LSM: Prepare for reorganizing "security=" logic

This moves the string handling for "security=" boot parameter into
a stored pointer instead of a string duplicate. This will allow
easier handling of the string when switching logic to use the coming
enable/disable infrastructure.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
Kees Cook 2018-09-19 13:11:41 -07:00
parent a8027fb0d1
commit 5ef4e41918

View File

@ -34,9 +34,6 @@
#define MAX_LSM_EVM_XATTR 2
/* Maximum number of letters for an LSM name string */
#define SECURITY_NAME_MAX 10
/* How many LSMs were built into the kernel? */
#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
@ -45,9 +42,8 @@ static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
char *lsm_names;
/* Boot-time LSM user choice */
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
CONFIG_DEFAULT_SECURITY;
static __initdata const char *chosen_lsm_order;
static __initdata const char *chosen_major_lsm;
static __initconst const char * const builtin_lsm_order = CONFIG_LSM;
@ -138,7 +134,7 @@ static bool __init lsm_allowed(struct lsm_info *lsm)
return true;
/* Disabled if this LSM isn't the chosen one. */
if (strcmp(lsm->name, chosen_lsm) != 0)
if (strcmp(lsm->name, chosen_major_lsm) != 0)
return false;
return true;
@ -168,6 +164,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
struct lsm_info *lsm;
char *sep, *name, *next;
if (!chosen_major_lsm)
chosen_major_lsm = CONFIG_DEFAULT_SECURITY;
sep = kstrdup(order, GFP_KERNEL);
next = sep;
/* Walk the list, looking for matching LSMs. */
@ -257,12 +256,12 @@ int __init security_init(void)
}
/* Save user chosen LSM */
static int __init choose_lsm(char *str)
static int __init choose_major_lsm(char *str)
{
strncpy(chosen_lsm, str, SECURITY_NAME_MAX);
chosen_major_lsm = str;
return 1;
}
__setup("security=", choose_lsm);
__setup("security=", choose_major_lsm);
/* Explicitly choose LSM initialization order. */
static int __init choose_lsm_order(char *str)