lkml.org 
[lkml]   [2021]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 4/6] sh/mm/mmap.c: Check length of unmapped area before allowing MAP_FIXED
Date
arch_get_unmapped_area() and arch_get_unmapped_area_topdown() could
potentially allow a larger than possible length when using the MAP_FIXED
flag. The bound check should come before the check for MAP_FIXED.

Fixes: 2cd841c0b3a8 (v2.4.9.5 -> v2.4.9.6)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
arch/sh/mm/mmap.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
index 6a1a1297baae..3d46c475198d 100644
--- a/arch/sh/mm/mmap.c
+++ b/arch/sh/mm/mmap.c
@@ -39,6 +39,9 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
int do_colour_align;
struct vm_unmapped_area_info info;

+ if (unlikely(len > TASK_SIZE))
+ return -ENOMEM;
+
if (flags & MAP_FIXED) {
/* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
@@ -49,9 +52,6 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
return addr;
}

- if (unlikely(len > TASK_SIZE))
- return -ENOMEM;
-
do_colour_align = 0;
if (filp || (flags & MAP_SHARED))
do_colour_align = 1;
@@ -88,6 +88,9 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
int do_colour_align;
struct vm_unmapped_area_info info;

+ if (unlikely(len > TASK_SIZE))
+ return -ENOMEM;
+
if (flags & MAP_FIXED) {
/* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
@@ -98,9 +101,6 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
return addr;
}

- if (unlikely(len > TASK_SIZE))
- return -ENOMEM;
-
do_colour_align = 0;
if (filp || (flags & MAP_SHARED))
do_colour_align = 1;
--
2.30.2
\
 
 \ /
  Last update: 2021-12-06 16:05    [W:0.051 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site