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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2019 Richard Palethorpe <rpalethorpe@suse.com>
*
* Check if eBPF can do arithmetic with 64bits. This targets a specific
* regression which only effects unprivileged users who are subject to extra
* pointer arithmetic checks during verification.
*
* Fixed by commit 3612af783cf52c74a031a2f11b82247b2599d3cd.
* https://new.blog.cloudflare.com/ebpf-cant-count/
*
* This test is very similar in structure to bpf_prog01 which is better
* annotated.
*/
#include <limits.h>
#include <string.h>
#include <stdio.h>
#include <inttypes.h>
#include "config.h"
#include "tst_test.h"
#include "tst_capability.h"
#include "bpf_common.h"
#define A64INT (((uint64_t)1) << 60)
const char MSG[] = "Ahoj!";
static char *msg;
static char *log;
static uint32_t *key;
static uint64_t *val;
static union bpf_attr *attr;
static int load_prog(int fd)
{
struct bpf_insn insn[] = {
BPF_MOV64_IMM(BPF_REG_6, 1), /* 0: r6 = 1 */
BPF_LD_MAP_FD(BPF_REG_1, fd), /* 1: r1 = &fd */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), /* 3: r2 = fp */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* 4: r2 = r2 - 4 */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0), /* 5: *r2 = 0 */
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),/* 6: map_lookup_elem */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 17), /* 7: if(!r0) goto 25 */
BPF_MOV64_REG(BPF_REG_3, BPF_REG_0), /* 8: r3 = r0 */
BPF_LD_IMM64(BPF_REG_4, A64INT), /* 9: r4 = 2^61 */
BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_6), /* 11: r4 += r6 */
BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_4, 0), /* 12: *r3 = r4 */
BPF_LD_MAP_FD(BPF_REG_1, fd), /* 13: r1 = &fd */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), /* 15: r2 = fp */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* 16: r2 = r2 - 4 */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 1), /* 17: *r2 = 1 */
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),/* 18: map_lookup_elem */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5), /* 19: if(!r0) goto 25 */
BPF_MOV64_REG(BPF_REG_3, BPF_REG_0), /* 20: r3 = r0 */
BPF_LD_IMM64(BPF_REG_4, A64INT), /* 21: r4 = 2^60 */
BPF_ALU64_REG(BPF_SUB, BPF_REG_4, BPF_REG_6), /* 23: r4 -= r6 */
BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_4, 0), /* 24: *r3 = r4 */
BPF_MOV64_IMM(BPF_REG_0, 0), /* 25: r0 = 0 */
BPF_EXIT_INSN(), /* 26: return r0 */
};
bpf_init_prog_attr(attr, insn, sizeof(insn), log, BUFSIZE);
return bpf_load_prog(attr, log);
}
static void setup(void)
{
rlimit_bump_memlock();
memcpy(msg, MSG, sizeof(MSG));
}
static void run(void)
{
int map_fd, prog_fd;
map_fd = bpf_map_array_create(2);
prog_fd = load_prog(map_fd);
bpf_run_prog(prog_fd, msg, sizeof(MSG));
SAFE_CLOSE(prog_fd);
*key = 0;
bpf_map_array_get(map_fd, key, val);
if (*val != A64INT + 1) {
tst_res(TFAIL,
"val = %"PRIu64", but should be val = %"PRIu64" + 1",
*val, A64INT);
} else {
tst_res(TPASS, "val = %"PRIu64" + 1", A64INT);
}
*key = 1;
bpf_map_array_get(map_fd, key, val);
if (*val != A64INT - 1) {
tst_res(TFAIL,
"val = %"PRIu64", but should be val = %"PRIu64" - 1",
*val, A64INT);
} else {
tst_res(TPASS, "val = %"PRIu64" - 1", A64INT);
}
SAFE_CLOSE(map_fd);
}
static struct tst_test test = {
.setup = setup,
.test_all = run,
.min_kver = "3.18",
.caps = (struct tst_cap []) {
TST_CAP(TST_CAP_DROP, CAP_SYS_ADMIN),
{}
},
.bufs = (struct tst_buffers []) {
{&key, .size = sizeof(*key)},
{&val, .size = sizeof(*val)},
{&log, .size = BUFSIZE},
{&attr, .size = sizeof(*attr)},
{&msg, .size = sizeof(MSG)},
{},
},
.tags = (const struct tst_tag[]) {
{"linux-git", "3612af783cf5"},
{}
}
};
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