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Commit cb622bbb authored by Ahmed S. Darwish's avatar Ahmed S. Darwish Committed by Linus Torvalds
Browse files

smackfs: remove redundant lock, fix open(,O_RDWR) 



Older smackfs was parsing MAC rules by characters, thus a need of locking
write sessions on open() was needed.  This lock is no longer useful now since
each rule is handled by a single write() call.

This is also a bugfix since seq_open() was not called if an open() O_RDWR flag
was given, leading to a seq_read() without an initialized seq_file, thus an
Oops.

Signed-off-by: default avatarAhmed S. Darwish <darwish.07@gmail.com>
Reported-by: default avatarJonathan Corbet <corbet@lwn.net>
Acked-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 58336114

security/smack/smackfs.c

+2 −33
Original line number Original line Diff line number Diff line
@@ -73,11 +73,6 @@ struct smk_list_entry *smack_list; 




#define	SEQ_READ_FINISHED	1

#define	SEQ_READ_FINISHED	1





/*

 * Disable concurrent writing open() operations

 */

static struct semaphore smack_write_sem;



/*

/*

 * Values for parsing cipso rules

 * Values for parsing cipso rules

 * SMK_DIGITLEN: Length of a digit field in a rule.

 * SMK_DIGITLEN: Length of a digit field in a rule.
@@ -168,32 +163,7 @@ static struct seq_operations load_seq_ops = { 
 */

 */

static int smk_open_load(struct inode *inode, struct file *file)

static int smk_open_load(struct inode *inode, struct file *file)

{

{

	if ((file->f_flags & O_ACCMODE) == O_RDONLY)

	return seq_open(file, &load_seq_ops);

	return seq_open(file, &load_seq_ops);



	if (down_interruptible(&smack_write_sem))

		return -ERESTARTSYS;



	return 0;

}



/**

 * smk_release_load - release() for /smack/load

 * @inode: inode structure representing file

 * @file: "load" file pointer

 *

 * For a reading session, use the seq_file release

 * implementation.

 * Otherwise, we are at the end of a writing session so

 * clean everything up.

 */

static int smk_release_load(struct inode *inode, struct file *file)

{

	if ((file->f_flags & O_ACCMODE) == O_RDONLY)

		return seq_release(inode, file);



	up(&smack_write_sem);

	return 0;

}

}





/**

/**
@@ -341,7 +311,7 @@ static const struct file_operations smk_load_ops = { 
	.read		= seq_read,

	.read		= seq_read,

	.llseek         = seq_lseek,

	.llseek         = seq_lseek,

	.write		= smk_write_load,

	.write		= smk_write_load,

	.release        = smk_release_load,

	.release        = seq_release,

};

};





/**

/**
@@ -1011,7 +981,6 @@ static int __init init_smk_fs(void) 
		}

		}

	}

	}





	sema_init(&smack_write_sem, 1);

	smk_cipso_doi();

	smk_cipso_doi();

	smk_unlbl_ambient(NULL);

	smk_unlbl_ambient(NULL);