[PATCH bpf-next v9 03/10] bpf,landlock: Define an eBPF program type for Landlock hooks

@@ -8807,6 +8807,19 @@ F:	net/core/skmsg.c
 F:	net/core/sock_map.c
 F:	net/ipv4/tcp_bpf.c
 
+LANDLOCK SECURITY MODULE
+M:	Mickaël Salaün <mic@digikod.net>
+S:	Supported
+F:	Documentation/security/landlock/
+F:	include/linux/landlock.h
+F:	include/uapi/linux/landlock.h
+F:	samples/bpf/landlock*
+F:	security/landlock/
+F:	tools/include/uapi/linux/landlock.h
+F:	tools/testing/selftests/landlock/
+K:	landlock
+K:	LANDLOCK
+
 LANTIQ / INTEL Ethernet drivers
 M:	Hauke Mehrtens <hauke@hauke-m.de>
 L:	netdev@vger.kernel.org

@@ -37,6 +37,9 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2)
 #ifdef CONFIG_INET
 BPF_PROG_TYPE(BPF_PROG_TYPE_SK_REUSEPORT, sk_reuseport)
 #endif
+#ifdef CONFIG_SECURITY_LANDLOCK
+BPF_PROG_TYPE(BPF_PROG_TYPE_LANDLOCK_HOOK, landlock)
+#endif
 
 BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops)

@@ -170,6 +170,7 @@ enum bpf_prog_type {
 	BPF_PROG_TYPE_FLOW_DISSECTOR,
 	BPF_PROG_TYPE_CGROUP_SYSCTL,
 	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+	BPF_PROG_TYPE_LANDLOCK_HOOK,
 };
 
