From 98e828a0650f348be85728c69875260cf78069e6 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 29 Mar 2020 01:43:50 +0100 Subject: security: Refactor declaration of LSM hooks The information about the different types of LSM hooks is scattered in two locations i.e. union security_list_options and struct security_hook_heads. Rather than duplicating this information even further for BPF_PROG_TYPE_LSM, define all the hooks with the LSM_HOOK macro in lsm_hook_defs.h which is then used to generate all the data structures required by the LSM framework. The LSM hooks are defined as: LSM_HOOK(, , , args...) with acccessible in security.c as: LSM_RET_DEFAULT() Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Reviewed-by: Kees Cook Reviewed-by: Casey Schaufler Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-3-kpsingh@chromium.org --- security/security.c | 41 ++++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 11 deletions(-) (limited to 'security') diff --git a/security/security.c b/security/security.c index 565bc9b67276..7fed24b9d57e 100644 --- a/security/security.c +++ b/security/security.c @@ -668,6 +668,25 @@ static void __init lsm_early_task(struct task_struct *task) panic("%s: Early task alloc failed.\n", __func__); } +/* + * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and + * can be accessed with: + * + * LSM_RET_DEFAULT() + * + * The macros below define static constants for the default value of each + * LSM hook. + */ +#define LSM_RET_DEFAULT(NAME) (NAME##_default) +#define DECLARE_LSM_RET_DEFAULT_void(DEFAULT, NAME) +#define DECLARE_LSM_RET_DEFAULT_int(DEFAULT, NAME) \ + static const int LSM_RET_DEFAULT(NAME) = (DEFAULT); +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + DECLARE_LSM_RET_DEFAULT_##RET(DEFAULT, NAME) + +#include +#undef LSM_HOOK + /* * Hook list operation macros. * @@ -1338,16 +1357,16 @@ int security_inode_getsecurity(struct inode *inode, const char *name, void **buf int rc; if (unlikely(IS_PRIVATE(inode))) - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_getsecurity); /* * Only one module will provide an attribute with a given name. */ hlist_for_each_entry(hp, &security_hook_heads.inode_getsecurity, list) { rc = hp->hook.inode_getsecurity(inode, name, buffer, alloc); - if (rc != -EOPNOTSUPP) + if (rc != LSM_RET_DEFAULT(inode_getsecurity)) return rc; } - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_getsecurity); } int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags) @@ -1356,17 +1375,17 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void int rc; if (unlikely(IS_PRIVATE(inode))) - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_setsecurity); /* * Only one module will provide an attribute with a given name. */ hlist_for_each_entry(hp, &security_hook_heads.inode_setsecurity, list) { rc = hp->hook.inode_setsecurity(inode, name, value, size, flags); - if (rc != -EOPNOTSUPP) + if (rc != LSM_RET_DEFAULT(inode_setsecurity)) return rc; } - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_setsecurity); } int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size) @@ -1740,12 +1759,12 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) { int thisrc; - int rc = -ENOSYS; + int rc = LSM_RET_DEFAULT(task_prctl); struct security_hook_list *hp; hlist_for_each_entry(hp, &security_hook_heads.task_prctl, list) { thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5); - if (thisrc != -ENOSYS) { + if (thisrc != LSM_RET_DEFAULT(task_prctl)) { rc = thisrc; if (thisrc != 0) break; @@ -1917,7 +1936,7 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name, continue; return hp->hook.getprocattr(p, name, value); } - return -EINVAL; + return LSM_RET_DEFAULT(getprocattr); } int security_setprocattr(const char *lsm, const char *name, void *value, @@ -1930,7 +1949,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value, continue; return hp->hook.setprocattr(name, value, size); } - return -EINVAL; + return LSM_RET_DEFAULT(setprocattr); } int security_netlink_send(struct sock *sk, struct sk_buff *skb) @@ -2315,7 +2334,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x, const struct flowi *fl) { struct security_hook_list *hp; - int rc = 1; + int rc = LSM_RET_DEFAULT(xfrm_state_pol_flow_match); /* * Since this function is expected to return 0 or 1, the judgment -- cgit From 520b7aa00d8cd8e411ecc09f63a2acd90feb6d29 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 29 Mar 2020 01:43:53 +0100 Subject: bpf: lsm: Initialize the BPF LSM hooks * The hooks are initialized using the definitions in include/linux/lsm_hook_defs.h. * The LSM can be enabled / disabled with CONFIG_BPF_LSM. Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Acked-by: Kees Cook Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-6-kpsingh@chromium.org --- security/Kconfig | 10 +++++----- security/Makefile | 2 ++ security/bpf/Makefile | 5 +++++ security/bpf/hooks.c | 26 ++++++++++++++++++++++++++ 4 files changed, 38 insertions(+), 5 deletions(-) create mode 100644 security/bpf/Makefile create mode 100644 security/bpf/hooks.c (limited to 'security') 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..32d32d485451 --- /dev/null +++ b/security/bpf/hooks.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ +#include +#include + +static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = { + #define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + LSM_HOOK_INIT(NAME, bpf_lsm_##NAME), + #include + #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, +}; -- cgit