diff mbox series

[v16,12/12] selftests/bpf: Add tests for dynamic pointers parameters in kfuncs

Message ID 20220905143318.1592015-13-roberto.sassu@huaweicloud.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf: Add kfuncs for PKCS#7 signature verification | expand

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Commit Message

Roberto Sassu Sept. 5, 2022, 2:33 p.m. UTC 
From: Roberto Sassu <roberto.sassu@huawei.com>

Add tests to ensure that only supported dynamic pointer types are accepted,
that the passed argument is actually a dynamic pointer, and that the passed
argument is a pointer to the stack.

The tests are currently in the deny list for s390x (JIT does not support
calling kernel function).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 tools/testing/selftests/bpf/DENYLIST.s390x    |   1 +
 .../bpf/prog_tests/kfunc_dynptr_param.c       | 103 ++++++++++++++++++
 .../bpf/progs/test_kfunc_dynptr_param.c       |  57 ++++++++++
 3 files changed, 161 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c

Comments

Kumar Kartikeya Dwivedi Sept. 6, 2022, 3:15 a.m. UTC | #1 
On Mon, 5 Sept 2022 at 16:36, Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> From: Roberto Sassu <roberto.sassu@huawei.com>
>
> Add tests to ensure that only supported dynamic pointer types are accepted,
> that the passed argument is actually a dynamic pointer, and that the passed
> argument is a pointer to the stack.
>
> The tests are currently in the deny list for s390x (JIT does not support
> calling kernel function).
>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  tools/testing/selftests/bpf/DENYLIST.s390x    |   1 +
>  .../bpf/prog_tests/kfunc_dynptr_param.c       | 103 ++++++++++++++++++
>  .../bpf/progs/test_kfunc_dynptr_param.c       |  57 ++++++++++
>  3 files changed, 161 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
>
> diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
> index 4e305baa5277..9a6dc3671c65 100644
> --- a/tools/testing/selftests/bpf/DENYLIST.s390x
> +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
> @@ -71,3 +71,4 @@ cgroup_hierarchical_stats                # JIT does not support calling kernel f
>  htab_update                              # failed to attach: ERROR: strerror_r(-524)=22                                (trampoline)
>  lookup_key                               # JIT does not support calling kernel function                                (kfunc)
>  verify_pkcs7_sig                         # JIT does not support calling kernel function                                (kfunc)
> +kfunc_dynptr_param                       # JIT does not support calling kernel function                                (kfunc)
> diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> new file mode 100644
> index 000000000000..ea655a5c9d8b
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> @@ -0,0 +1,103 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Copyright (c) 2022 Facebook
> + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
> + *
> + * Author: Roberto Sassu <roberto.sassu@huawei.com>
> + */
> +
> +#include <test_progs.h>
> +#include "test_kfunc_dynptr_param.skel.h"
> +
> +static size_t log_buf_sz = 1048576; /* 1 MB */
> +static char obj_log_buf[1048576];
> +
> +static struct {
> +       const char *prog_name;
> +       const char *expected_err_msg;
> +} kfunc_dynptr_tests[] = {
> +       {"dynptr_type_not_supp",
> +        "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type"},
> +       {"not_valid_dynptr",
> +        "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized"},
> +       {"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack"},
> +};
> +
> +static bool kfunc_not_supported;
> +
> +static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt,
> +                          va_list args)
> +{
> +       if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found in kernel or module BTFs\n"))
> +               return 0;
> +
> +       if (strcmp(va_arg(args, char *), "bpf_verify_pkcs7_signature"))
> +               return 0;
> +
> +       kfunc_not_supported = true;
> +       return 0;
> +}
> +
