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@xxxxxxxxxx>
---
include/uapi/linux/bpf.h | 1 +
kernel/bpf/syscall.c | 20 ++++++++++++++++++--
tools/include/uapi/linux/bpf.h | 1 +
3 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 59764ba48ec9..fa6a9e2396e6 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1536,6 +1536,7 @@ 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 cc15b1d5dc26..f295458a35c0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4484,15 +4484,31 @@ 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);
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 59764ba48ec9..fa6a9e2396e6 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1536,6 +1536,7 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 btf_log_true_size;
+ __u32 btf_token_fd;
};
struct {
--
2.34.1
