Commit b845c898 authored Aug 21, 2018 by Daniel Borkmann

bpf, sockmap: fix sock_hash_alloc and reject zero-sized keys



Currently, it is possible to create a sock hash map with key size
of 0 and have the kernel return a fd back to user space. This is
invalid for hash maps (and kernel also hasn't been tested for zero
key size support in general at this point). Thus, reject such
configuration.

Fixes: 81110384 ("bpf: sockmap, add hash map support")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>

parent 96c26e04

kernel/bpf/sockmap.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2140,7 +2140,9 @@ static struct bpf_map sock_hash_alloc(union bpf_attr attr)
		return ERR_PTR(-EPERM);

		/* check sanity of attributes */
		if (attr->max_entries == 0 \|\| attr->value_size != 4 \|\|
		if (attr->max_entries == 0 \|\|
		attr->key_size == 0 \|\|
		attr->value_size != 4 \|\|
		attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
		return ERR_PTR(-EINVAL);

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