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// SPDX-License-Identifier: GPL-2.0
/* The verifier log of a prog whose constants are blinded */
#include <test_progs.h>
#include <linux/filter.h>
#include "sysctl_helpers.h"
#define NR_CONSTS 11000
#define LOG_SIZE 65536
/*
* A prog of one function gets its constants blinded when its runtime is
* selected. Each 'r0 += 1' becomes 3 insns, which pushes the jump over them
* out of its 16-bit range. Serial, because it sets bpf_jit_harden.
*/
void serial_test_blinding_log(void)
{
const char *harden = "/proc/sys/net/core/bpf_jit_harden";
LIBBPF_OPTS(bpf_prog_load_opts, opts);
struct bpf_insn *insns;
char old[16] = {}, *log;
int i, cnt = 0, fd;
if (!is_jit_enabled()) {
printf("%s:SKIP:JIT is disabled\n", __func__);
test__skip();
return;
}
insns = calloc(NR_CONSTS + 3, sizeof(*insns));
log = calloc(1, LOG_SIZE);
if (!ASSERT_OK_PTR(insns, "insns") || !ASSERT_OK_PTR(log, "log"))
goto out;
insns[cnt++] = BPF_EMIT_CALL(BPF_FUNC_get_prandom_u32);
insns[cnt++] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, NR_CONSTS);
for (i = 0; i < NR_CONSTS; i++)
insns[cnt++] = BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1);
insns[cnt++] = BPF_EXIT_INSN();
opts.log_buf = log;
opts.log_size = LOG_SIZE;
/* log stats only: level 1 logs each insn, which wraps the buffer */
opts.log_level = 4;
if (sysctl_set_or_fail(harden, old, "2"))
goto out;
fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, cnt, &opts);
sysctl_set_or_fail(harden, NULL, old);
/* don't mind whether the interpreter takes the prog or the load fails */
if (fd >= 0)
close(fd);
/* expect the message about the jump in the log and in log_true_size */
ASSERT_HAS_SUBSTR(log, "cannot be patched due to 16-bit range", "log");
ASSERT_EQ(opts.log_true_size, strlen(log) + 1, "log_true_size");
out:
free(insns);
free(log);
}
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