> +static void verify_fail(const char *prog_name, const char *expected_err_msg)
> +{
> +       struct test_kfunc_dynptr_param *skel;
> +       LIBBPF_OPTS(bpf_object_open_opts, opts);
> +       libbpf_print_fn_t old_print_cb;
> +       struct bpf_program *prog;
> +       int err;
> +
> +       opts.kernel_log_buf = obj_log_buf;
> +       opts.kernel_log_size = log_buf_sz;
> +       opts.kernel_log_level = 1;
> +
> +       skel = test_kfunc_dynptr_param__open_opts(&opts);
> +       if (!ASSERT_OK_PTR(skel, "test_kfunc_dynptr_param__open_opts"))
> +               goto cleanup;
> +
> +       prog = bpf_object__find_program_by_name(skel->obj, prog_name);
> +       if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
> +               goto cleanup;
> +
> +       bpf_program__set_autoload(prog, true);
> +
> +       bpf_map__set_max_entries(skel->maps.ringbuf, getpagesize());
> +
> +       kfunc_not_supported = false;
> +
> +       old_print_cb = libbpf_set_print(libbpf_print_cb);
> +       err = test_kfunc_dynptr_param__load(skel);
> +       libbpf_set_print(old_print_cb);
> +
> +       if (err < 0 && kfunc_not_supported) {
> +               fprintf(stderr,
> +                 "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not supported\n",
> +                 __func__);
> +               test__skip();
> +               goto cleanup;
> +       }
> +
> +       if (!ASSERT_ERR(err, "unexpected load success"))
> +               goto cleanup;
> +
> +       if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) {
> +               fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg);
> +               fprintf(stderr, "Verifier output: %s\n", obj_log_buf);
> +       }
> +
> +cleanup:
> +       test_kfunc_dynptr_param__destroy(skel);
> +}
> +
> +void test_kfunc_dynptr_param(void)
> +{
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(kfunc_dynptr_tests); i++) {
> +               if (!test__start_subtest(kfunc_dynptr_tests[i].prog_name))
> +                       continue;
> +
> +               verify_fail(kfunc_dynptr_tests[i].prog_name,
> +                           kfunc_dynptr_tests[i].expected_err_msg);
> +       }
> +}
> diff --git a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> new file mode 100644
> index 000000000000..2f09f91a1576
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> @@ -0,0 +1,57 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
> + *
> + * Author: Roberto Sassu <roberto.sassu@huawei.com>
> + */
> +
> +#include "vmlinux.h"
> +#include <errno.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +
> +struct bpf_dynptr {
> +       __u64 :64;
> +       __u64 :64;
> +} __attribute__((aligned(8)));
> +
> +extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
> +                                     struct bpf_dynptr *sig_ptr,
> +                                     struct bpf_key *trusted_keyring) __ksym;
> +
> +struct {
> +       __uint(type, BPF_MAP_TYPE_RINGBUF);
> +} ringbuf SEC(".maps");
> +
> +char _license[] SEC("license") = "GPL";
> +
> +SEC("?lsm.s/bpf")
> +int BPF_PROG(dynptr_type_not_supp, int cmd, union bpf_attr *attr,
> +            unsigned int size)
> +{
> +       char write_data[64] = "hello there, world!!";
> +       struct bpf_dynptr ptr;
> +
> +       bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0, &ptr);
> +
> +       return bpf_verify_pkcs7_signature(&ptr, &ptr, NULL);
> +}
> +
> +SEC("?lsm.s/bpf")
> +int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr, unsigned int size)
> +{
> +       unsigned long val;
> +
> +       return bpf_verify_pkcs7_signature((struct bpf_dynptr *)&val,
> +                                         (struct bpf_dynptr *)&val, NULL);
> +}
> +
> +SEC("?lsm.s/bpf")
> +int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr, unsigned int size)
> +{
> +       unsigned long val;
> +
> +       return bpf_verify_pkcs7_signature((struct bpf_dynptr *)val,
> +                                         (struct bpf_dynptr *)val, NULL);

Please also include a test where you cause the dynptr to be set to
NULL, e.g. by passing invalid stuff to ringbuf_reserve_dynptr, and
then try to pass it to bpf_verify_pkc7_signature.

