[PATCH] prng; bring prng into better alignment with specification
From: Neil Horman
Date: Wed Jul 16 2008 - 16:32:35 EST
Bring prng into better alignment with specificaion:
- Convert to using Generic AES 128 bit cipher
- Convert DT to be a non-shifted counter, increasing counter period
Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
prng.c | 69 +++++++++++++++++++----------------------------------------------
1 file changed, 21 insertions(+), 48 deletions(-)
diff --git a/crypto/prng.c b/crypto/prng.c
index 933b4bc..9e2d277 100644
--- a/crypto/prng.c
+++ b/crypto/prng.c
@@ -1,7 +1,7 @@
/*
* PRNG: Pseudo Random Number Generator
* Based on NIST Recommended PRNG From ANSI X9.31 Appendix A.2.4 using
- * AES 128 cipher in RFC3686 ctr mode
+ * AES 128 cipher
*
* (C) Neil Horman <nhorman@xxxxxxxxxxxxx>
*
@@ -32,10 +32,8 @@
#define TEST_PRNG_ON_START 0
-#define DEFAULT_PRNG_KEY "0123456789abcdef1011"
-#define DEFAULT_PRNG_KSZ 20
-#define DEFAULT_PRNG_IV "defaultv"
-#define DEFAULT_PRNG_IVSZ 8
+#define DEFAULT_PRNG_KEY "0123456789abcdef"
+#define DEFAULT_PRNG_KSZ 16
#define DEFAULT_BLK_SZ 16
#define DEFAULT_V_SEED "zaybxcwdveuftgsh"
@@ -63,7 +61,7 @@ struct prng_context {
unsigned char I[DEFAULT_BLK_SZ];
unsigned char V[DEFAULT_BLK_SZ];
u32 rand_data_valid;
- struct crypto_blkcipher *tfm;
+ struct crypto_cipher *tfm;
u32 flags;
};
@@ -100,13 +98,8 @@ static void xor_vectors(unsigned char *in1, unsigned char *in2,
static int _get_more_prng_bytes(struct prng_context *ctx)
{
int i;
- struct blkcipher_desc desc;
- struct scatterlist sg_in, sg_out;
- int ret;
unsigned char tmp[DEFAULT_BLK_SZ];
-
- desc.tfm = ctx->tfm;
- desc.flags = 0;
+ unsigned char *output = NULL;
dbgprint(KERN_CRIT "Calling _get_more_prng_bytes for context %p\n",
@@ -121,8 +114,6 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
*/
for (i = 0; i < 3; i++) {
- desc.tfm = ctx->tfm;
- desc.flags = 0;
switch (i) {
case 0:
/*
@@ -130,7 +121,7 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
* This gives us an intermediate value I
*/
memcpy(tmp, ctx->DT, DEFAULT_BLK_SZ);
- sg_init_one(&sg_out, &ctx->I[0], DEFAULT_BLK_SZ);
+ output = ctx->I;
hexdump("tmp stage 0: ", tmp, DEFAULT_BLK_SZ);
break;
case 1:
@@ -141,9 +132,8 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
* pseudo random data which we output
*/
xor_vectors(ctx->I, ctx->V, tmp, DEFAULT_BLK_SZ);
- sg_init_one(&sg_out, &ctx->rand_data[0],
- DEFAULT_BLK_SZ);
hexdump("tmp stage 1: ", tmp, DEFAULT_BLK_SZ);
+ output = ctx->rand_data;
break;
case 2:
/*
@@ -167,34 +157,25 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
*/
xor_vectors(ctx->rand_data, ctx->I, tmp,
DEFAULT_BLK_SZ);
- sg_init_one(&sg_out, &ctx->V[0], DEFAULT_BLK_SZ);
+ output = ctx->V;
hexdump("tmp stage 2: ", tmp, DEFAULT_BLK_SZ);
break;
}
- /* Initialize our input buffer */
- sg_init_one(&sg_in, &tmp[0], DEFAULT_BLK_SZ);
