From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 077B8303C97; Mon, 17 Aug 2026 14:10:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786975822; cv=none; b=G4PHsaLgbElfHuMS26QPPAv1bb9YnUpP4Z9nlFIEYeE39/ELn8v6t0THWHbt/ZroU9MXxl6iGWgCu5psKK0M7wcEHuDknvsIWkjV24WlZDX9zYReqJQGAyNm/9D04zcfeBTlnazJdaMxND566r830/RGzUne5Vl8giC5MM0h3js= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786975822; c=relaxed/simple; bh=cfCsZYXp1CeSp0NWC2XaEz0mV5RIklZvXfVcBpK4rx0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YGBB2HeVgDL3zfBqZQj6f8D8G7+NhvJhJnQxBZmSgf0S9IOBp1w2S3rasRLWgAh52dxr3vTRdxkiM/gmAHUlfJYRU7qZynhlGo+rvV5jG3ixLtLaNzf5rWpV7CX0jDNkJDhNahnuYFxBfwB6vpEOHInqXybnKieP/oL9iG3kRxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Agd7moFm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Agd7moFm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 582C31F00A3A; Mon, 17 Aug 2026 14:10:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786975820; bh=B33tnM32NTZa66KFwDiTusPS02b0SsXFaef5soJ/5a8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Agd7moFmm6nWcqvd25KuPzNzl08P+K9QrOohu/O0oOULXUMjyAvOUqe/B45HnCJBS C+3LsCDu7A9VCxzt6kgPfS7Or2Nc2pbnDhz7vy8/s4ISp2xWb3ZcNBC4Rsvw/H+425 YpRpu7/Lz3Cj8WNw9RulXt09BXaTmcvCXajq6j+hYE+g8WXn+w12C6/yVJwIHqCHVn Rhu0Cs5dgRBQcDFR16u0yEuAr7gpoaI3A8mNN35ZRBEZN8XkgkjZ9oHReQQsxS2EkL sC9+Nb6EDeumy4FAIl91nbX6F1adATQlMm+qrA8d7KDbjBQs3+khxzBtY9sDC73gVs Cp/OMrqqu9aAQ== Date: Mon, 17 Aug 2026 15:10:16 +0100 From: Simon Horman To: "Cen Zhang (Microsoft)" Cc: magnus.karlsson@intel.com, kerneljasonxing@gmail.com, maciej.fijalkowski@intel.com, sdf@fomichev.me, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, AutonomousCodeSecurity@microsoft.com, tgopinath@linux.microsoft.com, kys@microsoft.com Subject: Re: [PATCH net v4] xsk: fix NULL pointer dereference in __xsk_rcv() Message-ID: <20260817141016.GZ265046@horms.kernel.org> References: <20260813215328.99311-1-blbllhy@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260813215328.99311-1-blbllhy@gmail.com> On Thu, Aug 13, 2026 at 05:53:28PM -0400, Cen Zhang (Microsoft) wrote: > In the __xsk_rcv() multi-buffer path, xsk_buff_alloc() is called in a > loop without checking its return value. xsk_buff_can_alloc() only > counts fill queue entries without validating their addresses, so it > can succeed while xsk_buff_alloc() rejects all remaining entries and > returns NULL. > > Oops: general protection fault, probably for non-canonical address > 0xdffffc0000000000 > KASAN: null-ptr-deref in range > [0x0000000000000000-0x0000000000000007] > RIP: 0010:__xsk_rcv+0x426/0xc20 (net/xdp/xsk.c:350) > Call Trace: > xsk_generic_rcv+0x26d/0x5f0 > xdp_do_generic_redirect+0x3c5/0xcf0 > do_xdp_generic+0x92f/0xe70 > __netif_receive_skb_core.constprop.0+0xf7e/0x2b30 > > Fix this with a two-stage transaction. First allocate and stage all > buffers required for the packet, recycling all staged buffers with > xsk_buff_free() if any allocation fails. Only after this stage > succeeds, copy the data, reserve the RX descriptors, and release the > buffers in an error-free loop. > > Fixes: 804627751b42 ("xsk: add support for AF_XDP multi-buffer on Rx path") > Reported-by: AutonomousCodeSecurity@microsoft.com > Signed-off-by: Cen Zhang (Microsoft) Reviewed-by: Simon Horman