xnu-2422.110.17.tar.gz

[apple/xnu.git] / bsd / dev / random / randomdev.c

diff --git a/bsd/dev/random/randomdev.c b/bsd/dev/random/randomdev.c
index 6f99d775d205f5e1eb1fad86c65703acc0adae51..c73553994b5d0d97d8058d95e93c69a87924b4e0 100644 (file)
--- 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@
  * 
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 


@@ -26,6 +26,17 @@
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
  * @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>
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/proc.h>


@@ -36,18 +47,29 @@
 #include <string.h>
 #include <miscfs/devfs/devfs.h>
 #include <kern/lock.h>
 #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 <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 */
 
 d_ioctl_t       random_ioctl;
 
 
 #define RANDOM_MAJOR  -1 /* let the kernel pick the device number */
 
 d_ioctl_t       random_ioctl;
 

+/* To generate the seed for the RNG */
+extern uint64_t early_random();
+

 /*
  * A struct describing which functions will get invoked for certain
  * actions.
 /*
  * A struct describing which functions will get invoked for certain
  * actions.


@@ -70,27 +92,41 @@ static struct cdevsw random_cdevsw =
        0                                       /* type */
 };
 
        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 */
 /* 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 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 */
 
 
 
 #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];
 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);
 
 /* 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);
 
 /*
 u_int32_t CalculateCRC(u_int8_t* buffer, size_t length);
 
 /*


@@ -103,26 +139,26 @@ u_int32_t CalculateCRC(u_int8_t* buffer, size_t length);
 void
 add_blocks(Block a, Block b, BlockWord carry)
 {
 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[] =
 {
 
 static const u_int32_t g_crc_table[] =
 {


@@ -185,29 +221,52 @@ u_int32_t CalculateCRC(u_int8_t* buffer, size_t length)
  * get a random block of data per fips 186-2
  */
 void
  * 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
        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"
                // 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
                
                // 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
                
                // 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;
                
                // make sure we don't repeat
                int cmp = new_crc == gLastBlockChecksum;


@@ -252,8 +311,27 @@ void
 PreliminarySetup(void)
 {
     prng_error_status perr;
 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);
 
     /* create a Yarrow object */
     perr = prngInitialize(&gPrngRef);


@@ -265,48 +343,61 @@ PreliminarySetup(void)
        /* clear the error flag, reads and write should then work */
     gRandomError = 0;
 
        /* clear the error flag, reads and write should then work */
     gRandomError = 0;
 

+    uint64_t tt;
+    char buffer [16];
+

     /* get a little non-deterministic data as an initial seed. */
     /* get a little non-deterministic data as an initial seed. */

-    microtime(&tt);
-
-    /*
-        * So how much of the system clock is entropic?
-        * It's hard to say, but assume that at least the
-        * least significant byte of a 64 bit structure
-        * is entropic.  It's probably more, how can you figure
-        * the exact time the user turned the computer on, for example.
-    */
+       /* On OSX, securityd will add much more entropy as soon as it */
+       /* comes up.  On iOS, entropy is added with each system interrupt. */
+    tt = early_random();
+

     perr = prngInput(gPrngRef, (BYTE*) &tt, sizeof (tt), SYSTEM_SOURCE, 8);
     if (perr != 0) {
         /* an error, complain */
         printf ("Couldn't seed Yarrow.\n");
     perr = prngInput(gPrngRef, (BYTE*) &tt, sizeof (tt), SYSTEM_SOURCE, 8);
     if (perr != 0) {
         /* an error, complain */
         printf ("Couldn't seed Yarrow.\n");

-        return;
+        goto function_exit;

     }
     
     /* turn the data around */
     }
     
     /* 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 */
     
     /* 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 ();
        
        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)
 {
 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;
        
        /* 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 +409,11 @@ random_init(void)
 {
        int ret;
 
 {
        int ret;
 

