TOMOYO: Use RCU primitives for list operation
Replace list operation with RCU primitives and replace
down_read()/up_read() with srcu_read_lock()/srcu_read_unlock().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index ad9555f..714daa3 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -76,8 +76,18 @@
* Execute permission is checked against pathname passed to do_execve()
* using current domain.
*/
- if (!domain)
- return tomoyo_find_next_domain(bprm);
+ if (!domain) {
+ /*
+ * We will need to protect whole execve() operation when GC
+ * starts kfree()ing "struct tomoyo_domain_info" because
+ * bprm->cred->security points to "struct tomoyo_domain_info"
+ * but "struct tomoyo_domain_info" does not have a refcounter.
+ */
+ const int idx = tomoyo_read_lock();
+ const int err = tomoyo_find_next_domain(bprm);
+ tomoyo_read_unlock(idx);
+ return err;
+ }
/*
* Read permission is checked against interpreters using next domain.
* '1' is the result of open_to_namei_flags(O_RDONLY).
@@ -278,6 +288,9 @@
.sb_pivotroot = tomoyo_sb_pivotroot,
};
+/* Lock for GC. */
+struct srcu_struct tomoyo_ss;
+
static int __init tomoyo_init(void)
{
struct cred *cred = (struct cred *) current_cred();
@@ -285,7 +298,8 @@
if (!security_module_enable(&tomoyo_security_ops))
return 0;
/* register ourselves with the security framework */
- if (register_security(&tomoyo_security_ops))
+ if (register_security(&tomoyo_security_ops) ||
+ init_srcu_struct(&tomoyo_ss))
panic("Failure registering TOMOYO Linux");
printk(KERN_INFO "TOMOYO Linux initialized\n");
cred->security = &tomoyo_kernel_domain;