> +}
> --
> 2.25.1
>
Roberto Sassu Sept. 6, 2022, 8:30 a.m. UTC | #2 
On Tue, 2022-09-06 at 05:15 +0200, Kumar Kartikeya Dwivedi wrote:
> On Mon, 5 Sept 2022 at 16:36, Roberto Sassu
> <roberto.sassu@huaweicloud.com> wrote:
> > From: Roberto Sassu <roberto.sassu@huawei.com>
> > 
> > Add tests to ensure that only supported dynamic pointer types are
> > accepted,
> > that the passed argument is actually a dynamic pointer, and that
> > the passed
> > argument is a pointer to the stack.
> > 
> > The tests are currently in the deny list for s390x (JIT does not
> > support
> > calling kernel function).
> > 
> > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > ---
> >  tools/testing/selftests/bpf/DENYLIST.s390x    |   1 +
> >  .../bpf/prog_tests/kfunc_dynptr_param.c       | 103
> > ++++++++++++++++++
> >  .../bpf/progs/test_kfunc_dynptr_param.c       |  57 ++++++++++
> >  3 files changed, 161 insertions(+)
> >  create mode 100644
> > tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> >  create mode 100644
> > tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > 
> > diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x
> > b/tools/testing/selftests/bpf/DENYLIST.s390x
> > index 4e305baa5277..9a6dc3671c65 100644
> > --- a/tools/testing/selftests/bpf/DENYLIST.s390x
> > +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
> > @@ -71,3 +71,4 @@ cgroup_hierarchical_stats                # JIT
> > does not support calling kernel f
> >  htab_update                              # failed to attach:
> > ERROR: strerror_r(-
> > 524)=22                                (trampoline)
> >  lookup_key                               # JIT does not support
> > calling kernel function                                (kfunc)
> >  verify_pkcs7_sig                         # JIT does not support
> > calling kernel function                                (kfunc)
> > +kfunc_dynptr_param                       # JIT does not support
> > calling kernel function                                (kfunc)
> > diff --git
> > a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > new file mode 100644
> > index 000000000000..ea655a5c9d8b
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > @@ -0,0 +1,103 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/*
> > + * Copyright (c) 2022 Facebook
> > + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
> > + *
> > + * Author: Roberto Sassu <roberto.sassu@huawei.com>
> > + */
> > +
> > +#include <test_progs.h>
> > +#include "test_kfunc_dynptr_param.skel.h"
> > +
> > +static size_t log_buf_sz = 1048576; /* 1 MB */
> > +static char obj_log_buf[1048576];
> > +
> > +static struct {
> > +       const char *prog_name;
> > +       const char *expected_err_msg;
> > +} kfunc_dynptr_tests[] = {
> > +       {"dynptr_type_not_supp",
> > +        "arg#0 pointer type STRUCT bpf_dynptr_kern points to
> > unsupported dynamic pointer type"},
> > +       {"not_valid_dynptr",
> > +        "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid
> > and initialized"},
> > +       {"not_ptr_to_stack", "arg#0 pointer type STRUCT
> > bpf_dynptr_kern not to stack"},
> > +};
> > +
> > +static bool kfunc_not_supported;
> > +
> > +static int libbpf_print_cb(enum libbpf_print_level level, const
> > char *fmt,
> > +                          va_list args)
> > +{
> > +       if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found
> > in kernel or module BTFs\n"))
> > +               return 0;
> > +
> > +       if (strcmp(va_arg(args, char *),
> > "bpf_verify_pkcs7_signature"))
> > +               return 0;
> > +
> > +       kfunc_not_supported = true;
> > +       return 0;
> > +}
> > +
> > +static void verify_fail(const char *prog_name, const char
> > *expected_err_msg)
> > +{
> > +       struct test_kfunc_dynptr_param *skel;
> > +       LIBBPF_OPTS(bpf_object_open_opts, opts);
> > +       libbpf_print_fn_t old_print_cb;
> > +       struct bpf_program *prog;
> > +       int err;
> > +
> > +       opts.kernel_log_buf = obj_log_buf;
> > +       opts.kernel_log_size = log_buf_sz;
> > +       opts.kernel_log_level = 1;
> > +
> > +       skel = test_kfunc_dynptr_param__open_opts(&opts);
