Commit 2e21865f authored by David Howells's avatar David Howells
Browse files

keys: sparse: Fix key_fs[ug]id_changed() 



Sparse warnings are incurred by key_fs[ug]id_changed() due to unprotected
accesses of tsk->cred, which is marked __rcu.

Fix this by passing the new cred struct to these functions from
commit_creds() rather than the task pointer.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJames Morris <jamorris@linux.microsoft.com>
parent a188339c

include/linux/key.h

+4 −4
Original line number Diff line number Diff line
@@ -402,8 +402,8 @@ extern struct ctl_table key_sysctls[]; 
 * the userspace interface

 */

extern int install_thread_keyring_to_cred(struct cred *cred);

extern void key_fsuid_changed(struct task_struct *tsk);

extern void key_fsgid_changed(struct task_struct *tsk);

extern void key_fsuid_changed(struct cred *new_cred);

extern void key_fsgid_changed(struct cred *new_cred);

extern void key_init(void);



#else /* CONFIG_KEYS */
@@ -418,8 +418,8 @@ extern void key_init(void); 
#define make_key_ref(k, p)		NULL

#define key_ref_to_ptr(k)		NULL

#define is_key_possessed(k)		0

#define key_fsuid_changed(t)		do { } while(0)

#define key_fsgid_changed(t)		do { } while(0)

#define key_fsuid_changed(c)		do { } while(0)

#define key_fsgid_changed(c)		do { } while(0)

#define key_init()			do { } while(0)



#endif /* CONFIG_KEYS */

kernel/cred.c

+2 −2
Original line number Diff line number Diff line
@@ -455,9 +455,9 @@ int commit_creds(struct cred *new) 


	/* alter the thread keyring */

	if (!uid_eq(new->fsuid, old->fsuid))

		key_fsuid_changed(task);

		key_fsuid_changed(new);

	if (!gid_eq(new->fsgid, old->fsgid))

		key_fsgid_changed(task);

		key_fsgid_changed(new);



	/* do it

	 * RLIMIT_NPROC limits on user->processes have already been checked

security/keys/process_keys.c

+10 −12
Original line number Diff line number Diff line
@@ -293,28 +293,26 @@ static int install_session_keyring(struct key *keyring) 
/*

 * Handle the fsuid changing.

 */

void key_fsuid_changed(struct task_struct *tsk)

void key_fsuid_changed(struct cred *new_cred)

{

	/* update the ownership of the thread keyring */

	BUG_ON(!tsk->cred);

	if (tsk->cred->thread_keyring) {

		down_write(&tsk->cred->thread_keyring->sem);

		tsk->cred->thread_keyring->uid = tsk->cred->fsuid;

		up_write(&tsk->cred->thread_keyring->sem);

	if (new_cred->thread_keyring) {

		down_write(&new_cred->thread_keyring->sem);

		new_cred->thread_keyring->uid = new_cred->fsuid;

		up_write(&new_cred->thread_keyring->sem);

	}

}



/*

 * Handle the fsgid changing.

 */

void key_fsgid_changed(struct task_struct *tsk)

void key_fsgid_changed(struct cred *new_cred)

{

	/* update the ownership of the thread keyring */

	BUG_ON(!tsk->cred);

	if (tsk->cred->thread_keyring) {

		down_write(&tsk->cred->thread_keyring->sem);

		tsk->cred->thread_keyring->gid = tsk->cred->fsgid;

		up_write(&tsk->cred->thread_keyring->sem);

	if (new_cred->thread_keyring) {

		down_write(&new_cred->thread_keyring->sem);

		new_cred->thread_keyring->gid = new_cred->fsgid;

		up_write(&new_cred->thread_keyring->sem);

	}

}

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