 enum bpf_attach_type {

@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Landlock - UAPI headers
+ *
+ * Copyright © 2017-2019 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2019 ANSSI
+ */
+
+#ifndef _UAPI__LINUX_LANDLOCK_H__
+#define _UAPI__LINUX_LANDLOCK_H__
+
+#include <linux/types.h>
+
+#define LANDLOCK_RET_ALLOW	0
+#define LANDLOCK_RET_DENY	1
+
+/**
+ * enum landlock_hook_type - hook type for which a Landlock program is called
+ *
+ * A hook is a policy decision point which exposes the same context type for
+ * each program evaluation.
+ *
+ * @LANDLOCK_HOOK_FS_PICK: called for the last element of a file path
+ * @LANDLOCK_HOOK_FS_WALK: called for each directory of a file path (excluding
+ *			   the directory passed to fs_pick, if any)
+ */
+enum landlock_hook_type {
+	LANDLOCK_HOOK_FS_PICK = 1,
+	LANDLOCK_HOOK_FS_WALK,
+};
+
+/**
+ * DOC: landlock_triggers
+ *
+ * A landlock trigger is used as a bitmask in subtype.landlock_hook.triggers
+ * for a fs_pick program.  It defines a set of actions for which the program
+ * should verify an access request.
+ *
+ * - %LANDLOCK_TRIGGER_FS_PICK_APPEND
+ * - %LANDLOCK_TRIGGER_FS_PICK_CHDIR
+ * - %LANDLOCK_TRIGGER_FS_PICK_CHROOT
+ * - %LANDLOCK_TRIGGER_FS_PICK_CREATE
+ * - %LANDLOCK_TRIGGER_FS_PICK_EXECUTE
+ * - %LANDLOCK_TRIGGER_FS_PICK_FCNTL
+ * - %LANDLOCK_TRIGGER_FS_PICK_GETATTR
+ * - %LANDLOCK_TRIGGER_FS_PICK_IOCTL
+ * - %LANDLOCK_TRIGGER_FS_PICK_LINK
+ * - %LANDLOCK_TRIGGER_FS_PICK_LINKTO
+ * - %LANDLOCK_TRIGGER_FS_PICK_LOCK
+ * - %LANDLOCK_TRIGGER_FS_PICK_MAP
+ * - %LANDLOCK_TRIGGER_FS_PICK_MOUNTON
+ * - %LANDLOCK_TRIGGER_FS_PICK_OPEN
+ * - %LANDLOCK_TRIGGER_FS_PICK_READ
+ * - %LANDLOCK_TRIGGER_FS_PICK_READDIR
+ * - %LANDLOCK_TRIGGER_FS_PICK_RECEIVE
+ * - %LANDLOCK_TRIGGER_FS_PICK_RENAME
+ * - %LANDLOCK_TRIGGER_FS_PICK_RENAMETO
+ * - %LANDLOCK_TRIGGER_FS_PICK_RMDIR
+ * - %LANDLOCK_TRIGGER_FS_PICK_SETATTR
+ * - %LANDLOCK_TRIGGER_FS_PICK_TRANSFER
+ * - %LANDLOCK_TRIGGER_FS_PICK_UNLINK
+ * - %LANDLOCK_TRIGGER_FS_PICK_WRITE
+ */
+#define LANDLOCK_TRIGGER_FS_PICK_APPEND			(1ULL << 0)
+#define LANDLOCK_TRIGGER_FS_PICK_CHDIR			(1ULL << 1)
+#define LANDLOCK_TRIGGER_FS_PICK_CHROOT			(1ULL << 2)
