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prctl: PR_SET_MM -- factor out mmap_sem when updating mm::exe_file

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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 <gorcunov@openvz.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Acked-by: 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>
Cc: Julien Tinnes <jln@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Cyrill Gorcunov 2014-10-09 15:27:34 -07:00 committed by Linus Torvalds
parent 8764b338b3
commit 71fe97e185
1 changed files with 11 additions and 10 deletions
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21
kernel/sys.c
View file

@ -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 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.
*/
@ -1667,7 +1667,7 @@ 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;
}
/*
@ -1678,13 +1678,10 @@ 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;
@ -1703,8 +1700,12 @@ 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;