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| author | Eric Paris <eparis@redhat.com> | 2007-11-26 18:47:26 -0500 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2007-12-06 00:24:48 +1100 |
| commit | 8869477a49c3e99def1fcdadd6bbc407fea14b45 (patch) | |
| tree | a3f77dcac695a12986715b119750f85f124179bb | |
| parent | ab5a91a8364c3d6fc617abc47cc81d162c01d90a (diff) | |
| download | lwn-8869477a49c3e99def1fcdadd6bbc407fea14b45.tar.gz lwn-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>
| -rw-r--r-- | mm/mmap.c | 8 |
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) { |