+#define LANDLOCK_TRIGGER_FS_PICK_CREATE			(1ULL << 3)
+#define LANDLOCK_TRIGGER_FS_PICK_EXECUTE		(1ULL << 4)
+#define LANDLOCK_TRIGGER_FS_PICK_FCNTL			(1ULL << 5)
+#define LANDLOCK_TRIGGER_FS_PICK_GETATTR		(1ULL << 6)
+#define LANDLOCK_TRIGGER_FS_PICK_IOCTL			(1ULL << 7)
+#define LANDLOCK_TRIGGER_FS_PICK_LINK			(1ULL << 8)
+#define LANDLOCK_TRIGGER_FS_PICK_LINKTO			(1ULL << 9)
+#define LANDLOCK_TRIGGER_FS_PICK_LOCK			(1ULL << 10)
+#define LANDLOCK_TRIGGER_FS_PICK_MAP			(1ULL << 11)
+#define LANDLOCK_TRIGGER_FS_PICK_MOUNTON		(1ULL << 12)
+#define LANDLOCK_TRIGGER_FS_PICK_OPEN			(1ULL << 13)
+#define LANDLOCK_TRIGGER_FS_PICK_READ			(1ULL << 14)
+#define LANDLOCK_TRIGGER_FS_PICK_READDIR		(1ULL << 15)
+#define LANDLOCK_TRIGGER_FS_PICK_RECEIVE		(1ULL << 16)
+#define LANDLOCK_TRIGGER_FS_PICK_RENAME			(1ULL << 17)
+#define LANDLOCK_TRIGGER_FS_PICK_RENAMETO		(1ULL << 18)
+#define LANDLOCK_TRIGGER_FS_PICK_RMDIR			(1ULL << 19)
+#define LANDLOCK_TRIGGER_FS_PICK_SETATTR		(1ULL << 20)
+#define LANDLOCK_TRIGGER_FS_PICK_TRANSFER		(1ULL << 21)
+#define LANDLOCK_TRIGGER_FS_PICK_UNLINK			(1ULL << 22)
+#define LANDLOCK_TRIGGER_FS_PICK_WRITE			(1ULL << 23)
+
+/**
+ * struct landlock_ctx_fs_pick - context accessible to a fs_pick program
+ *
+ * @inode: pointer to the current kernel object that can be used to compare
+ *         inodes from an inode map.
+ */
+struct landlock_ctx_fs_pick {
+	__u64 inode;
+};
+
+/**
+ * struct landlock_ctx_fs_walk - context accessible to a fs_walk program
+ *
+ * @inode: pointer to the current kernel object that can be used to compare
+ *         inodes from an inode map.
+ */
+struct landlock_ctx_fs_walk {
+	__u64 inode;
+};
+
+#endif /* _UAPI__LINUX_LANDLOCK_H__ */

@@ -237,6 +237,7 @@ source "security/apparmor/Kconfig"
 source "security/loadpin/Kconfig"
 source "security/yama/Kconfig"
 source "security/safesetid/Kconfig"
+source "security/landlock/Kconfig"
 
 source "security/integrity/Kconfig"
 

@@ -11,6 +11,7 @@ subdir-$(CONFIG_SECURITY_APPARMOR)	+= apparmor
 subdir-$(CONFIG_SECURITY_YAMA)		+= yama
 subdir-$(CONFIG_SECURITY_LOADPIN)	+= loadpin
 subdir-$(CONFIG_SECURITY_SAFESETID)    += safesetid
+subdir-$(CONFIG_SECURITY_LANDLOCK)		+= landlock
 
