selftests/bpf: add a test case to check verifier pointer arithmetic
authorYonghong Song <yhs@fb.com>
Wed, 3 May 2017 02:58:14 +0000 (19:58 -0700)
committerDavid S. Miller <davem@davemloft.net>
Wed, 3 May 2017 13:51:25 +0000 (09:51 -0400)
commit6ead18fb18c8182a81d70f24942f9547e56a35d2
tree06dfd33dbb26086f8cc593f51a6e47f53f784200
parent4d463c4dbc5c1c5d73e488d52faeec05570443a0
selftests/bpf: add a test case to check verifier pointer arithmetic

With clang/llvm 4.0+, the test case is able to generate
the following pattern:
....
440: (b7) r1 = 15
441: (05) goto pc+73
515: (79) r6 = *(u64 *)(r10 -152)
516: (bf) r7 = r10
517: (07) r7 += -112
518: (bf) r2 = r7
519: (0f) r2 += r1
520: (71) r1 = *(u8 *)(r8 +0)
521: (73) *(u8 *)(r2 +45) = r1
....

commit 332270fdc8b6 ("bpf: enhance verifier to understand stack
pointer arithmetic") improved verifier to handle such a pattern.
This patch adds a C test case to actually generate such a pattern.
A dummy tracepoint interface is used to load the program
into the kernel.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
tools/testing/selftests/bpf/Makefile
tools/testing/selftests/bpf/test_progs.c
tools/testing/selftests/bpf/test_tcp_estats.c [new file with mode: 0644]