iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

selftests/bpf: add tests for LIBBPF_BPF_TOKEN_PATH envvar

Browse Source 
Add new subtest validating LIBBPF_BPF_TOKEN_PATH envvar semantics.
Extend existing test to validate that LIBBPF_BPF_TOKEN_PATH allows to
disable implicit BPF token creation by setting envvar to empty string.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231213190842.3844987-11-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko 2023-12-13 11:08:42 -08:00 committed by Alexei Starovoitov
parent ed54124b88
commit 322122bf8c
1 changed files with 112 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

112
tools/testing/selftests/bpf/prog_tests/token.c
View File

@ -769,6 +769,9 @@ static int userns_obj_priv_btf_success(int mnt_fd)
return validate_struct_ops_load(mnt_fd, true /* should succeed */);
}
#define TOKEN_ENVVAR "LIBBPF_BPF_TOKEN_PATH"
#define TOKEN_BPFFS_CUSTOM "/bpf-token-fs"
static int userns_obj_priv_implicit_token(int mnt_fd)
{
LIBBPF_OPTS(bpf_object_open_opts, opts);
@ -791,6 +794,20 @@ static int userns_obj_priv_implicit_token(int mnt_fd)
if (!ASSERT_OK(err, "move_mount_bpffs"))
return -EINVAL;
/* disable implicit BPF token creation by setting
* LIBBPF_BPF_TOKEN_PATH envvar to empty value, load should fail
*/
err = setenv(TOKEN_ENVVAR, "", 1 /*overwrite*/);
if (!ASSERT_OK(err, "setenv_token_path"))
return -EINVAL;
skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_ERR_PTR(skel, "obj_token_envvar_disabled_load")) {
unsetenv(TOKEN_ENVVAR);
dummy_st_ops_success__destroy(skel);
return -EINVAL;
}
unsetenv(TOKEN_ENVVAR);
/* now the same struct_ops skeleton should succeed thanks to libppf
* creating BPF token from /sys/fs/bpf mount point
*/
@ -826,6 +843,90 @@ static int userns_obj_priv_implicit_token(int mnt_fd)
return 0;
}
static int userns_obj_priv_implicit_token_envvar(int mnt_fd)
{
LIBBPF_OPTS(bpf_object_open_opts, opts);
struct dummy_st_ops_success *skel;
int err;
/* before we mount BPF FS with token delegation, struct_ops skeleton
* should fail to load
*/
skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load")) {
dummy_st_ops_success__destroy(skel);
return -EINVAL;
}
/* mount custom BPF FS over custom location, so libbpf can't create
* BPF token implicitly, unless pointed to it through
* LIBBPF_BPF_TOKEN_PATH envvar
*/
rmdir(TOKEN_BPFFS_CUSTOM);
if (!ASSERT_OK(mkdir(TOKEN_BPFFS_CUSTOM, 0777), "mkdir_bpffs_custom"))
goto err_out;
err = sys_move_mount(mnt_fd, "", AT_FDCWD, TOKEN_BPFFS_CUSTOM, MOVE_MOUNT_F_EMPTY_PATH);
if (!ASSERT_OK(err, "move_mount_bpffs"))
goto err_out;
/* even though we have BPF FS with delegation, it's not at default
* /sys/fs/bpf location, so we still fail to load until envvar is set up
*/
skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load2")) {
dummy_st_ops_success__destroy(skel);
goto err_out;
}
err = setenv(TOKEN_ENVVAR, TOKEN_BPFFS_CUSTOM, 1 /*overwrite*/);
if (!ASSERT_OK(err, "setenv_token_path"))
goto err_out;
/* now the same struct_ops skeleton should succeed thanks to libppf
* creating BPF token from custom mount point
*/
skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_OK_PTR(skel, "obj_implicit_token_load"))
goto err_out;
dummy_st_ops_success__destroy(skel);
/* now disable implicit token through empty bpf_token_path, envvar
* will be ignored, should fail
*/
opts.bpf_token_path = "";
skel = dummy_st_ops_success__open_opts(&opts);
if (!ASSERT_OK_PTR(skel, "obj_empty_token_path_open"))
goto err_out;
err = dummy_st_ops_success__load(skel);
dummy_st_ops_success__destroy(skel);
if (!ASSERT_ERR(err, "obj_empty_token_path_load"))
goto err_out;
/* now disable implicit token through negative bpf_token_fd, envvar
* will be ignored, should fail
*/
opts.bpf_token_path = NULL;
opts.bpf_token_fd = -1;
skel = dummy_st_ops_success__open_opts(&opts);
if (!ASSERT_OK_PTR(skel, "obj_neg_token_fd_open"))
goto err_out;
err = dummy_st_ops_success__load(skel);
dummy_st_ops_success__destroy(skel);
if (!ASSERT_ERR(err, "obj_neg_token_fd_load"))
goto err_out;
rmdir(TOKEN_BPFFS_CUSTOM);
unsetenv(TOKEN_ENVVAR);
return 0;
err_out:
rmdir(TOKEN_BPFFS_CUSTOM);
unsetenv(TOKEN_ENVVAR);
return -EINVAL;
}
#define bit(n) (1ULL << (n))
void test_token(void)
@ -904,4 +1005,15 @@ void test_token(void)
subtest_userns(&opts, userns_obj_priv_implicit_token);
}
if (test__start_subtest("obj_priv_implicit_token_envvar")) {
struct bpffs_opts opts = {
/* allow BTF loading */
.cmds = bit(BPF_BTF_LOAD) | bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD),
.maps = bit(BPF_MAP_TYPE_STRUCT_OPS),
.progs = bit(BPF_PROG_TYPE_STRUCT_OPS),
.attachs = ~0ULL,
};
subtest_userns(&opts, userns_obj_priv_implicit_token_envvar);
}
}