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 18/30] bpf: fail BPF_TOKEN_CREATE if no delegation option was set on BPF FS
Date: Tue, 23 Jan 2024 18:21:15 -0800 [thread overview]
Message-ID: <20240124022127.2379740-19-andrii@kernel.org> (raw)
In-Reply-To: <20240124022127.2379740-1-andrii@kernel.org>
It's quite confusing in practice when it's possible to successfully
create a BPF token from BPF FS that didn't have any of delegate_xxx
mount options set up. While it's not wrong, it's actually more
meaningful to reject BPF_TOKEN_CREATE with specific error code (-ENOENT)
to let user-space know that no token delegation is setup up.
So, instead of creating empty BPF token that will be always ignored
because it doesn't have any of the allow_xxx bits set, reject it with
-ENOENT. If we ever need empty BPF token to be possible, we can support
that with extra flag passed into BPF_TOKEN_CREATE.
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/bpf/token.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c
index 64c568f47f69..0bca93b60c43 100644
--- a/kernel/bpf/token.c
+++ b/kernel/bpf/token.c
@@ -162,6 +162,15 @@ int bpf_token_create(union bpf_attr *attr)
goto out_path;
}
+ mnt_opts = path.dentry->d_sb->s_fs_info;
+ if (mnt_opts->delegate_cmds == 0 &&
+ mnt_opts->delegate_maps == 0 &&
+ mnt_opts->delegate_progs == 0 &&
+ mnt_opts->delegate_attachs == 0) {
+ err = -ENOENT; /* no BPF token delegation is set up */
+ goto out_path;
+ }
+
mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
inode = bpf_get_inode(path.mnt->mnt_sb, NULL, mode);
if (IS_ERR(inode)) {
@@ -191,7 +200,6 @@ int bpf_token_create(union bpf_attr *attr)
/* remember bpffs owning userns for future ns_capable() checks */
token->userns = get_user_ns(userns);
- mnt_opts = path.dentry->d_sb->s_fs_info;
token->allowed_cmds = mnt_opts->delegate_cmds;
token->allowed_maps = mnt_opts->delegate_maps;
token->allowed_progs = mnt_opts->delegate_progs;
--
2.34.1
next prev parent reply other threads:[~2024-01-24 2:22 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 ` [PATCH v2 bpf-next 05/30] bpf: add BPF token support to BPF_BTF_LOAD command Andrii Nakryiko
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 ` Andrii Nakryiko [this message]
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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