// SPDX-License-Identifier: GPL-2.0// Copyright (c) 2019 Facebook #include <fcntl.h>#include <stdint.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h> #include <linux/filter.h> #include <bpf/bpf.h>#include <bpf/libbpf.h> #include <bpf/bpf_endian.h>#include "bpf_rlimit.h"#include "bpf_util.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;}; 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 == __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 == __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),

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