From: Cyrill Gorcunov <gorcu...@openvz.org>
ML: 71fe97e185040c5dac3216cd54e186dfa534efa0
Instead of taking mm->mmap_sem inside prctl_set_mm_exe_file() move it out
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 <gorcu...@openvz.org>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Tejun Heo <t...@kernel.org>
Cc: Andrew Vagin <ava...@openvz.org>
Cc: Eric W. Biederman <ebied...@xmission.com>
Cc: H. Peter Anvin <h...@zytor.com>
Acked-by: Serge Hallyn <serge.hal...@canonical.com>
Cc: Pavel Emelyanov <xe...@parallels.com>
Cc: Vasiliy Kulikov <seg...@openwall.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hir...@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpa...@gmail.com>
Cc: Julien Tinnes <j...@google.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Andrew Vagin <ava...@openvz.org>
---
kernel/sys.c | 21 +++++++++++----------
1 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/kernel/sys.c b/kernel/sys.c
index a2d5644..cf580a7 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2036,12 +2036,14 @@ 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;
@@ -2062,8 +2064,6 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm,
unsigned int fd)
if (err)
goto exit;
- down_write(&mm->mmap_sem);
-
/*
* Forbid mm->exe_file change if old file still mapped.
*/
@@ -2075,7 +2075,7 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm,
unsigned int fd)
if (vma->vm_file &&
path_equal(&vma->vm_file->f_path,
&mm->exe_file->f_path))
- goto exit_unlock;
+ goto exit;
}
/*
@@ -2086,13 +2086,10 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm,
unsigned int fd)
*/
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;
@@ -2112,8 +2109,12 @@ static int prctl_set_mm(int opt, unsigned long addr,
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;
--
1.7.1
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