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From: Jakub Kicinski <kuba@kernel.org>
To: Emil Tsalapatis <emil@etsalapatis.com>
Cc: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org,
	eddyz87@gmail.com, memxor@gmail.com, daniel@iogearbox.net,
	netdev@vger.kernel.org, Nicholas Carlini <nicholas@carlini.com>
Subject: Re: [PATCH bpf 01/11] bpf: Fix bounds check for skb-backed dynptrs
Date: Wed, 16 Sep 2026 16:08:46 -0700	[thread overview]
Message-ID: <20260916160846.557e2ee9@kernel.org> (raw)
In-Reply-To: <20260916050830.8774-2-emil@etsalapatis.com>

On Wed, 16 Sep 2026 05:08:19 +0000 Emil Tsalapatis wrote:
> -	if (likely(skb_headlen(skb) - offset >= len))
> +	if (likely((u64)offset <= skb_headlen(skb) && 
> +			(u64)len <= skb_headlen(skb) - (u64)offset))

I don't think the 64b arithmetic is needed since the max value
(headlen) itself is 32b. You can cast to unsigned int.

Also the continuation line is mis-aligned 

  parent reply	other threads:[~2026-09-16 23:08 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-16  5:08 [PATCH bpf 00/11] skb/arena bugfixes Emil Tsalapatis
2026-09-16  5:08 ` [PATCH bpf 01/11] bpf: Fix bounds check for skb-backed dynptrs Emil Tsalapatis
2026-09-16 11:52   ` Jiayuan Chen
2026-09-16 23:08   ` Jakub Kicinski [this message]
2026-09-16  5:08 ` [PATCH bpf 02/11] selftests/bpf: Test dynptr slices past end of skb Emil Tsalapatis
2026-09-16  5:18   ` sashiko-bot
2026-09-16  5:08 ` [PATCH bpf 03/11] bpf: Fix bpf_sock context code generation Emil Tsalapatis
2026-09-16 12:21   ` Jiayuan Chen
2026-09-16  5:08 ` [PATCH bpf 04/11] selftests/bpf: Add selftests for rx_queue_mapping context access Emil Tsalapatis
2026-09-16  5:08 ` [PATCH bpf 05/11] bpf: Reject pkt arguments in mutating subprogs Emil Tsalapatis
2026-09-16  5:57   ` Amery Hung
2026-09-16  5:58     ` Amery Hung
2026-09-16 18:41     ` Emil Tsalapatis
2026-09-16 19:26       ` Amery Hung
2026-09-16  5:08 ` [PATCH bpf 06/11] selftests/bpf: Test rejection of pkt args to " Emil Tsalapatis
2026-09-16  5:08 ` [PATCH bpf 07/11] bpf: Prevent variable arena/non-arena register contents Emil Tsalapatis
2026-09-16  5:08 ` [PATCH bpf 08/11] selftests/bpf: Test for mixed arena/nonarena code paths Emil Tsalapatis
2026-09-16  5:17   ` sashiko-bot
2026-09-16  5:08 ` [PATCH bpf 09/11] bpf: Track whether dynptr type is known Emil Tsalapatis
2026-09-16  5:22   ` sashiko-bot
2026-09-16 18:41     ` Emil Tsalapatis
2026-09-16  5:08 ` [PATCH bpf 10/11] bpf: Track skb memory invalidation by packet-backed dynptrs Emil Tsalapatis
2026-09-16  5:08 ` [PATCH bpf 11/11] selftests/bpf: Test dynptr slice invalidation on skb clobber Emil Tsalapatis

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