Eric Lee / linux-smarc-t335x-v3.2

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Commit 8869477a49c3e99def1fcdadd6bbc407fea14b45

Authored by Eric Paris
Committed by James Morris
1 parent ab5a91a836
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

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>

Showing 1 changed file with 6 additions and 2 deletions Side-by-side Diff

... ... @@ -1615,6 +1615,12 @@
1615 1615 */
1616 1616 if (unlikely(anon_vma_prepare(vma)))
1617 1617 return -ENOMEM;
  1618 +
  1619 + address &= PAGE_MASK;
  1620 + error = security_file_mmap(0, 0, 0, 0, address, 1);
  1621 + if (error)
  1622 + return error;
  1623 +
1618 1624 anon_vma_lock(vma);
1619 1625  
1620 1626 /*
... ... @@ -1622,8 +1628,6 @@
1622 1628 * is required to hold the mmap_sem in read mode. We need the
1623 1629 * anon_vma lock to serialize against concurrent expand_stacks.
1624 1630 */
1625   - address &= PAGE_MASK;
1626   - error = 0;
1627 1631  
1628 1632 /* Somebody else might have raced and expanded it already */
1629 1633 if (address < vma->vm_start) {