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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id i29-20020a056a00005d00b0056b6c7a17c6sm5695671pfk.12.2022.12.02.13.24.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Dec 2022 13:24:24 -0800 (PST) From: Kees Cook To: Samuel Mendoza-Jonas Cc: Kees Cook , Joel Stanley , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] net/ncsi: Silence runtime memcpy() false positive warning Date: Fri, 2 Dec 2022 13:24:22 -0800 Message-Id: <20221202212418.never.837-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1371; h=from:subject:message-id; bh=2sUnLG3FFN8pFif3YWCnaOEtrm0LjtacXGcVGEiw/+Y=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjim0FA4ytswXqmWp1hRMca/r2avtZHR15euW2n+B3 jQs7mISJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCY4ptBQAKCRCJcvTf3G3AJpzCD/ 9E+a3vKrpcpU0BDeu4dr57dQgQ9SeaSG2Ag/XejMzr19dmuMerdXl6P1NqOmAWo7UYt/D4qId4z3Hp X7E/W5FiDu3uI/Bt2w1ibs7eZ0HcN5Uvu059rx1xAkoiryxEICiHyrHuXyCL622b3Dph3tyPjFTpbJ vl7cDe374WWh8g1Drj90IaHF7ZNq7ZpzJU+EL+/DseIcncBX5KMoNH8bcOqnKCfLhp0Rn+cRE2oOWP GocayW8y41PU4VijiPtVY+NPP86UOKTvko6/5mIlOudbLFUm39KlmXEkdxAHiZUK5wg0OJ56uXnSv0 8OMxyQoFPjmZe7Pw/UErnIxW/ReOejRN6mVzDFV8r12CXTwzSqfFGgzUfep1o6HVoRKSrun+eA9dxR +6iRUGEp0uDIFIDHPJoZvmMC3VGzvxT6krGxWgMOYB8bNUOTjkNkp6iheICNV4sk8OUCoIJzSKZYDY g5STXOgCghnpRCfC4jGxQsSAxRsqlurLMP2ej83Q0ExoR+U1E7dCG/vnxQMrZnb33q2vGyWUwuVdoS ujQgFyXD1gqgQmeBE2BlbEuLkCeLHJLT5gAypd9TnZ6aVe8SQ6d5sHFPQbc4ZAO0MrgPo2Yv3l0t1d VREmX/tud/ODKGuWxensvuZM9kgb3XFccEt8oeVwHZiFZ4L9xCx+yJ9Vhopg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The memcpy() in ncsi_cmd_handler_oem deserializes nca->data into a flexible array structure that overlapping with non-flex-array members (mfr_id) intentionally. Since the mem_to_flex() API is not finished, temporarily silence this warning, since it is a false positive, using unsafe_memcpy(). Reported-by: Joel Stanley Link: https://lore.kernel.org/netdev/CACPK8Xdfi=3DOJKP0x0D1w87fQeFZ4A2DP2qz= GCRcuVbpU-9=3D4sQ@mail.gmail.com/ Cc: Samuel Mendoza-Jonas Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- net/ncsi/ncsi-cmd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c index dda8b76b7798..fd2236ee9a79 100644 --- a/net/ncsi/ncsi-cmd.c +++ b/net/ncsi/ncsi-cmd.c @@ -228,7 +228,8 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb, len +=3D max(payload, padding_bytes); =20 cmd =3D skb_put_zero(skb, len); - memcpy(&cmd->mfr_id, nca->data, nca->payload); + unsafe_memcpy(&cmd->mfr_id, nca->data, nca->payload, + /* skb allocated with enough to load the payload */); ncsi_cmd_build_header(&cmd->cmd.common, nca); =20 return 0; --=20 2.34.1