Commit 098362e7 authored by David Daney's avatar David Daney Committed by Ralf Baechle

[MIPS] Add len and addr validation for MAP_FIXED mappings.

Mmap with MAP_FIXED was not validating the addr and len parameters.  This
leads to the failure of GCC's gcc.c-torture/execute/loop-2[fg].c testcases
when using the o32 ABI on a 64 bit kernel.

These testcases try to mmap 65536 bytes at 0x7fff8000 and then access all
the memory.  In 2.6.18 and 2.6.23.1 (and likely other versions as well)
the kernel maps the requested memory, but since half of it is above
0x80000000 a SIGBUS is generated when it is accessed.

This patch moves the len validation above the MAP_FIXED processing so that
it is always validated.  It also adds validation to the addr parameter for
MAP_FIXED mappings.
Signed-off-by: default avatarDavid Daney  <ddaney@avtrex.com>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent c4e8308c
......@@ -73,7 +73,14 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
task_size = STACK_TOP;
if (len > task_size)
return -ENOMEM;
if (flags & MAP_FIXED) {
/* Even MAP_FIXED mappings must reside within task_size. */
if (task_size - len < addr)
return -EINVAL;
/*
* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
......@@ -83,8 +90,6 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
return addr;
}
if (len > task_size)
return -ENOMEM;
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = 1;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment