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VM/Security: add security hook to do_brk

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Given a specifically crafted binary do_brk() can be used to get low
pages available in userspace virtually memory and can thus be used to
circumvent the mmap_min_addr low memory protection.  Add security checks
in do_brk().

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Eric Paris 2007-12-04 11:06:55 -05:00 committed by James Morris
parent 7cd94146cd
commit 5a211a5dea
1 changed files with 4 additions and 0 deletions
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4
mm/mmap.c
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@ -1941,6 +1941,10 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
if (is_hugepage_only_range(mm, addr, len))
return -EINVAL;
error = security_file_mmap(0, 0, 0, 0, addr, 1);
if (error)
return error;
flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
error = arch_mmap_check(addr, len, flags);