> > +       if (!ASSERT_OK_PTR(skel,
> > "test_kfunc_dynptr_param__open_opts"))
> > +               goto cleanup;
> > +
> > +       prog = bpf_object__find_program_by_name(skel->obj,
> > prog_name);
> > +       if (!ASSERT_OK_PTR(prog,
> > "bpf_object__find_program_by_name"))
> > +               goto cleanup;
> > +
> > +       bpf_program__set_autoload(prog, true);
> > +
> > +       bpf_map__set_max_entries(skel->maps.ringbuf,
> > getpagesize());
> > +
> > +       kfunc_not_supported = false;
> > +
> > +       old_print_cb = libbpf_set_print(libbpf_print_cb);
> > +       err = test_kfunc_dynptr_param__load(skel);
> > +       libbpf_set_print(old_print_cb);
> > +
> > +       if (err < 0 && kfunc_not_supported) {
> > +               fprintf(stderr,
> > +                 "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not
> > supported\n",
> > +                 __func__);
> > +               test__skip();
> > +               goto cleanup;
> > +       }
> > +
> > +       if (!ASSERT_ERR(err, "unexpected load success"))
> > +               goto cleanup;
> > +
> > +       if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg),
> > "expected_err_msg")) {
> > +               fprintf(stderr, "Expected err_msg: %s\n",
> > expected_err_msg);
> > +               fprintf(stderr, "Verifier output: %s\n",
> > obj_log_buf);
> > +       }
> > +
> > +cleanup:
> > +       test_kfunc_dynptr_param__destroy(skel);
> > +}
> > +
> > +void test_kfunc_dynptr_param(void)
> > +{
> > +       int i;
> > +
> > +       for (i = 0; i < ARRAY_SIZE(kfunc_dynptr_tests); i++) {
> > +               if
> > (!test__start_subtest(kfunc_dynptr_tests[i].prog_name))
> > +                       continue;
> > +
> > +               verify_fail(kfunc_dynptr_tests[i].prog_name,
> > +                           kfunc_dynptr_tests[i].expected_err_msg)
> > ;
> > +       }
> > +}
> > diff --git
> > a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > new file mode 100644
> > index 000000000000..2f09f91a1576
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > @@ -0,0 +1,57 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/*
> > + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
> > + *
> > + * Author: Roberto Sassu <roberto.sassu@huawei.com>
> > + */
> > +
> > +#include "vmlinux.h"
> > +#include <errno.h>
> > +#include <bpf/bpf_helpers.h>
> > +#include <bpf/bpf_tracing.h>
> > +
> > +struct bpf_dynptr {
> > +       __u64 :64;
> > +       __u64 :64;
> > +} __attribute__((aligned(8)));
> > +
> > +extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
> > +                                     struct bpf_dynptr *sig_ptr,
> > +                                     struct bpf_key
> > *trusted_keyring) __ksym;
> > +
> > +struct {
> > +       __uint(type, BPF_MAP_TYPE_RINGBUF);
> > +} ringbuf SEC(".maps");
> > +
> > +char _license[] SEC("license") = "GPL";
> > +
> > +SEC("?lsm.s/bpf")
> > +int BPF_PROG(dynptr_type_not_supp, int cmd, union bpf_attr *attr,
> > +            unsigned int size)
> > +{
> > +       char write_data[64] = "hello there, world!!";
> > +       struct bpf_dynptr ptr;
> > +
> > +       bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0,
> > &ptr);
> > +
> > +       return bpf_verify_pkcs7_signature(&ptr, &ptr, NULL);
> > +}
> > +
> > +SEC("?lsm.s/bpf")
> > +int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr,
> > unsigned int size)
> > +{
> > +       unsigned long val;
> > +
> > +       return bpf_verify_pkcs7_signature((struct bpf_dynptr
> > *)&val,
> > +                                         (struct bpf_dynptr
> > *)&val, NULL);
> > +}
> > +
> > +SEC("?lsm.s/bpf")
> > +int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr,
> > unsigned int size)
> > +{
> > +       unsigned long val;
> > +
> > +       return bpf_verify_pkcs7_signature((struct bpf_dynptr *)val,
> > +                                         (struct bpf_dynptr *)val,
> > NULL);
> 
> Please also include a test where you cause the dynptr to be set to
> NULL, e.g. by passing invalid stuff to ringbuf_reserve_dynptr, and
> then try to pass it to bpf_verify_pkc7_signature.

