random: replace non-blocking pool with a Chacha20-based CRNG

The CRNG is faster, and we don't pretend to track entropy usage in the CRNG any more. Signed-off-by: Theodore Ts'o <[email protected]>
fracktal · Jul 3, 2016 · e192be9 · e192be9
1 parent b1132de
commit e192be9
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Showing 5 changed files with 357 additions and 164 deletions.
diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c
@@ -15,72 +15,11 @@
 #include <linux/module.h>
 #include <crypto/chacha20.h>
 
-static inline u32 rotl32(u32 v, u8 n)
-{
-	return (v << n) | (v >> (sizeof(v) * 8 - n));
-}
-
 static inline u32 le32_to_cpuvp(const void *p)
 {
 	return le32_to_cpup(p);
 }
 
-static void chacha20_block(u32 *state, void *stream)
-{
-	u32 x[16], *out = stream;
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(x); i++)
-		x[i] = state[i];
-
-	for (i = 0; i < 20; i += 2) {
-		x[0]  += x[4];    x[12] = rotl32(x[12] ^ x[0],  16);
-		x[1]  += x[5];    x[13] = rotl32(x[13] ^ x[1],  16);
-		x[2]  += x[6];    x[14] = rotl32(x[14] ^ x[2],  16);
-		x[3]  += x[7];    x[15] = rotl32(x[15] ^ x[3],  16);
-
-		x[8]  += x[12];   x[4]  = rotl32(x[4]  ^ x[8],  12);
-		x[9]  += x[13];   x[5]  = rotl32(x[5]  ^ x[9],  12);
-		x[10] += x[14];   x[6]  = rotl32(x[6]  ^ x[10], 12);
-		x[11] += x[15];   x[7]  = rotl32(x[7]  ^ x[11], 12);
-
-		x[0]  += x[4];    x[12] = rotl32(x[12] ^ x[0],   8);
-		x[1]  += x[5];    x[13] = rotl32(x[13] ^ x[1],   8);
-		x[2]  += x[6];    x[14] = rotl32(x[14] ^ x[2],   8);
-		x[3]  += x[7];    x[15] = rotl32(x[15] ^ x[3],   8);
-
-		x[8]  += x[12];   x[4]  = rotl32(x[4]  ^ x[8],   7);
-		x[9]  += x[13];   x[5]  = rotl32(x[5]  ^ x[9],   7);
-		x[10] += x[14];   x[6]  = rotl32(x[6]  ^ x[10],  7);
-		x[11] += x[15];   x[7]  = rotl32(x[7]  ^ x[11],  7);
-
-		x[0]  += x[5];    x[15] = rotl32(x[15] ^ x[0],  16);
-		x[1]  += x[6];    x[12] = rotl32(x[12] ^ x[1],  16);
-		x[2]  += x[7];    x[13] = rotl32(x[13] ^ x[2],  16);
-		x[3]  += x[4];    x[14] = rotl32(x[14] ^ x[3],  16);
-
-		x[10] += x[15];   x[5]  = rotl32(x[5]  ^ x[10], 12);
-		x[11] += x[12];   x[6]  = rotl32(x[6]  ^ x[11], 12);
-		x[8]  += x[13];   x[7]  = rotl32(x[7]  ^ x[8],  12);
-		x[9]  += x[14];   x[4]  = rotl32(x[4]  ^ x[9],  12);
-
-		x[0]  += x[5];    x[15] = rotl32(x[15] ^ x[0],   8);
-		x[1]  += x[6];    x[12] = rotl32(x[12] ^ x[1],   8);
-		x[2]  += x[7];    x[13] = rotl32(x[13] ^ x[2],   8);
-		x[3]  += x[4];    x[14] = rotl32(x[14] ^ x[3],   8);
-
-		x[10] += x[15];   x[5]  = rotl32(x[5]  ^ x[10],  7);
-		x[11] += x[12];   x[6]  = rotl32(x[6]  ^ x[11],  7);
-		x[8]  += x[13];   x[7]  = rotl32(x[7]  ^ x[8],   7);
-		x[9]  += x[14];   x[4]  = rotl32(x[4]  ^ x[9],   7);
-	}
-
-	for (i = 0; i < ARRAY_SIZE(x); i++)
-		out[i] = cpu_to_le32(x[i] + state[i]);
-
-	state[12]++;
-}
-
 static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
 			     unsigned int bytes)
 {