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From: Lorenz Bauer <lmb@cloudflare.com>
To: ast@kernel.org, yhs@fb.com, daniel@iogearbox.net, kafai@fb.com
Cc: bpf@vger.kernel.org, kernel-team@cloudflare.com,
	Lorenz Bauer <lmb@cloudflare.com>
Subject: [PATCH bpf-next 07/11] bpf: always check access to PTR_TO_CTX regardless of arg_type
Date: Fri,  4 Sep 2020 12:23:57 +0100	[thread overview]
Message-ID: <20200904112401.667645-8-lmb@cloudflare.com> (raw)
In-Reply-To: <20200904112401.667645-1-lmb@cloudflare.com>

Always check context access if the register we're operating on is
PTR_TO_CTX, rather than relying on ARG_PTR_TO_CTX.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
 kernel/bpf/verifier.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c7df4ccad8e2..ba710a702cae 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3979,9 +3979,6 @@ 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;
@@ -4081,6 +4078,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		meta->ref_obj_id = reg->ref_obj_id;
 	}
 
+	if (type == PTR_TO_CTX) {
+		err = check_ctx_reg(env, reg, regno);
+		if (err < 0)
+			return err;
+	}
+
 	if (arg_type == ARG_CONST_MAP_PTR) {
 		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
 		meta->map_ptr = reg->map_ptr;
-- 
2.25.1


  parent reply	other threads:[~2020-09-04 11:29 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-04 11:23 [PATCH bpf-next 00/11] RFC: Make check_func_arg table driven Lorenz Bauer
2020-09-04 11:23 ` [PATCH bpf-next 01/11] btf: Fix BTF_SET_START_GLOBAL macro Lorenz Bauer
2020-09-09  4:04   ` Andrii Nakryiko
2020-09-09  9:51     ` Lorenz Bauer
2020-09-04 11:23 ` [PATCH bpf-next 02/11] btf: add a global set of valid BTF socket ids Lorenz Bauer
2020-09-09  4:12   ` Andrii Nakryiko
2020-09-04 11:23 ` [PATCH bpf-next 03/11] btf: make btf_set_contains take a const pointer Lorenz Bauer
2020-09-09  4:13   ` Andrii Nakryiko
2020-09-04 11:23 ` [PATCH bpf-next 04/11] bpf: check scalar or invalid register in check_helper_mem_access Lorenz Bauer
2020-09-09  4:22   ` Andrii Nakryiko
2020-09-09 10:02     ` Lorenz Bauer
2020-09-04 11:23 ` [PATCH bpf-next 05/11] bpf: allow specifying a set of BTF IDs for helper arguments Lorenz Bauer
2020-09-06 23:04   ` Martin KaFai Lau
2020-09-07  9:15     ` Lorenz Bauer
2020-09-09  4:47   ` Andrii Nakryiko
2020-09-09  5:56     ` Martin KaFai Lau
2020-09-09 10:06       ` Lorenz Bauer
2020-09-09 10:11     ` Lorenz Bauer
2020-09-04 11:23 ` [PATCH bpf-next 06/11] bpf: make reference tracking in check_func_arg generic Lorenz Bauer
2020-09-09  4:50   ` Andrii Nakryiko
2020-09-04 11:23 ` Lorenz Bauer [this message]
2020-09-04 11:23 ` [PATCH bpf-next 08/11] bpf: set meta->raw_mode for pointers to memory closer to it's use Lorenz Bauer
2020-09-04 11:23 ` [PATCH bpf-next 09/11] bpf: check ARG_PTR_TO_SPINLOCK register type in check_func_arg Lorenz Bauer
2020-09-04 11:24 ` [PATCH bpf-next 10/11] bpf: hoist type checking for nullable arg types Lorenz Bauer
2020-09-09  5:07   ` Andrii Nakryiko
2020-09-04 11:24 ` [PATCH bpf-next 11/11] bpf: use a table to drive helper arg type checks Lorenz Bauer
2020-09-09  6:17 ` [PATCH bpf-next 00/11] RFC: Make check_func_arg table driven Martin KaFai Lau
2020-09-09 10:15   ` Lorenz Bauer

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