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Add SHA1 support

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In theory vendors could blacklist binaries with SHA1, so make sure we
calculate and check that hash as well.
This commit is contained in:
Matthew Garrett 2012-10-11 11:30:41 -04:00
parent e204505d2d
commit ce6a5748b0
1 changed files with 49 additions and 28 deletions
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77
shim.c
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@ -290,7 +290,8 @@ static CHECK_STATUS check_db_cert(CHAR16 *dbname, WIN_CERTIFICATE_EFI_PKCS *data
return DATA_NOT_FOUND;
}
static CHECK_STATUS check_db_hash(CHAR16 *dbname, UINT8 *data)
static CHECK_STATUS check_db_hash(CHAR16 *dbname, UINT8 *data,
int SignatureSize, EFI_GUID CertType)
{
EFI_STATUS efi_status;
EFI_GUID secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID;
@ -301,8 +302,6 @@ static CHECK_STATUS check_db_hash(CHAR16 *dbname, UINT8 *data)
UINT32 attributes;
BOOLEAN IsFound = FALSE;
void *db;
unsigned int SignatureSize = SHA256_DIGEST_SIZE;
EFI_GUID CertType = EfiHashSha256Guid;
efi_status = get_variable(dbname, secure_var, &attributes, &dbsize, &db);
@ -344,21 +343,31 @@ static CHECK_STATUS check_db_hash(CHAR16 *dbname, UINT8 *data)
return DATA_NOT_FOUND;
}
static EFI_STATUS check_blacklist (WIN_CERTIFICATE_EFI_PKCS *cert, UINT8 *hash)
static EFI_STATUS check_blacklist (WIN_CERTIFICATE_EFI_PKCS *cert,
UINT8 *sha256hash, UINT8 *sha1hash)
{
if (check_db_hash(L"dbx", hash) == DATA_FOUND)
if (check_db_hash(L"db", sha256hash, SHA256_DIGEST_SIZE,
EfiHashSha256Guid) == DATA_FOUND)
return EFI_ACCESS_DENIED;
if (check_db_cert(L"dbx", cert, hash) == DATA_FOUND)
if (check_db_hash(L"db", sha1hash, SHA1_DIGEST_SIZE,
EfiHashSha1Guid) == DATA_FOUND)
return EFI_ACCESS_DENIED;
if (check_db_cert(L"dbx", cert, sha256hash) == DATA_FOUND)
return EFI_ACCESS_DENIED;
return EFI_SUCCESS;
}
static EFI_STATUS check_whitelist (WIN_CERTIFICATE_EFI_PKCS *cert, UINT8 *hash)
static EFI_STATUS check_whitelist (WIN_CERTIFICATE_EFI_PKCS *cert,
UINT8 *sha256hash, UINT8 *sha1hash)
{
if (check_db_hash(L"db", hash) == DATA_FOUND)
if (check_db_hash(L"db", sha256hash, SHA256_DIGEST_SIZE,
EfiHashSha256Guid) == DATA_FOUND)
return EFI_SUCCESS;
if (check_db_cert(L"db", cert, hash) == DATA_FOUND)
if (check_db_hash(L"db", sha1hash, SHA1_DIGEST_SIZE,
EfiHashSha1Guid) == DATA_FOUND)
return EFI_SUCCESS;
if (check_db_cert(L"db", cert, sha256hash) == DATA_FOUND)
return EFI_SUCCESS;
return EFI_ACCESS_DENIED;
@ -404,9 +413,10 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
{
EFI_GUID shim_lock_guid = SHIM_LOCK_GUID;
unsigned int size = datasize;
unsigned int ctxsize;
void *ctx = NULL;
UINT8 hash[SHA256_DIGEST_SIZE];
unsigned int sha256ctxsize, sha1ctxsize;
void *sha256ctx = NULL, *sha1ctx = NULL;
UINT8 sha256hash[SHA256_DIGEST_SIZE];
UINT8 sha1hash[SHA1_DIGEST_SIZE];
EFI_STATUS status = EFI_ACCESS_DENIED;
char *hashbase;
unsigned int hashsize;
@ -437,15 +447,18 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
/* FIXME: Check which kind of hash */
ctxsize = Sha256GetContextSize();
ctx = AllocatePool(ctxsize);
sha256ctxsize = Sha256GetContextSize();
sha256ctx = AllocatePool(sha256ctxsize);
if (!ctx) {
sha1ctxsize = Sha1GetContextSize();
sha1ctx = AllocatePool(sha1ctxsize);
if (!sha256ctx || !sha1ctx) {
Print(L"Unable to allocate memory for hash context\n");
return EFI_OUT_OF_RESOURCES;
}
if (!Sha256Init(ctx)) {
if (!Sha256Init(sha256ctx) || !Sha1Init(sha1ctx)) {
