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Fri, 20 May 2022 11:38:00 +0000 Received: from DB9PR04MB8107.eurprd04.prod.outlook.com ([fe80::40a2:1b77:8319:a7fa]) by DB9PR04MB8107.eurprd04.prod.outlook.com ([fe80::40a2:1b77:8319:a7fa%5]) with mapi id 15.20.5273.016; Fri, 20 May 2022 11:38:00 +0000 From: Shung-Hsi Yu To: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org CC: Shung-Hsi Yu , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh Subject: [PATCH bpf-next 3/4] bpf: verifier: remove redundant opcode checks Date: Fri, 20 May 2022 19:37:27 +0800 Message-ID: <20220520113728.12708-4-shung-hsi.yu@suse.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220520113728.12708-1-shung-hsi.yu@suse.com> References: <20220520113728.12708-1-shung-hsi.yu@suse.com> Content-Transfer-Encoding: quoted-printable Content-Type: text/plain X-ClientProxiedBy: AS9PR04CA0076.eurprd04.prod.outlook.com (2603:10a6:20b:48b::18) To DB9PR04MB8107.eurprd04.prod.outlook.com (2603:10a6:10:243::20) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: b9124e83-b4d8-4745-ec1f-08da3a55317a X-MS-TrafficTypeDiagnostic: DB6PR04MB3253:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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Opcode code check is not removed for BPF_LD_{ABS,IND} in check_ld_abs() and BPF_JMP_{JA,CALL,EXIT} in do_check() because they cover opcode validation not done in bpf_opcode_in_insntable(). Signed-off-by: Shung-Hsi Yu --- kernel/bpf/verifier.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 133929751f80..d528848083b9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4797,11 +4797,6 @@ static int check_atomic(struct bpf_verifier_env *env= , int insn_idx, struct bpf_i return -EINVAL; } =20 - if (BPF_SIZE(insn->code) !=3D BPF_W && BPF_SIZE(insn->code) !=3D BPF_DW) = { - verbose(env, "invalid atomic operand size\n"); - return -EINVAL; - } - /* check src1 operand */ err =3D check_reg_arg(env, insn->src_reg, SRC_OP); if (err) @@ -8793,8 +8788,7 @@ static int check_alu_op(struct bpf_verifier_env *env,= struct bpf_insn *insn) } } else { if (insn->src_reg !=3D BPF_REG_0 || insn->off !=3D 0 || - (insn->imm !=3D 16 && insn->imm !=3D 32 && insn->imm !=3D 64) || - BPF_CLASS(insn->code) =3D=3D BPF_ALU64) { + (insn->imm !=3D 16 && insn->imm !=3D 32 && insn->imm !=3D 64)) { verbose(env, "BPF_END uses reserved fields\n"); return -EINVAL; } @@ -11874,9 +11868,8 @@ static int do_check(struct bpf_verifier_env *env) return err; env->insn_idx++; continue; - } - - if (BPF_MODE(insn->code) !=3D BPF_MEM || insn->imm !=3D 0) { + } else if (insn->imm !=3D 0) { + /* check for mode is already done, so mode can only be BPF_MEM */ verbose(env, "BPF_STX uses reserved fields\n"); return -EINVAL; } @@ -11909,8 +11902,7 @@ static int do_check(struct bpf_verifier_env *env) } =20 } else if (class =3D=3D BPF_ST) { - if (BPF_MODE(insn->code) !=3D BPF_MEM || - insn->src_reg !=3D BPF_REG_0) { + if (insn->src_reg !=3D BPF_REG_0) { verbose(env, "BPF_ST uses reserved fields\n"); return -EINVAL; } @@ -11944,8 +11936,7 @@ static int do_check(struct bpf_verifier_env *env) (insn->src_reg !=3D BPF_REG_0 && insn->src_reg !=3D BPF_PSEUDO_CALL && insn->src_reg !=3D BPF_PSEUDO_KFUNC_CALL) || - insn->dst_reg !=3D BPF_REG_0 || - class =3D=3D BPF_JMP32) { + insn->dst_reg !=3D BPF_REG_0) { verbose(env, "BPF_CALL uses reserved fields\n"); return -EINVAL; } @@ -11968,8 +11959,7 @@ static int do_check(struct bpf_verifier_env *env) if (BPF_SRC(insn->code) !=3D BPF_K || insn->imm !=3D 0 || insn->src_reg !=3D BPF_REG_0 || - insn->dst_reg !=3D BPF_REG_0 || - class =3D=3D BPF_JMP32) { + insn->dst_reg !=3D BPF_REG_0) { verbose(env, "BPF_JA uses reserved fields\n"); return -EINVAL; } @@ -11981,8 +11971,7 @@ static int do_check(struct bpf_verifier_env *env) if (BPF_SRC(insn->code) !=3D BPF_K || insn->imm !=3D 0 || insn->src_reg !=3D BPF_REG_0 || - insn->dst_reg !=3D BPF_REG_0 || - class =3D=3D BPF_JMP32) { + insn->dst_reg !=3D BPF_REG_0) { verbose(env, "BPF_EXIT uses reserved fields\n"); return -EINVAL; } @@ -14751,6 +14740,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_att= r *attr, bpfptr_t uattr) if (ret) goto skip_full_check; =20 + /* checks for validity of opcodes */ ret =3D resolve_pseudo_ldimm64(env); if (ret < 0) goto skip_full_check; --=20 2.36.1