X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/21362eb3e66fd2c787aee132bce100a44d71a99c..ebb1b9f42b62218f29061826217bb0f71cd375a6:/bsd/dev/random/randomdev.c
diff --git a/bsd/dev/random/randomdev.c b/bsd/dev/random/randomdev.c
index 6f99d775d..c29e9f877 100644
--- a/bsd/dev/random/randomdev.c
+++ b/bsd/dev/random/randomdev.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c)1999-2004 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1999-2009 Apple, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
@@ -26,6 +26,17 @@
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
+/*
+ WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
+
+ THIS FILE IS NEEDED TO PASS FIPS ACCEPTANCE FOR THE RANDOM NUMBER GENERATOR.
+ IF YOU ALTER IT IN ANY WAY, WE WILL NEED TO GO THOUGH FIPS ACCEPTANCE AGAIN,
+ AN OPERATION THAT IS VERY EXPENSIVE AND TIME CONSUMING. IN OTHER WORDS,
+ DON'T MESS WITH THIS FILE.
+
+ WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
+*/
+
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
@@ -36,13 +47,21 @@
#include <string.h>
#include <miscfs/devfs/devfs.h>
#include <kern/lock.h>
+#include <kern/clock.h>
#include <sys/time.h>
#include <sys/malloc.h>
#include <sys/uio_internal.h>
#include <dev/random/randomdev.h>
#include <dev/random/YarrowCoreLib/include/yarrow.h>
-#include <crypto/sha1.h>
+
+#include <libkern/OSByteOrder.h>
+#include <libkern/OSAtomic.h>
+
+#include <mach/mach_time.h>
+#include <machine/machine_routines.h>
+
+#include "fips_sha1.h"
#define RANDOM_MAJOR -1 /* let the kernel pick the device number */
@@ -70,27 +89,41 @@ static struct cdevsw random_cdevsw =
0 /* type */
};
+
+/*
+ WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
+
+ ANY CODE PROTECTED UNDER "#ifdef __arm__" IS SERIOUSLY SUPPOSED TO BE THERE!
+ IF YOU REMOVE ARM CODE, RANDOM WILL NOT MEAN ANYTHING FOR iPHONES ALL OVER.
+ PLEASE DON'T TOUCH __arm__ CODE IN THIS FILE!
+
+ WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!
+*/
+
+
/* Used to detect whether we've already been initialized */
-static int gRandomInstalled = 0;
+static UInt8 gRandomInstalled = 0;
static PrngRef gPrngRef;
static int gRandomError = 1;
-static mutex_t *gYarrowMutex = 0;
+static lck_grp_t *gYarrowGrp;
+static lck_attr_t *gYarrowAttr;
+static lck_grp_attr_t *gYarrowGrpAttr;
+static lck_mtx_t *gYarrowMutex = 0;
+static UInt8 gYarrowInitializationLock = 0;
#define RESEED_TICKS 50 /* how long a reseed operation can take */
-enum {kBSizeInBits = 160}; // MUST be a multiple of 32!!!
