// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook

#include "test_progs.h"
#include "cgroup_helpers.h"

#define CG_PATH                 "/foo"
#define MAX_INSNS               512
#define FIXUP_SYSCTL_VALUE      0

char bpf_log_buf[BPF_LOG_BUF_SIZE];

struct sysctl_test {
        const char *descr;
        size_t fixup_value_insn;
        struct bpf_insn insns[MAX_INSNS];
        const char *prog_file;
        enum bpf_attach_type attach_type;
        const char *sysctl;
        int open_flags;
        int seek;
        const char *newval;
        const char *oldval;
        enum {
                LOAD_REJECT,
                ATTACH_REJECT,
                OP_EPERM,
                SUCCESS,
        } result;
        struct bpf_object *obj;
};

static struct sysctl_test tests[] = {
        {
                .descr = "sysctl wrong attach_type",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = 0,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = ATTACH_REJECT,
        },
        {
                .descr = "sysctl:read allow all",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl:read deny all",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = OP_EPERM,
        },
        {
                .descr = "ctx:write sysctl:read read ok",
                .insns = {
                        /* If (write) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, write)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 1, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "ctx:write sysctl:write read ok",
                .insns = {
                        /* If (write) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, write)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 1, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/domainname",
                .open_flags = O_WRONLY,
                .newval = "(none)", /* same as default, should fail anyway */
                .result = OP_EPERM,
        },
        {
                .descr = "ctx:write sysctl:write read ok narrow",
                .insns = {
                        /* u64 w = (u16)write & 1; */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                        BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, write)),
#else
                        BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, write) + 2),
#endif
                        BPF_ALU64_IMM(BPF_AND, BPF_REG_7, 1),
                        /* return 1 - w; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_7),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/domainname",
                .open_flags = O_WRONLY,
                .newval = "(none)", /* same as default, should fail anyway */
                .result = OP_EPERM,
        },
        {
                .descr = "ctx:write sysctl:read write reject",
                .insns = {
                        /* write = X */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0,
                                    offsetof(struct bpf_sysctl, write)),
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = LOAD_REJECT,
        },
        {
                .descr = "ctx:file_pos sysctl:read read ok",
                .insns = {
                        /* If (file_pos == X) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, file_pos)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 3, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .seek = 3,
                .result = SUCCESS,
        },
        {
                .descr = "ctx:file_pos sysctl:read read ok narrow",
                .insns = {
                        /* If (file_pos == X) */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                        BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, file_pos)),
#else
                        BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_1,
                                    offsetof(struct bpf_sysctl, file_pos) + 3),
#endif
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 4, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .seek = 4,
                .result = SUCCESS,
        },
        {
                .descr = "ctx:file_pos sysctl:read write ok",
                .insns = {
                        /* file_pos = X */
                        BPF_MOV64_IMM(BPF_REG_0, 2),
                        BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0,
                                    offsetof(struct bpf_sysctl, file_pos)),
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .oldval = "nux\n",
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_name sysctl_value:base ok",
                .insns = {
                        /* sysctl_get_name arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_name arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 8),

                        /* sysctl_get_name arg4 (flags) */
                        BPF_MOV64_IMM(BPF_REG_4, BPF_F_SYSCTL_BASE_NAME),

                        /* sysctl_get_name(ctx, buf, buf_len, flags) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, sizeof("tcp_mem") - 1, 6),
                        /*     buf == "tcp_mem\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x7463705f6d656d00ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_name sysctl_value:base E2BIG truncated",
                .insns = {
                        /* sysctl_get_name arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_name arg3 (buf_len) too small */
                        BPF_MOV64_IMM(BPF_REG_3, 7),

                        /* sysctl_get_name arg4 (flags) */
                        BPF_MOV64_IMM(BPF_REG_4, BPF_F_SYSCTL_BASE_NAME),

                        /* sysctl_get_name(ctx, buf, buf_len, flags) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 6),

                        /*     buf[0:7] == "tcp_me\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x7463705f6d650000ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_name sysctl:full ok",
                .insns = {
                        /* sysctl_get_name arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -24),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 16),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_name arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 17),

