Commit eb04bbb6 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: btf: check name validity for various types 



This patch added name checking for the following types:
 . BTF_KIND_PTR, BTF_KIND_ARRAY, BTF_KIND_VOLATILE,
   BTF_KIND_CONST, BTF_KIND_RESTRICT:
     the name must be null
 . BTF_KIND_STRUCT, BTF_KIND_UNION: the struct/member name
     is either null or a valid identifier
 . BTF_KIND_ENUM: the enum type name is either null or a valid
     identifier; the enumerator name must be a valid identifier.
 . BTF_KIND_FWD: the name must be a valid identifier
 . BTF_KIND_TYPEDEF: the name must be a valid identifier

For those places a valid name is required, the name must be
a valid C identifier. This can be relaxed later if we found
use cases for a different (non-C) frontend.

Fixes: 69b693f0 ("bpf: btf: Introduce BPF Type Format (BTF)")
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent cdbb096a

kernel/bpf/btf.c

+57 −0
Original line number Diff line number Diff line
@@ -1168,6 +1168,22 @@ static int btf_ref_type_check_meta(struct btf_verifier_env *env, 
		return -EINVAL;

	}



	/* typedef type must have a valid name, and other ref types,

	 * volatile, const, restrict, should have a null name.

	 */

	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {

		if (!t->name_off ||

		    !btf_name_valid_identifier(env->btf, t->name_off)) {

			btf_verifier_log_type(env, t, "Invalid name");

			return -EINVAL;

		}

	} else {

		if (t->name_off) {

			btf_verifier_log_type(env, t, "Invalid name");

			return -EINVAL;

		}

	}



	btf_verifier_log_type(env, t, NULL);



	return 0;
@@ -1325,6 +1341,13 @@ static s32 btf_fwd_check_meta(struct btf_verifier_env *env, 
		return -EINVAL;

	}



	/* fwd type must have a valid name */

	if (!t->name_off ||

	    !btf_name_valid_identifier(env->btf, t->name_off)) {

		btf_verifier_log_type(env, t, "Invalid name");

		return -EINVAL;

	}



	btf_verifier_log_type(env, t, NULL);



	return 0;
@@ -1381,6 +1404,12 @@ static s32 btf_array_check_meta(struct btf_verifier_env *env, 
		return -EINVAL;

	}



	/* array type should not have a name */

	if (t->name_off) {

		btf_verifier_log_type(env, t, "Invalid name");

		return -EINVAL;

	}



	if (btf_type_vlen(t)) {

		btf_verifier_log_type(env, t, "vlen != 0");

		return -EINVAL;
@@ -1557,6 +1586,13 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env, 
		return -EINVAL;

	}



	/* struct type either no name or a valid one */

	if (t->name_off &&

	    !btf_name_valid_identifier(env->btf, t->name_off)) {

		btf_verifier_log_type(env, t, "Invalid name");

		return -EINVAL;

	}



	btf_verifier_log_type(env, t, NULL);



	last_offset = 0;
@@ -1568,6 +1604,12 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env, 
			return -EINVAL;

		}



		/* struct member either no name or a valid one */

		if (member->name_off &&

		    !btf_name_valid_identifier(btf, member->name_off)) {

			btf_verifier_log_member(env, t, member, "Invalid name");

			return -EINVAL;

		}

		/* A member cannot be in type void */

		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {

			btf_verifier_log_member(env, t, member,
@@ -1755,6 +1797,13 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env, 
		return -EINVAL;

	}



	/* enum type either no name or a valid one */

	if (t->name_off &&

	    !btf_name_valid_identifier(env->btf, t->name_off)) {

		btf_verifier_log_type(env, t, "Invalid name");

		return -EINVAL;

	}



	btf_verifier_log_type(env, t, NULL);



	for (i = 0; i < nr_enums; i++) {
@@ -1764,6 +1813,14 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env, 
			return -EINVAL;

		}



		/* enum member must have a valid name */

		if (!enums[i].name_off ||

		    !btf_name_valid_identifier(btf, enums[i].name_off)) {

			btf_verifier_log_type(env, t, "Invalid name");

			return -EINVAL;

		}





		btf_verifier_log(env, "\t%s val=%d\n",

				 btf_name_by_offset(btf, enums[i].name_off),

				 enums[i].val);

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