Re: [Qemu-devel] [PATCH repost 0/4] add mitigation against buffer overflows

[Paolo Bonzini <pbonzini@redhat.com>]

On 27/09/2015 12:14, Michael S. Tsirkin wrote:
> Multiple places in QEMU map guest memory, then access it
> directly. Unfortunately since we are using C, there's always
> a chance that we'll miss a bounds check when we do this.
> This has a potential to corrupt QEMU memory.
> 
> As a mitigation strategy against such exploits,
> allocate a page in HVA space on top of each RAM chunk
> with PROT_NONE protection.
> 
> Buffer overflows will now cause QEMU to crash.
> 
> This is a repost, combining separate patches into a single
> series. No changes to patches themselves.
> 
> Michael S. Tsirkin (4):
>   oslib: rework anonimous RAM allocation
>   oslib: allocate PROT_NONE pages on top of RAM
>   exec: allocate PROT_NONE pages on top of RAM
>   exec: factor out duplicate mmap code
> 
>  include/qemu/mmap-alloc.h | 10 +++++++++
>  exec.c                    | 19 ++++++++++++-----
>  util/mmap-alloc.c         | 52 +++++++++++++++++++++++++++++++++++++++++++++++
>  util/oslib-posix.c        | 20 ++++--------------
>  util/Makefile.objs        |  2 +-
>  5 files changed, 81 insertions(+), 22 deletions(-)
>  create mode 100644 include/qemu/mmap-alloc.h
>  create mode 100644 util/mmap-alloc.c
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Regarding my request to add comments in patch 2, feel free to add them
directly in patch 4 instead.

Paolo