Add porting layer for MSCode on top of MbedTLS ASN1 library.
Signed-off-by: Raymond Mao raymond.mao@linaro.org --- Changes in v2 - Move the porting layer to MbedTLS dir. Changes in v3 - None.
lib/mbedtls/Makefile | 1 + lib/mbedtls/mscode_parser.c | 111 ++++++++++++++++++++++++++++++++++++ 2 files changed, 112 insertions(+) create mode 100644 lib/mbedtls/mscode_parser.c
diff --git a/lib/mbedtls/Makefile b/lib/mbedtls/Makefile index 005b8a25320..f0b8a1c4003 100644 --- a/lib/mbedtls/Makefile +++ b/lib/mbedtls/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_MBEDTLS_LIB_X509) += x509_mbedtls.o x509_mbedtls-$(CONFIG_$(SPL_)ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o x509_mbedtls-$(CONFIG_$(SPL_)X509_CERTIFICATE_PARSER) += x509_cert_parser.o x509_mbedtls-$(CONFIG_$(SPL_)PKCS7_MESSAGE_PARSER) += pkcs7_parser.o +x509_mbedtls-$(CONFIG_$(SPL_)MSCODE_PARSER) += mscode_parser.o
obj-$(CONFIG_MBEDTLS_LIB_CRYPTO) += mbedtls_lib_crypto.o mbedtls_lib_crypto-y := \ diff --git a/lib/mbedtls/mscode_parser.c b/lib/mbedtls/mscode_parser.c new file mode 100644 index 00000000000..34715f3a137 --- /dev/null +++ b/lib/mbedtls/mscode_parser.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * MSCode parser using MbedTLS ASN1 library + * + * Copyright (c) 2024 Linaro Limited + * Author: Raymond Mao raymond.mao@linaro.org + */ + +#include <linux/kernel.h> +#include <linux/err.h> +#include <crypto/pkcs7.h> +#include <crypto/mscode.h> + +/* + * Parse a Microsoft Individual Code Signing blob + * + * U.P.SEQUENCE { + * U.P.OBJECTIDENTIFIER 1.3.6.1.4.1.311.2.1.15 (SPC_PE_IMAGE_DATA_OBJID) + * U.P.SEQUENCE { + * U.P.BITSTRING NaN : 0 unused bit(s); + * [C.P.0] { + * [C.P.2] { + * [C.P.0] <arbitrary string> + * } + * } + * } + * } + * U.P.SEQUENCE { + * U.P.SEQUENCE { + * U.P.OBJECTIDENTIFIER <digest algorithm OID> + * U.P.NULL + * } + * U.P.OCTETSTRING <PE image digest> + * } + * + */ +int mscode_parse(void *_ctx, const void *content_data, size_t data_len, + size_t asn1hdrlen) +{ + struct pefile_context *ctx = _ctx; + unsigned char *p = (unsigned char *)content_data; + unsigned char *end = (unsigned char *)content_data + data_len; + size_t len = 0; + int ret; + unsigned char *inner_p; + size_t seq_len = 0; + + ret = mbedtls_asn1_get_tag(&p, end, &seq_len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE); + if (ret) + return ret; + + inner_p = p; + ret = mbedtls_asn1_get_tag(&inner_p, inner_p + seq_len, &len, MBEDTLS_ASN1_OID); + if (ret) + return ret; + + /* Sanity check on the PE Image Data OID (1.3.6.1.4.1.311.2.1.15) */ + if (MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_MICROSOFT_PEIMAGEDATA, inner_p, len)) + return -EINVAL; + + p += seq_len; + ret = mbedtls_asn1_get_tag(&p, end, &seq_len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE); + if (ret) + return ret; + + ret = mbedtls_asn1_get_tag(&p, p + seq_len, &seq_len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE); + if (ret) + return ret; + + inner_p = p; + + /* + * Check if the inner sequence contains a supported hash + * algorithm OID + */ + ret = mbedtls_asn1_get_tag(&inner_p, inner_p + seq_len, &len, MBEDTLS_ASN1_OID); + if (ret) + return ret; + + if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_MD5, inner_p, len)) + ctx->digest_algo = "md5"; + else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA1, inner_p, len)) + ctx->digest_algo = "sha1"; + else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA224, inner_p, len)) + ctx->digest_algo = "sha224"; + else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA256, inner_p, len)) + ctx->digest_algo = "sha256"; + else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA384, inner_p, len)) + ctx->digest_algo = "sha384"; + else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA512, inner_p, len)) + ctx->digest_algo = "sha512"; + + if (!ctx->digest_algo) + return -EINVAL; + + p += seq_len; + ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING); + if (ret) + return ret; + + ctx->digest = p; + ctx->digest_len = len; + + return 0; +}