[PATCH security-next v3 05/29] LSM: Convert from initcall to struct lsm_info

From: Kees Cook
Date: Mon Sep 24 2018 - 20:20:21 EST


In preparation for doing more interesting LSM init probing, this converts
the existing initcall system into an explicit call into a function pointer
from a section-collected struct lsm_info array.

Cc: James Morris <jmorris@xxxxxxxxx>
Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
Cc: linux-security-module@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
include/linux/init.h | 2 --
include/linux/lsm_hooks.h | 12 ++++++++++++
include/linux/module.h | 1 -
security/integrity/iint.c | 1 +
security/security.c | 14 +++++---------
5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 77636539e77c..9c2aba1dbabf 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -133,7 +133,6 @@ static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
#endif

extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
-extern initcall_entry_t __start_lsm_info[], __end_lsm_info[];

/* Used for contructor calls. */
typedef void (*ctor_fn_t)(void);
@@ -236,7 +235,6 @@ extern bool initcall_debug;
static exitcall_t __exitcall_##fn __exit_call = fn

#define console_initcall(fn) ___define_initcall(fn,, .con_initcall)
-#define security_initcall(fn) ___define_initcall(fn,, .lsm_info)

struct obs_kernel_param {
const char *str;
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 97a020c616ad..ad04761e5587 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -2039,6 +2039,18 @@ extern char *lsm_names;
extern void security_add_hooks(struct security_hook_list *hooks, int count,
char *lsm);

+struct lsm_info {
+ int (*init)(void);
+};
+
+extern struct lsm_info __start_lsm_info[], __end_lsm_info[];
+
+#define security_initcall(lsm) \
+ static struct lsm_info __lsm_##lsm \
+ __used __section(.lsm_info.init) \
+ __aligned(sizeof(unsigned long)) \
+ = { .init = lsm, }
+
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
/*
* Assuring the safety of deleting a security module is up to
diff --git a/include/linux/module.h b/include/linux/module.h
index f807f15bebbe..264979283756 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -123,7 +123,6 @@ extern void cleanup_module(void);
#define late_initcall_sync(fn) module_init(fn)

#define console_initcall(fn) module_init(fn)
-#define security_initcall(fn) module_init(fn)

/* Each module must use one module_init(). */
#define module_init(initfn) \
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index 5a6810041e5c..70d21b566955 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -22,6 +22,7 @@
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/security.h>
+#include <linux/lsm_hooks.h>
#include "integrity.h"

static struct rb_root integrity_iint_tree = RB_ROOT;
diff --git a/security/security.c b/security/security.c
index 41a5da2c7faf..e74f46fba591 100644
--- a/security/security.c
+++ b/security/security.c
@@ -43,16 +43,12 @@ char *lsm_names;
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
CONFIG_DEFAULT_SECURITY;

-static void __init do_security_initcalls(void)
+static void __init major_lsm_init(void)
{
- initcall_t call;
- initcall_entry_t *ce;
+ struct lsm_info *lsm;

- ce = __start_lsm_info;
- while (ce < __end_lsm_info) {
- call = initcall_from_entry(ce);
- call();
- ce++;
+ for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
+ lsm->init();
}
}

@@ -82,7 +78,7 @@ int __init security_init(void)
/*
* Load all the remaining security modules.
*/
- do_security_initcalls();
+ major_lsm_init();

return 0;
}
--
2.17.1