From e2bc445b66cad25b0627391df8138a83d0e48f97 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 19 Sep 2018 17:48:21 -0700 Subject: LSM: Introduce enum lsm_order In preparation for distinguishing the "capability" LSM from other LSMs, it must be ordered first. This introduces LSM_ORDER_MUTABLE for the general LSMs and LSM_ORDER_FIRST for capability. In the future LSM_ORDER_LAST for could be added for anything that must run last (e.g. Landlock may use this). Signed-off-by: Kees Cook --- include/linux/lsm_hooks.h | 6 ++++++ security/security.c | 9 ++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 2849e9b2c01d..27d4db9588bb 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2045,8 +2045,14 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, #define LSM_FLAG_LEGACY_MAJOR BIT(0) #define LSM_FLAG_EXCLUSIVE BIT(1) +enum lsm_order { + LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ + LSM_ORDER_MUTABLE = 0, +}; + struct lsm_info { const char *name; /* Required. */ + enum lsm_order order; /* Optional: default is LSM_ORDER_MUTABLE */ unsigned long flags; /* Optional: flags describing LSM */ int *enabled; /* Optional: controlled by CONFIG_LSM */ int (*init)(void); /* Required. */ diff --git a/security/security.c b/security/security.c index 35f93b7c585b..8b673bb2a0dd 100644 --- a/security/security.c +++ b/security/security.c @@ -174,6 +174,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) struct lsm_info *lsm; char *sep, *name, *next; + /* LSM_ORDER_FIRST is always first. */ + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { + if (lsm->order == LSM_ORDER_FIRST) + append_ordered_lsm(lsm, "first"); + } + /* Process "security=", if given. */ if (chosen_major_lsm) { struct lsm_info *major; @@ -202,7 +208,8 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) bool found = false; for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { - if (strcmp(lsm->name, name) == 0) { + if (lsm->order == LSM_ORDER_MUTABLE && + strcmp(lsm->name, name) == 0) { append_ordered_lsm(lsm, origin); found = true; } -- cgit v1.2.3-59-g8ed1b