Uhm, bpf_ringbuf_reserve_dynptr() is expecting a valid map. How else I
can achieve it?

Thanks

Roberto
Kumar Kartikeya Dwivedi Sept. 7, 2022, 2:34 a.m. UTC | #3 
On Tue, 6 Sept 2022 at 10:31, Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> On Tue, 2022-09-06 at 05:15 +0200, Kumar Kartikeya Dwivedi wrote:
> > On Mon, 5 Sept 2022 at 16:36, Roberto Sassu
> > <roberto.sassu@huaweicloud.com> wrote:
> > > From: Roberto Sassu <roberto.sassu@huawei.com>
> > >
> > > Add tests to ensure that only supported dynamic pointer types are
> > > accepted,
> > > that the passed argument is actually a dynamic pointer, and that
> > > the passed
> > > argument is a pointer to the stack.
> > >
> > > The tests are currently in the deny list for s390x (JIT does not
> > > support
> > > calling kernel function).
> > >
> > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > > ---
> > >  tools/testing/selftests/bpf/DENYLIST.s390x    |   1 +
> > >  .../bpf/prog_tests/kfunc_dynptr_param.c       | 103
> > > ++++++++++++++++++
> > >  .../bpf/progs/test_kfunc_dynptr_param.c       |  57 ++++++++++
> > >  3 files changed, 161 insertions(+)
> > >  create mode 100644
> > > tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > >  create mode 100644
> > > tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > >
> > > diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x
> > > b/tools/testing/selftests/bpf/DENYLIST.s390x
> > > index 4e305baa5277..9a6dc3671c65 100644
> > > --- a/tools/testing/selftests/bpf/DENYLIST.s390x
> > > +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
> > > @@ -71,3 +71,4 @@ cgroup_hierarchical_stats                # JIT
> > > does not support calling kernel f
> > >  htab_update                              # failed to attach:
> > > ERROR: strerror_r(-
> > > 524)=22                                (trampoline)
> > >  lookup_key                               # JIT does not support
> > > calling kernel function                                (kfunc)
> > >  verify_pkcs7_sig                         # JIT does not support
> > > calling kernel function                                (kfunc)
> > > +kfunc_dynptr_param                       # JIT does not support
> > > calling kernel function                                (kfunc)
> > > diff --git
> > > a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > > b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > > new file mode 100644
> > > index 000000000000..ea655a5c9d8b
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
> > > @@ -0,0 +1,103 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +
> > > +/*
> > > + * Copyright (c) 2022 Facebook
> > > + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
> > > + *
> > > + * Author: Roberto Sassu <roberto.sassu@huawei.com>
> > > + */
> > > +
> > > +#include <test_progs.h>
> > > +#include "test_kfunc_dynptr_param.skel.h"
> > > +
> > > +static size_t log_buf_sz = 1048576; /* 1 MB */
> > > +static char obj_log_buf[1048576];
> > > +
> > > +static struct {
> > > +       const char *prog_name;
> > > +       const char *expected_err_msg;
> > > +} kfunc_dynptr_tests[] = {
> > > +       {"dynptr_type_not_supp",
> > > +        "arg#0 pointer type STRUCT bpf_dynptr_kern points to
> > > unsupported dynamic pointer type"},
> > > +       {"not_valid_dynptr",
> > > +        "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid
> > > and initialized"},
> > > +       {"not_ptr_to_stack", "arg#0 pointer type STRUCT
> > > bpf_dynptr_kern not to stack"},
> > > +};
> > > +
> > > +static bool kfunc_not_supported;
> > > +
> > > +static int libbpf_print_cb(enum libbpf_print_level level, const
