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From: Andrii Nakryiko <andrii@kernel.org>
To: bpf@vger.kernel.org, netdev@vger.kernel.org, paul@paul-moore.com,
	brauner@kernel.org
Cc: torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org, kernel-team@meta.com
Subject: [PATCH v2 bpf-next 05/30] bpf: add BPF token support to BPF_BTF_LOAD command
Date: Tue, 23 Jan 2024 18:21:02 -0800	[thread overview]
Message-ID: <20240124022127.2379740-6-andrii@kernel.org> (raw)
In-Reply-To: <20240124022127.2379740-1-andrii@kernel.org>

Accept BPF token FD in BPF_BTF_LOAD command to allow BTF data loading
through delegated BPF token. BPF_F_TOKEN_FD flag has to be specified
when passing BPF token FD. Given BPF_BTF_LOAD command didn't have flags
field before, we also add btf_flags field.

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@kernel.org>
---
 include/uapi/linux/bpf.h       |  5 +++++
 kernel/bpf/syscall.c           | 23 +++++++++++++++++++++--
 tools/include/uapi/linux/bpf.h |  5 +++++
 3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 62f8be885731..9745521f0aad 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1623,6 +1623,11 @@ union bpf_attr {
 		 * truncated), or smaller (if log buffer wasn't filled completely).
 		 */
 		__u32		btf_log_true_size;
+		__u32		btf_flags;
+		/* BPF token FD to use with BPF_BTF_LOAD operation.
+		 * If provided, btf_flags should have BPF_F_TOKEN_FD flag set.
+		 */
+		__s32		btf_token_fd;
 	};
 
 	struct {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 5144c046c52a..39b20436306f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4829,15 +4829,34 @@ 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_flags & ~BPF_F_TOKEN_FD)
+		return -EINVAL;
+
+	if (attr->btf_flags & BPF_F_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 62f8be885731..9745521f0aad 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1623,6 +1623,11 @@ union bpf_attr {
 		 * truncated), or smaller (if log buffer wasn't filled completely).
 		 */
 		__u32		btf_log_true_size;
+		__u32		btf_flags;
+		/* BPF token FD to use with BPF_BTF_LOAD operation.
+		 * If provided, btf_flags should have BPF_F_TOKEN_FD flag set.
+		 */
+		__s32		btf_token_fd;
 	};
 
 	struct {
-- 
2.34.1


  parent reply	other threads:[~2024-01-24  2:21 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-24  2:20 [PATCH v2 bpf-next 00/30] BPF token Andrii Nakryiko
2024-01-24  2:20 ` [PATCH v2 bpf-next 01/30] bpf: align CAP_NET_ADMIN checks with bpf_capable() approach Andrii Nakryiko
2024-01-24  2:20 ` [PATCH v2 bpf-next 02/30] bpf: add BPF token delegation mount options to BPF FS Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 03/30] bpf: introduce BPF token object Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 04/30] bpf: add BPF token support to BPF_MAP_CREATE command Andrii Nakryiko
2024-01-24  2:21 ` Andrii Nakryiko [this message]
2024-01-24  2:21 ` [PATCH v2 bpf-next 06/30] bpf: add BPF token support to BPF_PROG_LOAD command Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 07/30] bpf: take into account BPF token when fetching helper protos Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 08/30] bpf: consistently use BPF token throughout BPF verifier logic Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 09/30] bpf,lsm: refactor bpf_prog_alloc/bpf_prog_free LSM hooks Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 10/30] bpf,lsm: refactor bpf_map_alloc/bpf_map_free " Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 11/30] bpf,lsm: add BPF token " Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 12/30] libbpf: add bpf_token_create() API Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 13/30] libbpf: add BPF token support to bpf_map_create() API Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 14/30] libbpf: add BPF token support to bpf_btf_load() API Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 15/30] libbpf: add BPF token support to bpf_prog_load() API Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 16/30] selftests/bpf: add BPF token-enabled tests Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 17/30] bpf,selinux: allocate bpf_security_struct per BPF token Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 18/30] bpf: fail BPF_TOKEN_CREATE if no delegation option was set on BPF FS Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 19/30] bpf: support symbolic BPF FS delegation mount options Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 20/30] selftests/bpf: utilize string values for delegate_xxx " Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 21/30] libbpf: split feature detectors definitions from cached results Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 22/30] libbpf: further decouple feature checking logic from bpf_object Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 23/30] libbpf: move feature detection code into its own file Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 24/30] libbpf: wire up token_fd into feature probing logic Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 25/30] libbpf: wire up BPF token support at BPF object level Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 26/30] selftests/bpf: add BPF object loading tests with explicit token passing Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 27/30] selftests/bpf: add tests for BPF object load with implicit token Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 28/30] libbpf: support BPF token path setting through LIBBPF_BPF_TOKEN_PATH envvar Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 29/30] selftests/bpf: add tests for " Andrii Nakryiko
2024-01-24  2:21 ` [PATCH v2 bpf-next 30/30] selftests/bpf: incorporate LSM policy to token-based tests Andrii Nakryiko
2024-01-25  0:10 ` [PATCH v2 bpf-next 00/30] BPF token patchwork-bot+netdevbpf

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