Messages in this thread Patch in this message | | | Subject | [PATCH 1/3] mmap: protect from stack expantion into low vm addresses | From | Eric Paris <> | Date | Mon, 26 Nov 2007 18:47:26 -0500 |
| |
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>
---
** Be very careful applying/rediffing this patch. Standard 3 lines of context from git diff will misapply the first hunk to expand_upwards instead of properly in expand_downwards. This patch was generated using -U 4 to make sure it applies in the correct place. **
mm/mmap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- kernel-1/mm/mmap.c +++ kernel-2/mm/mmap.c @@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc * so that the anon_vma locking is not a noop. */ 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); /* * vma->vm_start/vm_end cannot change under us because the caller * 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) { unsigned long size, grow;
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |