Commit 05679ca6 authored Oct 17, 2019 by Toke Høiland-Jørgensen Committed by Alexei Starovoitov Oct 18, 2019

xdp: Prevent overflow in devmap_hash cost calculation for 32-bit builds



Tetsuo pointed out that without an explicit cast, the cost calculation for
devmap_hash type maps could overflow on 32-bit builds. This adds the
missing cast.

Fixes: 6f9d451a ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191017105702.2807093-1-toke@redhat.com

parent 11875ba7

kernel/bpf/devmap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -128,7 +128,7 @@ static int dev_map_init_map(struct bpf_dtab dtab, union bpf_attr attr)

		if (!dtab->n_buckets) /* Overflow check */
		return -EINVAL;
		cost += sizeof(struct hlist_head) * dtab->n_buckets;
		cost += (u64) sizeof(struct hlist_head) * dtab->n_buckets;
		}

		/* if map size is larger than memlock limit, reject it */

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