bpf: fix wrong helper enablement in cgroup local storage
Commit cd339431 ("bpf: introduce the bpf_get_local_storage() helper function") enabled the bpf_get_local_storage() helper also for BPF program types where it does not make sense to use them. They have been added both in sk_skb_func_proto() and sk_msg_func_proto() even though both program types are not invoked in combination with cgroups, and neither through BPF_PROG_RUN_ARRAY(). In the latter the bpf_cgroup_storage_set() is set shortly before BPF program invocation. Later, the helper bpf_get_local_storage() retrieves this prior set up per-cpu pointer and hands the buffer to the BPF program. The map argument in there solely retrieves the enum bpf_cgroup_storage_type from a local storage map associated with the program and based on the type returns either the global or per-cpu storage. However, there is no specific association between the program's map and the actual content in bpf_cgroup_storage[]. Meaning, any BPF program that would have been properly run from the cgroup side through BPF_PROG_RUN_ARRAY() where bpf_cgroup_storage_set() was performed, and that is later unloaded such that prog / maps are teared down will cause a use after free if that pointer is retrieved from programs that are not run through BPF_PROG_RUN_ARRAY() but have the cgroup local storage helper enabled in their func proto. Lets just remove it from the two sock_map program types to fix it. Auditing through the types where this helper is enabled, it appears that these are the only ones where it was mistakenly allowed. Fixes: cd339431 ("bpf: introduce the bpf_get_local_storage() helper function") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Roman Gushchin <guro@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Roman Gushchin <guro@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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