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authorEric Paris <eparis@redhat.com>2007-11-26 18:47:26 -0500
committerJames Morris <jmorris@namei.org>2007-12-06 00:24:48 +1100
commit8869477a49c3e99def1fcdadd6bbc407fea14b45 (patch)
treea3f77dcac695a12986715b119750f85f124179bb /mm
parentSecurity: allow capable check to permit mmap or low vm space (diff)
downloadlinux-dev-8869477a49c3e99def1fcdadd6bbc407fea14b45.tar.xz
linux-dev-8869477a49c3e99def1fcdadd6bbc407fea14b45.zip
security: protect from stack expantion into low vm addresses
Add security checks to make sure we are not attempting to expand the stack into memory protected by mmap_min_addr Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index facc1a75bd4f..938313c76d02 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1615,6 +1615,12 @@ static inline int expand_downwards(struct vm_area_struct *vma,
*/
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
+
+ address &= PAGE_MASK;
+ error = security_file_mmap(0, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
anon_vma_lock(vma);
/*
@@ -1622,8 +1628,6 @@ static inline int expand_downwards(struct vm_area_struct *vma,
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
- address &= PAGE_MASK;
- error = 0;
/* Somebody else might have raced and expanded it already */
if (address < vma->vm_start) {