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authorDavidlohr Bueso <dave@stgolabs.net>2015-02-22 18:20:09 -0800
committerPaul Moore <pmoore@redhat.com>2015-02-23 16:57:00 -0500
commit5b28255278dd7e594c8dde317c2498b7dcbf900d (patch)
tree62cf451d72fc542652da81f7d9555a52afc136ed /kernel/audit.c
parent4766b199ef9e1ca6316ee4f8f9d80c2ba1ed0290 (diff)
downloadlinux-sh-5b28255278dd7e594c8dde317c2498b7dcbf900d.tar.gz
audit: reduce mmap_sem hold for mm->exe_file
The mm->exe_file is currently serialized with mmap_sem (shared) in order to both safely (1) read the file and (2) audit it via audit_log_d_path(). Good users will, on the other hand, make use of the more standard get_mm_exe_file(), requiring only holding the mmap_sem to read the value, and relying on reference counting to make sure that the exe file won't dissapear underneath us. Additionally, upon NULL return of get_mm_exe_file, we also call audit_log_format(ab, " exe=(null)"). Signed-off-by: Davidlohr Bueso <dbueso@suse.de> [PM: tweaked subject line] Signed-off-by: Paul Moore <pmoore@redhat.com>
Diffstat (limited to 'kernel/audit.c')
-rw-r--r--kernel/audit.c22
1 files changed, 14 insertions, 8 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index 684b51d612a3..52ee8eee0e07 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -43,6 +43,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/file.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/atomic.h>
@@ -1851,15 +1852,20 @@ EXPORT_SYMBOL(audit_log_task_context);
void audit_log_d_path_exe(struct audit_buffer *ab,
struct mm_struct *mm)
{
- if (!mm) {
- audit_log_format(ab, " exe=(null)");
- return;
- }
+ struct file *exe_file;
+
+ if (!mm)
+ goto out_null;
- down_read(&mm->mmap_sem);
- if (mm->exe_file)
- audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
- up_read(&mm->mmap_sem);
+ exe_file = get_mm_exe_file(mm);
+ if (!exe_file)
+ goto out_null;
+
+ audit_log_d_path(ab, " exe=", &exe_file->f_path);
+ fput(exe_file);
+ return;
+out_null:
+ audit_log_format(ab, " exe=(null)");
}
void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)