Re: [PATCH 4.14 0/4] BPF fixes for CVE-2021-3444 and CVE-2021-3600

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Aug 30, 2021 at 03:32:07PM -0300, Thadeu Lima de Souza Cascardo wrote:
> The upstream changes necessary to fix these CVEs rely on the presence of JMP32,
> which is not a small backport and brings its own potential set of necessary
> follow-ups.
> 
> Daniel Borkmann, John Fastabend and Alexei Starovoitov came up with a fix
> involving the use of the AX register.
> 
> This has been tested against the test_verifier in 4.14.y tree and some tests
> specific to the two referred CVEs. The test_bpf module was also tested.
> 
> Daniel Borkmann (4):
>   bpf: Do not use ax register in interpreter on div/mod
>   bpf: fix subprog verifier bypass by div/mod by 0 exception
>   bpf: Fix 32 bit src register truncation on div/mod
>   bpf: Fix truncation handling for mod32 dst reg wrt zero
> 
>  include/linux/filter.h | 24 ++++++++++++++++++++++++
>  kernel/bpf/core.c      | 40 +++++++++++++++-------------------------
>  kernel/bpf/verifier.c  | 39 +++++++++++++++++++++++++++++++--------
>  net/core/filter.c      |  9 ++++++++-
>  4 files changed, 78 insertions(+), 34 deletions(-)
> 
> -- 
> 2.30.2
> 

All now queued up, thanks.

greg k-h