#ifdef ENTROPY_RTC
REQUIRE_OBJECT ( rtc_entropy );
#endif
-#ifdef ENTROPY_EFI
+#ifdef ENTROPY_EFITICK
REQUIRE_OBJECT ( efi_entropy );
#endif
+#ifdef ENTROPY_EFIRNG
+REQUIRE_OBJECT ( efi_rng );
+#endif
#ifdef ENTROPY_LINUX
REQUIRE_OBJECT ( linux_entropy );
#endif
#define SMBIOS_EFI
#define SANBOOT_EFI
#define BOFM_EFI
-#define ENTROPY_EFI
+#define ENTROPY_EFITICK
+#define ENTROPY_EFIRNG
#define TIME_EFI
#define REBOOT_EFI
#define ACPI_EFI
#define ERRFILE_pci_cmd ( ERRFILE_OTHER | 0x00590000 )
#define ERRFILE_dhe ( ERRFILE_OTHER | 0x005a0000 )
#define ERRFILE_efi_cmdline ( ERRFILE_OTHER | 0x005b0000 )
+#define ERRFILE_efi_rng ( ERRFILE_OTHER | 0x005c0000 )
/** @} */
#include <errno.h>
#include <ipxe/entropy.h>
-#include <ipxe/crc32.h>
#include <ipxe/profile.h>
#include <ipxe/efi/efi.h>
-#include <ipxe/efi/Protocol/Rng.h>
/** @file
*
*
*/
-struct entropy_source efi_entropy __entropy_source ( ENTROPY_NORMAL );
-
-/** Random number generator protocol */
-static EFI_RNG_PROTOCOL *efirng;
-EFI_REQUEST_PROTOCOL ( EFI_RNG_PROTOCOL, &efirng );
-
-/** Minimum number of bytes to request from RNG
- *
- * The UEFI spec states (for no apparently good reason) that "When a
- * Deterministic Random Bit Generator (DRBG) is used on the output of
- * a (raw) entropy source, its security level must be at least 256
- * bits." The EDK2 codebase (mis)interprets this to mean that the
- * call to GetRNG() should fail if given a buffer less than 32 bytes.
- *
- * Incidentally, nothing in the EFI RNG protocol provides any way to
- * report the actual amount of entropy returned by GetRNG().
- */
-#define EFI_ENTROPY_RNG_LEN 32
+struct entropy_source efitick_entropy __entropy_source ( ENTROPY_FALLBACK );
/** Time (in 100ns units) to delay waiting for timer tick
*
EFI_STATUS efirc;
int rc;
- DBGC ( &tick, "ENTROPY %s RNG protocol\n",
- ( efirng ? "has" : "has no" ) );
-
/* Drop to external TPL to allow timer tick event to take place */
bs->RestoreTPL ( efi_external_tpl );
* RTC-based entropy source, and so assume the same
* min-entropy per sample.
*/
- entropy_init ( &efi_entropy, MIN_ENTROPY ( 1.3 ) );
+ entropy_init ( &efitick_entropy, MIN_ENTROPY ( 1.3 ) );
return 0;
}
* @ret noise Noise sample
* @ret rc Return status code
*/
-static int efi_get_noise_ticks ( noise_sample_t *noise ) {
+static int efi_get_noise ( noise_sample_t *noise ) {
int before;
int after;
int rc;
return 0;
}
-/**
- * Get noise sample from RNG protocol
- *
- * @ret noise Noise sample
- * @ret rc Return status code
- */
-static int efi_get_noise_rng ( noise_sample_t *noise ) {
- static uint8_t prev[EFI_ENTROPY_RNG_LEN];
- uint8_t buf[EFI_ENTROPY_RNG_LEN];
- EFI_STATUS efirc;
- int rc;
-
- /* Fail if we have no EFI RNG protocol */
- if ( ! efirng )
- return -ENOTSUP;
-
- /* Get the minimum allowed number of random bytes */
- if ( ( efirc = efirng->GetRNG ( efirng, NULL, EFI_ENTROPY_RNG_LEN,
- buf ) ) != 0 ) {
- rc = -EEFI ( efirc );
- DBGC ( &tick, "ENTROPY could not read from RNG: %s\n",
- strerror ( rc ) );
- return rc;
- }
-
- /* Fail (and permanently disable the EFI RNG) if we get
- * consecutive identical results.
