From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.158.5]) by mx.groups.io with SMTP id smtpd.web09.3607.1625561724507003185 for ; Tue, 06 Jul 2021 01:55:24 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@ibm.com header.s=pp1 header.b=mma4o7iF; spf=pass (domain: linux.ibm.com, ip: 148.163.158.5, mailfrom: dovmurik@linux.ibm.com) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 1668XSsE020012; Tue, 6 Jul 2021 04:55:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : content-transfer-encoding : mime-version; s=pp1; bh=Ho7niA+Pe93asD8iqg1QfQoDROmUA03oiROIq5qLl8Q=; b=mma4o7iFeDlhXpEIeuAjQgYn2uyjwrUv9SS/FYTLa/xfTa/3KHqR5CTIxd7DazZ3slEO MKzvnuVB/hTupJNaTBeo4N65Ug93US9btRmpgFLgiog+jz7PRiwq+HMijHKsYnLJH56a HK3EjjznjMpJARpkmRCaM6VU1wfGV9WC2yKgGplJsssWiuji5E+o3bBrxoCthBNtQFq5 g8367QA0WR+JUr8dzNim0pbGTH6alUgV1lcGkT5xTFb/9qIbniIU+wGAkJAKeaL/6svR DDJBvwAhatYkgSpB+eN8lb32WLPVoO3k93dc6+0nuTZLMW8V5HhY8GlqUJ9Wd3Fy/yv/ fw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 39me2b07u1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 06 Jul 2021 04:55:22 -0400 Received: from m0098413.ppops.net (m0098413.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 1668XWO0020463; Tue, 6 Jul 2021 04:55:22 -0400 Received: from ppma02wdc.us.ibm.com (aa.5b.37a9.ip4.static.sl-reverse.com [169.55.91.170]) by mx0b-001b2d01.pphosted.com with ESMTP id 39me2b07tq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 06 Jul 2021 04:55:22 -0400 Received: from pps.filterd (ppma02wdc.us.ibm.com [127.0.0.1]) by ppma02wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 1668q5ql006534; Tue, 6 Jul 2021 08:55:21 GMT Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by ppma02wdc.us.ibm.com with ESMTP id 39jfhaqunm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 06 Jul 2021 08:55:21 +0000 Received: from b03ledav003.gho.boulder.ibm.com (b03ledav003.gho.boulder.ibm.com [9.17.130.234]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 1668tJ6415860236 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 6 Jul 2021 08:55:19 GMT Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7A4BA6A058; Tue, 6 Jul 2021 08:55:19 +0000 (GMT) Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 684C96A057; Tue, 6 Jul 2021 08:55:18 +0000 (GMT) Received: from localhost.localdomain (unknown [9.2.130.16]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 6 Jul 2021 08:55:18 +0000 (GMT) From: "Dov Murik" To: devel@edk2.groups.io Cc: Dov Murik , Tobin Feldman-Fitzthum , Tobin Feldman-Fitzthum , Jim Cadden , James Bottomley , Hubertus Franke , Laszlo Ersek , Ard Biesheuvel , Jordan Justen , Ashish Kalra , Brijesh Singh , Erdem Aktas , Jiewen Yao , Min Xu , Tom Lendacky Subject: [PATCH v2 10/11] OvmfPkg: add SevHashesBlobVerifierLib Date: Tue, 6 Jul 2021 08:55:00 +0000 Message-Id: <20210706085501.1260662-11-dovmurik@linux.ibm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210706085501.1260662-1-dovmurik@linux.ibm.com> References: <20210706085501.1260662-1-dovmurik@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 7nw3kmfYp8tMCgwC65nfAqi0oPmRboHO X-Proofpoint-GUID: tB77jTjObGsLdUqVBmQ4IqFGrEtYUs5F X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-06_04:2021-07-02,2021-07-06 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 impostorscore=0 adultscore=0 bulkscore=0 spamscore=0 mlxlogscore=999 mlxscore=0 phishscore=0 priorityscore=1501 clxscore=1015 malwarescore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107060042 Content-Transfer-Encoding: quoted-printable Add an implementation for BlobVerifierLib that locates the SEV hashes table and verifies that the calculated hashes of the kernel, initrd, and cmdline blobs indeed match the expected hashes stated in the hashes table. If there's a missing hash or a hash mismatch then EFI_ACCESS_DENIED is returned which will cause a failure to load a kernel image. Cc: Laszlo Ersek Cc: Ard Biesheuvel Cc: Jordan Justen Cc: Ashish Kalra Cc: Brijesh Singh Cc: Erdem Aktas Cc: James Bottomley Cc: Jiewen Yao Cc: Min Xu Cc: Tom Lendacky Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3D3457 Co-developed-by: James Bottomley Signed-off-by: James Bottomley Signed-off-by: Dov Murik --- OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifierLib.inf | 36 ++++ OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifier.c | 199 +++++++= +++++++++++++ 2 files changed, 235 insertions(+) diff --git a/OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifierLib.inf b= /OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifierLib.inf new file mode 100644 index 000000000000..b060d6a1b545 --- /dev/null +++ b/OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifierLib.inf @@ -0,0 +1,36 @@ +## @file=0D +#=0D +# Blob verifier library that uses SEV hashes table.=0D +#=0D +# Copyright (C) 2021, IBM Corp=0D +#=0D +# SPDX-License-Identifier: BSD-2-Clause-Patent=0D +#=0D +##=0D +=0D +[Defines]=0D + INF_VERSION =3D 0x00010005=0D + BASE_NAME =3D SevHashesBlobVerifierLib=0D + FILE_GUID =3D 59e713b5-eff3-46a7-8d8b-46f4c004ad7b= =0D + MODULE_TYPE =3D BASE=0D + VERSION_STRING =3D 1.0=0D + LIBRARY_CLASS =3D BlobVerifierLib=0D + CONSTRUCTOR =3D SevHashesBlobVerifierLibConstructor=0D +=0D +[Sources]=0D + SevHashesBlobVerifier.c=0D +=0D +[Packages]=0D + CryptoPkg/CryptoPkg.dec=0D + MdePkg/MdePkg.dec=0D + OvmfPkg/OvmfPkg.dec=0D +=0D +[LibraryClasses]=0D + BaseCryptLib=0D + BaseMemoryLib=0D + DebugLib=0D + PcdLib=0D +=0D +[FixedPcd]=0D + gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableBase=0D + gUefiOvmfPkgTokenSpaceGuid.PcdQemuHashTableSize=0D diff --git a/OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifier.c b/Ovmf= Pkg/Library/BlobVerifierLib/SevHashesBlobVerifier.c new file mode 100644 index 000000000000..961ee29f5df3 --- /dev/null +++ b/OvmfPkg/Library/BlobVerifierLib/SevHashesBlobVerifier.c @@ -0,0 +1,199 @@ +/** @file=0D +=0D + Blob verifier library that uses SEV hashes table.