bpf: fix possible spectre-v1 in find_and_alloc_map()
It's possible for userspace to control attr->map_type. Sanitize it when using it as an array index to prevent an out-of-bounds value being used under speculation. Found by smatch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: netdev@vger.kernel.org Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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@ -26,6 +26,7 @@
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#include <linux/cred.h>
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#include <linux/timekeeping.h>
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#include <linux/ctype.h>
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#include <linux/nospec.h>
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#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY || \
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(map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
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@ -102,12 +103,14 @@ const struct bpf_map_ops bpf_map_offload_ops = {
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static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
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{
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const struct bpf_map_ops *ops;
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u32 type = attr->map_type;
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struct bpf_map *map;
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int err;
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if (attr->map_type >= ARRAY_SIZE(bpf_map_types))
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if (type >= ARRAY_SIZE(bpf_map_types))
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return ERR_PTR(-EINVAL);
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ops = bpf_map_types[attr->map_type];
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type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types));
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ops = bpf_map_types[type];
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if (!ops)
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return ERR_PTR(-EINVAL);
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@ -122,7 +125,7 @@ static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
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if (IS_ERR(map))
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return map;
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map->ops = ops;
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map->map_type = attr->map_type;
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map->map_type = type;
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return map;
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}
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