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Commit b2ea47a7 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Revert "cred: switch to using atomic_long_t" 



This reverts commit 123e44b9 which is
commit f8fa5d76925991976b3e7076f9d1052515ec1fca upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way.

Bug: 161946584
Bug: 317347552
Change-Id: I9eb52866bc3b2a9f02e3f7fbee0bacbcc06b0849
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent db2162fa

include/linux/cred.h

+3 −3
Original line number Diff line number Diff line
@@ -114,7 +114,7 @@ static inline int groups_search(const struct group_info *group_info, kgid_t grp) 
 * same context as task->real_cred.

 */

struct cred {

	atomic_long_t	usage;

	atomic_t	usage;

#ifdef CONFIG_DEBUG_CREDENTIALS

	atomic_t	subscribers;	/* number of processes subscribed */

	void		*put_addr;
@@ -231,7 +231,7 @@ static inline bool cap_ambient_invariant_ok(const struct cred *cred) 
 */

static inline struct cred *get_new_cred(struct cred *cred)

{

	atomic_long_inc(&cred->usage);

	atomic_inc(&cred->usage);

	return cred;

}
@@ -275,7 +275,7 @@ static inline void put_cred(const struct cred *_cred) 


	if (cred) {

		validate_creds(cred);

		if (atomic_long_dec_and_test(&(cred)->usage))

		if (atomic_dec_and_test(&(cred)->usage))

			__put_cred(cred);

	}

}

kernel/cred.c

+33 −33
Original line number Diff line number Diff line
@@ -101,17 +101,17 @@ static void put_cred_rcu(struct rcu_head *rcu) 


#ifdef CONFIG_DEBUG_CREDENTIALS

	if (cred->magic != CRED_MAGIC_DEAD ||

	    atomic_long_read(&cred->usage) != 0 ||

	    atomic_read(&cred->usage) != 0 ||

	    read_cred_subscribers(cred) != 0)

		panic("CRED: put_cred_rcu() sees %p with"

		      " mag %x, put %p, usage %ld, subscr %d\n",

		      " mag %x, put %p, usage %d, subscr %d\n",

		      cred, cred->magic, cred->put_addr,

		      atomic_long_read(&cred->usage),

		      atomic_read(&cred->usage),

		      read_cred_subscribers(cred));

#else

	if (atomic_long_read(&cred->usage) != 0)

		panic("CRED: put_cred_rcu() sees %p with usage %ld\n",

		      cred, atomic_long_read(&cred->usage));

	if (atomic_read(&cred->usage) != 0)

		panic("CRED: put_cred_rcu() sees %p with usage %d\n",

		      cred, atomic_read(&cred->usage));

#endif



	security_cred_free(cred);
@@ -134,11 +134,11 @@ static void put_cred_rcu(struct rcu_head *rcu) 
 */

void __put_cred(struct cred *cred)

{

	kdebug("__put_cred(%p{%ld,%d})", cred,

	       atomic_long_read(&cred->usage),

	kdebug("__put_cred(%p{%d,%d})", cred,

	       atomic_read(&cred->usage),

	       read_cred_subscribers(cred));



	BUG_ON(atomic_long_read(&cred->usage) != 0);

	BUG_ON(atomic_read(&cred->usage) != 0);

#ifdef CONFIG_DEBUG_CREDENTIALS

	BUG_ON(read_cred_subscribers(cred) != 0);

	cred->magic = CRED_MAGIC_DEAD;
@@ -161,8 +161,8 @@ void exit_creds(struct task_struct *tsk) 
{

	struct cred *cred;



	kdebug("exit_creds(%u,%p,%p,{%ld,%d})", tsk->pid, tsk->real_cred, tsk->cred,

	       atomic_long_read(&tsk->cred->usage),

	kdebug("exit_creds(%u,%p,%p,{%d,%d})", tsk->pid, tsk->real_cred, tsk->cred,

	       atomic_read(&tsk->cred->usage),

	       read_cred_subscribers(tsk->cred));



	cred = (struct cred *) tsk->real_cred;
@@ -197,7 +197,7 @@ const struct cred *get_task_cred(struct task_struct *task) 
	do {

		cred = __task_cred((task));

		BUG_ON(!cred);

	} while (!atomic_long_inc_not_zero(&((struct cred *)cred)->usage));

	} while (!atomic_inc_not_zero(&((struct cred *)cred)->usage));



	rcu_read_unlock();

	return cred;
@@ -215,7 +215,7 @@ struct cred *cred_alloc_blank(void) 
	if (!new)

		return NULL;



	atomic_long_set(&new->usage, 1);

	atomic_set(&new->usage, 1);

#ifdef CONFIG_DEBUG_CREDENTIALS

	new->magic = CRED_MAGIC;

