Re: [PATCH 0/7 v21] LSM: Multiple concurrent LSMs

Tetsuo Handa
2015-04-10T11:25:37Z

This patchset seems to be blocked for waiting for an ACK from AppArmor
people. John, can you give us ACK?

Apart from ACK from John, I wrote a cleanup patch (shown below) which
we might want to append to this patchset, though we anyway need to
refresh this patchset with commit 58bc19542455 in linux-next.git included.
----------------------------------------
>From 49f753bb197ed2dda9c7958b5acf9d5458d102ef Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Fri, 10 Apr 2015 13:57:45 +0900
Subject: [PATCH] Cleanups for LSM: Multiple concurrent LSMs

(1) Move definition of SECURITY_NAME_MAX from include/linux/security.h and
include/linux/lsm_hooks.h to security/security.c.

(2) Drop "#ifdef CONFIG_SECURITY" from include/linux/lsm_hooks.h because
all files which include this file depend on CONFIG_SECURITY=y.

(3) Drop comment of removed "union security_list_options"->name member.

(4) Drop cap_netlink_send() which always returns 0.

(5) Simplify security_add_hooks(), and move it from security/security.c
to include/linux/lsm_hooks.h as an inline function.

(6) Move prototype of yama_add_hooks() and capability_add_hooks() from
include/linux/security.h to include/linux/lsm_hooks.h, and mark them
as __init functions.

(7) Move security_delete_hooks() from security/security.c to
security/selinux/hooks.c.

(8) Update comment of prototype of commoncap functions.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
include/linux/lsm_hooks.h | 33 +++++++++++++++------------------
include/linux/security.h | 17 ++---------------
security/commoncap.c | 7 +------
security/security.c | 28 +++-------------------------
security/selinux/hooks.c | 8 ++++++++
security/yama/yama_lsm.c | 2 +-
6 files changed, 30 insertions(+), 65 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index c86aaf0..3b805de 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -25,19 +25,10 @@
#define __LINUX_LSM_HOOKS_H

#include <linux/security.h>
-
-/* Maximum number of letters for an LSM name string */
-#define SECURITY_NAME_MAX 10
-
-#ifdef CONFIG_SECURITY
+#include <linux/init.h>
+#include <linux/rculist.h>

/**
- * Security module identifier.
- *
- * @name:
- * A string that acts as a unique identifier for the LSM with max number
- * of characters = SECURITY_NAME_MAX.
- *
* Security hooks for program execution operations.
*
* @bprm_set_creds:
@@ -1859,14 +1850,20 @@ struct security_hook_list {

extern struct security_hook_heads security_hook_heads;

+static inline void security_add_hooks(struct security_hook_list *hooks,
+ int count)
+{
+ int i;
+
+ for (i = 0; i < count; i++)
+ list_add_tail_rcu(&hooks[i].list, hooks[i].head);
+}
+
/* prototypes */
-extern int security_module_enable(const char *module);
-extern void security_add_hooks(struct security_hook_list *hooks, int count);
-#ifdef CONFIG_SECURITY_SELINUX_DISABLE
-extern void security_delete_hooks(struct security_hook_list *hooks, int count);
+extern int __init security_module_enable(const char *module);
+extern void __init capability_add_hooks(void);
+#ifdef CONFIG_SECURITY_YAMA_STACKED
+void __init yama_add_hooks(void);
#endif

-#endif /* CONFIG_SECURITY */
-
#endif /* ! __LINUX_LSM_HOOKS_H */
-
diff --git a/include/linux/security.h b/include/linux/security.h
index 04e2a3e..337105f 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -55,9 +55,6 @@ struct xattr;
struct xfrm_sec_ctx;
struct mm_struct;

-/* Maximum number of letters for an LSM name string */
-#define SECURITY_NAME_MAX 10
-
/* If capable should audit the security request */
#define SECURITY_CAP_NOAUDIT 0
#define SECURITY_CAP_AUDIT 1
@@ -70,10 +67,7 @@ struct audit_krule;
struct user_namespace;
struct timezone;

