From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>,
<martin.lau@kernel.org>
Cc: <andrii@kernel.org>, <kernel-team@meta.com>
Subject: [PATCH bpf-next 1/3] bpf: drop unnecessary bpf_capable() check in BPF_MAP_FREEZE command
Date: Wed, 24 May 2023 15:54:19 -0700 [thread overview]
Message-ID: <20230524225421.1587859-2-andrii@kernel.org> (raw)
In-Reply-To: <20230524225421.1587859-1-andrii@kernel.org>
Seems like that extra bpf_capable() check in BPF_MAP_FREEZE handler was
unintentionally left when we switched to a model that all BPF map
operations should be allowed regardless of CAP_BPF (or any other
capabilities), as long as process got BPF map FD somehow.
This patch replaces bpf_capable() check in BPF_MAP_FREEZE handler with
writeable access check, given conceptually freezing the map is modifying
it: map becomes unmodifiable for subsequent updates.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/bpf/syscall.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c7f6807215e6..c9a201e4c457 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1931,6 +1931,11 @@ static int map_freeze(const union bpf_attr *attr)
return -ENOTSUPP;
}
+ if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
+ err = -EPERM;
+ goto err_put;
+ }
+
mutex_lock(&map->freeze_mutex);
if (bpf_map_write_active(map)) {
err = -EBUSY;
@@ -1940,10 +1945,6 @@ static int map_freeze(const union bpf_attr *attr)
err = -EBUSY;
goto err_put;
}
- if (!bpf_capable()) {
- err = -EPERM;
- goto err_put;
- }
WRITE_ONCE(map->frozen, true);
err_put:
--
2.34.1
next prev parent reply other threads:[~2023-05-24 22:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-24 22:54 [PATCH bpf-next 0/3] Relax checks for unprivileged bpf() commands Andrii Nakryiko
2023-05-24 22:54 ` Andrii Nakryiko [this message]
2023-05-24 22:54 ` [PATCH bpf-next 2/3] bpf: don't require CAP_SYS_ADMIN for getting NEXT_ID Andrii Nakryiko
2023-05-25 3:22 ` Alexei Starovoitov
2023-05-25 17:04 ` Andrii Nakryiko
2023-05-25 17:11 ` Alexei Starovoitov
2023-05-25 17:30 ` Andrii Nakryiko
2023-05-24 22:54 ` [PATCH bpf-next 3/3] bpf: don't require bpf_capable() for GET_INFO_BY_FD Andrii Nakryiko
2023-05-25 13:13 ` Daniel Borkmann
2023-05-25 17:20 ` Andrii Nakryiko
2023-05-25 19:49 ` Daniel Borkmann
2023-05-25 17:20 ` [PATCH bpf-next 0/3] Relax checks for unprivileged bpf() commands patchwork-bot+netdevbpf
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