btf.h"
#include "bpf/libbpf_internal.h"
static char log[16 * 1024];
/* Check that verifier rejects BPF program containing relocation
* pointing to non-existent BTF type.
*/
static void test_bad_local_id(void)
{
struct test_btf {
struct btf_header hdr;
__u32 types[15];
char strings[128];
} raw_btf = {
.hdr = {
.magic = BTF_MAGIC,
.version = BTF_VERSION,
.hdr_len = sizeof(struct btf_header),
.type_off = 0,
.type_len = sizeof(raw_btf.types),
.str_off = offsetof(struct test_btf, strings) -
offsetof(struct test_btf, types),
.str_len = sizeof(raw_btf.strings),
},
.types = {
BTF_PTR_ENC(0), /* [1] void* */
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [2] int */
BTF_FUNC_PROTO_ENC(2, 1), /* [3] int (*)(void*) */
BTF_FUNC_PROTO_ARG_ENC(8, 1),
BTF_FUNC_ENC(8, 3) /* [4] FUNC 'foo' type_id=2 */
},
.strings = "\0int\0 0\0foo\0"
};
__u32 log_level = 1 | 2 | 4;
LIBBPF_OPTS(bpf_btf_load_opts, opts,
.log_buf = log,
.log_size = sizeof(log),
.log_level = log_level,
);
struct bpf_insn insns[] = {
BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
struct bpf_func_info funcs[] = {
{
.insn_off = 0,
.type_id = 4,
}
};
struct bpf_core_relo relos[] = {
{
.insn_off = 0, /* patch first instruction (r0 = 0) */
.type_id = 100500, /* !!! this type id does not exist */
.access_str_off = 6, /* offset of "0" */
.kind = BPF_CORE_TYPE_ID_LOCAL,
}
};
union bpf_attr attr;
int saved_errno;
int prog_fd = -1;
int btf_fd = -1;
btf_fd = bpf_btf_load(&raw_btf, sizeof(raw_btf), &opts);
saved_errno = errno;
if (btf_fd < 0 || env.verbosity > VERBOSE_NORMAL) {
printf("-------- BTF load log start --------\n");
printf("%s", log);
printf("-------- BTF load log end ----------\n");
}
if (btf_fd < 0) {
PRINT_FAIL("bpf_btf_load() failed, errno=%d\n", saved_errno);
return;
}
log[0] = 0;
memset(&attr, 0, sizeof(attr));
attr.prog_btf_fd = btf_fd;
attr.prog_type = BPF_TRACE_RAW_TP;
attr.license = (__u64)"GPL";
attr.insns = (__u64)&insns;
attr.insn_cnt = sizeof(insns) / sizeof(*insns);
attr.log_buf = (__u64)log;
attr.log_size = sizeof(log);
attr.log_level = log_level;
attr.func_info = (__u64)funcs;
attr.func_info_cnt = sizeof(funcs) / sizeof(*funcs);
attr.func_info_rec_size = sizeof(*funcs);
attr.core_relos = (__u64)relos;
attr.core_relo_cnt = sizeof(relos) / sizeof(*relos);
attr.core_relo_rec_size = sizeof(*relos);
prog_fd = sys_bpf_prog_load(&attr, sizeof(attr), 1);
saved_errno = errno;
if (prog_fd < 0 || env.verbosity > VERBOSE_NORMAL) {
printf("-------- program load log start --------\n");
printf("%s", log);
printf("-------- program load log end ----------\n");
}
if (prog_fd >= 0) {
PRINT_FAIL("sys_bpf_prog_load() expected to fail\n");
goto out;
}
ASSERT_HAS_SUBSTR(log, "relo #0: bad type id 100500", "program load log");
out:
close(prog_fd);
close(btf_fd);
}
void test_core_reloc_raw(void)
{
if (test__start_subtest("bad_local_id"))
test_bad_local_id();
}