-enum {kBSizeInBytes = kBSizeInBits / 8};
-typedef u_int32_t BlockWord;
-enum {kWordSizeInBits = 32};
-enum {kBSize = 5};
+typedef u_int8_t BlockWord;
+enum {kBSize = 20};
typedef BlockWord Block[kBSize];
+enum {kBlockSize = sizeof(Block)};
/* define prototypes to keep the compiler happy... */
void add_blocks(Block a, Block b, BlockWord carry);
void fips_initialize(void);
-void random_block(Block b);
+void random_block(Block b, int addOptional);
u_int32_t CalculateCRC(u_int8_t* buffer, size_t length);
/*
@@ -103,26 +136,26 @@ u_int32_t CalculateCRC(u_int8_t* buffer, size_t length);
void
add_blocks(Block a, Block b, BlockWord carry)
{
- int i = kBSize;
- while (--i >= 0)
+ int i = kBlockSize - 1;
+ while (i >= 0)
{
- u_int64_t c = (u_int64_t)carry +
- (u_int64_t)a[i] +
- (u_int64_t)b[i];
- a[i] = c & ((1LL << kWordSizeInBits) - 1);
- carry = c >> kWordSizeInBits;
+ u_int32_t c = (u_int32_t)carry +
+ (u_int32_t)a[i] +
+ (u_int32_t)b[i];
+ a[i] = c & 0xff;
+ carry = c >> 8;
+ i -= 1;
}
}
-struct sha1_ctxt g_sha1_ctx;
-char zeros[(512 - kBSizeInBits) / 8];
-Block g_xkey;
-Block g_random_data;
-int g_bytes_used;
-unsigned char g_SelfTestInitialized = 0;
-u_int32_t gLastBlockChecksum;
+static char zeros[(512 - kBSize * 8) / 8];
+static Block g_xkey;
+static Block g_random_data;
+static int g_bytes_used;
+static unsigned char g_SelfTestInitialized = 0;
+static u_int32_t gLastBlockChecksum;
static const u_int32_t g_crc_table[] =
{
@@ -185,29 +218,52 @@ u_int32_t CalculateCRC(u_int8_t* buffer, size_t length)
* get a random block of data per fips 186-2
*/
void
-random_block(Block b)
+random_block(Block b, int addOptional)
{
+ SHA1_CTX sha1_ctx;
+
int repeatCount = 0;
do
{
// do one iteration
- Block xSeed;
- prngOutput (gPrngRef, (BYTE*) &xSeed, sizeof (xSeed));
- // add the seed to the previous value of g_xkey
- add_blocks (g_xkey, xSeed, 0);
-
+ if (addOptional)
+ {
+ // create an xSeed to add.
+ Block xSeed;
+ prngOutput (gPrngRef, (BYTE*) &xSeed, sizeof (xSeed));
+
+ // add the seed to the previous value of g_xkey
+ add_blocks (g_xkey, xSeed, 0);
+ }
+
+ // initialize the value of H
+ FIPS_SHA1Init(&sha1_ctx);
+
+ // to stay compatible with the FIPS specification, we need to flip the bytes in
+ // g_xkey to little endian byte order. In our case, this makes exactly no difference
+ // (random is random), but we need to do it anyway to keep FIPS happy
+
// compute "G"
- SHA1Update (&g_sha1_ctx, (const u_int8_t *) &g_xkey, sizeof (g_xkey));
+ FIPS_SHA1Update(&sha1_ctx, g_xkey, kBlockSize);
// add zeros to fill the internal SHA-1 buffer
- SHA1Update (&g_sha1_ctx, (const u_int8_t *)zeros, sizeof (zeros));
+ FIPS_SHA1Update (&sha1_ctx, (const u_int8_t *)zeros, sizeof (zeros));
+
+ // we have to do a byte order correction here because the sha1 math is being done internally
+ // as u_int32_t, not a stream of bytes. Since we maintain our data as a byte stream, we need
+ // to convert
+
+ u_int32_t* finger = (u_int32_t*) b;
- // write the resulting block
- memmove(b, g_sha1_ctx.h.b8, sizeof (Block));
+ unsigned j;
+ for (j = 0; j < kBlockSize / sizeof (u_int32_t); ++j)
+ {
+ *finger++ = OSSwapHostToBigInt32(sha1_ctx.h.b32[j]);
+ }
// calculate the CRC-32 of the block
- u_int32_t new_crc = CalculateCRC(g_sha1_ctx.h.b8, sizeof (Block));
+ u_int32_t new_crc = CalculateCRC(sha1_ctx.h.b8, sizeof (Block));
// make sure we don't repeat
int cmp = new_crc == gLastBlockChecksum;
@@ -252,8 +308,27 @@ void
PreliminarySetup(void)
{
prng_error_status perr;
- struct timeval tt;
- char buffer [16];
+
+ /* Multiple threads can enter this as a result of an earlier
+ * check of gYarrowMutex. We make sure that only one of them
+ * can enter at a time. If one of them enters and discovers
+ * that gYarrowMutex is no longer NULL, we know that another
+ * thread has initialized the Yarrow state and we can exit.
+ */
+
+ /* The first thread that enters this function will find
+ * gYarrowInitializationLock set to 0. It will atomically
+ * set the value to 1 and, seeing that it was zero, drop
+ * out of the loop. Other threads will see that the value is
+ * 1 and continue to loop until we are initialized.
