From patchwork Mon Nov 18 12:46:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= X-Patchwork-Id: 13878497 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5A954D49212 for ; Mon, 18 Nov 2024 12:49:30 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tD1BO-0005Cd-Ee; Mon, 18 Nov 2024 07:48:46 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tD1B2-0004XT-S3 for qemu-devel@nongnu.org; Mon, 18 Nov 2024 07:48:29 -0500 Received: from mail-wr1-x433.google.com ([2a00:1450:4864:20::433]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1tD1Ah-0005Rf-70 for qemu-devel@nongnu.org; Mon, 18 Nov 2024 07:48:19 -0500 Received: by mail-wr1-x433.google.com with SMTP id ffacd0b85a97d-3823194a879so1563296f8f.0 for ; Mon, 18 Nov 2024 04:48:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1731934080; x=1732538880; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=e4ERK3ElD4P8I6nFF+NaMJMN4ukbGaWKpf0tkMteE1E=; b=uCGhJvQJ8NsMdpwTKTXLIJAG+S9b3WJJfpPvg2ZTPvL6qOaOmRneJAcwnIoRax1X1d 6glAE1TgSHhPRskIq4lpF3O+ZswWdRi0i1MvvA4erpfsVdxJhA+2DIAnPiCV4Qwp/RyC TPziHyLhMG+lu5ZW0/951zYsYPFGxgMqL5D4NV5bAnZMZ96tC60qAXg/oCP0+Zl+VPPH qbvlL8oZ2AxkMlQ594q0sqY72iNht16ruxwbURT1obhTfZPc646MO6RGyqw38VT07yME cHOCvU2PHzUoVbB2rbcmrltjy8XMRG+xbuDogm6jfGJ959rNx8tyeFGpEUFM4A7uZWC2 MaRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731934080; x=1732538880; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=e4ERK3ElD4P8I6nFF+NaMJMN4ukbGaWKpf0tkMteE1E=; b=wXqRTAMpjIU/oHei0hbsZ8tUf8GCMVcr5GER0TqGZ5yzwOrcsBQBu8fw8kKfn4yhfv 4RQ9Tn3rFwNBEk+DyUPyJ9PnrCxPaos9I1LigjUEKDvIpPz0XOAfTl8u2RqBWbxM7rro tNGSbpbKmk8jaeY7xzrroh/FzckzuhVz1E85QQ209LwC/pVtGL1JAslCEma4mtNBAJOk A2qTWdMZmjTzRr48V8tvnjW7CTAYJjcWO4ZoTCfZyMXFgk8kqTFdjlcmadePTjV/2+lP DcZH6p5p723oR4fcn66A3TQIvrQ0Qv3F1Mt1HIGqLioJR0O41EIJAv6czIn6CEQnepWx QJDQ== X-Gm-Message-State: AOJu0YzVLbcKSww7cmuGGzbMzJ6FwfhTiVhI2/ycJd7jjgzAzmekD3K4 34CAOTxfWtH4X6/60i9k717m9c1LPz7I/NfW4Ipl57KsxkYyyfXaz/EBkTF8OIdS3ZHtU47YTkk c X-Google-Smtp-Source: AGHT+IGDo9Z850DXH8dv/QoH1s3wkaezvP+GTpZf2e8NqZYZktsOkQw0d2uqhbjTIgvkgPiZAq492Q== X-Received: by 2002:a05:6000:2a8:b0:382:372a:5718 with SMTP id ffacd0b85a97d-382372a5a17mr5566122f8f.26.1731934079649; Mon, 18 Nov 2024 04:47:59 -0800 (PST) Received: from localhost.localdomain ([176.187.198.1]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38244ff1ca3sm3810943f8f.26.2024.11.18.04.47.58 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 18 Nov 2024 04:47:59 -0800 (PST) From: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Cc: Peter Maydell , =?utf-8?q?Philippe_Mathieu-Dau?= =?utf-8?q?d=C3=A9?= Subject: [PULL 13/15] hw/net/virtio-net.c: Don't assume IP length field is aligned Date: Mon, 18 Nov 2024 13:46:40 +0100 Message-ID: <20241118124643.6958-14-philmd@linaro.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241118124643.6958-1-philmd@linaro.org> References: <20241118124643.6958-1-philmd@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::433; envelope-from=philmd@linaro.org; helo=mail-wr1-x433.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Peter Maydell In virtio-net.c we assume that the IP length field in the packet is aligned, and we copy its address into a uint16_t* in the VirtioNetRscUnit struct which we then dereference later. This isn't a safe assumption; it will also result in compilation failures if we mark the ip_header struct as QEMU_PACKED because the compiler will not let you take the address of an unaligned struct field. Make the ip_plen field in VirtioNetRscUnit a void*, and make all the places where we read or write through that pointer instead use some new accessor functions read_unit_ip_len() and write_unit_ip_len() which account for the pointer being potentially unaligned and also do the network-byte-order conversion we were previously using htons() to perform. Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé Message-ID: <20241114141619.806652-2-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé --- include/hw/virtio/virtio-net.h | 2 +- hw/net/virtio-net.c | 23 +++++++++++++++++++---- 2 files changed, 20 insertions(+), 5 deletions(-) diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h index 060c23c04d..b9ea9e824e 100644 --- a/include/hw/virtio/virtio-net.h +++ b/include/hw/virtio/virtio-net.h @@ -102,7 +102,7 @@ typedef struct VirtioNetRscStat { /* Rsc unit general info used to checking if can coalescing */ typedef struct VirtioNetRscUnit { void *ip; /* ip header */ - uint16_t *ip_plen; /* data len pointer in ip header field */ + void *ip_plen; /* pointer to unaligned uint16_t data len in ip header */ struct tcp_header *tcp; /* tcp header */ uint16_t tcp_hdrlen; /* tcp header len */ uint16_t payload; /* pure payload without virtio/eth/ip/tcp */ diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index f2104ed364..75b4a28fb3 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -2049,6 +2049,21 @@ static ssize_t virtio_net_do_receive(NetClientState *nc, const uint8_t *buf, return virtio_net_receive_rcu(nc, buf, size, false); } +/* + * Accessors to read and write the IP packet data length field. This + * is a potentially unaligned network-byte-order 16 bit unsigned integer + * pointed to by unit->ip_len. + */ +static uint16_t read_unit_ip_len(VirtioNetRscUnit *unit) +{ + return lduw_be_p(unit->ip_plen); +} + +static void write_unit_ip_len(VirtioNetRscUnit *unit, uint16_t l) +{ + stw_be_p(unit->ip_plen, l); +} + static void virtio_net_rsc_extract_unit4(VirtioNetRscChain *chain, const uint8_t *buf, VirtioNetRscUnit *unit) @@ -2063,7 +2078,7 @@ static void virtio_net_rsc_extract_unit4(VirtioNetRscChain *chain, unit->ip_plen = &ip->ip_len; unit->tcp = (struct tcp_header *)(((uint8_t *)unit->ip) + ip_hdrlen); unit->tcp_hdrlen = (htons(unit->tcp->th_offset_flags) & 0xF000) >> 10; - unit->payload = htons(*unit->ip_plen) - ip_hdrlen - unit->tcp_hdrlen; + unit->payload = read_unit_ip_len(unit) - ip_hdrlen - unit->tcp_hdrlen; } static void virtio_net_rsc_extract_unit6(VirtioNetRscChain *chain, @@ -2082,7 +2097,7 @@ static void virtio_net_rsc_extract_unit6(VirtioNetRscChain *chain, /* There is a difference between payload length in ipv4 and v6, ip header is excluded in ipv6 */ - unit->payload = htons(*unit->ip_plen) - unit->tcp_hdrlen; + unit->payload = read_unit_ip_len(unit) - unit->tcp_hdrlen; } static size_t virtio_net_rsc_drain_seg(VirtioNetRscChain *chain, @@ -2231,7 +2246,7 @@ static int32_t virtio_net_rsc_coalesce_data(VirtioNetRscChain *chain, VirtioNetRscUnit *o_unit; o_unit = &seg->unit; - o_ip_len = htons(*o_unit->ip_plen); + o_ip_len = read_unit_ip_len(o_unit); nseq = htonl(n_unit->tcp->th_seq); oseq = htonl(o_unit->tcp->th_seq); @@ -2267,7 +2282,7 @@ coalesce: o_unit->payload += n_unit->payload; /* update new data len */ /* update field in ip header */ - *o_unit->ip_plen = htons(o_ip_len + n_unit->payload); + write_unit_ip_len(o_unit, o_ip_len + n_unit->payload); /* Bring 'PUSH' big, the whql test guide says 'PUSH' can be coalesced for windows guest, while this may change the behavior for linux