> > > char *fmt,
> > > +                          va_list args)
> > > +{
> > > +       if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found
> > > in kernel or module BTFs\n"))
> > > +               return 0;
> > > +
> > > +       if (strcmp(va_arg(args, char *),
> > > "bpf_verify_pkcs7_signature"))
> > > +               return 0;
> > > +
> > > +       kfunc_not_supported = true;
> > > +       return 0;
> > > +}
> > > +
> > > +static void verify_fail(const char *prog_name, const char
> > > *expected_err_msg)
> > > +{
> > > +       struct test_kfunc_dynptr_param *skel;
> > > +       LIBBPF_OPTS(bpf_object_open_opts, opts);
> > > +       libbpf_print_fn_t old_print_cb;
> > > +       struct bpf_program *prog;
> > > +       int err;
> > > +
> > > +       opts.kernel_log_buf = obj_log_buf;
> > > +       opts.kernel_log_size = log_buf_sz;
> > > +       opts.kernel_log_level = 1;
> > > +
> > > +       skel = test_kfunc_dynptr_param__open_opts(&opts);
> > > +       if (!ASSERT_OK_PTR(skel,
> > > "test_kfunc_dynptr_param__open_opts"))
> > > +               goto cleanup;
> > > +
> > > +       prog = bpf_object__find_program_by_name(skel->obj,
> > > prog_name);
> > > +       if (!ASSERT_OK_PTR(prog,
> > > "bpf_object__find_program_by_name"))
> > > +               goto cleanup;
> > > +
> > > +       bpf_program__set_autoload(prog, true);
> > > +
> > > +       bpf_map__set_max_entries(skel->maps.ringbuf,
> > > getpagesize());
> > > +
> > > +       kfunc_not_supported = false;
> > > +
> > > +       old_print_cb = libbpf_set_print(libbpf_print_cb);
> > > +       err = test_kfunc_dynptr_param__load(skel);
> > > +       libbpf_set_print(old_print_cb);
> > > +
> > > +       if (err < 0 && kfunc_not_supported) {
> > > +               fprintf(stderr,
> > > +                 "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not
> > > supported\n",
> > > +                 __func__);
> > > +               test__skip();
> > > +               goto cleanup;
> > > +       }
> > > +
> > > +       if (!ASSERT_ERR(err, "unexpected load success"))
> > > +               goto cleanup;
> > > +
> > > +       if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg),
> > > "expected_err_msg")) {
> > > +               fprintf(stderr, "Expected err_msg: %s\n",
> > > expected_err_msg);
> > > +               fprintf(stderr, "Verifier output: %s\n",
> > > obj_log_buf);
> > > +       }
> > > +
> > > +cleanup:
> > > +       test_kfunc_dynptr_param__destroy(skel);
> > > +}
> > > +
> > > +void test_kfunc_dynptr_param(void)
> > > +{
> > > +       int i;
> > > +
> > > +       for (i = 0; i < ARRAY_SIZE(kfunc_dynptr_tests); i++) {
> > > +               if
> > > (!test__start_subtest(kfunc_dynptr_tests[i].prog_name))
> > > +                       continue;
> > > +
> > > +               verify_fail(kfunc_dynptr_tests[i].prog_name,
> > > +                           kfunc_dynptr_tests[i].expected_err_msg)
> > > ;
> > > +       }
> > > +}
> > > diff --git
> > > a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > > b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > > new file mode 100644
> > > index 000000000000..2f09f91a1576
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
> > > @@ -0,0 +1,57 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +
> > > +/*
> > > + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
> > > + *
> > > + * Author: Roberto Sassu <roberto.sassu@huawei.com>
> > > + */
> > > +
> > > +#include "vmlinux.h"
> > > +#include <errno.h>
> > > +#include <bpf/bpf_helpers.h>
> > > +#include <bpf/bpf_tracing.h>
> > > +
> > > +struct bpf_dynptr {