-       if (gRandomInstalled)
+       if (OSTestAndSet(0, &gRandomInstalled)) {
+               /* do this atomically so that it works correctly with
+                multiple threads */

                return;
                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) {
 
        ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw);
        if (ret < 0) {


@@ -343,6 +431,9 @@ random_init(void)
         */
        devfs_make_node(makedev (ret, 1), DEVFS_CHAR,
                UID_ROOT, GID_WHEEL, 0666, "urandom", 0);
         */
        devfs_make_node(makedev (ret, 1), DEVFS_CHAR,
                UID_ROOT, GID_WHEEL, 0666, "urandom", 0);

+
+       /* setup yarrow and the mutex if needed*/
+       PreliminarySetup();

 }
 
 int
 }
 
 int


@@ -416,20 +507,19 @@ random_write (__unused dev_t dev, struct uio *uio, __unused int ioflag)
     }
     
     /* get control of the Yarrow instance, Yarrow is NOT thread safe */
     }
     
     /* 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 */
     
     /* 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 */
         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;
                        bytesToInput, SYSTEM_SOURCE,
                bytesToInput * 8) != 0) {
             retCode = EIO;


@@ -446,53 +536,10 @@ 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. */
     /* 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 (retCode);
 }
 

-/*
- * return data to the caller.  Results unpredictable.
- */ 
-int random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
-{
-    int retCode = 0;
-       
-    if (gRandomError != 0)
-        return (ENOTSUP);
-
-   /* lock down the mutex */
-    mutex_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;
-        if (bytes_available == 0)
-               {
-                       random_block(g_random_data);
-                       g_bytes_used = 0;
-                       bytes_available = kBSizeInBytes;
-               }
-               
-               bytes_to_read = min (bytes_remaining, bytes_available);
-               
-        retCode = uiomove(((u_int8_t*)g_random_data)+ g_bytes_used, bytes_to_read, uio);
-        g_bytes_used += bytes_to_read;
-
-        if (retCode != 0)
-            goto error_exit;
-               
-               bytes_remaining = uio_resid(uio);
-    }
-    
-    retCode = 0;
-    
-error_exit:
-    mutex_unlock(gYarrowMutex);
-    return retCode;
-}

 
 /* export good random numbers to the rest of the kernel */
 void
 
 /* export good random numbers to the rest of the kernel */
 void


@@ -502,36 +549,67 @@ read_random(void* buffer, u_int numbytes)
         PreliminarySetup ();
     }
     
         PreliminarySetup ();
     }
     

-    mutex_lock(gYarrowMutex);
-       
+    lck_mtx_lock(gYarrowMutex);
+
+

        int bytes_read = 0;
 
        int bytes_remaining = numbytes;
     while (bytes_remaining > 0) {
        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)
                {
         if (bytes_to_read == 0)
                {

-                       random_block(g_random_data);
+                       random_block(g_random_data, TRUE);

                        g_bytes_used = 0;
                        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;
     }
 
                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 data to the caller.  Results unpredictable.
+ */ 
+int
+random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
+{
+    int retCode = 0;
+       
+    if (gRandomError != 0)
+        return (ENOTSUP);
+
+    char buffer[64];
+
+       user_ssize_t bytes_remaining = uio_resid(uio);
+    while (bytes_remaining > 0 && retCode == 0) {
+               user_ssize_t bytesToRead = min(sizeof(buffer), bytes_remaining);
+        read_random(buffer, bytesToRead);
+        retCode = uiomove(buffer, bytesToRead, uio);
+
+        if (retCode != 0)
+            goto error_exit;
+               
+               bytes_remaining = uio_resid(uio);
+    }
+    
+    retCode = 0;
+    
+error_exit:
+    return retCode;
+}
+/*
+ * Return an u_int32_t pseudo-random number.

  */
  */

-u_long
+u_int32_t

 RandomULong(void)
 {
 RandomULong(void)
 {

-       u_long buf;
+       u_int32_t buf;

        read_random(&buf, sizeof (buf));
        return (buf);
 }
        read_random(&buf, sizeof (buf));
        return (buf);
 }