Daniel Borkmann e94fa1d931 bpf, xskmap: fix crash in xsk_map_alloc error path handling ...

If bpf_map_precharge_memlock() did not fail, then we set err to zero.
However, any subsequent failure from either alloc_percpu() or the
bpf_map_area_alloc() will return ERR_PTR(0) which in find_and_alloc_map()
will cause NULL pointer deref.

In devmap we have the convention that we return -EINVAL on page count
overflow, so keep the same logic here and just set err to -ENOMEM
after successful bpf_map_precharge_memlock().

Fixes: fbfc504a24 ("bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAP")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Björn Töpel <bjorn.topel@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2018-05-04 14:55:54 -07:00

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