[PATCH RESEND bpf-next 10/18] bpf: add BPF token support to BPF_BTF_LOAD command
Andrii Nakryiko
andrii at kernel.org
Fri Jun 2 15:00:03 UTC 2023
Accept BPF token FD in BPF_BTF_LOAD command to allow BTF data loading
through delegated BPF token. BTF loading is a pretty straightforward
operation, so as long as BPF token is created with allow_cmds granting
BPF_BTF_LOAD command, kernel proceeds to parsing BTF data and creating
BTF object.
Signed-off-by: Andrii Nakryiko <andrii at kernel.org>
---
include/uapi/linux/bpf.h | 1 +
kernel/bpf/syscall.c | 21 +++++++++++++++++--
tools/include/uapi/linux/bpf.h | 1 +
.../selftests/bpf/prog_tests/libbpf_probes.c | 2 ++
4 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7cfaa2da84ee..d30fb567d22a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1549,6 +1549,7 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 btf_log_true_size;
+ __u32 btf_token_fd;
};
struct {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index eb77ba71fbcf..05e941e9bbe6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4475,15 +4475,31 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
return err;
}
-#define BPF_BTF_LOAD_LAST_FIELD btf_log_true_size
+#define BPF_BTF_LOAD_LAST_FIELD btf_token_fd
static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
{
+ struct bpf_token *token = NULL;
+
if (CHECK_ATTR(BPF_BTF_LOAD))
return -EINVAL;
- if (!bpf_capable())
+ if (attr->btf_token_fd) {
+ token = bpf_token_get_from_fd(attr->btf_token_fd);
+ if (IS_ERR(token))
+ return PTR_ERR(token);
+ if (!bpf_token_allow_cmd(token, BPF_BTF_LOAD)) {
+ bpf_token_put(token);
+ token = NULL;
+ }
+ }
+
+ if (!bpf_token_capable(token, CAP_BPF)) {
+ bpf_token_put(token);
return -EPERM;
+ }
+
+ bpf_token_put(token);
return btf_new_fd(attr, uattr, uattr_size);
}
@@ -5120,6 +5136,7 @@ static int bpf_prog_bind_map(union bpf_attr *attr)
#define BPF_TOKEN_CMDS_MASK ( \
(1ULL << BPF_TOKEN_CREATE) \
| (1ULL << BPF_MAP_CREATE) \
+ | (1ULL << BPF_BTF_LOAD) \
)
#define BPF_TOKEN_MAP_TYPES_MASK \
((BIT_ULL(__MAX_BPF_MAP_TYPE) - 1) & ~BIT_ULL(BPF_MAP_TYPE_UNSPEC))
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7cfaa2da84ee..d30fb567d22a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1549,6 +1549,7 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 btf_log_true_size;
+ __u32 btf_token_fd;
};
struct {
diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
index 9f766ddd946a..573249a2814d 100644
--- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
+++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
@@ -68,6 +68,8 @@ void test_libbpf_probe_map_types(void)
if (map_type == BPF_MAP_TYPE_UNSPEC)
continue;
+ if (strcmp(map_type_name, "__MAX_BPF_MAP_TYPE") == 0)
+ continue;
if (!test__start_subtest(map_type_name))
continue;
--
2.34.1
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