On Sat, Aug 10, 2024 at 10:45:01PM +0600, Dorjoy Chowdhury wrote:
> AWS Nitro Enclaves have built-in Nitro Secure Module (NSM) device which
> is used for stripped down TPM functionality like attestation. This commit
> adds the built-in NSM device in the nitro-enclave machine type.
>
> In Nitro Enclaves, all the PCRs start in a known zero state and the first
> 16 PCRs are locked from boot and reserved. The PCR0, PCR1, PCR2 and PCR8
> contain the SHA384 hashes related to the EIF file used to boot the
> VM for validation.
>
> A new optional nitro-enclave machine option 'id' has been added which will
> be the enclave identifier reflected in the module-id of the NSM device.
> Otherwise, the device will have a default id set.
>
> Signed-off-by: Dorjoy Chowdhury <[email protected]>
> ---
> hw/core/eif.c | 205 +++++++++++++++++++++++++++++++-
> hw/core/eif.h | 5 +-
> hw/core/meson.build | 4 +-
> hw/i386/Kconfig | 1 +
> hw/i386/nitro_enclave.c | 85 ++++++++++++-
> include/hw/i386/nitro_enclave.h | 19 +++
> 6 files changed, 310 insertions(+), 9 deletions(-)
>
> diff --git a/hw/core/eif.c b/hw/core/eif.c
> index 5558879a96..d2c65668ef 100644
> --- a/hw/core/eif.c
> +++ b/hw/core/eif.c
> @@ -12,6 +12,9 @@
> #include "qemu/bswap.h"
> #include "qapi/error.h"
> #include <zlib.h> /* for crc32 */
> +#include <cbor.h>
> +#include <gnutls/gnutls.h>
> +#include <gnutls/x509.h>
>
> #include "hw/core/eif.h"
>
> @@ -269,6 +284,125 @@ static bool read_eif_ramdisk(FILE *eif, FILE *initrd,
> uint64_t size,
> return false;
> }
>
> +static bool get_fingerprint_sha384_from_cert(uint8_t *cert, size_t size,
> + uint8_t *sha384, Error **errp)
> +{
> + gnutls_x509_crt_t crt;
> + size_t hash_size = 48;
> + gnutls_datum_t datum = {.data = cert, .size = size};
> +
> + gnutls_global_init();
> + gnutls_x509_crt_init(&crt);
> +
> + if (gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM) != 0) {
> + error_setg(errp, "Failed to import certificate");
> + goto cleanup;
> + }
> +
> + if (gnutls_x509_crt_get_fingerprint(crt, GNUTLS_DIG_SHA384, sha384,
> + &hash_size) != 0) {
> + error_setg(errp, "Failed to compute SHA384 fingerprint");
> + goto cleanup;
> + }
> +
> + return true;
> +
> + cleanup:
> + gnutls_x509_crt_deinit(crt);
> + gnutls_global_deinit();
> + return false;
> +}
I'd suggest this go into qcrypto/x509-utils.c & include/qcrypto/x509-utils.h,
as:
int qcrypto_get_x509_cert_fingerprint(uint8_t *cert,
size_t size,
QCryptoHashAlgorith hash,
Error **errp);
there's no need to be calling gnutls_global_init() / deinit() either.
> @@ -299,7 +433,9 @@ static long get_file_size(FILE *f, Error **errp)
> */
> bool read_eif_file(const char *eif_path, const char *machine_initrd,
> char **kernel_path, char **initrd_path, char **cmdline,
> - Error **errp)
> + uint8_t *image_sha384, uint8_t *bootstrap_sha384,
> + uint8_t *app_sha384, uint8_t *fingerprint_sha384,
> + bool *signature_found, Error **errp)
> {
> FILE *f = NULL;
> FILE *machine_initrd_f = NULL;
> @@ -308,9 +444,33 @@ bool read_eif_file(const char *eif_path, const char
> *machine_initrd,
> uint32_t crc = 0;
> EifHeader eif_header;
> bool seen_sections[EIF_SECTION_MAX] = {false};
> -
> + /* kernel + ramdisks + cmdline sha384 hash */
> + GChecksum *image_hasher = NULL;
> + /* kernel + boot ramdisk + cmdline sha384 hash */
> + GChecksum *bootstrap_hasher = NULL;
> + /* application ramdisk(s) hash */
> + GChecksum *app_hasher = NULL;
> + size_t digest_len;
> +
> + *signature_found = false;
> *kernel_path = *initrd_path = *cmdline = NULL;
>
> + image_hasher = g_checksum_new(G_CHECKSUM_SHA384);
> + if (image_hasher == NULL) {
> + error_setg(errp, "Failed to initialize sha384 hash for image");
> + goto cleanup;
> + }
> + bootstrap_hasher = g_checksum_new(G_CHECKSUM_SHA384);
> + if (bootstrap_hasher == NULL) {
> + error_setg(errp, "Failed to initialize sha384 hash for bootstrap");
> + goto cleanup;
> + }
> + app_hasher = g_checksum_new(G_CHECKSUM_SHA384);
> + if (app_hasher == NULL) {
> + error_setg(errp, "Failed to initialize sha384 hash for app");
> + goto cleanup;
> + }
Don't use GChecksum APIs please, use the qcrypto hash APIs instead,
as we need all code to be using the designated QEMU crypto backend.
With regards,
Daniel
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