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

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
...@@ -19,6 +19,7 @@ ...@@ -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) ...@@ -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);
} }
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