X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/2d21ac55c334faf3a56e5634905ed6987fc787d4..ca66cea69e6e866fd781ae2260d9474bdd48f2ca:/bsd/dev/random/randomdev.c

diff --git a/bsd/dev/random/randomdev.c b/bsd/dev/random/randomdev.c
index 4a7741e2a..9208ff6b6 100644
--- a/bsd/dev/random/randomdev.c
+++ b/bsd/dev/random/randomdev.c
@@ -99,7 +99,7 @@ typedef BlockWord Block[kBSize];
 
 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);
 
 /*
@@ -194,18 +194,22 @@ 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)
 {
 	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)
+		{
+			Block xSeed;
+			prngOutput (gPrngRef, (BYTE*) &xSeed, sizeof (xSeed));
+			
+			// add the seed to the previous value of g_xkey
+			add_blocks (g_xkey, xSeed, 0);
+		}
+		
 		// compute "G"
 		SHA1Update (&g_sha1_ctx, (const u_int8_t *) &g_xkey, sizeof (g_xkey));
 		
@@ -309,11 +313,13 @@ PreliminarySetup(void)
 	fips_initialize ();
 }
 
+const Block kKnownAnswer = {0x92b404e5, 0x56588ced, 0x6c1acd4e, 0xbf053f68, 0x9f73a93};
+
 void
 fips_initialize(void)
 {
-	/* Read the initial value of g_xkey from yarrow */
-	prngOutput (gPrngRef, (BYTE*) &g_xkey, sizeof (g_xkey));
+	/* So that we can do the self test, set the seed to zero */
+	memset(&g_xkey, 0, sizeof(g_xkey));
 	
 	/* initialize our SHA1 generator */
 	SHA1Init (&g_sha1_ctx);
@@ -321,7 +327,20 @@ fips_initialize(void)
 	/* 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
+	int i;
+	for (i = 0; i < kBSize; ++i)
+	{
+		if (kKnownAnswer[i] != g_random_data[i])
+		{
+			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);
 }
 
 /*
@@ -490,7 +509,7 @@ random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
 		int bytes_available = kBSizeInBytes - 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;
 		}
@@ -533,7 +552,7 @@ read_random(void* buffer, u_int numbytes)
         int bytes_to_read = min(bytes_remaining, kBSizeInBytes - 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);
 		}