2018-10-02 02:42:26

by Roman Gushchin

Subject: [PATCH bpf] bpf: don't accept cgroup local storage with zero value size

Explicitly forbid creating cgroup local storage maps with zero value
size, as it makes no sense and might even cause a panic.

Reported-by: [email protected]
Signed-off-by: Roman Gushchin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
---
kernel/bpf/local_storage.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index 944eb297465f..9f79956bff7d 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -261,6 +261,9 @@ static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
if (attr->key_size != sizeof(struct bpf_cgroup_storage_key))
return ERR_PTR(-EINVAL);

+ if (attr->value_size == 0)
+ return ERR_PTR(-EINVAL);
+
if (attr->value_size > PAGE_SIZE)
return ERR_PTR(-E2BIG);

--
2.17.1

2018-10-02 12:44:55

by Daniel Borkmann

Subject: Re: [PATCH bpf] bpf: don't accept cgroup local storage with zero value size

On 10/02/2018 04:41 AM, Roman Gushchin wrote:
> Explicitly forbid creating cgroup local storage maps with zero value
> size, as it makes no sense and might even cause a panic.
>
> Reported-by: [email protected]
> Signed-off-by: Roman Gushchin <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
> Cc: Daniel Borkmann <[email protected]>

Applied to bpf, thanks Roman!