lkml.org 
[lkml]   [2012]   [Aug]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[ 34/37] s390/compat: fix mmap compat system calls
3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiko Carstens <heiko.carstens@de.ibm.com>

commit e85871218513c54f7dfdb6009043cb638f2fecbe upstream.

The native 31 bit and the compat behaviour for the mmap system calls differ:

In native 31 bit mode the passed in address for the mmap system call will be
unmodified passed to sys_mmap_pgoff().
In compat mode however the passed in address will be modified with
compat_ptr() which masks out the most significant bit.

The result is that in native 31 bit mode each mmap request (with MAP_FIXED)
will fail where the most significat bit is set, while in compat mode it
may succeed.

This odd behaviour was introduced with d3815898 "[S390] mmap: add missing
compat_ptr conversion to both mmap compat syscalls".

To restore a consistent behaviour accross native and compat mode this
patch functionally reverts the above mentioned commit.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/s390/kernel/compat_linux.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index d122508..f606d93 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -620,7 +620,6 @@ asmlinkage unsigned long old32_mmap(struct mmap_arg_struct_emu31 __user *arg)
return -EFAULT;
if (a.offset & ~PAGE_MASK)
return -EINVAL;
- a.addr = (unsigned long) compat_ptr(a.addr);
return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
a.offset >> PAGE_SHIFT);
}
@@ -631,7 +630,6 @@ asmlinkage long sys32_mmap2(struct mmap_arg_struct_emu31 __user *arg)

if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
- a.addr = (unsigned long) compat_ptr(a.addr);
return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
}




\
 
 \ /
  Last update: 2012-08-17 08:21    [W:0.175 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site