From: Cyrill Gorcunov <gorcunov@openvz.org>
To: linux-kernel@vger.kernel.org
Cc: gorcunov@openvz.org, Kees Cook <keescook@chromium.org>,
Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andrew Vagin <avagin@openvz.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Pavel Emelyanov <xemul@parallels.com>,
Vasiliy Kulikov <segoon@openwall.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: [RFC 1/2] prctl: PR_SET_MM -- Factor out mmap_sem when update mm::exe_file
Date: Thu, 03 Jul 2014 18:33:19 +0400 [thread overview]
Message-ID: <20140703151102.745184283@openvz.org> (raw)
In-Reply-To: 20140703143318.568554771@openvz.org
[-- Attachment #1: prctl-rework-prctl_set_mm_exe_file-locked --]
[-- Type: text/plain, Size: 2529 bytes --]
Instead of taking mm->mmap_sem inside prctl_set_mm_exe_file move
it out of and rename the helper to prctl_set_mm_exe_file_locked.
This will allow to reuse this function in a next patch.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
---
kernel/sys.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
Index: linux-2.6.git/kernel/sys.c
===================================================================
--- linux-2.6.git.orig/kernel/sys.c
+++ linux-2.6.git/kernel/sys.c
@@ -1628,12 +1628,14 @@ SYSCALL_DEFINE1(umask, int, mask)
return mask;
}
-static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
+static int prctl_set_mm_exe_file_locked(struct mm_struct *mm, unsigned int fd)
{
struct fd exe;
struct inode *inode;
int err;
+ VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+
exe = fdget(fd);
if (!exe.file)
return -EBADF;
@@ -1654,8 +1656,6 @@ static int prctl_set_mm_exe_file(struct
if (err)
goto exit;
- down_write(&mm->mmap_sem);
-
/*
* Forbid mm->exe_file change if old file still mapped.
*/
@@ -1667,7 +1667,7 @@ static int prctl_set_mm_exe_file(struct
if (vma->vm_file &&
path_equal(&vma->vm_file->f_path,
&mm->exe_file->f_path))
- goto exit_unlock;
+ goto exit;
}
/*
@@ -1678,13 +1678,10 @@ static int prctl_set_mm_exe_file(struct
*/
err = -EPERM;
if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
- goto exit_unlock;
+ goto exit;
err = 0;
set_mm_exe_file(mm, exe.file); /* this grabs a reference to exe.file */
-exit_unlock:
- up_write(&mm->mmap_sem);
-
exit:
fdput(exe);
return err;
@@ -1704,8 +1701,12 @@ static int prctl_set_mm(int opt, unsigne
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
- if (opt == PR_SET_MM_EXE_FILE)
- return prctl_set_mm_exe_file(mm, (unsigned int)addr);
+ if (opt == PR_SET_MM_EXE_FILE) {
+ down_write(&mm->mmap_sem);
+ error = prctl_set_mm_exe_file_locked(mm, (unsigned int)addr);
+ up_write(&mm->mmap_sem);
+ return error;
+ }
if (addr >= TASK_SIZE || addr < mmap_min_addr)
return -EINVAL;
next prev parent reply other threads:[~2014-07-03 15:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-03 14:33 [RFC 0/2] prctl: set-mm -- Rework interface Cyrill Gorcunov
2014-07-03 14:33 ` Cyrill Gorcunov [this message]
2014-07-03 14:33 ` [RFC 2/2] prctl: PR_SET_MM -- Introduce PR_SET_MM_MAP operation Cyrill Gorcunov
2014-07-03 20:34 ` Cyrill Gorcunov
2014-07-04 7:52 ` Andrew Vagin
2014-07-04 8:11 ` Cyrill Gorcunov
2014-07-08 19:08 ` Cyrill Gorcunov
2014-07-08 21:38 ` Andrew Morton
2014-07-08 22:13 ` Cyrill Gorcunov
2014-07-09 14:13 ` Cyrill Gorcunov
2014-07-09 14:53 ` Kees Cook
2014-07-09 15:06 ` Cyrill Gorcunov
2014-07-11 17:36 ` Cyrill Gorcunov
2014-07-22 20:07 ` Kees Cook
2014-07-22 20:36 ` Cyrill Gorcunov
2014-07-24 13:48 ` Andrew Vagin
2014-07-24 16:42 ` Cyrill Gorcunov
2014-07-24 18:44 ` Kees Cook
2014-07-24 18:50 ` Cyrill Gorcunov
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