+ */
+
+ while (OSTestAndSet(0, &gYarrowInitializationLock)); /* serialize access to this function */
+
+ if (gYarrowMutex) {
+ /* we've already been initialized, clear and get out */
+ goto function_exit;
+ }
/* create a Yarrow object */
perr = prngInitialize(&gPrngRef);
@@ -265,7 +340,12 @@ PreliminarySetup(void)
/* clear the error flag, reads and write should then work */
gRandomError = 0;
+ struct timeval tt;
+ char buffer [16];
+
/* get a little non-deterministic data as an initial seed. */
+ /* On OSX, securityd will add much more entropy as soon as it */
+ /* comes up. On iOS, entropy is added with each system interrupt. */
microtime(&tt);
/*
@@ -279,34 +359,49 @@ PreliminarySetup(void)
if (perr != 0) {
/* an error, complain */
printf ("Couldn't seed Yarrow.\n");
- return;
+ goto function_exit;
}
/* turn the data around */
- perr = prngOutput(gPrngRef, (BYTE*)buffer, sizeof (buffer));
+ perr = prngOutput(gPrngRef, (BYTE*) buffer, sizeof (buffer));
/* and scramble it some more */
perr = prngForceReseed(gPrngRef, RESEED_TICKS);
/* make a mutex to control access */
- gYarrowMutex = mutex_alloc(0);
+ gYarrowGrpAttr = lck_grp_attr_alloc_init();
+ gYarrowGrp = lck_grp_alloc_init("random", gYarrowGrpAttr);
+ gYarrowAttr = lck_attr_alloc_init();
+ gYarrowMutex = lck_mtx_alloc_init(gYarrowGrp, gYarrowAttr);
fips_initialize ();
+
+function_exit:
+ /* allow other threads to figure out whether or not we have been initialized. */
+ gYarrowInitializationLock = 0;
}
+const Block kKnownAnswer = {0x92, 0xb4, 0x04, 0xe5, 0x56, 0x58, 0x8c, 0xed, 0x6c, 0x1a, 0xcd, 0x4e, 0xbf, 0x05, 0x3f, 0x68, 0x09, 0xf7, 0x3a, 0x93};
+
void
fips_initialize(void)
{
- /* Read the initial value of g_xkey from yarrow */
- prngOutput (gPrngRef, (BYTE*) &g_xkey, sizeof (g_xkey));
-
- /* initialize our SHA1 generator */
- SHA1Init (&g_sha1_ctx);
+ /* So that we can do the self test, set the seed to zero */
+ memset(&g_xkey, 0, sizeof(g_xkey));
/* other initializations */
memset (zeros, 0, sizeof (zeros));
g_bytes_used = 0;
- random_block(g_random_data);
+ random_block(g_random_data, FALSE);
+
+ // check here to see if we got the initial data we were expecting
+ if (memcmp(kKnownAnswer, g_random_data, kBlockSize) != 0)
+ {
+ panic("FIPS random self test failed");
+ }
+
+ // now do the random block again to make sure that userland doesn't get predicatable data
+ random_block(g_random_data, TRUE);
}
/*
@@ -318,14 +413,11 @@ random_init(void)
{
int ret;
- if (gRandomInstalled)
+ if (OSTestAndSet(0, &gRandomInstalled)) {
+ /* do this atomically so that it works correctly with
+ multiple threads */
return;
-
- /* install us in the file system */
- gRandomInstalled = 1;
-
- /* setup yarrow and the mutex */
- PreliminarySetup();
+ }
ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw);
if (ret < 0) {
@@ -343,6 +435,9 @@ random_init(void)
*/
devfs_make_node(makedev (ret, 1), DEVFS_CHAR,
UID_ROOT, GID_WHEEL, 0666, "urandom", 0);
+
+ /* setup yarrow and the mutex if needed*/
+ PreliminarySetup();
}
int
@@ -416,20 +511,19 @@ random_write (__unused dev_t dev, struct uio *uio, __unused int ioflag)
}
/* get control of the Yarrow instance, Yarrow is NOT thread safe */
- mutex_lock(gYarrowMutex);
+ lck_mtx_lock(gYarrowMutex);
/* Security server is sending us entropy */
while (uio_resid(uio) > 0 && retCode == 0) {
/* get the user's data */
- // LP64todo - fix this! uio_resid may be 64-bit value
int bytesToInput = min(uio_resid(uio), sizeof (rdBuffer));
retCode = uiomove(rdBuffer, bytesToInput, uio);
if (retCode != 0)
goto /*ugh*/ error_exit;
/* put it in Yarrow */
- if (prngInput(gPrngRef, (BYTE*)rdBuffer,
+ if (prngInput(gPrngRef, (BYTE*) rdBuffer,
bytesToInput, SYSTEM_SOURCE,
bytesToInput * 8) != 0) {
retCode = EIO;
@@ -446,14 +540,15 @@ random_write (__unused dev_t dev, struct uio *uio, __unused int ioflag)
/* retCode should be 0 at this point */
error_exit: /* do this to make sure the mutex unlocks. */
- mutex_unlock(gYarrowMutex);
+ lck_mtx_unlock(gYarrowMutex);
return (retCode);
}
/*
* return data to the caller. Results unpredictable.
