On 6/28/19 4:10 PM, Stanislav Fomichev wrote:
> Make sure that wide stores are allowed at proper (aligned) addresses.
> Note that user_ip6 is naturally aligned on 8-byte boundary, so
> correct addresses are user_ip6[0] and user_ip6[2]. msg_src_ip6 is,
> however, aligned on a 4-byte bondary, so only msg_src_ip6[1]
> can be wide-stored.
>
> Cc: Andrii Nakryiko <andriin@xxxxxx>
> Cc: Yonghong Song <yhs@xxxxxx>
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/test_verifier.c | 17 ++++++--
> .../selftests/bpf/verifier/wide_store.c | 40 +++++++++++++++++++
> 2 files changed, 54 insertions(+), 3 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c
>
> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
> index c5514daf8865..b0773291012a 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -105,6 +105,7 @@ struct bpf_test {
> __u64 data64[TEST_DATA_LEN / 8];
> };
> } retvals[MAX_TEST_RUNS];
> + enum bpf_attach_type expected_attach_type;
> };
>
> /* Note we want this to be 64 bit aligned so that the end of our array is
> @@ -850,6 +851,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
> int fd_prog, expected_ret, alignment_prevented_execution;
> int prog_len, prog_type = test->prog_type;
> struct bpf_insn *prog = test->insns;
> + struct bpf_load_program_attr attr;
> int run_errs, run_successes;
> int map_fds[MAX_NR_MAPS];
> const char *expected_err;
> @@ -881,8 +883,17 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
> pflags |= BPF_F_STRICT_ALIGNMENT;
> if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)
> pflags |= BPF_F_ANY_ALIGNMENT;
> - fd_prog = bpf_verify_program(prog_type, prog, prog_len, pflags,
> - "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 4);
> +
> + memset(&attr, 0, sizeof(attr));
> + attr.prog_type = prog_type;
> + attr.expected_attach_type = test->expected_attach_type;
> + attr.insns = prog;
> + attr.insns_cnt = prog_len;
> + attr.license = "GPL";
> + attr.log_level = 4;
> + attr.prog_flags = pflags;
> +
> + fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog));
> if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) {
> printf("SKIP (unsupported program type %d)\n", prog_type);
> skips++;
> @@ -912,7 +923,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
> printf("FAIL\nUnexpected success to load!\n");
> goto fail_log;
> }
> - if (!strstr(bpf_vlog, expected_err)) {
> + if (!expected_err || !strstr(bpf_vlog, expected_err)) {
> printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n",
> expected_err, bpf_vlog);
> goto fail_log;
> diff --git a/tools/testing/selftests/bpf/verifier/wide_store.c b/tools/testing/selftests/bpf/verifier/wide_store.c
> new file mode 100644
> index 000000000000..c6385f45b114
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/verifier/wide_store.c
> @@ -0,0 +1,40 @@
> +#define BPF_SOCK_ADDR(field, off, res, err) \
> +{ \
> + "wide store to bpf_sock_addr." #field "[" #off "]", \
> + .insns = { \
> + BPF_MOV64_IMM(BPF_REG_0, 1), \
> + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \
> + offsetof(struct bpf_sock_addr, field[off])), \
> + BPF_EXIT_INSN(), \
> + }, \
> + .result = res, \
> + .prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \
> + .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \
> + .errstr = err, \
> +}
> +
> +/* user_ip6[0] is u64 aligned */
> +BPF_SOCK_ADDR(user_ip6, 0, ACCEPT,
> + NULL),
> +BPF_SOCK_ADDR(user_ip6, 1, REJECT,
> + "invalid bpf_context access off=12 size=8"),
> +BPF_SOCK_ADDR(user_ip6, 2, ACCEPT,
> + NULL),
> +BPF_SOCK_ADDR(user_ip6, 3, REJECT,
> + "invalid bpf_context access off=20 size=8"),
> +BPF_SOCK_ADDR(user_ip6, 4, REJECT,
> + "invalid bpf_context access off=24 size=8"),
With offset 4, we have
#968/p wide store to bpf_sock_addr.user_ip6[4] OK
This test case can be removed. user code typically
won't write bpf_sock_addr.user_ip6[4], and compiler
typically will give a warning since it is out of
array bound. Any particular reason you want to
include this one?
> +
> +/* msg_src_ip6[0] is _not_ u64 aligned */
> +BPF_SOCK_ADDR(msg_src_ip6, 0, REJECT,
> + "invalid bpf_context access off=44 size=8"),
> +BPF_SOCK_ADDR(msg_src_ip6, 1, ACCEPT,
> + NULL),
> +BPF_SOCK_ADDR(msg_src_ip6, 2, REJECT,
> + "invalid bpf_context access off=52 size=8"),
> +BPF_SOCK_ADDR(msg_src_ip6, 3, REJECT,
> + "invalid bpf_context access off=56 size=8"),
> +BPF_SOCK_ADDR(msg_src_ip6, 4, REJECT,
> + "invalid bpf_context access off=60 size=8"),
The same as above, offset=4 case can be removed?
> +
> +#undef BPF_SOCK_ADDR
>
