audit: fix exe_file access in audit_exe_compare (5efc2443) · Commits · 戴 / test

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:

Mateusz Guzik <mguzik@redhat.com> Acked-by:

Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by:

Richard Guy Briggs <rgb@redhat.com> Cc: <stable@vger.kernel.org> # 4.3.x Signed-off-by:

Paul Moore <paul@paul-moore.com>

kernel/audit_watch.c

+5 −3

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

		#include <linux/file.h>
		#include <linux/kernel.h>
		#include <linux/audit.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;
		dev_t dev;

		rcu_read_lock();
		exe_file = rcu_dereference(tsk->mm->exe_file);
		exe_file = get_task_exe_file(tsk);
		if (!exe_file)
		return 0;
		ino = exe_file->f_inode->i_ino;
		dev = exe_file->f_inode->i_sb->s_dev;
		rcu_read_unlock();
		fput(exe_file);
		return audit_mark_compare(mark, ino, dev);
		}

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