lkml.org 
[lkml]   [2018]   [Sep]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH v4 25/27] mm/mmap: Prevent Shadow Stack VMA merges
Date
Function returns could unwind stacks beyond its allocated area.
We do not merge shadow stack areas.

This and VMA guards prevent shadow stack underflow.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
mm/mmap.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/mm/mmap.c b/mm/mmap.c
index de2d0faa1c61..fa581ced3f56 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1123,6 +1123,12 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
if (vm_flags & VM_SPECIAL)
return NULL;

+ /*
+ * Do not merge shadow stack areas.
+ */
+ if (vm_flags & VM_SHSTK)
+ return NULL;
+
if (prev)
next = prev->vm_next;
else
--
2.17.1
\
 
 \ /
  Last update: 2018-09-21 17:14    [W:0.535 / U:0.768 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site