> > > +       __u64 :64;
> > > +       __u64 :64;
> > > +} __attribute__((aligned(8)));
> > > +
> > > +extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
> > > +                                     struct bpf_dynptr *sig_ptr,
> > > +                                     struct bpf_key
> > > *trusted_keyring) __ksym;
> > > +
> > > +struct {
> > > +       __uint(type, BPF_MAP_TYPE_RINGBUF);
> > > +} ringbuf SEC(".maps");
> > > +
> > > +char _license[] SEC("license") = "GPL";
> > > +
> > > +SEC("?lsm.s/bpf")
> > > +int BPF_PROG(dynptr_type_not_supp, int cmd, union bpf_attr *attr,
> > > +            unsigned int size)
> > > +{
> > > +       char write_data[64] = "hello there, world!!";
> > > +       struct bpf_dynptr ptr;
> > > +
> > > +       bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0,
> > > &ptr);
> > > +
> > > +       return bpf_verify_pkcs7_signature(&ptr, &ptr, NULL);
> > > +}
> > > +
> > > +SEC("?lsm.s/bpf")
> > > +int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr,
> > > unsigned int size)
> > > +{
> > > +       unsigned long val;
> > > +
> > > +       return bpf_verify_pkcs7_signature((struct bpf_dynptr
> > > *)&val,
> > > +                                         (struct bpf_dynptr
> > > *)&val, NULL);
> > > +}
> > > +
> > > +SEC("?lsm.s/bpf")
> > > +int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr,
> > > unsigned int size)
> > > +{
> > > +       unsigned long val;
> > > +
> > > +       return bpf_verify_pkcs7_signature((struct bpf_dynptr *)val,
> > > +                                         (struct bpf_dynptr *)val,
> > > NULL);
> >
> > Please also include a test where you cause the dynptr to be set to
> > NULL, e.g. by passing invalid stuff to ringbuf_reserve_dynptr, and
> > then try to pass it to bpf_verify_pkc7_signature.
>
> Uhm, bpf_ringbuf_reserve_dynptr() is expecting a valid map. How else I
> can achieve it?

So? Just define a ringbuf map and pass to it? I'm missing why that is
undesirable.
It also needs to be a runtime test, not verifier test, I probably
replied to the wrong patch.
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index 4e305baa5277..9a6dc3671c65 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -71,3 +71,4 @@  cgroup_hierarchical_stats                # JIT does not support calling kernel f
 htab_update                              # failed to attach: ERROR: strerror_r(-524)=22                                (trampoline)
 lookup_key                               # JIT does not support calling kernel function                                (kfunc)
 verify_pkcs7_sig                         # JIT does not support calling kernel function                                (kfunc)
+kfunc_dynptr_param                       # JIT does not support calling kernel function                                (kfunc)
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
new file mode 100644
index 000000000000..ea655a5c9d8b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
@@ -0,0 +1,103 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (c) 2022 Facebook
+ * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
+ *
+ * Author: Roberto Sassu <roberto.sassu@huawei.com>
+ */
+
+#include <test_progs.h>
+#include "test_kfunc_dynptr_param.skel.h"
+
+static size_t log_buf_sz = 1048576; /* 1 MB */
+static char obj_log_buf[1048576];
+
+static struct {
+	const char *prog_name;
+	const char *expected_err_msg;
+} kfunc_dynptr_tests[] = {
+	{"dynptr_type_not_supp",
+	 "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type"},
+	{"not_valid_dynptr",
+	 "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized"},