                        /* sysctl_get_name arg4 (flags) */
                        BPF_MOV64_IMM(BPF_REG_4, 0),

                        /* sysctl_get_name(ctx, buf, buf_len, flags) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 16, 14),

                        /*     buf[0:8] == "net/ipv4" && */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x6e65742f69707634ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 10),

                        /*     buf[8:16] == "/tcp_mem" && */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x2f7463705f6d656dULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 8),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 6),

                        /*     buf[16:24] == "\0") */
                        BPF_LD_IMM64(BPF_REG_8, 0x0ULL),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 16),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_name sysctl:full E2BIG truncated",
                .insns = {
                        /* sysctl_get_name arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -16),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 8),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_name arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 16),

                        /* sysctl_get_name arg4 (flags) */
                        BPF_MOV64_IMM(BPF_REG_4, 0),

                        /* sysctl_get_name(ctx, buf, buf_len, flags) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 10),

                        /*     buf[0:8] == "net/ipv4" && */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x6e65742f69707634ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 6),

                        /*     buf[8:16] == "/tcp_me\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x2f7463705f6d6500ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 8),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_name sysctl:full E2BIG truncated small",
                .insns = {
                        /* sysctl_get_name arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_name arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 7),

                        /* sysctl_get_name arg4 (flags) */
                        BPF_MOV64_IMM(BPF_REG_4, 0),

                        /* sysctl_get_name(ctx, buf, buf_len, flags) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 6),

                        /*     buf[0:8] == "net/ip\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x6e65742f69700000ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_current_value sysctl:read ok, gt",
                .insns = {
                        /* sysctl_get_current_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_current_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 8),

                        /* sysctl_get_current_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_current_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 6, 6),

                        /*     buf[0:6] == "Linux\n\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x4c696e75780a0000ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_current_value sysctl:read ok, eq",
                .insns = {
                        /* sysctl_get_current_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_B, BPF_REG_7, BPF_REG_0, 7),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_current_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 7),

                        /* sysctl_get_current_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_current_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 6, 6),

                        /*     buf[0:6] == "Linux\n\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x4c696e75780a0000ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_current_value sysctl:read E2BIG truncated",
                .insns = {
                        /* sysctl_get_current_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_H, BPF_REG_7, BPF_REG_0, 6),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_current_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 6),

                        /* sysctl_get_current_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_current_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 6),

                        /*     buf[0:6] == "Linux\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x4c696e7578000000ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "kernel/ostype",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_current_value sysctl:read EINVAL",
                .insns = {
                        /* sysctl_get_current_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_current_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 8),

                        /* sysctl_get_current_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_current_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 4),

                        /*     buf[0:8] is NUL-filled) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv6/conf/lo/stable_secret", /* -EIO */
                .open_flags = O_RDONLY,
                .result = OP_EPERM,
        },
        {
                .descr = "sysctl_get_current_value sysctl:write ok",
                .fixup_value_insn = 6,
                .insns = {
                        /* sysctl_get_current_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_current_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 8),

                        /* sysctl_get_current_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_current_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 4, 6),

                        /*     buf[0:4] == expected) */
                        BPF_LD_IMM64(BPF_REG_8, FIXUP_SYSCTL_VALUE),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_WRONLY,
                .newval = "600", /* same as default, should fail anyway */
                .result = OP_EPERM,
        },
        {
                .descr = "sysctl_get_new_value sysctl:read EINVAL",
                .insns = {
                        /* sysctl_get_new_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_new_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 8),

                        /* sysctl_get_new_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_get_new_value sysctl:write ok",
                .insns = {
                        /* sysctl_get_new_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_new_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 4),

                        /* sysctl_get_new_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 3, 4),

                        /*     buf[0:4] == "606\0") */
                        BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9,
                                    bpf_ntohl(0x36303600), 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_WRONLY,
                .newval = "606",
                .result = OP_EPERM,
        },
        {
                .descr = "sysctl_get_new_value sysctl:write ok long",
                .insns = {
                        /* sysctl_get_new_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -24),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_new_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 24),