 # always enable default capabilities
 obj-y					+= commoncap.o

@@ -27,6 +28,7 @@ obj-$(CONFIG_SECURITY_APPARMOR)		+= apparmor/
 obj-$(CONFIG_SECURITY_YAMA)		+= yama/
 obj-$(CONFIG_SECURITY_LOADPIN)		+= loadpin/
 obj-$(CONFIG_SECURITY_SAFESETID)       += safesetid/
+obj-$(CONFIG_SECURITY_LANDLOCK)	+= landlock/
 obj-$(CONFIG_CGROUP_DEVICE)		+= device_cgroup.o
 
 # Object integrity file lists

@@ -0,0 +1,18 @@
+config SECURITY_LANDLOCK
+	bool "Landlock support"
+	depends on SECURITY
+	depends on BPF_SYSCALL
+	depends on SECCOMP_FILTER
+	default n
+	help
+	  This selects Landlock, a programmatic access control.  It enables to
+	  restrict processes on the fly (i.e. create a sandbox).  The security
+	  policy is a set of eBPF programs, dedicated to deny a list of actions
+	  on specific kernel objects (e.g. file).
+
+	  You need to enable seccomp filter to apply a security policy to a
+	  process hierarchy (e.g. application with built-in sandboxing).
+
+	  See Documentation/security/landlock/ for further information.
+
+	  If you are unsure how to answer this question, answer N.

@@ -0,0 +1,3 @@
+obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o
+
+landlock-y := init.o

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock LSM - private headers
+ *
+ * Copyright © 2016-2019 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2019 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_COMMON_H
+#define _SECURITY_LANDLOCK_COMMON_H
+
+#include <linux/bpf.h> /* enum bpf_prog_aux */
+#include <linux/filter.h> /* bpf_prog */
+#include <linux/refcount.h> /* refcount_t */
+#include <uapi/linux/landlock.h> /* enum landlock_hook_type */
+
+#define LANDLOCK_NAME "landlock"
+
+/* UAPI bounds and bitmasks */
+
+#define _LANDLOCK_HOOK_LAST LANDLOCK_HOOK_FS_WALK
+
+#define _LANDLOCK_TRIGGER_FS_PICK_LAST	LANDLOCK_TRIGGER_FS_PICK_WRITE
+#define _LANDLOCK_TRIGGER_FS_PICK_MASK	((_LANDLOCK_TRIGGER_FS_PICK_LAST << 1ULL) - 1)
+
+#endif /* _SECURITY_LANDLOCK_COMMON_H */

@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock LSM - init
+ *
+ * Copyright © 2016-2019 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2019 ANSSI
+ */
+
+#include <linux/bpf.h> /* enum bpf_access_type */
+#include <linux/capability.h> /* capable */
+#include <linux/filter.h> /* struct bpf_prog */
+
+#include "common.h" /* LANDLOCK_* */
+
+static bool bpf_landlock_is_valid_access(int off, int size,
+		enum bpf_access_type type, const struct bpf_prog *prog,
+		struct bpf_insn_access_aux *info)
+{
+	const union bpf_prog_subtype *prog_subtype;
+	enum bpf_reg_type reg_type = NOT_INIT;
+	int max_size = 0;
+
+	if (WARN_ON(!prog->aux->extra))
+		return false;
+	prog_subtype = &prog->aux->extra->subtype;
+
+	if (off < 0)
+		return false;
+	if (size <= 0 || size > sizeof(__u64))
+		return false;
+
+	/* check memory range access */
+	switch (reg_type) {
+	case NOT_INIT:
+		return false;
+	case SCALAR_VALUE:
+		/* allow partial raw value */
+		if (size > max_size)
+			return false;
+		info->ctx_field_size = max_size;
+		break;
+	default:
+		/* deny partial pointer */
+		if (size != max_size)
+			return false;
+	}
+
+	info->reg_type = reg_type;
+	return true;
+}
+
+static bool bpf_landlock_is_valid_subtype(struct bpf_prog_extra *prog_extra)
+{
+	const union bpf_prog_subtype *subtype;
+
+	if (!prog_extra)
+		return false;
+	subtype = &prog_extra->subtype;
+
+	switch (subtype->landlock_hook.type) {
+	case LANDLOCK_HOOK_FS_PICK:
+		if (!subtype->landlock_hook.triggers ||
+				subtype->landlock_hook.triggers &
+				~_LANDLOCK_TRIGGER_FS_PICK_MASK)
+			return false;
+		break;
+	case LANDLOCK_HOOK_FS_WALK:
+		if (subtype->landlock_hook.triggers)
+			return false;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static const struct bpf_func_proto *bpf_landlock_func_proto(
+		enum bpf_func_id func_id,
+		const struct bpf_prog *prog)
+{
+	u64 hook_type;
+
+	if (WARN_ON(!prog->aux->extra))
+		return NULL;
+	hook_type = prog->aux->extra->subtype.landlock_hook.type;
+
+	/* generic functions */
+	/* TODO: do we need/want update/delete functions for every LL prog?
+	 * => impurity vs. audit */
+	switch (func_id) {
+	case BPF_FUNC_map_lookup_elem:
+		return &bpf_map_lookup_elem_proto;
+	case BPF_FUNC_map_update_elem:
+		return &bpf_map_update_elem_proto;
+	case BPF_FUNC_map_delete_elem:
+		return &bpf_map_delete_elem_proto;
+	default:
+		break;
+	}
+	return NULL;
+}
+
+const struct bpf_verifier_ops landlock_verifier_ops = {
+	.get_func_proto	= bpf_landlock_func_proto,
+	.is_valid_access = bpf_landlock_is_valid_access,
+	.is_valid_subtype = bpf_landlock_is_valid_subtype,
+};
+
+const struct bpf_prog_ops landlock_prog_ops = {};

