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| author |   Yauheni Kaliuta <yauheni.kaliuta@redhat.com> | 2021-02-28 12:30:17 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-17 17:03:33 +0100 |
| commit | c2c3a85ab01f1689805759c03137bbef296de50f (patch) | |
| tree | d7592c0894059884c1ac00a5669d3e98c9722a3c /tools | |
| parent | selftests/bpf: No need to drop the packet when there is no geneve opt (diff) | |
| download | wireguard-linux-c2c3a85ab01f1689805759c03137bbef296de50f.tar.xz wireguard-linux-c2c3a85ab01f1689805759c03137bbef296de50f.zip | |
selftests/bpf: Mask bpf_csum_diff() return value to 16 bits in test_verifier
commit 6185266c5a853bb0f2a459e3ff594546f277609b upstream.
The verifier test labelled "valid read map access into a read-only array
2" calls the bpf_csum_diff() helper and checks its return value. However,
architecture implementations of csum_partial() (which is what the helper
uses) differ in whether they fold the return value to 16 bit or not. For
example, x86 version has ...
if (unlikely(odd)) {
result = from32to16(result);
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
}
... while generic lib/checksum.c does:
result = from32to16(result);
if (odd)
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
This makes the helper return different values on different architectures,
breaking the test on non-x86. To fix this, add an additional instruction
to always mask the return value to 16 bits, and update the expected return
value accordingly.
Fixes: fb2abb73e575 ("bpf, selftest: test {rd, wr}only flags and direct value access")
Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210228103017.320240-1-yauheni.kaliuta@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/verifier/array_access.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/verifier/array_access.c b/tools/testing/selftests/bpf/verifier/array_access.c index f3c33e128709..bcc87906c4c1 100644 --- a/tools/testing/selftests/bpf/verifier/array_access.c +++ b/tools/testing/selftests/bpf/verifier/array_access.c @@ -250,12 +250,13 @@ BPF_MOV64_IMM(BPF_REG_5, 0), BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_csum_diff), + BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xffff), BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .fixup_map_array_ro = { 3 }, .result = ACCEPT, - .retval = -29, + .retval = 65507, }, { "invalid write map access into a read-only array 1", |