From: daniel@iogearbox.net (Daniel Borkmann)
To: linux-security-module@vger.kernel.org
Subject: [PATCH net-next 1/4] bpf: Add file mode configuration into bpf maps
Date: Thu, 05 Oct 2017 01:29:49 +0200 [thread overview]
Message-ID: <59D56EED.1030804@iogearbox.net> (raw)
In-Reply-To: <20171004182932.140028-2-chenbofeng.kernel@gmail.com>
On 10/04/2017 08:29 PM, Chenbo Feng wrote:
> From: Chenbo Feng <fengc@google.com>
>
> Introduce the map read/write flags to the eBPF syscalls that returns the
> map fd. The flags is used to set up the file mode when construct a new
> file descriptor for bpf maps. To not break the backward capability, the
> f_flags is set to O_RDWR if the flag passed by syscall is 0. Otherwise
> it should be O_RDONLY or O_WRONLY. When the userspace want to modify or
> read the map content, it will check the file mode to see if it is
> allowed to make the change.
[...]
> +int bpf_get_file_flag(int flags)
> +{
> + if ((flags & BPF_F_RDONLY) && (flags & BPF_F_WRONLY))
> + return -EINVAL;
> + if (flags & BPF_F_RDONLY)
> + return O_RDONLY;
> + if (flags & BPF_F_WRONLY)
> + return O_WRONLY;
> + return O_RDWR;
> }
>
> /* helper macro to check that unused fields 'union bpf_attr' are zero */
> @@ -345,12 +376,17 @@ static int map_create(union bpf_attr *attr)
> {
> int numa_node = bpf_map_attr_numa_node(attr);
> struct bpf_map *map;
> + int f_flags;
> int err;
>
> err = CHECK_ATTR(BPF_MAP_CREATE);
> if (err)
> return -EINVAL;
>
> + f_flags = bpf_get_file_flag(attr->map_flags);
> + if (f_flags < 0)
> + return f_flags;
Wait, I just noticed, given you add BPF_F_RDONLY/BPF_F_WRONLY
to attr->map_flags, and later go into find_and_alloc_map(),
for map alloc, which is e.g. array_map_alloc(). There, we
bail out with EINVAL on attr->map_flags & ~BPF_F_NUMA_NODE,
which is the case for both BPF_F_RDONLY/BPF_F_WRONLY ... I
would have expected that the entire code was tested properly;
what was tested exactly in the set?
> if (numa_node != NUMA_NO_NODE &&
> ((unsigned int)numa_node >= nr_node_ids ||
> !node_online(numa_node)))
> @@ -376,7 +412,7 @@ static int map_create(union bpf_attr *attr)
> if (err)
> goto free_map;
>
> - err = bpf_map_new_fd(map);
> + err = bpf_map_new_fd(map, f_flags);
> if (err < 0) {
> /* failed to allocate fd.
> * bpf_map_put() is needed because the above
> @@ -491,6 +527,11 @@ static int map_lookup_elem(union bpf_attr *attr)
[...]
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next prev parent reply other threads:[~2017-10-04 23:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 18:29 [PATCH 0/4] net-next: security: New file mode and LSM hooks for eBPF object permission control Chenbo Feng
2017-10-04 18:29 ` [PATCH net-next 1/4] bpf: Add file mode configuration into bpf maps Chenbo Feng
2017-10-04 23:29 ` Daniel Borkmann [this message]
2017-10-04 23:58 ` Chenbo Feng
2017-10-05 0:51 ` Daniel Borkmann
2017-10-04 18:29 ` [PATCH net-next 2/4] security: bpf: Add LSM hooks for bpf object related syscall Chenbo Feng
2017-10-12 0:31 ` James Morris
2017-10-04 18:29 ` [PATCH net-next 3/4] selinux: bpf: Add selinux check for eBPF syscall operations Chenbo Feng
2017-10-05 13:28 ` Stephen Smalley
2017-10-05 16:12 ` Daniel Borkmann
2017-10-04 18:29 ` [PATCH net-next 4/4] selinux: bpf: Add addtional check for bpf object file receive Chenbo Feng
2017-10-04 23:44 ` Daniel Borkmann
2017-10-04 23:52 ` Daniel Borkmann
2017-10-05 13:37 ` Stephen Smalley
2017-10-05 18:26 ` Stephen Smalley
2017-10-06 21:10 ` Chenbo Feng
2017-10-06 21:00 ` Chenbo Feng
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