Commit fdb8ebb7 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by James Morris

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: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 86fc80f1
This diff is collapsed.
......@@ -269,6 +269,8 @@ struct tomoyo_io_buffer {
int (*write) (struct tomoyo_io_buffer *);
/* Exclusive lock for this structure. */
struct mutex io_sem;
/* Index returned by tomoyo_read_lock(). */
int reader_idx;
/* The position currently reading from. */
struct list_head *read_var1;
/* Extra variables for reading. */
......@@ -446,16 +448,28 @@ extern struct tomoyo_domain_info tomoyo_kernel_domain;
* @cookie: the &struct list_head to use as a cookie.
* @head: the head for your list.
*
* Same with list_for_each() except that this primitive uses @cookie
* Same with list_for_each_rcu() except that this primitive uses @cookie
* so that we can continue iteration.
* @cookie must be NULL when iteration starts, and @cookie will become
* NULL when iteration finishes.
*/
#define list_for_each_cookie(pos, cookie, head) \
for (({ if (!cookie) \
cookie = head; }), \
pos = (cookie)->next; \
prefetch(pos->next), pos != (head) || ((cookie) = NULL); \
(cookie) = pos, pos = pos->next)
#define list_for_each_cookie(pos, cookie, head) \
for (({ if (!cookie) \
cookie = head; }), \
pos = rcu_dereference((cookie)->next); \
prefetch(pos->next), pos != (head) || ((cookie) = NULL); \
(cookie) = pos, pos = rcu_dereference(pos->next))
extern struct srcu_struct tomoyo_ss;
static inline int tomoyo_read_lock(void)
{
return srcu_read_lock(&tomoyo_ss);
}
static inline void tomoyo_read_unlock(int idx)
{
srcu_read_unlock(&tomoyo_ss, idx);
}
#endif /* !defined(_SECURITY_TOMOYO_COMMON_H) */
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This diff is collapsed.
......@@ -402,11 +402,13 @@ void __init tomoyo_realpath_init(void)
INIT_LIST_HEAD(&tomoyo_name_list[i]);
INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
tomoyo_kernel_domain.domainname = tomoyo_save_name(TOMOYO_ROOT_NAME);
list_add_tail(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
down_read(&tomoyo_domain_list_lock);
/*
* tomoyo_read_lock() is not needed because this function is
* called before the first "delete" request.
*/
list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain)
panic("Can't register tomoyo_kernel_domain");
up_read(&tomoyo_domain_list_lock);
}
/* Memory allocated for temporary purpose. */
......
......@@ -76,8 +76,18 @@ static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
* 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 @@ static struct security_operations tomoyo_security_ops = {
.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 @@ static int __init tomoyo_init(void)
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;
......
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