mbox series

[bpf-next,0/2] bpf: permit map_ptr arithmetic with opcode add and offset 0

Message ID 20200904194900.3031319-1-yhs@fb.com
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Series bpf: permit map_ptr arithmetic with opcode add and offset 0 | expand

Message

Yonghong Song Sept. 4, 2020, 7:49 p.m. UTC 
With CORE, it is possible that the compiler may produce code like
  r1 = 0  // relocation instruction
  map_ptr += r1
  ...
Currently verifier does not allow map_ptr arithmetic, even for adding with 0.
This patch set relaxed the condition so the above code can be accepted.
Patch #1 is the kernel implementation and Patch #2 added selftest tests to
cover the new functionality.

Yonghong Song (2):
  bpf: permit map_ptr arithmetic with opcode add and offset 0
  selftests/bpf: add test for map_ptr arithmetic

 kernel/bpf/verifier.c                         |  3 ++
 .../selftests/bpf/progs/map_ptr_kern.c        |  4 +--
 .../testing/selftests/bpf/verifier/map_ptr.c  | 32 +++++++++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)