From patchwork Wed Sep 18 01:26:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AKASHI Takahiro X-Patchwork-Id: 1163644 X-Patchwork-Delegate: xypron.glpk@gmx.de Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.denx.de (client-ip=81.169.180.215; helo=lists.denx.de; envelope-from=u-boot-bounces@lists.denx.de; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b="ehvL+kt/"; dkim-atps=neutral Received: from lists.denx.de (dione.denx.de [81.169.180.215]) by ozlabs.org (Postfix) with ESMTP id 46Y2Qn5K5fz9s4Y for ; Wed, 18 Sep 2019 11:27:29 +1000 (AEST) Received: by lists.denx.de (Postfix, from userid 105) id 66EBFC21E7E; Wed, 18 Sep 2019 01:25:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lists.denx.de X-Spam-Level: X-Spam-Status: No, score=-0.0 required=5.0 tests=RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, T_DKIM_INVALID autolearn=unavailable autolearn_force=no version=3.4.0 Received: from lists.denx.de (localhost [IPv6:::1]) by lists.denx.de (Postfix) with ESMTP id E200FC21E8A; Wed, 18 Sep 2019 01:24:30 +0000 (UTC) Received: by lists.denx.de (Postfix, from userid 105) id 4E06FC21DF3; Wed, 18 Sep 2019 01:24:03 +0000 (UTC) Received: from mail-pl1-f195.google.com (mail-pl1-f195.google.com [209.85.214.195]) by lists.denx.de (Postfix) with ESMTPS id 49DC9C21E5B for ; Wed, 18 Sep 2019 01:24:00 +0000 (UTC) Received: by mail-pl1-f195.google.com with SMTP id t10so2315515plr.8 for ; Tue, 17 Sep 2019 18:24:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rGsJ0/W0dyNni4CKX0cJphu9PLPe47e2L0nAN3xf9OY=; b=ehvL+kt/lhTucz26B5uaPs3EE2nghlEXbIDIx61n8x1SsRTok529PBpNJVJeT6e5cN LGyg6tpyO/WA34DxQ00YIalf4j4Tqou3ryHP4nkwGCTJCpF5BTxDDDRs1zYy4xUTQbpt KAVtdT18u7qNkMFSBRxmyIq1/FLHrQQrB1jb4JrJQ39o7e3gwxrAr35ufGe75RvsVOSY MCmw5ja+JavLH/LD3AZ0AiI5zLyqDMrKgjQ6g+YuqcSHKFYsQjBaqKGio/iE0aKoUZ8o e0FmsHuMRdhlHtlsRpXewXSvLeAejVoBJoMxVLbxoEv+ZeGZxuCewIWAtsDBAdckkTEj NnQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=rGsJ0/W0dyNni4CKX0cJphu9PLPe47e2L0nAN3xf9OY=; b=AMfPRL29wJcPzmWOgoXc3XLE4LDhIhroy/dP7LtKhnWHGGLprDfm3tOz0f6jw5J6mo NI/zuumpgSE0AiDd4u333kxm5H3mOJLx92tAOFfu8n8MGru619QvE+B5KQWZQxaXcMIr z2Ga4NCRAJNiyNgtj/NQrlwA7Byd/w4tk1SXc1Q3Z2HzcJrbC167ddO5U5O2iy+tPsW5 wa44POAQMphvkeKQq9YCPPaa340jidbfVChi0R+Q8uV68dnXflVVHygY9MjamYZsr7s9 /ISf39sYn/wUk08c7mfEgFqPwW2BeUIRTEW0Pg3r7FmrlILBd/tVNusYNbwyBOTIS9k5 GW+w== X-Gm-Message-State: APjAAAV5L3TgYA0+GqT4RotfCvfRLwKhQDGeVBTm0uKd2KdqzQ1JHEZK 7elGdmBjcvcUPyvIr0ql80nEBQ== X-Google-Smtp-Source: APXvYqxAHDb7bisX47ZSlpkoJkq8jsRKzLW8T+/CCbgxwb1vEeYYjhoU/lTNtSKsv3pF5SDTUyaotQ== X-Received: by 2002:a17:902:fe81:: with SMTP id x1mr1640929plm.66.1568769838514; Tue, 17 Sep 2019 18:23:58 -0700 (PDT) Received: from linaro.org ([121.95.100.191]) by smtp.googlemail.com with ESMTPSA id f12sm3663079pgo.85.2019.09.17.18.23.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Sep 2019 18:23:58 -0700 (PDT) From: AKASHI Takahiro To: xypron.glpk@gmx.de, agraf@csgraf.de, trini@konsulko.com Date: Wed, 18 Sep 2019 10:26:38 +0900 Message-Id: <20190918012643.25192-11-takahiro.akashi@linaro.