[PATCH bpf-next v5 5/7] bpf: lsm: Initialize the BPF LSM hooks
flat view
STALE2391d
SUPERSEDED: 2 (0M)
From: KP Singh <hidden>
Date: 2020-03-23 16:44:49
Also in:
bpf, lkml
Subsystem:
bpf [security & lsm] (security audit and enforcement using bpf), security subsystem, the rest · Maintainers:
KP Singh, Matt Bobrowski, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
Revision v5 of 9 in this series; 2 review trailers.
Revisions (9)
From: KP Singh <redacted> The bpf_lsm_ nops are initialized into the LSM framework like any other LSM. Some LSM hooks do not have 0 as their default return value. The __weak symbol for these hooks is overridden by a corresponding definition in security/bpf/hooks.c The LSM can be enabled / disabled with CONFIG_LSM. Signed-off-by: KP Singh <redacted> Reviewed-by: Brendan Jackman <redacted> Reviewed-by: Florent Revest <redacted> --- security/Kconfig | 10 ++++---- security/Makefile | 2 ++ security/bpf/Makefile | 5 ++++ security/bpf/hooks.c | 55 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 67 insertions(+), 5 deletions(-) create mode 100644 security/bpf/Makefile create mode 100644 security/bpf/hooks.c
diff --git a/security/Kconfig b/security/Kconfig
index 2a1a2d396228..cd3cc7da3a55 100644
--- a/security/Kconfig
+++ b/security/Kconfig@@ -277,11 +277,11 @@ endchoice config LSM string "Ordered list of enabled LSMs" - default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK - default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR - default "lockdown,yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO - default "lockdown,yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC - default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor" + default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK + default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR + default "lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO + default "lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC + default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf" help A comma-separated list of LSMs, in initialization order. Any LSMs left off this list will be ignored. This can be
diff --git a/security/Makefile b/security/Makefile
index 746438499029..22e73a3482bd 100644
--- a/security/Makefile
+++ b/security/Makefile@@ -12,6 +12,7 @@ subdir-$(CONFIG_SECURITY_YAMA) += yama subdir-$(CONFIG_SECURITY_LOADPIN) += loadpin subdir-$(CONFIG_SECURITY_SAFESETID) += safesetid subdir-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown +subdir-$(CONFIG_BPF_LSM) += bpf # always enable default capabilities obj-y += commoncap.o
@@ -30,6 +31,7 @@ obj-$(CONFIG_SECURITY_LOADPIN) += loadpin/ obj-$(CONFIG_SECURITY_SAFESETID) += safesetid/ obj-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown/ obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o +obj-$(CONFIG_BPF_LSM) += bpf/ # Object integrity file lists subdir-$(CONFIG_INTEGRITY) += integrity
diff --git a/security/bpf/Makefile b/security/bpf/Makefile
new file mode 100644
index 000000000000..c7a89a962084
--- /dev/null
+++ b/security/bpf/Makefile@@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (C) 2020 Google LLC. + +obj-$(CONFIG_BPF_LSM) := hooks.o
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
new file mode 100644
index 000000000000..68e5824868f9
--- /dev/null
+++ b/security/bpf/hooks.c@@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ +#include <linux/lsm_hooks.h> +#include <linux/bpf_lsm.h> + +/* Some LSM hooks do not have 0 as their default return values. Override the + * __weak definitons generated by default for these hooks + */ +noinline int bpf_lsm_inode_getsecurity(struct inode *inode, const char *name, + void **buffer, bool alloc) +{ + return -EOPNOTSUPP; +} + +noinline int bpf_lsm_inode_setsecurity(struct inode *inode, const char *name, + const void *value, size_t size, + int flags) +{ + return -EOPNOTSUPP; +} + +noinline int bpf_lsm_task_prctl(int option, unsigned long arg2, + unsigned long arg3, unsigned long arg4, + unsigned long arg5) +{ + return -ENOSYS; +} + +noinline int bpf_lsm_xfrm_state_pol_flow_match(struct xfrm_state *x, + struct xfrm_policy *xp, + const struct flowi *fl) +{ + return 1; +} + +static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = { + #define LSM_HOOK(RET, NAME, ...) LSM_HOOK_INIT(NAME, bpf_lsm_##NAME), + #include <linux/lsm_hook_names.h> + #undef LSM_HOOK +}; + +static int __init bpf_lsm_init(void) +{ + security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), "bpf"); + pr_info("LSM support for eBPF active\n"); + return 0; +} + +DEFINE_LSM(bpf) = { + .name = "bpf", + .init = bpf_lsm_init, +};
--
2.20.1