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* [PATCH bpf] xdp: Prevent overflow in devmap_hash cost calculation for 32-bit builds
@ 2019-10-17 10:57 Toke Høiland-Jørgensen
  2019-10-17 18:52 ` Jakub Kicinski
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-17 10:57 UTC (permalink / raw)
  To: daniel, ast; +Cc: Toke Høiland-Jørgensen, bpf, netdev, Tetsuo Handa

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 <toke@redhat.com>
---
 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 */
-- 
2.23.0


^ permalink raw reply related	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2019-10-19  0:44 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-17 10:57 [PATCH bpf] xdp: Prevent overflow in devmap_hash cost calculation for 32-bit builds Toke Høiland-Jørgensen
2019-10-17 18:52 ` Jakub Kicinski
2019-10-18  9:15   ` Toke Høiland-Jørgensen
2019-10-18 17:19     ` Jakub Kicinski
2019-10-18 16:44 ` Yonghong Song
2019-10-18 23:25 ` Alexei Starovoitov
2019-10-18 23:31   ` Jakub Kicinski
2019-10-19  0:44   ` David Miller

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