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190918012643.25192-1-takahiro.akashi@linaro.org> References: <20190918012643.25192-1-takahiro.akashi@linaro.org> MIME-Version: 1.0 Cc: u-boot@lists.denx.de Subject: [U-Boot] [RFC 10/15] efi_loader: image_loader: support image authentication X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.18 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" With this commit, image validation can be enforced, as UEFI specification section 32.5 describes, if CONFIG_EFI_SECURE_BOOT is enabled. Currently we support * authentication based on db and dbx, so dbx-validated image will always be rejected. * following signature types: EFI_CERT_SHA256_GUID (SHA256 digest for unsigned images) EFI_CERT_X509_GUID (x509 certificate for signed images) Timestamp-based certifcate revocation is not supported here. Internally, authentication data is stored in one of certificates tables of PE image (See efi_image_parse()) and will be verified by efi_image_authenticate(), hence efi_signature_verify_with_db(), before loading a given image. Signed-off-by: AKASHI Takahiro --- include/efi_loader.h | 7 +- lib/efi_loader/efi_boottime.c | 2 +- lib/efi_loader/efi_image_loader.c | 364 +++++++++++++++++++++++++++++- 3 files changed, 366 insertions(+), 7 deletions(-) diff --git a/include/efi_loader.h b/include/efi_loader.h index caac8efba89a..b0e1a3b7902d 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -11,6 +11,7 @@ #include #include #include +#include /* No need for efi loader support in SPL */ #if CONFIG_IS_ENABLED(EFI_LOADER) @@ -385,7 +386,8 @@ efi_status_t efi_set_watchdog(unsigned long timeout); /* Called from places to check whether a timer expired */ void efi_timer_check(void); /* PE loader implementation */ -efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, +efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, + void *efi, size_t efi_size, struct efi_loaded_image *loaded_image_info); /* Called once to store the pristine gd pointer */ void efi_save_gd(void); @@ -703,6 +705,9 @@ efi_signature_store *efi_sigstore_parse_sigdb(u16 *name); bool efi_secure_boot_enabled(void); efi_status_t efi_init_secure_boot(void); + +bool efi_image_parse(void *efi, size_t len, efi_image_regions **regp, + WIN_CERTIFICATE **auth, size_t *auth_len); #endif /* CONFIG_EFI_SECURE_BOOT */ #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index b9bff894cbba..e27a52493291 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -1879,7 +1879,7 @@ efi_status_t EFIAPI efi_load_image(bool boot_policy, efi_dp_split_file_path(file_path, &dp, &fp); ret = efi_setup_loaded_image(dp, fp, image_obj, &info); if (ret == EFI_SUCCESS) - ret = efi_load_pe(*image_obj, dest_buffer, info); + ret = efi_load_pe(*image_obj, dest_buffer, source_size, info); if (!source_buffer) /* Release buffer to which file was loaded */ efi_free_pages((uintptr_t)dest_buffer, diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index 13541cfa7a28..3004cb34a3cd 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -9,7 +9,13 @@ #include #include +#include #include +/* + * avoid duplicated inclusion: + * #include "../lib/crypto/x509_parser.h" + */ +#include "../lib/crypto/pkcs7_parser.h" const efi_guid_t efi_global_variable_guid = EFI_GLOBAL_VARIABLE_GUID; const efi_guid_t efi_guid_device_path = EFI_DEVICE_PATH_PROTOCOL_GUID; @@ -205,6 +211,288 @@ static void efi_set_code_and_data_type( } } +#ifdef CONFIG_EFI_SECURE_BOOT +/* + * Parse image binary in PE32(+) format + * Assuming that sanity of PE image has been checked by a caller. + * + * Return: true on success, false on failure + */ +bool efi_image_parse(void *efi, size_t len, efi_image_regions **regp, + WIN_CERTIFICATE **auth, size_t *auth_len) +{ + efi_image_regions *regs; + IMAGE_DOS_HEADER *dos; + IMAGE_NT_HEADERS32 *nt; + IMAGE_SECTION_HEADER *sections; + int num_sections, i; + int ctidx = IMAGE_DIRECTORY_ENTRY_CERTTABLE; + u32 align, size, authsz, authoff; + size_t bytes_hashed; + + regs = calloc(1, sizeof(*regs)); + if (!regs) + goto err; + + dos = (void *)efi; + nt = (void *)(efi + dos->e_lfanew); + + /* + * Collect data regions for hash calculation + * 1. File headers + */ + if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) { + IMAGE_NT_HEADERS64 *nt64 = (void *)nt; + IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader; + + /* Skip CheckSum */ + efi_image_region_add(regs, efi, &opt->CheckSum, 0); + if (nt64->OptionalHeader.NumberOfRvaAndSizes <= ctidx) { + efi_image_region_add(regs, + &opt->CheckSum + 1, + efi + opt->SizeOfHeaders, 0); + } else { + /* Skip Certificates Table */ + efi_image_region_add(regs, + &opt->CheckSum + 1, + &opt->DataDirectory[ctidx], 0); + efi_image_region_add(regs, + &opt->DataDirectory[ctidx] + 1, + efi + opt->SizeOfHeaders, 0); + } + + bytes_hashed = opt->SizeOfHeaders; + align = opt->FileAlignment; + authoff = opt->DataDirectory[ctidx].VirtualAddress; + authsz = opt->DataDirectory[ctidx].Size; + } else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) { + IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader; + + efi_image_region_add(regs, efi, &opt->CheckSum, 0); + efi_image_region_add(regs, &opt->CheckSum + 1, + &opt->DataDirectory[ctidx], 0); + efi_image_region_add(regs, &opt->DataDirectory[ctidx] + 1, + efi + opt->SizeOfHeaders, 0); + + bytes_hashed = opt->SizeOfHeaders; + align = opt->FileAlignment; + authoff = opt->DataDirectory[ctidx].VirtualAddress; + authsz = opt->DataDirectory[ctidx].Size; + } else { + debug("%s: Invalid optional header magic %x\n", __func__, + nt->OptionalHeader.Magic); + goto err; + } + + /* 2. Sections */ + num_sections = nt->FileHeader.NumberOfSections; + sections = (void *)((uint8_t *)&nt->OptionalHeader + + nt->FileHeader.SizeOfOptionalHeader); + for (i = 0; i < num_sections; i++) { + if (!sections[i].SizeOfRawData) + continue; + + /* TODO: ensure ascending order */ + size = (sections[i].SizeOfRawData + align - 1) & ~(align - 1); + efi_image_region_add(regs, efi + sections[i].PointerToRawData, + efi + sections[i].PointerToRawData + size, + 0); + debug("section[%d](%s): raw: 0x%x-0x%x, virt: %x-%x\n", + i, sections[i].Name, + sections[i].PointerToRawData, + sections[i].PointerToRawData + size, + sections[i].VirtualAddress, + sections[i].VirtualAddress + + sections[i].Misc.VirtualSize); + + bytes_hashed += size; + } + + /* 3. Extra data excluding Certificates Table */ + if (bytes_hashed + authsz < len) { + debug("extra data for hash: %lu\n", + len - (bytes_hashed + authsz)); + efi_image_region_add(regs, efi + bytes_hashed, + efi + len - authsz, 0); + } + + /* Return Certificates Table */ + if (authsz) { + if (len < authoff + authsz) { + debug("%s: Size for auth too large: %u >= %zu\n", + __func__, authsz, len - authoff); + goto err; + } + if (authsz < sizeof(*auth)) { + debug("%s: Size for auth too small: %u < %zu\n", + __func__, authsz, sizeof(*auth)); + goto err; + } + *auth = efi + authoff; + *auth_len = authsz; + debug("WIN_CERTIFICATE: 0x%x, size: 0x%x\n", authoff, authsz); + } else { + *auth = NULL; + *auth_len = 0; + } + + *regp = regs; + + return true; + +err: + free(regs); + + return false; +} + +/* + * Authenticate unsigned image with SHA256 hash + * + * Return: true on success, false on failure + */ +static bool efi_image_unsigned_authenticate(efi_image_regions *regs) +{ + efi_signature_store *db; + bool ret; + + /* try black-list */ + ret = true; + db = efi_sigstore_parse_sigdb(L"dbx"); + if (db) { + if (efi_signature_verify_with_db(regs, NULL, db)) { + debug("Image is not signed and rejected by \"dbx\"\n"); + ret = false; + } + + efi_sigstore_free(db); + } else { + debug("Getting signature database(dbx) failed\n"); + } + + if (!ret) + goto out; + + /* try white-list */ + ret = false; + db = efi_sigstore_parse_sigdb(L"db"); + if (db) { + if (efi_signature_verify_with_db(regs, NULL, db)) + ret = true; + else + debug("Image is not signed and not found in \"db\" or \"dbx\"\n"); + + efi_sigstore_free(db); + } else { + debug("Getting signature database(db) failed\n"); + } + +out: + return ret; +} + +/* + * TODO: + * When AuditMode==0, if the image's signature is not found in + * the authorized database, or is found in the forbidden database, + * the image will not be started and instead, information about it + * will be placed in this table. + * When AuditMode==1, an EFI_IMAGE_EXECUTION_INFO element is created + * in the EFI_IMAGE_EXECUTION_INFO_TABLE for every certificate found + * in the certificate table of every image that is validated. + * + * Return: true on success, false on failure + */ +static bool efi_image_authenticate(void *efi, size_t len) +{ + efi_image_regions *regs = NULL; + WIN_CERTIFICATE *wincerts = NULL, *wincert; + size_t wincerts_len; + struct pkcs7_message *msg = NULL; + efi_signature_store *db = NULL, *dbx = NULL; + bool ret = false; + + if (!efi_secure_boot_enabled()) + return true; + + if (!efi_image_parse(efi, len, ®s, &wincerts, + &wincerts_len)) { + debug("Parsing PE executable image failed\n"); + return false; + } + + if (!wincerts) { + /* The image is not signed */ + ret = efi_image_unsigned_authenticate(regs); + free(regs); + + return ret; + } + + /* + * verify signature using db and dbx + */ + db = efi_sigstore_parse_sigdb(L"db"); + if (!db) { + debug("Getting signature database(db) failed\n"); + goto err; + } + + dbx = efi_sigstore_parse_sigdb(L"dbx"); + if (!dbx) { + /* FIXME: error or not found? */ + debug("Getting signature database(dbx) failed\n"); + goto err; + } + + /* go through WIN_CERTIFICATE list */ + for (wincert = wincerts; + (void *)wincert < (void *)wincerts + wincerts_len; + wincert = (void *)wincert + ALIGN(wincert->dwLength, 8)) { + if (wincert->dwLength < sizeof(*wincert)) { + debug("%s: dwLength too small: %u < %zu\n", + __func__, wincert->dwLength, sizeof(*wincert)); + goto err; + } + msg = pkcs7_parse_message((void *)wincert + sizeof(*wincert), + wincert->dwLength - sizeof(*wincert)); + if (!msg) { + debug("Parsing image's signature failed\n"); + goto err; + } + + /* try black-list first */ + if (dbx) { + if (efi_signature_revoke(regs, msg, dbx, NULL)) { + debug("Signature was revoked by \"dbx\"\n"); + goto err; + } + } + + /* try white-list */ + if (db) { + if (!efi_signature_verify_with_db(regs, msg, db)) + debug("Verifying signature with \"db\" failed\n"); + else + ret = true; + } + } + +err: + efi_sigstore_free(db); + efi_sigstore_free(dbx); + pkcs7_free_message(msg); + free(regs); + + return ret; +} +#else +static bool efi_image_authenticate(void *efi, size_t len) +{ + return true; +} +#endif /* CONFIG_EFI_SECURE_BOOT */ + /** * efi_load_pe() - relocate EFI binary * @@ -216,7 +504,8 @@ static void efi_set_code_and_data_type( * @loaded_image_info: loaded image protocol * Return: status code */ -efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, +efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, + void *efi, size_t efi_size, struct efi_loaded_image *loaded_image_info) { IMAGE_NT_HEADERS32 *nt; @@ -232,15 +521,56 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, unsigned long virt_size = 0; int supported = 0; + /* + * Size must be 8-byte aligned and the trailing bytes