From: David Miller <davem@davemloft.net>
To: john.r.fastabend@gmail.com
Cc: richard@nod.at, alexei.starovoitov@gmail.com,
netdev@vger.kernel.org, borkmann@iogearbox.net
Subject: Re: [net PATCH] bpf: devmap fix arithmetic overflow in bitmap_size calculation
Date: Sun, 22 Oct 2017 00:54:41 +0100 (WEST) [thread overview]
Message-ID: <20171022.005441.760530707225820143.davem@davemloft.net> (raw)
In-Reply-To: <150842903200.12537.10765604428561566031.stgit@john-XPS-13-9360>
From: John Fastabend <john.r.fastabend@gmail.com>
Date: Thu, 19 Oct 2017 09:03:52 -0700
> An integer overflow is possible in dev_map_bitmap_size() when
> calculating the BITS_TO_LONG logic which becomes, after macro
> replacement,
>
> (((n) + (d) - 1)/ (d))
>
> where 'n' is a __u32 and 'd' is (8 * sizeof(long)). To avoid
> overflow cast to u64 before arithmetic.
>
> Reported-by: Richard Weinberger <richard@nod.at>
> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
> Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Applied.
prev parent reply other threads:[~2017-10-21 23:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-19 16:03 [net PATCH] bpf: devmap fix arithmetic overflow in bitmap_size calculation John Fastabend
2017-10-19 22:12 ` Alexei Starovoitov
2017-10-21 23:54 ` David Miller [this message]
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