Re: [PATCH bpf] xdp: Prevent overflow in devmap_hash cost calculation for 32-bit builds
From: Yonghong Song <hidden>
Date: 2019-10-18 16:44:28
Also in:
bpf
On 10/17/19 3:57 AM, Toke Høiland-Jørgensen wrote:
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: 6f9d451ab1a3 ("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 <redacted>Acked-by: Yonghong Song <redacted>
quoted hunk ↗ jump to hunk
--- kernel/bpf/devmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index a0a1153da5ae..e34fac6022eb 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c@@ -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 */