From nobody Tue Apr 7 20:39:40 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECEF2C4332F for ; Wed, 19 Oct 2022 19:58:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231280AbiJST6W (ORCPT ); Wed, 19 Oct 2022 15:58:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230139AbiJST6U (ORCPT ); Wed, 19 Oct 2022 15:58:20 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 849CB1D79A6 for ; Wed, 19 Oct 2022 12:58:19 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id c10-20020a170902d48a00b001825736b382so12545485plg.15 for ; Wed, 19 Oct 2022 12:58:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=Dkeuj2JEjMdaDkWKpIRh1Qeplaf/0fGmD/fPQgm8zGI=; b=IJhpJfOhoGUoA0QwTgEDY7rZLC0hLsmivrkcFmq+vhvGf09EWyL9ERoeZzdYgo5og3 iY9YUk/drwmMfkXKEEbUXZPGHhCnIWPg0DXL7B5h/7WuQqBkZfnQ9TH6oVSXnvXHXL5E LEgLcO4iEKV5JFYuuVIuXynU0yvSZPUUB5eFGoPe+inStlQWSDZDMgO0YonTrctYj+Ba lVQK1PE2W2CAUZ9VYzshQheg26HOLysqgnQfeaPiA2dtOLsM1BD3ZTvFyZ3ITYUr0CId N1MpHMUMceby9zovEGJSjFudluwWIYKs3akXDDcB9/VWJumjFy5oOjaH/8lkFtixjQmH 5LvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Dkeuj2JEjMdaDkWKpIRh1Qeplaf/0fGmD/fPQgm8zGI=; b=B3iydu+TOlYYA1zNpXVCsDNgMchLSxN9r17a1wWjN4Ugio9n4dtbdE+mfaqvgQlHNW OgZ59sSCznugTAUdrwqOmoOn58+5pBcaOjh7dFA8Xvy4BRjlUeU7Gbz9efnrPCHojILw FsNVZblcD/fGS2oc6U0G4Iuj2DAz95JnKVo2RCG6HVqJwd9zTs7ug8dUiW8CzIXGMQ4q QZPjAFI8VN0VCHayGShweBIxdsolEeVsAnoIQXLrn8D+gJsdOtGfk+qS7ZPlsOLQ+1H1 zsACs84vC5KLck0ASzuqLkdrkT72JHssi3nMFES5SYbX4J5Ncg87ZnG7ikVFvicaozts AtAA== X-Gm-Message-State: ACrzQf1fw0xqbCGuwbET/V/HKtce2tgGmt2S5d/gK33GlnmmIU81iPkU p2es0EQpSzlyA1rtHd136F4VpaDIl+kiHGorQA== X-Google-Smtp-Source: AMsMyM4N+OlC1AYRnyBX6XJONm6qWUHbYHHjHt6Boqz4PSPHJLPd4X1VFNUvsSCXxpdVLGWvze3tEEmlvsUY0edlkQ== X-Received: from dionnaglaze.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2ee6]) (user=dionnaglaze job=sendgmr) by 2002:a05:6a00:13a1:b0:563:4c5:c3dd with SMTP id t33-20020a056a0013a100b0056304c5c3ddmr10413871pfg.5.1666209499042; Wed, 19 Oct 2022 12:58:19 -0700 (PDT) Date: Wed, 19 Oct 2022 19:58:15 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.0.413.g74048e4d9e-goog Message-ID: <20221019195815.1298915-1-dionnaglaze@google.com> Subject: [PATCH v2] virt/coco/sev-guest: Remove err in handle_guest_request From: Dionna Glaze To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Dionna Glaze , Tom Lendacky , Paolo Bonzini , Joerg Roedel , Peter Gonda , Thomas Gleixner , Dave Hansen Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The err variable may not be set in the call to snp_issue_guest_request, yet it is unconditionally written back to fw_err if fw_err is non-null. This is undefined behavior, and currently returns uninitialized kernel stack memory to user space. The fw_err argument is better to just pass through to snp_issue_guest_request, so we do that. Cc: Tom Lendacky Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Peter Gonda Cc: Thomas Gleixner Cc: Dave Hansen Signed-off-by: Dionna Glaze Reviewed-by: Tom Lendacky --- drivers/virt/coco/sev-guest/sev-guest.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/se= v-guest/sev-guest.c index f422f9c58ba7..00708b4491e0 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -305,7 +305,6 @@ static int handle_guest_request(struct snp_guest_dev *s= np_dev, u64 exit_code, in u8 type, void *req_buf, size_t req_sz, void *resp_buf, u32 resp_sz, __u64 *fw_err) { - unsigned long err; u64 seqno; int rc; =20 @@ -322,9 +321,7 @@ static int handle_guest_request(struct snp_guest_dev *s= np_dev, u64 exit_code, in return rc; =20 /* Call firmware to process the request */ - rc =3D snp_issue_guest_request(exit_code, &snp_dev->input, &err); - if (fw_err) - *fw_err =3D err; + rc =3D snp_issue_guest_request(exit_code, &snp_dev->input, fw_err); =20 if (rc) return rc; --=20 2.38.0.413.g74048e4d9e-goog