#endif
@@ -262,7 +262,7 @@ struct cred *prepare_creds(void) 
	memcpy(new, old, sizeof(struct cred));



	new->non_rcu = 0;

	atomic_long_set(&new->usage, 1);

	atomic_set(&new->usage, 1);

	set_cred_subscribers(new, 0);

	get_group_info(new->group_info);

	get_uid(new->user);
@@ -338,8 +338,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) 
		p->real_cred = get_cred(p->cred);

		get_cred(p->cred);

		alter_cred_subscribers(p->cred, 2);

		kdebug("share_creds(%p{%ld,%d})",

		       p->cred, atomic_long_read(&p->cred->usage),

		kdebug("share_creds(%p{%d,%d})",

		       p->cred, atomic_read(&p->cred->usage),

		       read_cred_subscribers(p->cred));

		atomic_inc(&p->cred->user->processes);

		return 0;
@@ -429,8 +429,8 @@ int commit_creds(struct cred *new) 
	struct task_struct *task = current;

	const struct cred *old = task->real_cred;



	kdebug("commit_creds(%p{%ld,%d})", new,

	       atomic_long_read(&new->usage),

	kdebug("commit_creds(%p{%d,%d})", new,

	       atomic_read(&new->usage),

	       read_cred_subscribers(new));



	BUG_ON(task->cred != old);
@@ -439,7 +439,7 @@ int commit_creds(struct cred *new) 
	validate_creds(old);

	validate_creds(new);

#endif

	BUG_ON(atomic_long_read(&new->usage) < 1);

	BUG_ON(atomic_read(&new->usage) < 1);



	get_cred(new); /* we will require a ref for the subj creds too */
@@ -512,14 +512,14 @@ EXPORT_SYMBOL(commit_creds); 
 */

void abort_creds(struct cred *new)

{

	kdebug("abort_creds(%p{%ld,%d})", new,

	       atomic_long_read(&new->usage),

	kdebug("abort_creds(%p{%d,%d})", new,

	       atomic_read(&new->usage),

	       read_cred_subscribers(new));



#ifdef CONFIG_DEBUG_CREDENTIALS

	BUG_ON(read_cred_subscribers(new) != 0);

#endif

	BUG_ON(atomic_long_read(&new->usage) < 1);

	BUG_ON(atomic_read(&new->usage) < 1);

	put_cred(new);

}

EXPORT_SYMBOL(abort_creds);
@@ -535,8 +535,8 @@ const struct cred *override_creds(const struct cred *new) 
{

	const struct cred *old = current->cred;



	kdebug("override_creds(%p{%ld,%d})", new,

	       atomic_long_read(&new->usage),

	kdebug("override_creds(%p{%d,%d})", new,

	       atomic_read(&new->usage),

	       read_cred_subscribers(new));



	validate_creds(old);
@@ -558,8 +558,8 @@ const struct cred *override_creds(const struct cred *new) 
	rcu_assign_pointer(current->cred, new);

	alter_cred_subscribers(old, -1);



	kdebug("override_creds() = %p{%ld,%d}", old,

	       atomic_long_read(&old->usage),

	kdebug("override_creds() = %p{%d,%d}", old,

	       atomic_read(&old->usage),

	       read_cred_subscribers(old));

	return old;

}
@@ -576,8 +576,8 @@ void revert_creds(const struct cred *old) 
{

	const struct cred *override = current->cred;



	kdebug("revert_creds(%p{%ld,%d})", old,

	       atomic_long_read(&old->usage),

	kdebug("revert_creds(%p{%d,%d})", old,

	       atomic_read(&old->usage),

	       read_cred_subscribers(old));



	validate_creds(old);
@@ -637,7 +637,7 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon) 


	*new = *old;

	new->non_rcu = 0;

	atomic_long_set(&new->usage, 1);

	atomic_set(&new->usage, 1);

	set_cred_subscribers(new, 0);

	get_uid(new->user);

	get_user_ns(new->user_ns);
@@ -760,8 +760,8 @@ static void dump_invalid_creds(const struct cred *cred, const char *label, 
	       cred == tsk->cred ? "[eff]" : "");

	printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n",

	       cred->magic, cred->put_addr);

	printk(KERN_ERR "CRED: ->usage=%ld, subscr=%d\n",

	       atomic_long_read(&cred->usage),

	printk(KERN_ERR "CRED: ->usage=%d, subscr=%d\n",

	       atomic_read(&cred->usage),

	       read_cred_subscribers(cred));

	printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n",

		from_kuid_munged(&init_user_ns, cred->uid),
@@ -833,9 +833,9 @@ EXPORT_SYMBOL(__validate_process_creds); 
 */

void validate_creds_for_do_exit(struct task_struct *tsk)

{

	kdebug("validate_creds_for_do_exit(%p,%p{%ld,%d})",

	kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})",

	       tsk->real_cred, tsk->cred,

	       atomic_long_read(&tsk->cred->usage),

	       atomic_read(&tsk->cred->usage),

	       read_cred_subscribers(tsk->cred));



	__validate_process_creds(tsk, __FILE__, __LINE__);