                        /* sysctl_get_new_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 23, 14),

                        /*     buf[0:8] == "3000000 " && */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x3330303030303020ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 10),

                        /*     buf[8:16] == "4000000 " && */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x3430303030303020ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 8),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 6),

                        /*     buf[16:24] == "6000000\0") */
                        BPF_LD_IMM64(BPF_REG_8,
                                     bpf_be64_to_cpu(0x3630303030303000ULL)),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 16),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_WRONLY,
                .newval = "3000000 4000000 6000000",
                .result = OP_EPERM,
        },
        {
                .descr = "sysctl_get_new_value sysctl:write E2BIG",
                .insns = {
                        /* sysctl_get_new_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_STX_MEM(BPF_B, BPF_REG_7, BPF_REG_0, 3),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_get_new_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 3),

                        /* sysctl_get_new_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 4),

                        /*     buf[0:3] == "60\0") */
                        BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9,
                                    bpf_ntohl(0x36300000), 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_WRONLY,
                .newval = "606",
                .result = OP_EPERM,
        },
        {
                .descr = "sysctl_set_new_value sysctl:read EINVAL",
                .insns = {
                        /* sysctl_set_new_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x36303000)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_set_new_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 3),

                        /* sysctl_set_new_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_set_new_value),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                .descr = "sysctl_set_new_value sysctl:write ok",
                .fixup_value_insn = 2,
                .insns = {
                        /* sysctl_set_new_value arg2 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_LD_IMM64(BPF_REG_0, FIXUP_SYSCTL_VALUE),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),

                        /* sysctl_set_new_value arg3 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_3, 3),

                        /* sysctl_set_new_value(ctx, buf, buf_len) */
                        BPF_EMIT_CALL(BPF_FUNC_sysctl_set_new_value),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_WRONLY,
                .newval = "606",
                .result = SUCCESS,
        },
        {
                "bpf_strtoul one number string",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x36303000)),
                        BPF_STX_MEM(BPF_W, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 3, 4),
                        /*     res == expected) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 600, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtoul multi number string",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        /* "600 602\0" */
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3630302036303200ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 8),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 3, 18),
                        /*     res == expected) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 600, 16),

                        /*     arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_ALU64_REG(BPF_ADD, BPF_REG_7, BPF_REG_0),
                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /*     arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 8),
                        BPF_ALU64_REG(BPF_SUB, BPF_REG_2, BPF_REG_0),

                        /*     arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /*     arg4 (res) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -16),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /*     if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 4, 4),
                        /*         res == expected) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 602, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtoul buf_len = 0, reject",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x36303000)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 0),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = LOAD_REJECT,
        },
        {
                "bpf_strtoul supported base, ok",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x30373700)),
                        BPF_STX_MEM(BPF_W, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 8),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 3, 4),
                        /*     res == expected) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 63, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtoul unsupported base, EINVAL",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x36303000)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 3),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtoul buf with spaces only, EINVAL",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x0d0c0a09)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtoul negative number, EINVAL",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        /* " -6\0" */
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x0a2d3600)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtoul),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtol negative number, ok",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        /* " -6\0" */
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x0a2d3600)),
                        BPF_STX_MEM(BPF_W, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 10),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtol),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 3, 4),
                        /*     res == expected) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, -6, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtol hex number, ok",
                .insns = {
                        /* arg1 (buf) */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        /* "0xfe" */
                        BPF_MOV64_IMM(BPF_REG_0,
                                      bpf_ntohl(0x30786665)),
                        BPF_STX_MEM(BPF_W, BPF_REG_7, BPF_REG_0, 0),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 4),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtol),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 4, 4),
                        /*     res == expected) */
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 254, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtol max long",
                .insns = {
                        /* arg1 (buf) 9223372036854775807 */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -24),
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3932323333373230ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3336383534373735ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 8),
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3830370000000000ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 16),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 19),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtol),

