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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2017-03-24 20:46:33 +0900
committerJames Morris <james.l.morris@oracle.com>2017-03-28 11:05:14 +1100
commite4e55b47ed9ae2c05ff062601ff6dacbe9dc4775 (patch)
tree24a332cc81000bf9bbd1e4db4dc17d16f29e1da8 /security
parent840c91dc6a13b160f5b6e5c79c430dffac11c945 (diff)
LSM: Revive security_task_alloc() hook and per "struct task_struct" security blob.
We switched from "struct task_struct"->security to "struct cred"->security in Linux 2.6.29. But not all LSM modules were happy with that change. TOMOYO LSM module is an example which want to use per "struct task_struct" security blob, for TOMOYO's security context is defined based on "struct task_struct" rather than "struct cred". AppArmor LSM module is another example which want to use it, for AppArmor is currently abusing the cred a little bit to store the change_hat and setexeccon info. Although security_task_free() hook was revived in Linux 3.4 because Yama LSM module wanted to release per "struct task_struct" security blob, security_task_alloc() hook and "struct task_struct"->security field were not revived. Nowadays, we are getting proposals of lightweight LSM modules which want to use per "struct task_struct" security blob. We are already allowing multiple concurrent LSM modules (up to one fully armored module which uses "struct cred"->security field or exclusive hooks like security_xfrm_state_pol_flow_match(), plus unlimited number of lightweight modules which do not use "struct cred"->security nor exclusive hooks) as long as they are built into the kernel. But this patch does not implement variable length "struct task_struct"->security field which will become needed when multiple LSM modules want to use "struct task_struct"-> security field. Although it won't be difficult to implement variable length "struct task_struct"->security field, let's think about it after we merged this patch. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Serge Hallyn <serge@hallyn.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Tested-by: Djalal Harouni <tixxdz@gmail.com> Acked-by: José Bollo <jobol@nonadev.net> Cc: Paul Moore <paul@paul-moore.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Eric Paris <eparis@parisplace.org> Cc: Kees Cook <keescook@chromium.org> Cc: James Morris <james.l.morris@oracle.com> Cc: José Bollo <jobol@nonadev.net> Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'security')
-rw-r--r--security/security.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c
index 2f15488dc6bc..549bddcc2116 100644
--- a/security/security.c
+++ b/security/security.c
@@ -937,6 +937,11 @@ int security_task_create(unsigned long clone_flags)
return call_int_hook(task_create, 0, clone_flags);
}
+int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
+{
+ return call_int_hook(task_alloc, 0, task, clone_flags);
+}
+
void security_task_free(struct task_struct *task)
{
call_void_hook(task_free, task);