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From: YiFei Zhu <zhuyifei1999@gmail.com>
To: containers@lists.linux.dev, bpf@vger.kernel.org
Cc: YiFei Zhu <yifeifz2@illinois.edu>,
	linux-security-module@vger.kernel.org,
	Alexei Starovoitov <ast@kernel.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Austin Kuo <hckuo2@illinois.edu>,
	Claudio Canella <claudio.canella@iaik.tugraz.at>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Daniel Gruss <daniel.gruss@iaik.tugraz.at>,
	Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
	Giuseppe Scrivano <gscrivan@redhat.com>,
	Hubertus Franke <frankeh@us.ibm.com>,
	Jann Horn <jannh@google.com>, Jinghao Jia <jinghao7@illinois.edu>,
	Josep Torrellas <torrella@illinois.edu>,
	Kees Cook <keescook@chromium.org>,
	Sargun Dhillon <sargun@sargun.me>, Tianyin Xu <tyxu@illinois.edu>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Tom Hromatka <tom.hromatka@oracle.com>,
	Will Drewry <wad@chromium.org>
Subject: [RFC PATCH bpf-next seccomp 11/12] bpf/verifier: support NULL-able ptr to BTF ID as helper argument
Date: Mon, 10 May 2021 12:22:48 -0500	[thread overview]
Message-ID: <ca047abace1883f3db0ae009173e3b811085d3e0.1620499942.git.yifeifz2@illinois.edu> (raw)
In-Reply-To: <cover.1620499942.git.yifeifz2@illinois.edu>

From: YiFei Zhu <yifeifz2@illinois.edu>

This is to allow progs with no access to ptr to BPF ID still be
able to call some helpers, with these arguments set as NULL, so
the helper implementation may set a fallback when NULL is passed in.

Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>
---
 include/linux/bpf.h   |  1 +
 kernel/bpf/verifier.c | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2019c0893250..efa6444b88d3 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -303,6 +303,7 @@ enum bpf_arg_type {
 	ARG_PTR_TO_SOCKET,	/* pointer to bpf_sock (fullsock) */
 	ARG_PTR_TO_SOCKET_OR_NULL,	/* pointer to bpf_sock (fullsock) or NULL */
 	ARG_PTR_TO_BTF_ID,	/* pointer to in-kernel struct */
+	ARG_PTR_TO_BTF_ID_OR_NULL,	/* pointer to in-kernel struct or NULL */
 	ARG_PTR_TO_ALLOC_MEM,	/* pointer to dynamically allocated memory */
 	ARG_PTR_TO_ALLOC_MEM_OR_NULL,	/* pointer to dynamically allocated memory or NULL */
 	ARG_CONST_ALLOC_SIZE_OR_ZERO,	/* number of allocated bytes requested */
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8eec1796caaa..8a08a27e0abc 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -484,7 +484,8 @@ static bool arg_type_may_be_null(enum bpf_arg_type type)
 	       type == ARG_PTR_TO_CTX_OR_NULL ||
 	       type == ARG_PTR_TO_SOCKET_OR_NULL ||
 	       type == ARG_PTR_TO_ALLOC_MEM_OR_NULL ||
-	       type == ARG_PTR_TO_STACK_OR_NULL;
+	       type == ARG_PTR_TO_STACK_OR_NULL ||
+	       type == ARG_PTR_TO_BTF_ID_OR_NULL;
 }
 
 /* Determine whether the function releases some resources allocated by another
@@ -4808,6 +4809,7 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
 	[ARG_PTR_TO_SOCKET]		= &fullsock_types,
 	[ARG_PTR_TO_SOCKET_OR_NULL]	= &fullsock_types,
 	[ARG_PTR_TO_BTF_ID]		= &btf_ptr_types,
+	[ARG_PTR_TO_BTF_ID_OR_NULL]	= &btf_ptr_types,
 	[ARG_PTR_TO_SPIN_LOCK]		= &spin_lock_types,
 	[ARG_PTR_TO_MEM]		= &mem_types,
 	[ARG_PTR_TO_MEM_OR_NULL]	= &mem_types,
@@ -5436,10 +5438,14 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
-		if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i])
+		if ((fn->arg_type[i] == ARG_PTR_TO_BTF_ID ||
+		     fn->arg_type[i] == ARG_PTR_TO_BTF_ID_OR_NULL) &&
+		    !fn->arg_btf_id[i])
 			return false;
 
-		if (fn->arg_type[i] != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i])
+		if ((fn->arg_type[i] != ARG_PTR_TO_BTF_ID &&
+		     fn->arg_type[i] != ARG_PTR_TO_BTF_ID_OR_NULL) &&
+		    fn->arg_btf_id[i])
 			return false;
 	}
 
-- 
2.31.1


  parent reply	other threads:[~2021-05-10 17:23 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 17:22 [RFC PATCH bpf-next seccomp 00/12] eBPF seccomp filters YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 01/12] seccomp: Move no_new_privs check to after prepare_filter YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 02/12] bpf, seccomp: Add eBPF filter capabilities YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 03/12] seccomp, ptrace: Add a mechanism to retrieve attached eBPF seccomp filters YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 04/12] libbpf: recognize section "seccomp" YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 05/12] samples/bpf: Add eBPF seccomp sample programs YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 06/12] lsm: New hook seccomp_extended YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 07/12] bpf/verifier: allow restricting direct map access YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 08/12] seccomp-ebpf: restrict filter to almost cBPF if LSM request such YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 09/12] yama: (concept) restrict seccomp-eBPF with ptrace_scope YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 10/12] seccomp-ebpf: Add ability to read user memory YiFei Zhu
2021-05-11  2:04   ` Alexei Starovoitov
2021-05-11  7:14     ` YiFei Zhu
2021-05-12 22:36       ` Alexei Starovoitov
2021-05-13  5:26         ` YiFei Zhu
2021-05-13 14:53           ` Andy Lutomirski
2021-05-13 17:12             ` YiFei Zhu
2021-05-13 17:15               ` Andy Lutomirski
2021-05-10 17:22 ` YiFei Zhu [this message]
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 12/12] seccomp-ebpf: support task storage from BPF-LSM, defaulting to group leader YiFei Zhu
2021-05-11  1:58   ` Alexei Starovoitov
2021-05-11  5:44     ` YiFei Zhu
2021-05-12 21:56       ` Alexei Starovoitov
2021-05-10 17:47 ` [RFC PATCH bpf-next seccomp 00/12] eBPF seccomp filters Andy Lutomirski
2021-05-11  5:21   ` YiFei Zhu
2021-05-15 15:49     ` Andy Lutomirski
2021-05-20  9:05       ` Christian Brauner
     [not found]     ` <fffbea8189794a8da539f6082af3de8e@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-16  8:38       ` Tianyin Xu
2021-05-17 15:40         ` Tycho Andersen
2021-05-17 17:07         ` Sargun Dhillon
     [not found]         ` <108b4b9c2daa4123805d2b92cf51374b@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-20  8:16           ` Tianyin Xu
2021-05-20  8:56             ` Christian Brauner
2021-05-20  9:37               ` Christian Brauner
2021-06-01 19:55               ` Kees Cook
2021-06-09  6:32                 ` Jinghao Jia
2021-06-09  6:27               ` Jinghao Jia
     [not found]             ` <00fe481c572d486289bc88780f48e88f@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-20 22:13               ` Tianyin Xu
     [not found]         ` <eae2a0e5038b41c4af87edcb3d4cdc13@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-20  8:22           ` Tianyin Xu
2021-05-24 18:55             ` Sargun Dhillon

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