                        /* if (ret == expected && */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 19, 6),
                        /*     res == expected) */
                        BPF_LD_IMM64(BPF_REG_8, 0x7fffffffffffffffULL),
                        BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
                        BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "bpf_strtol overflow, ERANGE",
                .insns = {
                        /* arg1 (buf) 9223372036854775808 */
                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -24),
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3932323333373230ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3336383534373735ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 8),
                        BPF_LD_IMM64(BPF_REG_0,
                                     bpf_be64_to_cpu(0x3830380000000000ULL)),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 16),

                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),

                        /* arg2 (buf_len) */
                        BPF_MOV64_IMM(BPF_REG_2, 19),

                        /* arg3 (flags) */
                        BPF_MOV64_IMM(BPF_REG_3, 0),

                        /* arg4 (res) */
                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
                        BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
                        BPF_MOV64_REG(BPF_REG_4, BPF_REG_7),

                        BPF_EMIT_CALL(BPF_FUNC_strtol),

                        /* if (ret == expected) */
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -ERANGE, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
        {
                "C prog: deny all writes",
                .prog_file = "./test_sysctl_prog.bpf.o",
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_WRONLY,
                .newval = "123 456 789",
                .result = OP_EPERM,
        },
        {
                "C prog: deny access by name",
                .prog_file = "./test_sysctl_prog.bpf.o",
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/route/mtu_expires",
                .open_flags = O_RDONLY,
                .result = OP_EPERM,
        },
        {
                "C prog: read tcp_mem",
                .prog_file = "./test_sysctl_prog.bpf.o",
                .attach_type = BPF_CGROUP_SYSCTL,
                .sysctl = "net/ipv4/tcp_mem",
                .open_flags = O_RDONLY,
                .result = SUCCESS,
        },
};

static size_t probe_prog_length(const struct bpf_insn *fp)
{
        size_t len;

        for (len = MAX_INSNS - 1; len > 0; --len)
                if (fp[len].code != 0 || fp[len].imm != 0)
                        break;
        return len + 1;
}

static int fixup_sysctl_value(const char *buf, size_t buf_len,
                              struct bpf_insn *prog, size_t insn_num)
{
        union {
                uint8_t raw[sizeof(uint64_t)];
                uint64_t num;
        } value = {};

        if (buf_len > sizeof(value)) {
                log_err("Value is too big (%zd) to use in fixup", buf_len);
                return -1;
        }
        if (prog[insn_num].code != (BPF_LD | BPF_DW | BPF_IMM)) {
                log_err("Can fixup only BPF_LD_IMM64 insns");
                return -1;
        }

        memcpy(value.raw, buf, buf_len);
        prog[insn_num].imm = (uint32_t)value.num;
        prog[insn_num + 1].imm = (uint32_t)(value.num >> 32);

        return 0;
}

static int load_sysctl_prog_insns(struct sysctl_test *test,
                                  const char *sysctl_path)
{
        struct bpf_insn *prog = test->insns;
        LIBBPF_OPTS(bpf_prog_load_opts, opts);
        int ret, insn_cnt;

        insn_cnt = probe_prog_length(prog);

        if (test->fixup_value_insn) {
                char buf[128];
                ssize_t len;
                int fd;

                fd = open(sysctl_path, O_RDONLY | O_CLOEXEC);
                if (fd < 0) {
                        log_err("open(%s) failed", sysctl_path);
                        return -1;
                }
                len = read(fd, buf, sizeof(buf));
                if (len == -1) {
                        log_err("read(%s) failed", sysctl_path);
                        close(fd);
                        return -1;
                }
                close(fd);
                if (fixup_sysctl_value(buf, len, prog, test->fixup_value_insn))
                        return -1;
        }

        opts.log_buf = bpf_log_buf;
        opts.log_size = BPF_LOG_BUF_SIZE;

        ret = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SYSCTL, NULL, "GPL", prog, insn_cnt, &opts);
        if (ret < 0 && test->result != LOAD_REJECT) {
                log_err(">>> Loading program error.\n"
                        ">>> Verifier output:\n%s\n-------\n", bpf_log_buf);
        }

