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200 lines
4.7 KiB
200 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2021. Huawei Technologies Co., Ltd |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/bpf_verifier.h> |
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#include <linux/bpf.h> |
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#include <linux/btf.h> |
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extern struct bpf_struct_ops bpf_bpf_dummy_ops; |
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/* A common type for test_N with return value in bpf_dummy_ops */ |
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typedef int (*dummy_ops_test_ret_fn)(struct bpf_dummy_ops_state *state, ...); |
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struct bpf_dummy_ops_test_args { |
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u64 args[MAX_BPF_FUNC_ARGS]; |
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struct bpf_dummy_ops_state state; |
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}; |
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static struct bpf_dummy_ops_test_args * |
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dummy_ops_init_args(const union bpf_attr *kattr, unsigned int nr) |
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{ |
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__u32 size_in; |
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struct bpf_dummy_ops_test_args *args; |
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void __user *ctx_in; |
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void __user *u_state; |
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size_in = kattr->test.ctx_size_in; |
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if (size_in != sizeof(u64) * nr) |
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return ERR_PTR(-EINVAL); |
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args = kzalloc(sizeof(*args), GFP_KERNEL); |
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if (!args) |
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return ERR_PTR(-ENOMEM); |
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ctx_in = u64_to_user_ptr(kattr->test.ctx_in); |
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if (copy_from_user(args->args, ctx_in, size_in)) |
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goto out; |
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/* args[0] is 0 means state argument of test_N will be NULL */ |
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u_state = u64_to_user_ptr(args->args[0]); |
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if (u_state && copy_from_user(&args->state, u_state, |
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sizeof(args->state))) |
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goto out; |
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return args; |
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out: |
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kfree(args); |
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return ERR_PTR(-EFAULT); |
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} |
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static int dummy_ops_copy_args(struct bpf_dummy_ops_test_args *args) |
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{ |
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void __user *u_state; |
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u_state = u64_to_user_ptr(args->args[0]); |
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if (u_state && copy_to_user(u_state, &args->state, sizeof(args->state))) |
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return -EFAULT; |
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return 0; |
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} |
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static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args) |
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{ |
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dummy_ops_test_ret_fn test = (void *)image; |
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struct bpf_dummy_ops_state *state = NULL; |
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/* state needs to be NULL if args[0] is 0 */ |
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if (args->args[0]) |
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state = &args->state; |
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return test(state, args->args[1], args->args[2], |
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args->args[3], args->args[4]); |
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} |
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int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, |
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union bpf_attr __user *uattr) |
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{ |
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const struct bpf_struct_ops *st_ops = &bpf_bpf_dummy_ops; |
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const struct btf_type *func_proto; |
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struct bpf_dummy_ops_test_args *args; |
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struct bpf_tramp_progs *tprogs; |
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void *image = NULL; |
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unsigned int op_idx; |
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int prog_ret; |
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int err; |
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if (prog->aux->attach_btf_id != st_ops->type_id) |
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return -EOPNOTSUPP; |
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func_proto = prog->aux->attach_func_proto; |
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args = dummy_ops_init_args(kattr, btf_type_vlen(func_proto)); |
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if (IS_ERR(args)) |
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return PTR_ERR(args); |
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tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL); |
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if (!tprogs) { |
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err = -ENOMEM; |
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goto out; |
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} |
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image = bpf_jit_alloc_exec(PAGE_SIZE); |
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if (!image) { |
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err = -ENOMEM; |
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goto out; |
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} |
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set_vm_flush_reset_perms(image); |
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op_idx = prog->expected_attach_type; |
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err = bpf_struct_ops_prepare_trampoline(tprogs, prog, |
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&st_ops->func_models[op_idx], |
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image, image + PAGE_SIZE); |
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if (err < 0) |
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goto out; |
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set_memory_ro((long)image, 1); |
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set_memory_x((long)image, 1); |
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prog_ret = dummy_ops_call_op(image, args); |
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err = dummy_ops_copy_args(args); |
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if (err) |
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goto out; |
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if (put_user(prog_ret, &uattr->test.retval)) |
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err = -EFAULT; |
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out: |
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kfree(args); |
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bpf_jit_free_exec(image); |
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kfree(tprogs); |
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return err; |
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} |
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static int bpf_dummy_init(struct btf *btf) |
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{ |
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return 0; |
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} |
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static bool bpf_dummy_ops_is_valid_access(int off, int size, |
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enum bpf_access_type type, |
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const struct bpf_prog *prog, |
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struct bpf_insn_access_aux *info) |
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{ |
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return bpf_tracing_btf_ctx_access(off, size, type, prog, info); |
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} |
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static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, |
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const struct btf *btf, |
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const struct btf_type *t, int off, |
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int size, enum bpf_access_type atype, |
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u32 *next_btf_id) |
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{ |
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const struct btf_type *state; |
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s32 type_id; |
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int err; |
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type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state", |
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BTF_KIND_STRUCT); |
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if (type_id < 0) |
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return -EINVAL; |
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state = btf_type_by_id(btf, type_id); |
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if (t != state) { |
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bpf_log(log, "only access to bpf_dummy_ops_state is supported\n"); |
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return -EACCES; |
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} |
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err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id); |
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if (err < 0) |
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return err; |
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return atype == BPF_READ ? err : NOT_INIT; |
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} |
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static const struct bpf_verifier_ops bpf_dummy_verifier_ops = { |
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.is_valid_access = bpf_dummy_ops_is_valid_access, |
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.btf_struct_access = bpf_dummy_ops_btf_struct_access, |
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}; |
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static int bpf_dummy_init_member(const struct btf_type *t, |
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const struct btf_member *member, |
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void *kdata, const void *udata) |
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{ |
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return -EOPNOTSUPP; |
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} |
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static int bpf_dummy_reg(void *kdata) |
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{ |
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return -EOPNOTSUPP; |
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} |
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static void bpf_dummy_unreg(void *kdata) |
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{ |
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} |
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struct bpf_struct_ops bpf_bpf_dummy_ops = { |
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.verifier_ops = &bpf_dummy_verifier_ops, |
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.init = bpf_dummy_init, |
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.init_member = bpf_dummy_init_member, |
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.reg = bpf_dummy_reg, |
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.unreg = bpf_dummy_unreg, |
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.name = "bpf_dummy_ops", |
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};
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