must be + * zero'ed. Otherwise hash value may be incorrect. + */ + if (efi_size & 0x7) { + void *new_efi; + size_t new_efi_size; + + new_efi_size = (efi_size + 0x7) & ~0x7ULL; + new_efi = calloc(new_efi_size, 1); + if (!new_efi) + return EFI_OUT_OF_RESOURCES; + memcpy(new_efi, efi, efi_size); + efi = new_efi; + efi_size = new_efi_size; + /* TODO: free */ + } + + /* Sanity check for a file header */ + if (efi_size < sizeof(*dos)) { + printf("%s: Truncated DOS Header\n", __func__); + + return EFI_LOAD_ERROR; + } + dos = efi; if (dos->e_magic != IMAGE_DOS_SIGNATURE) { printf("%s: Invalid DOS Signature\n", __func__); + + return EFI_LOAD_ERROR; + } + + /* assume sizeof(IMAGE_NT_HEADERS32) <= sizeof(IMAGE_NT_HEADERS64) */ + if (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS32)) { + printf("%s: Invalid offset for Extended Header\n", __func__); + return EFI_LOAD_ERROR; } nt = (void *) ((char *)efi + dos->e_lfanew); + if ((nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) && + (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS64))) { + printf("%s: Invalid offset for Extended Header\n", __func__); + + return EFI_LOAD_ERROR; + } + if (nt->Signature != IMAGE_NT_SIGNATURE) { printf("%s: Invalid NT Signature\n", __func__); + return EFI_LOAD_ERROR; } @@ -253,14 +583,32 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, if (!supported) { printf("%s: Machine type 0x%04x is not supported\n", __func__, nt->FileHeader.Machine); + return EFI_LOAD_ERROR; } - /* Calculate upper virtual address boundary */ num_sections = nt->FileHeader.NumberOfSections; sections = (void *)&nt->OptionalHeader + nt->FileHeader.SizeOfOptionalHeader; + if (efi_size < ((void *)sections + sizeof(sections[0]) * num_sections + - efi)) { + printf("%s: Invalid number of sections: %d\n", + __func__, num_sections); + + return EFI_LOAD_ERROR; + } + + /* + * Authenticate an image + * TODO: + * If authentication fails, relevant information must be + * recorded in executable information table. + */ + if (!efi_image_authenticate(efi, efi_size)) + return EFI_ACCESS_DENIED; + + /* Calculate upper virtual address boundary */ for (i = num_sections - 1; i >= 0; i--) { IMAGE_SECTION_HEADER *sec = §ions[i]; virt_size = max_t(unsigned long, virt_size, @@ -279,6 +627,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, if (!efi_reloc) { printf("%s: Could not allocate %lu bytes\n", __func__, virt_size); + return EFI_OUT_OF_RESOURCES; } handle->entry = efi_reloc + opt->AddressOfEntryPoint; @@ -295,6 +644,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, if (!efi_reloc) { printf("%s: Could not allocate %lu bytes\n", __func__, virt_size); + return EFI_OUT_OF_RESOURCES; } handle->entry = efi_reloc + opt->AddressOfEntryPoint; @@ -304,13 +654,16 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, } else { printf("%s: Invalid optional header magic %x\n", __func__, nt->OptionalHeader.Magic); + return EFI_LOAD_ERROR; } /* Copy PE headers */ - memcpy(efi_reloc, efi, sizeof(*dos) + sizeof(*nt) - + nt->FileHeader.SizeOfOptionalHeader - + num_sections * sizeof(IMAGE_SECTION_HEADER)); + memcpy(efi_reloc, efi, + sizeof(*dos) + + sizeof(*nt) + + nt->FileHeader.SizeOfOptionalHeader + + num_sections * sizeof(IMAGE_SECTION_HEADER)); /* Load sections into RAM */ for (i = num_sections - 1; i >= 0; i--) { @@ -327,6 +680,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, (unsigned long)image_base) != EFI_SUCCESS) { efi_free_pages((uintptr_t) efi_reloc, (virt_size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT); + return EFI_LOAD_ERROR; }