+	{"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack"},
+};
+
+static bool kfunc_not_supported;
+
+static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt,
+			   va_list args)
+{
+	if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found in kernel or module BTFs\n"))
+		return 0;
+
+	if (strcmp(va_arg(args, char *), "bpf_verify_pkcs7_signature"))
+		return 0;
+
+	kfunc_not_supported = true;
+	return 0;
+}
+
+static void verify_fail(const char *prog_name, const char *expected_err_msg)
+{
+	struct test_kfunc_dynptr_param *skel;
+	LIBBPF_OPTS(bpf_object_open_opts, opts);
+	libbpf_print_fn_t old_print_cb;
+	struct bpf_program *prog;
+	int err;
+
+	opts.kernel_log_buf = obj_log_buf;
+	opts.kernel_log_size = log_buf_sz;
+	opts.kernel_log_level = 1;
+
+	skel = test_kfunc_dynptr_param__open_opts(&opts);
+	if (!ASSERT_OK_PTR(skel, "test_kfunc_dynptr_param__open_opts"))
+		goto cleanup;
+
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+		goto cleanup;
+
+	bpf_program__set_autoload(prog, true);
+
+	bpf_map__set_max_entries(skel->maps.ringbuf, getpagesize());
+
+	kfunc_not_supported = false;
+
+	old_print_cb = libbpf_set_print(libbpf_print_cb);
+	err = test_kfunc_dynptr_param__load(skel);
+	libbpf_set_print(old_print_cb);
+
+	if (err < 0 && kfunc_not_supported) {
+		fprintf(stderr,
+		  "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not supported\n",
+		  __func__);
+		test__skip();
+		goto cleanup;
+	}
+
+	if (!ASSERT_ERR(err, "unexpected load success"))
+		goto cleanup;
+
+	if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) {
+		fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg);
+		fprintf(stderr, "Verifier output: %s\n", obj_log_buf);
+	}
+
+cleanup:
+	test_kfunc_dynptr_param__destroy(skel);
+}
+
+void test_kfunc_dynptr_param(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(kfunc_dynptr_tests); i++) {
+		if (!test__start_subtest(kfunc_dynptr_tests[i].prog_name))
+			continue;
+
+		verify_fail(kfunc_dynptr_tests[i].prog_name,
+			    kfunc_dynptr_tests[i].expected_err_msg);
+	}
+}
diff --git a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
new file mode 100644
index 000000000000..2f09f91a1576
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
@@ -0,0 +1,57 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
+ *
+ * Author: Roberto Sassu <roberto.sassu@huawei.com>
+ */
+
+#include "vmlinux.h"
+#include <errno.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct bpf_dynptr {
+	__u64 :64;
+	__u64 :64;
+} __attribute__((aligned(8)));
+
+extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
+				      struct bpf_dynptr *sig_ptr,
+				      struct bpf_key *trusted_keyring) __ksym;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_RINGBUF);
+} ringbuf SEC(".maps");
+
+char _license[] SEC("license") = "GPL";
+
+SEC("?lsm.s/bpf")
+int BPF_PROG(dynptr_type_not_supp, int cmd, union bpf_attr *attr,
+	     unsigned int size)
+{
+	char write_data[64] = "hello there, world!!";
+	struct bpf_dynptr ptr;
+
+	bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0, &ptr);
+
+	return bpf_verify_pkcs7_signature(&ptr, &ptr, NULL);
+}
+
+SEC("?lsm.s/bpf")
+int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr, unsigned int size)
+{
+	unsigned long val;
+
+	return bpf_verify_pkcs7_signature((struct bpf_dynptr *)&val,
+					  (struct bpf_dynptr *)&val, NULL);
+}
+
+SEC("?lsm.s/bpf")
+int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr, unsigned int size)
+{
+	unsigned long val;
+
+	return bpf_verify_pkcs7_signature((struct bpf_dynptr *)val,
+					  (struct bpf_dynptr *)val, NULL);
+}