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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 03/12] seccomp, ptrace: Add a mechanism to retrieve attached eBPF seccomp filters
Date: Mon, 10 May 2021 12:22:40 -0500	[thread overview]
Message-ID: <b09d7033ae669b3611edd13899d59d1cc437fbf6.1620499942.git.yifeifz2@illinois.edu> (raw)
In-Reply-To: <cover.1620499942.git.yifeifz2@illinois.edu>

From: Sargun Dhillon <sargun@sargun.me>

This extends the ptrace API to allow fetching eBPF seccomp filters
attached to programs. This is to enable checkpoint / restore cases.
The user will have to use the traditional PTRACE_SECCOMP_GET_FILTER
API call, and if they get an invalid medium type error they can switch
over to the eBPF variant of the API -- PTRACE_SECCOMP_GET_FILTER_EXTENDED.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Link: https://lists.linux-foundation.org/pipermail/containers/2018-February/038478.html
[YiFei: increase ptrace number to 0x4210]
Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>
---
 include/linux/seccomp.h     | 12 ++++++++++++
 include/uapi/linux/ptrace.h |  2 ++
 kernel/ptrace.c             |  4 ++++
 kernel/seccomp.c            | 37 +++++++++++++++++++++++++++++++++++++
 4 files changed, 55 insertions(+)

diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index c0750dc05de5..7ce9e3b3fa80 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -122,6 +122,18 @@ static inline long seccomp_get_metadata(struct task_struct *task,
 	return -EINVAL;
 }
 #endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */
+#if defined(CONFIG_SECCOMP_FILTER_EXTENDED) && defined(CONFIG_CHECKPOINT_RESTORE)
+extern long seccomp_get_filter_extended(struct task_struct *task,
+					unsigned long n,
+					void __user *data);
+#else
+static inline long seccomp_get_filter_extended(struct task_struct *task,
+					       unsigned long n,
+					       void __user *data)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_SECCOMP_FILTER_EXTENDED && CONFIG_CHECKPOINT_RESTORE */
 
 #ifdef CONFIG_SECCOMP_CACHE_DEBUG
 struct seq_file;
diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h
index 3747bf816f9a..725a03614c28 100644
--- a/include/uapi/linux/ptrace.h
+++ b/include/uapi/linux/ptrace.h
@@ -112,6 +112,8 @@ struct ptrace_rseq_configuration {
 	__u32 pad;
 };
 
+#define PTRACE_SECCOMP_GET_FILTER_EXTENDED	0x4210
+
 /*
  * These values are stored in task->ptrace_message
  * by tracehook_report_syscall_* to describe the current syscall-stop.
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 76f09456ec4b..1e8d2155231f 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -1247,6 +1247,10 @@ int ptrace_request(struct task_struct *child, long request,
 		break;
 #endif
 
+	case PTRACE_SECCOMP_GET_FILTER_EXTENDED:
+		ret = seccomp_get_filter_extended(child, addr, datavp);
+		break;
+
 	default:
 		break;
 	}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 1ef26a5bf93f..8550ae885245 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -2168,6 +2168,43 @@ long seccomp_get_metadata(struct task_struct *task,
 }
 #endif
 
+#if defined(CONFIG_SECCOMP_FILTER_EXTENDED) && defined(CONFIG_CHECKPOINT_RESTORE)
+long seccomp_get_filter_extended(struct task_struct *task,
+				 unsigned long filter_off,
+				 void __user *data)
+{
+	struct seccomp_filter *filter;
+	struct bpf_prog *prog;
+	long ret;
+
+	if (!capable(CAP_SYS_ADMIN) ||
+	    current->seccomp.mode != SECCOMP_MODE_DISABLED) {
+		return -EACCES;
+	}
+
+	filter = get_nth_filter(task, filter_off);
+	if (IS_ERR(filter))
+		return PTR_ERR(filter);
+
+	if (bpf_prog_was_classic(filter->prog)) {
+		ret = -EMEDIUMTYPE;
+		goto out;
+	}
+	prog = bpf_prog_inc_not_zero(filter->prog);
+	if (IS_ERR(prog)) {
+		ret = PTR_ERR(prog);
+		goto out;
+	}
+
+	ret = bpf_prog_new_fd(filter->prog);
+	if (ret < 0)
+		bpf_prog_put(prog);
+out:
+	__put_seccomp_filter(filter);
+	return ret;
+}
+#endif
+
 #ifdef CONFIG_SYSCTL
 
 /* Human readable action names for friendly sysctl interaction */
-- 
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 ` YiFei Zhu [this message]
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 ` [RFC PATCH bpf-next seccomp 11/12] bpf/verifier: support NULL-able ptr to BTF ID as helper argument YiFei Zhu
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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