Commit e044374a authored by Amir Goldstein's avatar Amir Goldstein Committed by Mimi Zohar
Browse files

ima: annotate iint mutex to avoid lockdep false positive warnings 



It is not clear that IMA should be nested at all, but as long is it
measures files both on overlayfs and on underlying fs, we need to
annotate the iint mutex to avoid lockdep false positives related to
IMA + overlayfs, same as overlayfs annotates the inode mutex.

Reported-and-tested-by: default avatar <syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMimi Zohar <zohar@linux.ibm.com>
parent 94f6f055

security/integrity/iint.c

+37 −11
Original line number Diff line number Diff line
@@ -66,9 +66,32 @@ struct integrity_iint_cache *integrity_iint_find(struct inode *inode) 
	return iint;

}



static void iint_free(struct integrity_iint_cache *iint)

#define IMA_MAX_NESTING (FILESYSTEM_MAX_STACK_DEPTH+1)



/*

 * It is not clear that IMA should be nested at all, but as long is it measures

 * files both on overlayfs and on underlying fs, we need to annotate the iint

 * mutex to avoid lockdep false positives related to IMA + overlayfs.

 * See ovl_lockdep_annotate_inode_mutex_key() for more details.

 */

static inline void iint_lockdep_annotate(struct integrity_iint_cache *iint,

					 struct inode *inode)

{

#ifdef CONFIG_LOCKDEP

	static struct lock_class_key iint_mutex_key[IMA_MAX_NESTING];



	int depth = inode->i_sb->s_stack_depth;



	if (WARN_ON_ONCE(depth < 0 || depth >= IMA_MAX_NESTING))

		depth = 0;



	lockdep_set_class(&iint->mutex, &iint_mutex_key[depth]);

#endif

}



static void iint_init_always(struct integrity_iint_cache *iint,

			     struct inode *inode)

{

	kfree(iint->ima_hash);

	iint->ima_hash = NULL;

	iint->version = 0;

	iint->flags = 0UL;
@@ -80,6 +103,14 @@ static void iint_free(struct integrity_iint_cache *iint) 
	iint->ima_creds_status = INTEGRITY_UNKNOWN;

	iint->evm_status = INTEGRITY_UNKNOWN;

	iint->measured_pcrs = 0;

	mutex_init(&iint->mutex);

	iint_lockdep_annotate(iint, inode);

}



static void iint_free(struct integrity_iint_cache *iint)

{

	kfree(iint->ima_hash);

	mutex_destroy(&iint->mutex);

	kmem_cache_free(iint_cache, iint);

}
@@ -104,6 +135,8 @@ struct integrity_iint_cache *integrity_inode_get(struct inode *inode) 
	if (!iint)

		return NULL;



	iint_init_always(iint, inode);



	write_lock(&integrity_iint_lock);



	p = &integrity_iint_tree.rb_node;
@@ -153,25 +186,18 @@ void integrity_inode_free(struct inode *inode) 
	iint_free(iint);

}



static void init_once(void *foo)

static void iint_init_once(void *foo)

{

	struct integrity_iint_cache *iint = (struct integrity_iint_cache *) foo;



	memset(iint, 0, sizeof(*iint));

	iint->ima_file_status = INTEGRITY_UNKNOWN;

	iint->ima_mmap_status = INTEGRITY_UNKNOWN;

	iint->ima_bprm_status = INTEGRITY_UNKNOWN;

	iint->ima_read_status = INTEGRITY_UNKNOWN;

	iint->ima_creds_status = INTEGRITY_UNKNOWN;

	iint->evm_status = INTEGRITY_UNKNOWN;

	mutex_init(&iint->mutex);

}



static int __init integrity_iintcache_init(void)

{

	iint_cache =

	    kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),

			      0, SLAB_PANIC, init_once);

			      0, SLAB_PANIC, iint_init_once);

	return 0;

}

DEFINE_LSM(integrity) = {