        return ret;
}

static int load_sysctl_prog_file(struct sysctl_test *test)
{
        struct bpf_object *obj;
        int prog_fd;

        if (bpf_prog_test_load(test->prog_file, BPF_PROG_TYPE_CGROUP_SYSCTL, &obj, &prog_fd)) {
                if (test->result != LOAD_REJECT)
                        log_err(">>> Loading program (%s) error.\n",
                                test->prog_file);
                return -1;
        }

        test->obj = obj;
        return prog_fd;
}

static int load_sysctl_prog(struct sysctl_test *test, const char *sysctl_path)
{
                return test->prog_file
                        ? load_sysctl_prog_file(test)
                        : load_sysctl_prog_insns(test, sysctl_path);
}

static int access_sysctl(const char *sysctl_path,
                         const struct sysctl_test *test)
{
        int err = 0;
        int fd;

        fd = open(sysctl_path, test->open_flags | O_CLOEXEC);
        if (fd < 0)
                return fd;

        if (test->seek && lseek(fd, test->seek, SEEK_SET) == -1) {
                log_err("lseek(%d) failed", test->seek);
                goto err;
        }

        if (test->open_flags == O_RDONLY) {
                char buf[128];

                if (read(fd, buf, sizeof(buf)) == -1)
                        goto err;
                if (test->oldval &&
                    strncmp(buf, test->oldval, strlen(test->oldval))) {
                        log_err("Read value %s != %s", buf, test->oldval);
                        goto err;
                }
        } else if (test->open_flags == O_WRONLY) {
                if (!test->newval) {
                        log_err("New value for sysctl is not set");
                        goto err;
                }
                if (write(fd, test->newval, strlen(test->newval)) == -1)
                        goto err;
        } else {
                log_err("Unexpected sysctl access: neither read nor write");
                goto err;
        }

        goto out;
err:
        err = -1;
out:
        close(fd);
        return err;
}

static int run_test_case(int cgfd, struct sysctl_test *test)
{
        enum bpf_attach_type atype = test->attach_type;
        char sysctl_path[128];
        int progfd = -1;
        int err = 0;

        printf("Test case: %s .. ", test->descr);

        snprintf(sysctl_path, sizeof(sysctl_path), "/proc/sys/%s",
                 test->sysctl);

        progfd = load_sysctl_prog(test, sysctl_path);
        if (progfd < 0) {
                if (test->result == LOAD_REJECT)
                        goto out;
                else
                        goto err;
        }

        if (bpf_prog_attach(progfd, cgfd, atype, BPF_F_ALLOW_OVERRIDE) < 0) {
                if (test->result == ATTACH_REJECT)
                        goto out;
                else
                        goto err;
        }

        errno = 0;
        if (access_sysctl(sysctl_path, test) == -1) {
                if (test->result == OP_EPERM && errno == EPERM)
                        goto out;
                else
                        goto err;
        }

        if (test->result != SUCCESS) {
                log_err("Unexpected success");
                goto err;
        }

        goto out;
err:
        err = -1;
out:
        /* Detaching w/o checking return code: best effort attempt. */
        if (progfd != -1)
                bpf_prog_detach(cgfd, atype);
        bpf_object__close(test->obj);
        close(progfd);
        printf("[%s]\n", err ? "FAIL" : "PASS");
        return err;
}

static int run_tests(int cgfd)
{
        int passes = 0;
        int fails = 0;
        int i;

        for (i = 0; i < ARRAY_SIZE(tests); ++i) {
                if (run_test_case(cgfd, &tests[i]))
                        ++fails;
                else
                        ++passes;
        }
        printf("Summary: %d PASSED, %d FAILED\n", passes, fails);
        return fails ? -1 : 0;
}

void test_sysctl(void)
{
        int cgfd;

        cgfd = cgroup_setup_and_join(CG_PATH);
        if (!ASSERT_OK_FD(cgfd < 0, "create_cgroup"))
                goto out;

        if (!ASSERT_OK(run_tests(cgfd), "run_tests"))
                goto out;

out:
        close(cgfd);
        cleanup_cgroup_environment();
        return;
}