diff options
Diffstat (limited to 'security/security.c')
| -rw-r--r-- | security/security.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/security/security.c b/security/security.c index 2ef593ec70f..dd0c6baed49 100644 --- a/security/security.c +++ b/security/security.c @@ -17,6 +17,8 @@ #include <linux/kernel.h> #include <linux/security.h> +/* Boot-time LSM user choice */ +static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1]; /* things that live in dummy.c */ extern struct security_operations dummy_security_ops; @@ -67,13 +69,47 @@ int __init security_init(void) return 0; } +/* Save user chosen LSM */ +static int __init choose_lsm(char *str) +{ + strncpy(chosen_lsm, str, SECURITY_NAME_MAX); + return 1; +} +__setup("security=", choose_lsm); + +/** + * security_module_enable - Load given security module on boot ? + * @ops: a pointer to the struct security_operations that is to be checked. + * + * Each LSM must pass this method before registering its own operations + * to avoid security registration races. This method may also be used + * to check if your LSM is currently loaded. + * + * Return true if: + * -The passed LSM is the one chosen by user at boot time, + * -or user didsn't specify a specific LSM and we're the first to ask + * for registeration permissoin, + * -or the passed LSM is currently loaded. + * Otherwise, return false. + */ +int __init security_module_enable(struct security_operations *ops) +{ + if (!*chosen_lsm) + strncpy(chosen_lsm, ops->name, SECURITY_NAME_MAX); + else if (strncmp(ops->name, chosen_lsm, SECURITY_NAME_MAX)) + return 0; + + return 1; +} + /** * register_security - registers a security framework with the kernel * @ops: a pointer to the struct security_options that is to be registered * * This function is to allow a security module to register itself with the * kernel security subsystem. Some rudimentary checking is done on the @ops - * value passed to this function. + * value passed to this function. You'll need to check first if your LSM + * is allowed to register its @ops by calling security_module_enable(@ops). * * If there is already a security module registered with the kernel, * an error will be returned. Otherwise 0 is returned on success. |