Currently we don't support sha384/512 for the X.509 certificate To-Be-Signed contents. Moreover if we come across such a hash we skip the check and approve the image, although the image might needs to be rejected.
It's worth noting here that efi_hash_regions() can now be reused from efi_signature_lookup_digest() and add sha348/512 support there as well Signed-off-by: Ilias Apalodimas <[email protected]> --- include/efi_api.h | 6 ++++ lib/efi_loader/efi_signature.c | 62 ++++++++++++++++++++++++++-------- 2 files changed, 53 insertions(+), 15 deletions(-) diff --git a/include/efi_api.h b/include/efi_api.h index 982c2001728d..b9a04958f9ba 100644 --- a/include/efi_api.h +++ b/include/efi_api.h @@ -1873,6 +1873,12 @@ struct efi_system_resource_table { #define EFI_CERT_X509_SHA256_GUID \ EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) +#define EFI_CERT_X509_SHA384_GUID \ + EFI_GUID(0x7076876e, 0x80c2, 0x4ee6, \ + 0xaa, 0xd2, 0x28, 0xb3, 0x49, 0xa6, 0x86, 0x5b) +#define EFI_CERT_X509_SHA512_GUID \ + EFI_GUID(0x446dbf63, 0x2502, 0x4cda, \ + 0xbc, 0xfa, 0x24, 0x65, 0xd2, 0xb0, 0xfe, 0x9d) #define EFI_CERT_TYPE_PKCS7_GUID \ EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c index 79ed077ae7dd..392eae6c0d64 100644 --- a/lib/efi_loader/efi_signature.c +++ b/lib/efi_loader/efi_signature.c @@ -24,6 +24,8 @@ const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; +const efi_guid_t efi_guid_cert_x509_sha384 = EFI_CERT_X509_SHA384_GUID; +const efi_guid_t efi_guid_cert_x509_sha512 = EFI_CERT_X509_SHA512_GUID; const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID; static u8 pkcs7_hdr[] = { @@ -124,23 +126,32 @@ struct pkcs7_message *efi_parse_pkcs7_header(const void *buf, * Return: true on success, false on error */ static bool efi_hash_regions(struct image_region *regs, int count, - void **hash, size_t *size) + void **hash, size_t size) { + char hash_algo[16]; + int ret; + + /* basic sanity checking */ + if (!size) + return false; + + ret = snprintf(hash_algo, sizeof(hash_algo), "sha%ld", size * 8); + if (ret >= sizeof(hash_algo)) + return false; + if (!*hash) { - *hash = calloc(1, SHA256_SUM_LEN); + *hash = calloc(1, size); if (!*hash) { EFI_PRINT("Out of memory\n"); return false; } } - if (size) - *size = SHA256_SUM_LEN; - hash_calculate("sha256", regs, count, *hash); + hash_calculate(hash_algo, regs, count, *hash); #ifdef DEBUG EFI_PRINT("hash calculated:\n"); print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, - *hash, SHA256_SUM_LEN, false); + *hash, size, false); #endif return true; @@ -190,7 +201,7 @@ bool efi_signature_lookup_digest(struct efi_image_regions *regs, struct efi_signature_store *siglist; struct efi_sig_data *sig_data; void *hash = NULL; - size_t size = 0; + size_t size = SHA256_SUM_LEN; bool found = false; bool hash_done = false; @@ -216,7 +227,7 @@ bool efi_signature_lookup_digest(struct efi_image_regions *regs, continue; if (!hash_done && - !efi_hash_regions(regs->reg, regs->num, &hash, &size)) { + !efi_hash_regions(regs->reg, regs->num, &hash, size)) { EFI_PRINT("Digesting an image failed\n"); break; } @@ -263,7 +274,7 @@ static bool efi_lookup_certificate(struct x509_certificate *cert, struct efi_sig_data *sig_data; struct image_region reg[1]; void *hash = NULL, *hash_tmp = NULL; - size_t size = 0; + size_t size = SHA256_SUM_LEN; bool found = false; EFI_PRINT("%s: Enter, %p, %p\n", __func__, cert, db); @@ -278,7 +289,7 @@ static bool efi_lookup_certificate(struct x509_certificate *cert, /* calculate hash of TBSCertificate */ reg[0].data = cert->tbs; reg[0].size = cert->tbs_size; - if (!efi_hash_regions(reg, 1, &hash, &size)) + if (!efi_hash_regions(reg, 1, &hash, size)) goto out; EFI_PRINT("%s: searching for %s\n", __func__, cert->subject); @@ -300,7 +311,7 @@ static bool efi_lookup_certificate(struct x509_certificate *cert, cert_tmp->subject); reg[0].data = cert_tmp->tbs; reg[0].size = cert_tmp->tbs_size; - if (!efi_hash_regions(reg, 1, &hash_tmp, NULL)) + if (!efi_hash_regions(reg, 1, &hash_tmp, size)) goto out; x509_free_certificate(cert_tmp); @@ -377,6 +388,26 @@ out: return verified; } +/** guid_to_sha_len - return the sha size in bytes for a given guid + * used of EFI security databases + * + * @guid: guid to check + * + * Return: len or 0 if no match is found + */ +static int guid_to_sha_len(efi_guid_t *guid) +{ + int size = 0; + + if (!guidcmp(guid, &efi_guid_cert_x509_sha256)) + size = SHA256_SUM_LEN; + else if (!guidcmp(guid, &efi_guid_cert_x509_sha384)) + size = SHA384_SUM_LEN; + else if (!guidcmp(guid, &efi_guid_cert_x509_sha512)) + size = SHA512_SUM_LEN; + + return size; +} /** * efi_signature_check_revocation - check revocation with dbx * @sinfo: Signer's info @@ -400,7 +431,7 @@ static bool efi_signature_check_revocation(struct pkcs7_signed_info *sinfo, struct efi_sig_data *sig_data; struct image_region reg[1]; void *hash = NULL; - size_t size = 0; + size_t size = SHA256_SUM_LEN; time64_t revoc_time; bool revoked = false; @@ -411,13 +442,14 @@ static bool efi_signature_check_revocation(struct pkcs7_signed_info *sinfo, EFI_PRINT("Checking revocation against %s\n", cert->subject); for (siglist = dbx; siglist; siglist = siglist->next) { - if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) + size = guid_to_sha_len(&siglist->sig_type); + if (!size) continue; /* calculate hash of TBSCertificate */ reg[0].data = cert->tbs; reg[0].size = cert->tbs_size; - if (!efi_hash_regions(reg, 1, &hash, &size)) + if (!efi_hash_regions(reg, 1, &hash, size)) goto out; for (sig_data = siglist->sig_data_list; sig_data; @@ -500,7 +532,7 @@ bool efi_signature_verify(struct efi_image_regions *regs, */ if (!msg->data && !efi_hash_regions(regs->reg, regs->num, - (void **)&sinfo->sig->digest, NULL)) { + (void **)&sinfo->sig->digest, SHA256_SUM_LEN)) { EFI_PRINT("Digesting an image failed\n"); goto out; } -- 2.32.0