*/
-int random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
+int
+random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
{
int retCode = 0;
@@ -461,24 +556,25 @@ int random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
return (ENOTSUP);
/* lock down the mutex */
- mutex_lock(gYarrowMutex);
+ lck_mtx_lock(gYarrowMutex);
+
int bytes_remaining = uio_resid(uio);
while (bytes_remaining > 0 && retCode == 0) {
/* get the user's data */
int bytes_to_read = 0;
- int bytes_available = kBSizeInBytes - g_bytes_used;
+ int bytes_available = kBlockSize - g_bytes_used;
if (bytes_available == 0)
{
- random_block(g_random_data);
+ random_block(g_random_data, TRUE);
g_bytes_used = 0;
- bytes_available = kBSizeInBytes;
+ bytes_available = kBlockSize;
}
bytes_to_read = min (bytes_remaining, bytes_available);
- retCode = uiomove(((u_int8_t*)g_random_data)+ g_bytes_used, bytes_to_read, uio);
+ retCode = uiomove(((caddr_t)g_random_data)+ g_bytes_used, bytes_to_read, uio);
g_bytes_used += bytes_to_read;
if (retCode != 0)
@@ -490,7 +586,7 @@ int random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
retCode = 0;
error_exit:
- mutex_unlock(gYarrowMutex);
+ lck_mtx_unlock(gYarrowMutex);
return retCode;
}
@@ -502,36 +598,35 @@ read_random(void* buffer, u_int numbytes)
PreliminarySetup ();
}
- mutex_lock(gYarrowMutex);
-
+ lck_mtx_lock(gYarrowMutex);
int bytes_read = 0;
int bytes_remaining = numbytes;
while (bytes_remaining > 0) {
- int bytes_to_read = min(bytes_remaining, kBSizeInBytes - g_bytes_used);
+ int bytes_to_read = min(bytes_remaining, kBlockSize - g_bytes_used);
if (bytes_to_read == 0)
{
- random_block(g_random_data);
+ random_block(g_random_data, TRUE);
g_bytes_used = 0;
- bytes_to_read = min(bytes_remaining, kBSizeInBytes);
+ bytes_to_read = min(bytes_remaining, kBlockSize);
}
- memmove (buffer, ((u_int8_t*)g_random_data)+ bytes_read, bytes_to_read);
+ memmove ((u_int8_t*) buffer + bytes_read, ((u_int8_t*)g_random_data)+ g_bytes_used, bytes_to_read);
g_bytes_used += bytes_to_read;
bytes_read += bytes_to_read;
bytes_remaining -= bytes_to_read;
}
- mutex_unlock(gYarrowMutex);
+ lck_mtx_unlock(gYarrowMutex);
}
/*
- * Return an unsigned long pseudo-random number.
+ * Return an u_int32_t pseudo-random number.
*/
-u_long
+u_int32_t
RandomULong(void)
{
- u_long buf;
+ u_int32_t buf;
read_random(&buf, sizeof (buf));
return (buf);
}