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selftests/bpf: Add tests for BPF object load with implicit token

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Add a test to validate libbpf's implicit BPF token creation from default
BPF FS location (/sys/fs/bpf). Also validate that disabling this
implicit BPF token creation works.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-28-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
2024-01-23 18:21:24 -08:00
committed by Alexei Starovoitov
parent d5baf0cac6
commit b73d08d131
1 changed files with 64 additions and 0 deletions
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64
tools/testing/selftests/bpf/prog_tests/token.c
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@@ -12,6 +12,7 @@
#include <linux/unistd.h>
#include <linux/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/un.h>
#include "priv_map.skel.h"
@@ -45,6 +46,13 @@ static inline int sys_fsmount(int fs_fd, unsigned flags, unsigned ms_flags)
return syscall(__NR_fsmount, fs_fd, flags, ms_flags);
}
static inline int sys_move_mount(int from_dfd, const char *from_path,
int to_dfd, const char *to_path,
unsigned flags)
{
return syscall(__NR_move_mount, from_dfd, from_path, to_dfd, to_path, flags);
}
static int drop_priv_caps(__u64 *old_caps)
{
return cap_disable_effective((1ULL << CAP_BPF) |
@@ -765,6 +773,51 @@ static int userns_obj_priv_btf_success(int mnt_fd)
return validate_struct_ops_load(mnt_fd, true /* should succeed */);
}
static int userns_obj_priv_implicit_token(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 /sys/fs/bpf so that libbpf can create BPF
* token automatically and implicitly
*/
err = sys_move_mount(mnt_fd, "", AT_FDCWD, "/sys/fs/bpf", MOVE_MOUNT_F_EMPTY_PATH);
if (!ASSERT_OK(err, "move_mount_bpffs"))
return -EINVAL;
/* now the same struct_ops skeleton should succeed thanks to libppf
* creating BPF token from /sys/fs/bpf mount point
*/
skel = dummy_st_ops_success__open_and_load();
if (!ASSERT_OK_PTR(skel, "obj_implicit_token_load"))
return -EINVAL;
dummy_st_ops_success__destroy(skel);
/* now disable implicit token through empty bpf_token_path, should fail */
opts.bpf_token_path = "";
skel = dummy_st_ops_success__open_opts(&opts);
if (!ASSERT_OK_PTR(skel, "obj_empty_token_path_open"))
return -EINVAL;
err = dummy_st_ops_success__load(skel);
dummy_st_ops_success__destroy(skel);
if (!ASSERT_ERR(err, "obj_empty_token_path_load"))
return -EINVAL;
return 0;
}
#define bit(n) (1ULL << (n))
void test_token(void)
@@ -832,4 +885,15 @@ void test_token(void)
subtest_userns(&opts, userns_obj_priv_btf_success);
}
if (test__start_subtest("obj_priv_implicit_token")) {
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);
}
}