4fc49b51ab
bpf_syscall_macro reads a long argument into an int variable, which
produces a wrong value on big-endian systems. Fix by reading the
argument into an intermediate long variable first.
Fixes: 77fc0330df ("selftests/bpf: Add a test to confirm PT_REGS_PARM4_SYSCALL")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-2-iii@linux.ibm.com
59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright 2022 Sony Group Corporation */
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#include <vmlinux.h>
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#include <bpf/bpf_core_read.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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int arg1 = 0;
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unsigned long arg2 = 0;
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unsigned long arg3 = 0;
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unsigned long arg4_cx = 0;
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unsigned long arg4 = 0;
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unsigned long arg5 = 0;
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int arg1_core = 0;
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unsigned long arg2_core = 0;
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unsigned long arg3_core = 0;
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unsigned long arg4_core_cx = 0;
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unsigned long arg4_core = 0;
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unsigned long arg5_core = 0;
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const volatile pid_t filter_pid = 0;
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SEC("kprobe/" SYS_PREFIX "sys_prctl")
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int BPF_KPROBE(handle_sys_prctl)
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{
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struct pt_regs *real_regs;
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pid_t pid = bpf_get_current_pid_tgid() >> 32;
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unsigned long tmp;
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if (pid != filter_pid)
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return 0;
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real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
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/* test for PT_REGS_PARM */
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bpf_probe_read_kernel(&tmp, sizeof(tmp), &PT_REGS_PARM1_SYSCALL(real_regs));
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arg1 = tmp;
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bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
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bpf_probe_read_kernel(&arg3, sizeof(arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
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bpf_probe_read_kernel(&arg4_cx, sizeof(arg4_cx), &PT_REGS_PARM4(real_regs));
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bpf_probe_read_kernel(&arg4, sizeof(arg4), &PT_REGS_PARM4_SYSCALL(real_regs));
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bpf_probe_read_kernel(&arg5, sizeof(arg5), &PT_REGS_PARM5_SYSCALL(real_regs));
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/* test for the CORE variant of PT_REGS_PARM */
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arg1_core = PT_REGS_PARM1_CORE_SYSCALL(real_regs);
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arg2_core = PT_REGS_PARM2_CORE_SYSCALL(real_regs);
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arg3_core = PT_REGS_PARM3_CORE_SYSCALL(real_regs);
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arg4_core_cx = PT_REGS_PARM4_CORE(real_regs);
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arg4_core = PT_REGS_PARM4_CORE_SYSCALL(real_regs);
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arg5_core = PT_REGS_PARM5_CORE_SYSCALL(real_regs);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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