/* do the encryption */
- ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in,
- DEFAULT_BLK_SZ);
-
- /* And check the result */
- if (ret) {
- dbgprint(KERN_CRIT
- "Crypt of block failed for context %p\n", ctx);
- ctx->rand_data_valid = DEFAULT_BLK_SZ;
- return -EFAULT;
- }
+ crypto_cipher_encrypt_one(ctx->tfm, output, tmp);
}
/*
* Now update our DT value
*/
- for (i = DEFAULT_BLK_SZ-1; i > 0; i--)
- ctx->DT[i] = ctx->DT[i-1];
- ctx->DT[0] += 1;
+ for (i = 0; i < DEFAULT_BLK_SZ; i++) {
+ ctx->DT[i] += 1;
+ if (ctx->DT[i] != 0)
+ break;
+ }
dbgprint("Returning new block for context %p\n", ctx);
ctx->rand_data_valid = 0;
@@ -315,7 +296,7 @@ EXPORT_SYMBOL_GPL(alloc_prng_context);
void free_prng_context(struct prng_context *ctx)
{
- crypto_free_blkcipher(ctx->tfm);
+ crypto_free_cipher(ctx->tfm);
kfree(ctx);
}
EXPORT_SYMBOL_GPL(free_prng_context);
@@ -325,17 +306,13 @@ int reset_prng_context(struct prng_context *ctx,
unsigned char *V, unsigned char *DT)
{
int ret;
- int iv_len;
int rc = -EFAULT;
unsigned char *prng_key;
- unsigned char *prng_iv;
spin_lock(&ctx->prng_lock);
ctx->flags |= PRNG_NEED_RESET;
prng_key = (key != NULL) ? key : (unsigned char *)DEFAULT_PRNG_KEY;
- prng_iv = iv ? iv : (unsigned char *)DEFAULT_PRNG_IV;
-
if (V)
memcpy(ctx->V, V, DEFAULT_BLK_SZ);
else
@@ -350,9 +327,9 @@ int reset_prng_context(struct prng_context *ctx,
memset(ctx->last_rand_data, 0, DEFAULT_BLK_SZ);
if (ctx->tfm)
- crypto_free_blkcipher(ctx->tfm);
+ crypto_free_cipher(ctx->tfm);
- ctx->tfm = crypto_alloc_blkcipher("rfc3686(ctr(aes))", 0, 0);
+ ctx->tfm = crypto_alloc_cipher("aes", 0, 0);
if (IS_ERR(ctx->tfm)) {
dbgprint(KERN_CRIT "Failed to alloc tfm for context %p\n",
ctx);
@@ -362,18 +339,14 @@ int reset_prng_context(struct prng_context *ctx,
ctx->rand_data_valid = DEFAULT_BLK_SZ;
- ret = crypto_blkcipher_setkey(ctx->tfm, prng_key, strlen(prng_key));
+ ret = crypto_cipher_setkey(ctx->tfm, prng_key, strlen(prng_key));
if (ret) {
dbgprint(KERN_CRIT "PRNG: setkey() failed flags=%x\n",
- crypto_blkcipher_get_flags(ctx->tfm));
- crypto_free_blkcipher(ctx->tfm);
+ crypto_cipher_get_flags(ctx->tfm));
+ crypto_free_cipher(ctx->tfm);
goto out;
}
- iv_len = crypto_blkcipher_ivsize(ctx->tfm);
- if (iv_len)
- crypto_blkcipher_set_iv(ctx->tfm, prng_iv, iv_len);
-
rc = 0;
ctx->flags &= ~PRNG_NEED_RESET;
out:
@@ -395,7 +368,7 @@ static int __init prng_mod_init(void)
struct prng_context *ctx = alloc_prng_context();
if (ctx == NULL)
return -EFAULT;
- for (i = 0; i < 16; i++) {
+ for (i = 0; i < 512; i++) {
if (get_prng_bytes(tmpbuf, DEFAULT_BLK_SZ, ctx) < 0) {
free_prng_context(ctx);
return -EFAULT;
--
/****************************************************
* Neil Horman <nhorman@xxxxxxxxxxxxx>
* Software Engineer, Red Hat
****************************************************/
--
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