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.web11.4823.1626768289225588633 for ; Tue, 20 Jul 2021 01:04:49 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@ibm.com header.s=pp1 header.b=d9QPaA7+; spf=pass (domain: linux.ibm.com, ip: 148.163.158.5, mailfrom: dovmurik@linux.ibm.com) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 16K83OwV101311; Tue, 20 Jul 2021 04:04:47 -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=vB4lhbTly5DhP+jJL1/muVFdi7H1F7iyRgEcw2FLlc8=; b=d9QPaA7+WbYRrBQn8NzpoiKtBx8fFt9PjKzXL3/XcNMxGPwyGAgYk+q5yh0MxHmZ+yRr AzKr/5/HCbH1F8Vmn1igZK3uGm1KJ3QjzCn3oASWDr69qzg7shWkrebcjJlmWf5NhZNi LTP3/0VXnIPHSpDCnzSj5pQXVVqpothVL4GRksM/Ag0JNtz7V++PHe0ktIxfsmlj4g4D m8yLvH0sHED1XmzInA2MZrmIBmZsJI8f/eu8IXOpM3vvvHwOC13sa9F9N8ergGIqzZt2 ZbOqyhrRNX91nNNfz8d3yaGo0mOsbI6XQRAxN6bqgxLcmDJKcYhtb+nnbmuYWPEgHVJr rg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 39wny8pqvy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 20 Jul 2021 04:04:47 -0400 Received: from m0098416.ppops.net (m0098416.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 16K83mei103162; Tue, 20 Jul 2021 04:04:46 -0400 Received: from ppma03dal.us.ibm.com (b.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.11]) by mx0b-001b2d01.pphosted.com with ESMTP id 39wny8pqvh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 20 Jul 2021 04:04:46 -0400 Received: from pps.filterd (ppma03dal.us.ibm.com [127.0.0.1]) by ppma03dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 16K84D16019052; Tue, 20 Jul 2021 08:04:45 GMT Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by ppma03dal.us.ibm.com with ESMTP id 39upuc604t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 20 Jul 2021 08:04:45 +0000 Received: from b03ledav002.gho.boulder.ibm.com (b03ledav002.gho.boulder.ibm.com [9.17.130.233]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 16K84hJH21823786 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 20 Jul 2021 08:04:43 GMT Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 37DFC136051; Tue, 20 Jul 2021 08:04:43 +0000 (GMT) Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 06F87136053; Tue, 20 Jul 2021 08:04:42 +0000 (GMT) Received: from localhost.localdomain (unknown [9.2.130.16]) by b03ledav002.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 20 Jul 2021 08:04:41 +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 , Ard Biesheuvel , Jordan Justen , Ashish Kalra , Brijesh Singh , Erdem Aktas , Jiewen Yao , Min Xu , Tom Lendacky Subject: [PATCH v3 10/11] OvmfPkg: add BlobVerifierLibSevHashes Date: Tue, 20 Jul 2021 08:04:00 +0000 Message-Id: <20210720080401.3662854-11-dovmurik@linux.ibm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210720080401.3662854-1-dovmurik@linux.ibm.com> References: <20210720080401.3662854-1-dovmurik@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: nDnewPiL04lyhgWmmVgvhbHDj9pY7XEu X-Proofpoint-GUID: nd-mzQgNW3pQViziST6z_6Gc6AS6Frfr 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=2021-07-20_04:2021-07-19,2021-07-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 clxscore=1015 impostorscore=0 mlxscore=0 lowpriorityscore=0 spamscore=0 adultscore=0 malwarescore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107200047 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: 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/BlobVerifierLibSevHashes.inf | 37 ++++ OvmfPkg/Library/BlobVerifierLib/BlobVerifierSevHashes.c | 200 +++++++= +++++++++++++ 2 files changed, 237 insertions(+) diff --git a/OvmfPkg/Library/BlobVerifierLib/BlobVerifierLibSevHashes.inf b= /OvmfPkg/Library/BlobVerifierLib/BlobVerifierLibSevHashes.inf new file mode 100644 index 000000000000..76ca0b8154ce --- /dev/null +++ b/OvmfPkg/Library/BlobVerifierLib/BlobVerifierLibSevHashes.inf @@ -0,0 +1,37 @@ +## @file=0D +#=0D +# Blob verifier library that uses SEV hashes table. The hashes table hol= ds the=0D +# allowed hashes of the kernel, initrd, and cmdline blobs.=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 1.29=0D + BASE_NAME =3D BlobVerifierLibSevHashes=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 BlobVerifierLibSevHashesConstructor=0D +=0D +[Sources]=0D + BlobVerifierSevHashes.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/BlobVerifierSevHashes.c b/Ovmf= Pkg/Library/BlobVerifierLib/BlobVerifierSevHashes.c new file mode 100644 index 000000000000..797d63d18067 --- /dev/null +++ b/OvmfPkg/Library/BlobVerifierLib/BlobVerifierSevHashes.c @@ -0,0 +1,200 @@ +/** @file=0D +=0D + Blob verifier library that uses SEV hashes table. The hashes table hold= s the=0D + allowed hashes of the kernel, initrd, and cmdline blobs.=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[in] BlobName The name of the blob=0D + @param[in] Buf The data of the blob=0D + @param[in] 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 + IN UINT32 BufSize=0D + )=0D +{=0D + CONST GUID *Guid;=0D + INT32 Len;=0D + HASH_TABLE *Entry;=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 + 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 + UINT8 Hash[SHA256_DIGEST_SIZE];=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 + 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 + //=0D + // Calculate the buffer's hash and verify that it is identical to the= =0D + // expected hash table entry=0D + //=0D + Sha256HashAll (Buf, BufSize, Hash);=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 +BlobVerifierLibSevHashesConstructor (=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