From 5a211a5deabcafdc764817d5b4510c767d317ddc Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 4 Dec 2007 11:06:55 -0500 Subject: [PATCH] VM/Security: add security hook to do_brk 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 Acked-by: Alan Cox Signed-off-by: James Morris --- mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index f4cfc6ac08d..15678aa6ec7 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -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); -- 2.20.1