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 4.19.y tree and some tests
specific to the two referred CVEs.

Daniel Borkmann (3):
  bpf: Do not use ax register in interpreter on div/mod
  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      | 32 +++++++++++++++-----------------
 kernel/bpf/verifier.c  | 27 ++++++++++++++-------------
 3 files changed, 53 insertions(+), 30 deletions(-)

-- 
2.30.2