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Commit 5efc2443 authored by Mateusz Guzik's avatar Mateusz Guzik Committed by Paul Moore
Browse files

audit: fix exe_file access in audit_exe_compare 



Prior to the change the function would blindly deference mm, exe_file
and exe_file->f_inode, each of which could have been NULL or freed.

Use get_task_exe_file to safely obtain stable exe_file.

Signed-off-by: default avatarMateusz Guzik <mguzik@redhat.com>
Acked-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: default avatarRichard Guy Briggs <rgb@redhat.com>
Cc: <stable@vger.kernel.org> # 4.3.x
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent cd81a917

kernel/audit_watch.c

+5 −3
Original line number Original line Diff line number Diff line
@@ -19,6 +19,7 @@ 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

 */





#include <linux/file.h>

#include <linux/kernel.h>

#include <linux/kernel.h>

#include <linux/audit.h>

#include <linux/audit.h>

#include <linux/kthread.h>

#include <linux/kthread.h>
@@ -544,10 +545,11 @@ int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark) 
	unsigned long ino;

	unsigned long ino;

	dev_t dev;

	dev_t dev;





	rcu_read_lock();

	exe_file = get_task_exe_file(tsk);

	exe_file = rcu_dereference(tsk->mm->exe_file);

	if (!exe_file)

		return 0;

	ino = exe_file->f_inode->i_ino;

	ino = exe_file->f_inode->i_ino;

	dev = exe_file->f_inode->i_sb->s_dev;

	dev = exe_file->f_inode->i_sb->s_dev;

	rcu_read_unlock();

	fput(exe_file);

	return audit_mark_compare(mark, ino, dev);

	return audit_mark_compare(mark, ino, dev);

}
 
}