- */
- if ( memcmp ( buf, prev, sizeof ( buf ) ) == 0 ) {
- DBGC ( &tick, "ENTROPY detected broken EFI RNG:\n" );
- DBGC_HDA ( &tick, 0, buf, sizeof ( buf ) );
- efirng = NULL;
- return -EIO;
- }
- memcpy ( prev, buf, sizeof ( prev ) );
-
- /* Reduce random bytes to a single noise sample. This seems
- * like overkill, but we have no way of knowing how much
- * entropy is actually present in the bytes returned by the
- * RNG protocol.
- */
- *noise = crc32_le ( 0, buf, sizeof ( buf ) );
-
- return 0;
-}
-
-/**
- * Get noise sample
- *
- * @ret noise Noise sample
- * @ret rc Return status code
- */
-static int efi_get_noise ( noise_sample_t *noise ) {
- int rc;
-
- /* Try RNG first, falling back to timer ticks */
- if ( ( ( rc = efi_get_noise_rng ( noise ) ) != 0 ) &&
- ( ( rc = efi_get_noise_ticks ( noise ) ) != 0 ) )
- return rc;
-
- return 0;
-}
-
/** EFI entropy source */
-struct entropy_source efi_entropy __entropy_source ( ENTROPY_NORMAL ) = {
- .name = "efi",
+struct entropy_source efitick_entropy __entropy_source ( ENTROPY_FALLBACK ) = {
+ .name = "efitick",
.enable = efi_entropy_enable,
.disable = efi_entropy_disable,
.get_noise = efi_get_noise,
--- /dev/null
+/*
+ * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <errno.h>
+#include <ipxe/entropy.h>
+#include <ipxe/crc32.h>
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/Protocol/Rng.h>
+
+/** @file
+ *
+ * EFI random number generator protocol entropy source
+ *
+ */
+
+struct entropy_source efirng_entropy __entropy_source ( ENTROPY_NORMAL );
+
+/** Random number generator protocol */
+static EFI_RNG_PROTOCOL *efirng;
+EFI_REQUEST_PROTOCOL ( EFI_RNG_PROTOCOL, &efirng );
+
+/** Minimum number of bytes to request from RNG
+ *
+ * The UEFI spec states (for no apparently good reason) that "When a
+ * Deterministic Random Bit Generator (DRBG) is used on the output of
+ * a (raw) entropy source, its security level must be at least 256
+ * bits." The EDK2 codebase (mis)interprets this to mean that the
+ * call to GetRNG() should fail if given a buffer less than 32 bytes.
+ *
+ * Incidentally, nothing in the EFI RNG protocol provides any way to
+ * report the actual amount of entropy returned by GetRNG().
+ */
+#define EFIRNG_LEN 32
+
+/**
+ * Enable entropy gathering
+ *
+ * @ret rc Return status code
+ */
+static int efirng_enable ( void ) {
+
+ /* Check for RNG protocol support */
+ if ( ! efirng ) {
+ DBGC ( &efirng, "EFIRNG has no RNG protocol\n" );
+ return -ENOTSUP;
+ }
+
+ /* Nothing in the EFI specification provides any clue as to
+ * how much entropy will be returned by GetRNG(). Make a
+ * totally uninformed (and conservative guess) that each
+ * sample will contain at least one bit of entropy.
+ */
+ entropy_init ( &efirng_entropy, MIN_ENTROPY ( 1.0 ) );
+
+ return 0;
+}
+
+/**
+ * Get noise sample from RNG protocol
+ *
+ * @ret noise Noise sample
+ * @ret rc Return status code
+ */
+static int efirng_get_noise ( noise_sample_t *noise ) {
+ uint8_t buf[EFIRNG_LEN];
+ EFI_STATUS efirc;
+ int rc;
+
+ /* Sanity check */
+ assert ( efirng != NULL );
+
+ /* Get the minimum allowed number of random bytes */
+ if ( ( efirc = efirng->GetRNG ( efirng, NULL, sizeof ( buf ),
+ buf ) ) != 0 ) {
+ rc = -EEFI ( efirc );
+ DBGC ( &efirng, "ENTROPY could not read from RNG: %s\n",
+ strerror ( rc ) );
+ return rc;
+ }
+
+ /* Reduce random bytes to a single noise sample. This seems
+ * like overkill, but we have no way of knowing how much
+ * entropy is actually present in the bytes returned by the
+ * RNG protocol.
+ */
+ *noise = crc32_le ( 0, buf, sizeof ( buf ) );
+
+ return 0;
+}
+
+/** EFI random number generator protocol entropy source */
+struct entropy_source efirng_entropy __entropy_source ( ENTROPY_NORMAL ) = {
+ .name = "efirng",
+ .enable = efirng_enable,
+ .get_noise = efirng_get_noise,
+};
projects / thirdparty / ipxe.git / commitdiff
