[bpf-next,v4,07/11] bpf: make context access check generic

Message ID	20200921121227.255763-8-lmb@cloudflare.com
State	Accepted
Delegated to:	BPF Maintainers
Headers	show Return-Path: <netdev-owner@vger.kernel.org> From: Lorenz Bauer <lmb@cloudflare.com> To: ast@kernel.org, daniel@iogearbox.net Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Lorenz Bauer <lmb@cloudflare.com>, Martin KaFai Lau <kafai@fb.com> Subject: [PATCH bpf-next v4 07/11] bpf: make context access check generic Date: Mon, 21 Sep 2020 13:12:23 +0100 Message-Id: <20200921121227.255763-8-lmb@cloudflare.com> In-Reply-To: <20200921121227.255763-1-lmb@cloudflare.com> References: <20200921121227.255763-1-lmb@cloudflare.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Make check_func_arg type checks table driven \| expand [RESEND,bpf-next,v4,00/11] Make check_func_arg type checks table driven [bpf-next,v4,01/11] btf: make btf_set_contains take a const pointer [bpf-next,v4,02/11] bpf: check scalar or invalid register in check_helper_mem_access [bpf-next,v4,03/11] btf: Add BTF_ID_LIST_SINGLE macro [bpf-next,v4,04/11] bpf: allow specifying a BTF ID per argument in function protos [bpf-next,v4,05/11] bpf: make BTF pointer type checking generic [bpf-next,v4,06/11] bpf: make reference tracking generic [bpf-next,v4,07/11] bpf: make context access check generic [bpf-next,v4,08/11] bpf: set meta->raw_mode for pointers close to use [bpf-next,v4,09/11] bpf: check ARG_PTR_TO_SPINLOCK register type in check_func_arg [bpf-next,v4,10/11] bpf: hoist type checking for nullable arg types [bpf-next,v4,11/11] bpf: use a table to drive helper arg type checks

Message ID

20200921121227.255763-8-lmb@cloudflare.com

State

Accepted

Delegated to:

BPF Maintainers

Headers

From: Lorenz Bauer <lmb@cloudflare.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
        Lorenz Bauer <lmb@cloudflare.com>,
        Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH bpf-next v4 07/11] bpf: make context access check generic
Date: Mon, 21 Sep 2020 13:12:23 +0100
Message-Id: <20200921121227.255763-8-lmb@cloudflare.com>
In-Reply-To: <20200921121227.255763-1-lmb@cloudflare.com>
References: <20200921121227.255763-1-lmb@cloudflare.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Series

Make check_func_arg type checks table driven | expand

Commit Message

Lorenz Bauer Sept. 21, 2020, 12:12 p.m. UTC

Always check context access if the register we're operating on is
PTR_TO_CTX, rather than relying on ARG_PTR_TO_CTX. This allows
simplifying the arg_type checking section of the function.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 kernel/bpf/verifier.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0f7a9c65db5c..7d0f9ba18916 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3974,9 +3974,6 @@  static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		      arg_type == ARG_PTR_TO_CTX_OR_NULL)) {
 			if (type != expected_type)
 				goto err_type;
-			err = check_ctx_reg(env, reg, regno);
-			if (err < 0)
-				return err;
 		}
 	} else if (arg_type == ARG_PTR_TO_SOCK_COMMON) {
 		expected_type = PTR_TO_SOCK_COMMON;
@@ -4060,6 +4057,10 @@  static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 				regno);
 			return -EACCES;
 		}
+	} else if (type == PTR_TO_CTX) {
+		err = check_ctx_reg(env, reg, regno);
+		if (err < 0)
+			return err;
 	}
 
 	if (reg->ref_obj_id) {

[bpf-next,v4,07/11] bpf: make context access check generic

Commit Message

Patch