@@ -170,6 +170,7 @@ enum bpf_prog_type {
 	BPF_PROG_TYPE_FLOW_DISSECTOR,
 	BPF_PROG_TYPE_CGROUP_SYSCTL,
 	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+	BPF_PROG_TYPE_LANDLOCK_HOOK,
 };
 
 enum bpf_attach_type {

@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Landlock - UAPI headers
+ *
+ * Copyright © 2017-2019 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2019 ANSSI
+ */
+
+#ifndef _UAPI__LINUX_LANDLOCK_H__
+#define _UAPI__LINUX_LANDLOCK_H__
+
+#include <linux/types.h>
+
+#define LANDLOCK_RET_ALLOW	0
+#define LANDLOCK_RET_DENY	1
+
+/**
+ * enum landlock_hook_type - hook type for which a Landlock program is called
+ *
+ * A hook is a policy decision point which exposes the same context type for
+ * each program evaluation.
+ *
+ * @LANDLOCK_HOOK_FS_PICK: called for the last element of a file path
+ * @LANDLOCK_HOOK_FS_WALK: called for each directory of a file path (excluding
+ *			   the directory passed to fs_pick, if any)
+ */
+enum landlock_hook_type {
+	LANDLOCK_HOOK_FS_PICK = 1,
+	LANDLOCK_HOOK_FS_WALK,
+};
+
+/**
+ * DOC: landlock_triggers
+ *
+ * A landlock trigger is used as a bitmask in subtype.landlock_hook.triggers
+ * for a fs_pick program.  It defines a set of actions for which the program
+ * should verify an access request.
+ *
+ * - %LANDLOCK_TRIGGER_FS_PICK_APPEND
+ * - %LANDLOCK_TRIGGER_FS_PICK_CHDIR
+ * - %LANDLOCK_TRIGGER_FS_PICK_CHROOT
+ * - %LANDLOCK_TRIGGER_FS_PICK_CREATE
+ * - %LANDLOCK_TRIGGER_FS_PICK_EXECUTE
+ * - %LANDLOCK_TRIGGER_FS_PICK_FCNTL
+ * - %LANDLOCK_TRIGGER_FS_PICK_GETATTR
+ * - %LANDLOCK_TRIGGER_FS_PICK_IOCTL
+ * - %LANDLOCK_TRIGGER_FS_PICK_LINK
+ * - %LANDLOCK_TRIGGER_FS_PICK_LINKTO
+ * - %LANDLOCK_TRIGGER_FS_PICK_LOCK
+ * - %LANDLOCK_TRIGGER_FS_PICK_MAP
+ * - %LANDLOCK_TRIGGER_FS_PICK_MOUNTON
+ * - %LANDLOCK_TRIGGER_FS_PICK_OPEN
+ * - %LANDLOCK_TRIGGER_FS_PICK_READ
+ * - %LANDLOCK_TRIGGER_FS_PICK_READDIR
+ * - %LANDLOCK_TRIGGER_FS_PICK_RECEIVE
+ * - %LANDLOCK_TRIGGER_FS_PICK_RENAME
+ * - %LANDLOCK_TRIGGER_FS_PICK_RENAMETO
+ * - %LANDLOCK_TRIGGER_FS_PICK_RMDIR
+ * - %LANDLOCK_TRIGGER_FS_PICK_SETATTR
+ * - %LANDLOCK_TRIGGER_FS_PICK_TRANSFER
+ * - %LANDLOCK_TRIGGER_FS_PICK_UNLINK
+ * - %LANDLOCK_TRIGGER_FS_PICK_WRITE
+ */
+#define LANDLOCK_TRIGGER_FS_PICK_APPEND			(1ULL << 0)
+#define LANDLOCK_TRIGGER_FS_PICK_CHDIR			(1ULL << 1)
+#define LANDLOCK_TRIGGER_FS_PICK_CHROOT			(1ULL << 2)
+#define LANDLOCK_TRIGGER_FS_PICK_CREATE			(1ULL << 3)
+#define LANDLOCK_TRIGGER_FS_PICK_EXECUTE		(1ULL << 4)
+#define LANDLOCK_TRIGGER_FS_PICK_FCNTL			(1ULL << 5)
+#define LANDLOCK_TRIGGER_FS_PICK_GETATTR		(1ULL << 6)
+#define LANDLOCK_TRIGGER_FS_PICK_IOCTL			(1ULL << 7)
+#define LANDLOCK_TRIGGER_FS_PICK_LINK			(1ULL << 8)
+#define LANDLOCK_TRIGGER_FS_PICK_LINKTO			(1ULL << 9)
+#define LANDLOCK_TRIGGER_FS_PICK_LOCK			(1ULL << 10)
+#define LANDLOCK_TRIGGER_FS_PICK_MAP			(1ULL << 11)
+#define LANDLOCK_TRIGGER_FS_PICK_MOUNTON		(1ULL << 12)
+#define LANDLOCK_TRIGGER_FS_PICK_OPEN			(1ULL << 13)
+#define LANDLOCK_TRIGGER_FS_PICK_READ			(1ULL << 14)
+#define LANDLOCK_TRIGGER_FS_PICK_READDIR		(1ULL << 15)
+#define LANDLOCK_TRIGGER_FS_PICK_RECEIVE		(1ULL << 16)
+#define LANDLOCK_TRIGGER_FS_PICK_RENAME			(1ULL << 17)
+#define LANDLOCK_TRIGGER_FS_PICK_RENAMETO		(1ULL << 18)
+#define LANDLOCK_TRIGGER_FS_PICK_RMDIR			(1ULL << 19)
+#define LANDLOCK_TRIGGER_FS_PICK_SETATTR		(1ULL << 20)
+#define LANDLOCK_TRIGGER_FS_PICK_TRANSFER		(1ULL << 21)
+#define LANDLOCK_TRIGGER_FS_PICK_UNLINK			(1ULL << 22)
+#define LANDLOCK_TRIGGER_FS_PICK_WRITE			(1ULL << 23)
+
+/**
+ * struct landlock_ctx_fs_pick - context accessible to a fs_pick program
+ *
+ * @inode: pointer to the current kernel object that can be used to compare
+ *         inodes from an inode map.
+ */
+struct landlock_ctx_fs_pick {
+	__u64 inode;
+};
+
+/**
+ * struct landlock_ctx_fs_walk - context accessible to a fs_walk program
+ *
+ * @inode: pointer to the current kernel object that can be used to compare
+ *         inodes from an inode map.
+ */
+struct landlock_ctx_fs_walk {
+	__u64 inode;
+};
+
+#endif /* _UAPI__LINUX_LANDLOCK_H__ */

@@ -2646,6 +2646,7 @@ static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
 	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
 	case BPF_PROG_TYPE_PERF_EVENT:
 	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_LANDLOCK_HOOK:
 		return false;
 	case BPF_PROG_TYPE_KPROBE:
 	default:

@@ -101,6 +101,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
 	case BPF_PROG_TYPE_SK_REUSEPORT:
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_LANDLOCK_HOOK:
 	default:
 		break;
 	}