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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id 73sm4536385pfy.83.2021.06.21.15.21.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Jun 2021 15:21:13 -0700 (PDT) From: Kees Cook To: "K. Y. Srinivasan" Cc: Kees Cook , Haiyang Zhang , Stephen Hemminger , Wei Liu , Dexuan Cui , "David S. Miller" , Jakub Kicinski , linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] hv_netvsc: Avoid field-overflowing memcpy() Date: Mon, 21 Jun 2021 15:21:12 -0700 Message-Id: <20210621222112.1749650-1-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=52ca9d3ef6fdb378f4fb4390eb0f8bf4545fb2f0; i=KB/gBOM4hXq43bzNgE68y/CtxkQywhn1/IWky57D5OI=; m=5mFF/t04SK2neGS9/cim9EhIl8hHaSNFLWMm4iAy2p8=; p=viZ5h7L2XoQprZaaybqKRBXaA6Do0vJQSm4gKjZyktE= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmDRENcACgkQiXL039xtwCYneg/+O3l CHaMID0zQGdHzOpjdP/XRCBkbVhaJywyHQ8z6b7qmEv3f20zSEpANEIFxybZanrdt/CdTEEfq3rfp MnxIdOpQzllckLVio4CTSZVeSkhV5fW6cGgy6cGBfmmwo5L7lZPsQT99c7qkBCTuz/yX8s+yrRj5J JPoUt6IMHmYzT8V9qhdFBrY4Mj1yOWqTjTf5vrKQXkzRVEAIrAnmw6vQQqaNOQj8casITz+Bas2r9 1BnbHRha8kDtuvxErUrhSvElGt1QJBLTEbNJFaseHV1+hk/wYjf+IEDa7cTWDJv/MEzw14vLQ5lJ7 TpdODkKAEPK+ifpliTgNz5o0Z3WZvDkiS4mSCPmLfBxnZ4F2ckzR42tFpFT/6XUNWaba/O3Rdf96d YUzWdRdWnqrxJrZGAu1dgk/U76yd2ydcikd/yky9RmLEFMvosTJ2UUh344i3i6Jo3KrpJjLgYEmll N0SJ5HiAxLF8j052YiXUO/MNSDP8XVIScErnxTg/ah6x7Yq8PD5SPxkt1pGjJtC1MkMIcIw+XKK4H Prj0rfPvjCUvMXkjq82cEBgAMFwaMqO2wu0jaXbv6fZ+Ynxo3TZoYw53z2Eam0ohGAsszkNbZUdi6 4MvZ8f4iLqqz3cs5bnyFAomq2bEcQ2qM9HAd8Hk8LHIXIiQPe56MYO+diaNYmMDg= Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Add flexible array to represent start of buf_info, improving readability and avoid future warning where memcpy() thinks it is writing past the end of the structure. Signed-off-by: Kees Cook --- drivers/net/hyperv/hyperv_net.h | 1 + drivers/net/hyperv/rndis_filter.c | 6 ++---- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index b11aa68b44ec..bc48855dff10 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -1170,6 +1170,7 @@ struct rndis_set_request { u32 info_buflen; u32 info_buf_offset; u32 dev_vc_handle; + u8 info_buf[]; }; /* Response to NdisSetRequest */ diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c index 983bf362466a..f6c9c2a670f9 100644 --- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -1051,10 +1051,8 @@ static int rndis_filter_set_packet_filter(struct rndis_device *dev, set = &request->request_msg.msg.set_req; set->oid = RNDIS_OID_GEN_CURRENT_PACKET_FILTER; set->info_buflen = sizeof(u32); - set->info_buf_offset = sizeof(struct rndis_set_request); - - memcpy((void *)(unsigned long)set + sizeof(struct rndis_set_request), - &new_filter, sizeof(u32)); + set->info_buf_offset = offsetof(typeof(*set), info_buf); + memcpy(set->info_buf, &new_filter, sizeof(u32)); ret = rndis_filter_send_request(dev, request); if (ret == 0) {