diff options
| author | Davidlohr Bueso <dave@stgolabs.net> | 2015-02-22 18:20:09 -0800 |
|---|---|---|
| committer | Paul Moore <pmoore@redhat.com> | 2015-02-23 16:57:00 -0500 |
| commit | 5b28255278dd7e594c8dde317c2498b7dcbf900d (patch) | |
| tree | 62cf451d72fc542652da81f7d9555a52afc136ed | |
| parent | 4766b199ef9e1ca6316ee4f8f9d80c2ba1ed0290 (diff) | |
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>
| -rw-r--r-- | kernel/audit.c | 22 |
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) |