[PATCH 0/2] [RESEND] Fold checksum at the end of bpf_csum_diff and fix

[PATCH 0/2] [RESEND] Fold checksum at the end of bpf_csum_diff and fix

[Paolo Pisati]

From: Paolo Pisati <paolo.pisati@canonical.com>

After applying patch 0001, all checksum implementations i could test (x86-64, arm64 and
arm), now agree on the return value.

Patch 0002 fix the expected return value for test #13: i did the calculation manually,
and it correspond.

Unfortunately, after applying patch 0001, other test cases now fail in
test_verifier:

$ sudo ./tools/testing/selftests/bpf/test_verifier
...
#417/p helper access to variable memory: size = 0 allowed on NULL (ARG_PTR_TO_MEM_OR_NULL) FAIL retval 65535 != 0 
#419/p helper access to variable memory: size = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL) FAIL retval 65535 != 0 
#423/p helper access to variable memory: size possible = 0 allowed on != NULL packet pointer (ARG_PTR_TO_MEM_OR_NULL) FAIL retval 65535 != 0 
...
Summary: 1500 PASSED, 0 SKIPPED, 3 FAILED

And there are probably other fallouts in other selftests - someone familiar
should take a look before applying these patches.

Paolo Pisati (2):
  bpf: bpf_csum_diff: fold the checksum before returning the
    value
  bpf, selftest: fix checksum value for test #13

 net/core/filter.c                                   | 2 +-
 tools/testing/selftests/bpf/verifier/array_access.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
2.17.1

[PATCH 1/2] bpf: bpf_csum_diff: fold the checksum before returning the value

[Paolo Pisati]

From: Paolo Pisati <paolo.pisati@canonical.com>

With this change, bpf_csum_diff behave homogeneously among different
checksum calculation code / csum_partial() (tested on x86-64, arm64 and
arm).

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
---
 net/core/filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index f615e42cf4ef..8db7f58f1ea1 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1990,7 +1990,7 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size,
 	for (i = 0; i <   to_size / sizeof(__be32); i++, j++)
 		sp->diff[j] = to[i];
 
-	return csum_partial(sp->diff, diff_size, seed);
+	return csum_fold(csum_partial(sp->diff, diff_size, seed));
 }
 
 static const struct bpf_func_proto bpf_csum_diff_proto = {
-- 
2.17.1

[PATCH 2/2] bpf, selftest: fix checksum value for test #13

[Paolo Pisati]

From: Paolo Pisati <paolo.pisati@canonical.com>

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
---
 tools/testing/selftests/bpf/verifier/array_access.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/verifier/array_access.c b/tools/testing/selftests/bpf/verifier/array_access.c
index bcb83196e459..4698f560d756 100644
--- a/tools/testing/selftests/bpf/verifier/array_access.c
+++ b/tools/testing/selftests/bpf/verifier/array_access.c
@@ -255,7 +255,7 @@
 	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	.fixup_map_array_ro = { 3 },
 	.result = ACCEPT,
-	.retval = -29,
+	.retval = 28,
 },
 {
 	"invalid write map access into a read-only array 1",
-- 
2.17.1

Re: [PATCH 2/2] bpf, selftest: fix checksum value for test #13

[Andrii Nakryiko]

On Thu, Jul 11, 2019 at 2:41 AM Paolo Pisati <p.pisati@gmail.com> wrote:
>
> From: Paolo Pisati <paolo.pisati@canonical.com>
>

Please include description, in addition to subject.

Also, when submitting patches, please add bpf or bpf-next (e.g.,
[PATCH bpf 2/2] to indicate which tree it's supposed to go into). For
this one it's probably bpf.


> Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
> ---
>  tools/testing/selftests/bpf/verifier/array_access.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/verifier/array_access.c b/tools/testing/selftests/bpf/verifier/array_access.c
> index bcb83196e459..4698f560d756 100644
> --- a/tools/testing/selftests/bpf/verifier/array_access.c
> +++ b/tools/testing/selftests/bpf/verifier/array_access.c
> @@ -255,7 +255,7 @@
>         .prog_type = BPF_PROG_TYPE_SCHED_CLS,
>         .fixup_map_array_ro = { 3 },
>         .result = ACCEPT,
> -       .retval = -29,
> +       .retval = 28,
>  },
>  {
>         "invalid write map access into a read-only array 1",
> --
> 2.17.1
>