security: Add a cred_getsecid hook

For IMA purposes, we want to be able to obtain the prepared secid in the
bprm structure before the credentials are committed. Add a cred_getsecid
hook that makes this possible.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 8abd542c6b7c..b7d4473edbde 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3844,6 +3844,11 @@ static void selinux_cred_transfer(struct cred *new, const struct cred *old)
         *tsec = *old_tsec;
 }
 
+static void selinux_cred_getsecid(const struct cred *c, u32 *secid)
+{
+        *secid = cred_sid(c);
+}
+
 /*
  * set the security data for a kernel service
  * - all the creation contexts are set to unlabelled
@@ -6482,6 +6487,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
         LSM_HOOK_INIT(cred_free, selinux_cred_free),
         LSM_HOOK_INIT(cred_prepare, selinux_cred_prepare),
         LSM_HOOK_INIT(cred_transfer, selinux_cred_transfer),
+        LSM_HOOK_INIT(cred_getsecid, selinux_cred_getsecid),
         LSM_HOOK_INIT(kernel_act_as, selinux_kernel_act_as),
         LSM_HOOK_INIT(kernel_create_files_as, selinux_kernel_create_files_as),
         LSM_HOOK_INIT(kernel_module_request, selinux_kernel_module_request),