-/*
- * These functions are in security/capability.c and are used
- * as the default capabilities functions
- */
+/* These functions are in security/commoncap.c */
extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
int cap, int audit);
extern int cap_settime(const struct timespec *ts, const struct timezone *tz);
@@ -101,7 +95,6 @@ extern int cap_task_setscheduler(struct task_struct *p);
extern int cap_task_setioprio(struct task_struct *p, int ioprio);
extern int cap_task_setnice(struct task_struct *p, int nice);
extern int cap_vm_enough_memory(struct mm_struct *mm, long pages);
-extern void capability_add_hooks(void);

struct msghdr;
struct sk_buff;
@@ -116,8 +109,6 @@ struct xfrm_state;
struct xfrm_user_sec_ctx;
struct seq_file;

-extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb);
-
#ifdef CONFIG_MMU
extern unsigned long mmap_min_addr;
extern unsigned long dac_mmap_min_addr;
@@ -1078,7 +1069,7 @@ static inline int security_setprocattr(struct task_struct *p, char *name, void *

static inline int security_netlink_send(struct sock *sk, struct sk_buff *skb)
{
- return cap_netlink_send(sk, skb);
+ return 0;
}

static inline int security_ismaclabel(const char *name)
@@ -1653,9 +1644,5 @@ static inline void free_secdata(void *secdata)
{ }
#endif /* CONFIG_SECURITY */

-#ifdef CONFIG_SECURITY_YAMA_STACKED
-void yama_add_hooks(void);
-#endif
-
#endif /* ! __LINUX_SECURITY_H */

diff --git a/security/commoncap.c b/security/commoncap.c
index b7f341f..fe76865 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -53,11 +53,6 @@ static void warn_setuid_and_fcaps_mixed(const char *fname)
}
}

-int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
-{
- return 0;
-}
-
/**
* cap_capable - Determine whether a task has a particular effective capability
* @cred: The credentials to use
@@ -1005,7 +1000,7 @@ struct security_hook_list capability_hooks[] = {
LSM_HOOK_INIT(vm_enough_memory, cap_vm_enough_memory),
};

-void capability_add_hooks(void)
+void __init capability_add_hooks(void)
{
security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks));
}
diff --git a/security/security.c b/security/security.c
index be10ea4..e9d7171 100644
--- a/security/security.c
+++ b/security/security.c
@@ -29,6 +29,9 @@

#define MAX_LSM_EVM_XATTR 2

+/* Maximum number of letters for an LSM name string */
+#define SECURITY_NAME_MAX 10
+
/* Boot-time LSM user choice */
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
CONFIG_DEFAULT_SECURITY;
@@ -1888,28 +1891,3 @@ struct security_hook_heads security_hook_heads = {
LIST_HEAD_INIT(security_hook_heads.audit_rule_free),
#endif /* CONFIG_AUDIT */
};
-
-void security_add_hooks(struct security_hook_list *hooks, int count)
-{
- struct security_hook_list *shp;
- int i;
-
- for (i = 0; i < count; i++) {
- INIT_LIST_HEAD(&hooks[i].list);
- shp = list_last_entry(hooks[i].head,
- struct security_hook_list, list);
- list_add_rcu(&hooks[i].list, &shp->list);
- }
-}
-
-#ifdef CONFIG_SECURITY_SELINUX_DISABLE
-
-void security_delete_hooks(struct security_hook_list *hooks, int count)
-{
- int i;
-
- for (i = 0; i < count; i++)
- list_del_rcu(&hooks[i].list);
-}
-
-#endif /* CONFIG_SECURITY_SELINUX_DISABLE */
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3fd8610..cea78f2 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6161,6 +6161,14 @@ static void selinux_nf_ip_exit(void)
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static int selinux_disabled;

+static void security_delete_hooks(struct security_hook_list *hooks, int count)
+{
+ int i;
+
+ for (i = 0; i < count; i++)
+ list_del_rcu(&hooks[i].list);
+}
+
int selinux_disable(void)
{
if (ss_initialized) {
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index a6b876d..9ed3250 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -353,7 +353,7 @@ static struct security_hook_list yama_hooks[] = {
LSM_HOOK_INIT(task_free, yama_task_free),
};

-void yama_add_hooks(void)
+void __init yama_add_hooks(void)
{
security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks));
}
--
1.8.3.1