Print(L"Unable to initialise hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
@ -456,7 +469,8 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
hashsize = (char *)&context->PEHdr->Pe32.OptionalHeader.CheckSum -
hashbase;
if (!(Sha256Update(ctx, hashbase, hashsize))) {
if (!(Sha256Update(sha256ctx, hashbase, hashsize)) ||
!(Sha1Update(sha1ctx, hashbase, hashsize))) {
Print(L"Unable to generate hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
@ -467,7 +481,8 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
sizeof (int);
hashsize = (char *)context->SecDir - hashbase;
if (!(Sha256Update(ctx, hashbase, hashsize))) {
if (!(Sha256Update(sha256ctx, hashbase, hashsize)) ||
!(Sha1Update(sha1ctx, hashbase, hashsize))) {
Print(L"Unable to generate hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
@ -478,7 +493,8 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
hashsize = context->PEHdr->Pe32Plus.OptionalHeader.SizeOfHeaders -
(int) ((char *) (&context->PEHdr->Pe32Plus.OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - data);
if (!(Sha256Update(ctx, hashbase, hashsize))) {
if (!(Sha256Update(sha256ctx, hashbase, hashsize)) ||
!(Sha1Update(sha1ctx, hashbase, hashsize))) {
Print(L"Unable to generate hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
@ -537,7 +553,8 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
return EFI_INVALID_PARAMETER;
}
if (!(Sha256Update(ctx, hashbase, hashsize))) {
if (!(Sha256Update(sha256ctx, hashbase, hashsize)) ||
!(Sha1Update(sha1ctx, hashbase, hashsize))) {
Print(L"Unable to generate hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
@ -553,20 +570,22 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
context->PEHdr->Pe32Plus.OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size -
SumOfBytesHashed);
if (!(Sha256Update(ctx, hashbase, hashsize))) {
if (!(Sha256Update(sha256ctx, hashbase, hashsize)) ||
!(Sha1Update(sha1ctx, hashbase, hashsize))) {
Print(L"Unable to generate hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
}
}
if (!(Sha256Final(ctx, hash))) {
if (!(Sha256Final(sha256ctx, sha256hash)) ||
!(Sha1Final(sha1ctx, sha1hash))) {
Print(L"Unable to finalise hash\n");
status = EFI_OUT_OF_RESOURCES;
goto done;
}
status = check_blacklist(cert, hash);
status = check_blacklist(cert, sha256hash, sha1hash);
if (status != EFI_SUCCESS) {
Print(L"Binary is blacklisted\n");
@ -574,7 +593,7 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
}
if (whitelist) {
status = check_whitelist(cert, hash);
status = check_whitelist(cert, sha256hash, sha1hash);
if (status == EFI_SUCCESS) {
Print(L"Binary is whitelisted\n");
@ -584,7 +603,7 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
if (AuthenticodeVerify(cert->CertData,
context->SecDir->Size - sizeof(cert->Hdr),
vendor_cert, vendor_cert_size, hash,
vendor_cert, vendor_cert_size, sha256hash,
SHA256_DIGEST_SIZE)) {
status = EFI_SUCCESS;
Print(L"Binary is verified by the vendor certificate\n");
@ -628,7 +647,7 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
for (i = 0; i < MokNum; i++) {
if (AuthenticodeVerify(cert->CertData,
context->SecDir->Size - sizeof(cert->Hdr),
list[i].Mok, list[i].MokSize, hash,
list[i].Mok, list[i].MokSize, sha256hash,
SHA256_DIGEST_SIZE)) {
status = EFI_SUCCESS;
Print(L"Binary is verified by the machine owner key\n");
@ -641,8 +660,10 @@ static EFI_STATUS verify_buffer (char *data, int datasize,
done:
if (SectionHeader)
FreePool(SectionHeader);
if (ctx)
FreePool(ctx);
if (sha1ctx)
FreePool(sha1ctx);
if (sha256ctx)
FreePool(sha256ctx);
return status;
}