=0D +=0D + Copyright (C) 2021, IBM Corporation=0D +=0D + SPDX-License-Identifier: BSD-2-Clause-Patent=0D +**/=0D +=0D +#include =0D +#include =0D +#include =0D +#include =0D +#include =0D +=0D +/**=0D + The SEV Hashes table must be in encrypted memory and has the table=0D + and its entries described by=0D +=0D + |UINT16 |=0D +=0D + With the whole table GUID being 9438d606-4f22-4cc9-b479-a793d411fd21=0D +=0D + The current possible table entries are for the kernel, the initrd=0D + and the cmdline:=0D +=0D + 4de79437-abd2-427f-b835-d5b172d2045b kernel=0D + 44baf731-3a2f-4bd7-9af1-41e29169781d initrd=0D + 97d02dd8-bd20-4c94-aa78-e7714d36ab2a cmdline=0D +=0D + The size of the entry is used to identify the hash, but the=0D + expectation is that it will be 32 bytes of SHA-256.=0D +**/=0D +=0D +#define SEV_HASH_TABLE_GUID \=0D + (GUID) { 0x9438d606, 0x4f22, 0x4cc9, { 0xb4, 0x79, 0xa7, 0x93, 0xd4, 0x1= 1, 0xfd, 0x21 } }=0D +#define SEV_KERNEL_HASH_GUID \=0D + (GUID) { 0x4de79437, 0xabd2, 0x427f, { 0xb8, 0x35, 0xd5, 0xb1, 0x72, 0xd= 2, 0x04, 0x5b } }=0D +#define SEV_INITRD_HASH_GUID \=0D + (GUID) { 0x44baf731, 0x3a2f, 0x4bd7, { 0x9a, 0xf1, 0x41, 0xe2, 0x91, 0x6= 9, 0x78, 0x1d } }=0D +#define SEV_CMDLINE_HASH_GUID \=0D + (GUID) { 0x97d02dd8, 0xbd20, 0x4c94, { 0xaa, 0x78, 0xe7, 0x71, 0x4d, 0x3= 6, 0xab, 0x2a } }=0D +=0D +STATIC CONST EFI_GUID mSevKernelHashGuid =3D SEV_KERNEL_HASH_GUID;=0D +STATIC CONST EFI_GUID mSevInitrdHashGuid =3D SEV_INITRD_HASH_GUID;=0D +STATIC CONST EFI_GUID mSevCmdlineHashGuid =3D SEV_CMDLINE_HASH_GUID;=0D +=0D +#pragma pack (1)=0D +typedef struct {=0D + GUID Guid;=0D + UINT16 Len;=0D + UINT8 Data[];=0D +} HASH_TABLE;=0D +#pragma pack ()=0D +=0D +STATIC HASH_TABLE *mHashesTable;=0D +STATIC UINT16 mHashesTableSize;=0D +=0D +STATIC=0D +CONST GUID*=0D +FindBlobEntryGuid (=0D + IN CONST CHAR16 *BlobName=0D + )=0D +{=0D + if (StrCmp (BlobName, L"kernel") =3D=3D 0) {=0D + return &mSevKernelHashGuid;=0D + } else if (StrCmp (BlobName, L"initrd") =3D=3D 0) {=0D + return &mSevInitrdHashGuid;=0D + } else if (StrCmp (BlobName, L"cmdline") =3D=3D 0) {=0D + return &mSevCmdlineHashGuid;=0D + } else {=0D + return NULL;=0D + }=0D +}=0D +=0D +/**=0D + Verify blob from an external source.=0D +=0D + @param BlobName The name of the blob=0D + @param Buf The data of the blob=0D + @param BufSize The size of the blob in bytes=0D +=0D + @retval EFI_SUCCESS The blob was verified successfully.=0D + @retval EFI_ACCESS_DENIED The blob could not be verified, and theref= ore=0D + should be considered non-secure.=0D +**/=0D +EFI_STATUS=0D +EFIAPI=0D +VerifyBlob (=0D + IN CONST CHAR16 *BlobName,=0D + IN CONST VOID *Buf,=0D + UINT32 BufSize=0D + )=0D +{=0D + CONST GUID *Guid;=0D + INT32 Len;=0D + HASH_TABLE *Entry;=0D + UINT8 Hash[SHA256_DIGEST_SIZE];=0D +=0D + if (mHashesTable =3D=3D NULL || mHashesTableSize =3D=3D 0) {=0D + DEBUG ((DEBUG_ERROR,=0D + "%a: Verifier called but no hashes table discoverd in MEMFD\n",=0D + __FUNCTION__));=0D + return EFI_ACCESS_DENIED;=0D + }=0D +=0D + Guid =3D FindBlobEntryGuid (BlobName);=0D + if (Guid =3D=3D NULL) {=0D + DEBUG ((DEBUG_ERROR, "%a: Unknown blob name \"%s\"\n", __FUNCTION__,=0D + BlobName));=0D + return EFI_ACCESS_DENIED;=0D + }=0D +=0D + Sha256HashAll (Buf, BufSize, Hash);=0D +=0D + for (Entry =3D mHashesTable, Len =3D 0;=0D + Len < (INT32)mHashesTableSize;=0D + Len +=3D Entry->Len,=0D + Entry =3D (HASH_TABLE *)((UINT8 *)Entry + Entry->Len)) {=0D + UINTN EntrySize;=0D + EFI_STATUS Status;=0D +=0D + if (!CompareGuid (&Entry->Guid, Guid)) {=0D + continue;=0D + }=0D +=0D + DEBUG ((DEBUG_INFO, "%a: Found GUID %g in table\n", __FUNCTION__, Guid= ));=0D +=0D + //=0D + // Verify that the buffer's calculated hash is identical to the expect= ed=0D + // hash table entry=0D + //=0D + EntrySize =3D Entry->Len - sizeof (Entry->Guid) - sizeof (Entry->Len);= =0D + if (EntrySize !=3D SHA256_DIGEST_SIZE) {=0D + DEBUG ((DEBUG_ERROR, "%a: Hash has the wrong size %d !=3D %d\n",=0D + __FUNCTION__, EntrySize, SHA256_DIGEST_SIZE));=0D + return EFI_ACCESS_DENIED;=0D + }=0D +=0D + if (CompareMem (Entry->Data, Hash, EntrySize) =3D=3D 0) {=0D + Status =3D EFI_SUCCESS;=0D + DEBUG ((DEBUG_INFO, "%a: Hash comparison succeeded for \"%s\"\n",=0D + __FUNCTION__, BlobName));=0D + } else {=0D + Status =3D EFI_ACCESS_DENIED;=0D + DEBUG ((DEBUG_ERROR, "%a: Hash comparison failed for \"%s\"\n",=0D + __FUNCTION__, BlobName));=0D + }=0D + return Status;=0D + }=0D +=0D + DEBUG ((DEBUG_ERROR, "%a: Hash GUID %g not found in table\n", __FUNCTION= __,=0D + Guid));=0D + return EFI_ACCESS_DENIED;=0D +}=0D +=0D +/**=0D + Locate the SEV hashes table.=0D +=0D + This function always returns success, even if the table can't be found. = The=0D + subsequent VerifyBlob calls will fail if no table was found.=0D +=0D + @retval RETURN_SUCCESS The verifier tables were set up correctly=0D +**/=0D +RETURN_STATUS=0D +EFIAPI=0D +SevHashesBlobVerifierLibConstructor (=0D + VOID=0D + )=0D +{=0D + HASH_TABLE *Ptr =3D (void *)(UINTN)FixedPcdGet64 (PcdQemuHashTableBase);= =0D + UINT32 Size =3D FixedPcdGet32 (PcdQemuHashTableSize);=0D +=0D + mHashesTable =3D NULL;=0D + mHashesTableSize =3D 0;=0D +=0D + if (Ptr =3D=3D NULL || Size =3D=3D 0) {=0D + return RETURN_SUCCESS;=0D + }=0D +=0D + if (!CompareGuid (&Ptr->Guid, &SEV_HASH_TABLE_GUID)) {=0D + return RETURN_SUCCESS;=0D + }=0D +=0D + if (Ptr->Len < (sizeof Ptr->Guid + sizeof Ptr->Len)) {=0D + return RETURN_SUCCESS;=0D + }=0D +=0D + DEBUG ((DEBUG_INFO, "%a: Found injected hashes table in secure location\= n",=0D + __FUNCTION__));=0D +=0D + mHashesTable =3D (HASH_TABLE *)Ptr->Data;=0D + mHashesTableSize =3D Ptr->Len - sizeof Ptr->Guid - sizeof Ptr->Len;=0D +=0D + DEBUG ((DEBUG_VERBOSE, "%a: mHashesTable=3D0x%p, Size=3D%u\n", __FUNCTIO= N__,=0D + mHashesTable, mHashesTableSize));=0D +=0D + return RETURN_SUCCESS;=0D +}=0D --=20 2.25.1