Re: [PATCH] crypto: RSA algorithm patch (kernel version2.6.21-rc5-git6)

From: Randy Dunlap
Date: Fri Mar 30 2007 - 12:27:51 EST


On Fri, 30 Mar 2007 16:26:36 +0300 Tasos Parisinos wrote:

Hi,

Just a few whitespace nits that you can fix with any other
comments that you get...

> +static char rsa_op_compare(rsa_op *l, rsa_op *r)
> +{
> + int i;
> + u32 *lbuf, *rbuf;
> +
> + /* Compare the two operands based on sign */
> + if (l->sign != r->sign)
> + return (l->sign)? -1: 1;

-1 : 1;

> + /* Compare the two operands based on their size */
> + if (l->size > r->size && rsa_op_clz(l) < (l->size - r->size) * 32)
> + return 1;
> + else if (r->size > l->size && rsa_op_clz(r) < (r->size - l->size) * 32)
> + return -1;
> +
> + /* Compare the two operands based on their hex values */
> + lbuf = l->data;
> + rbuf = r->data;
> + for (i = min(l->size, r->size) - 1; i >= 0; i--)
> + if (lbuf[i] > rbuf[i])
> + return 1;
> + else if (lbuf[i] < rbuf[i])
> + return -1;
> + return 0;
> +}
> +
> +static int rsa_op_shift(rsa_op **n, int bits)
> +{
> + int i, distance, size, lz, retval;
> + u32 *buf;
> + rsa_op *handle;
> +
> + if (!bits)
> + return 0;
> + handle = *n;
> +
> + /* Shifting to the right, no resize needed */
> + if (bits > 0) {
> + /* Drop off one limb for each 32 bit shift */
> + distance = bits / 32;
> + size = handle->size;
> + buf = handle->data;
> + for (i = 0; i < size; i++)
> + buf[i] = (i + distance >= size)? 0: buf[i + distance];

0 :

> +
> + /* Shift the remaining 'bits' mod 32 */
> + bits = bits % 32;
> + if (bits) {
> + size -= distance;
> + distance = 32 - bits;
> + for (i = 0; i < size; i++) {
> + buf[i] = buf[i] >> bits;
> + if (i < size - 1)
> + buf[i] |= buf[i + 1] << distance;
> + }
> + }
> +
> + rsa_op_canonicalize(handle);
> + return 0;
> + }
> +
> + bits = -bits;
> + lz = rsa_op_clz(handle) + (handle->limbs - handle->size) * 32;
> +
> + /*
> + * Shifting to the left.
> + * Reallocation is needed when the leading zeroes are less than
> + * the shift distance
> + */
> + if (lz < bits) {
> + /* Compute the size of the reallocation */
> + size = (bits - lz + 31) / 32;
> + retval = rsa_op_resize(n, handle->limbs + size);
> + if (retval < 0)
> + return retval;
> + handle = *n;
> + }
> + else
> + handle->size += ((bits - rsa_op_clz(handle) + 31) / 32);
> +
> + buf = handle->data;
> + distance = bits / 32;
> + /* Shift data 1 byte to the left for each 32 bit shift */
> + if (distance) {
> + /* Shift bytes */
> + for (i = handle->size - distance - 1; i >= 0; i--)
> + buf[i + distance] = buf[i];
> +
> + /* Zero the shifted in bytes */
> + memset(handle->data, 0, distance * sizeof(u32));
> + }
> +
> + /* Shift the remaining 'bits' mod 32 */
> + bits = bits % 32;
> + distance = 32 - bits;
> + if (bits)
> + for (i = handle->size - 1; i >= 0; i--) {
> + buf[i] = buf[i] << bits;
> + if (i > 0)
> + buf[i] |= (buf[i - 1] >> distance);
> + }
> +
> + return 0;
> +}
> +
> +
> +
> +
> +
> +
> +
> +/**
> +/**
> + * rsa_op_print - print the value of an rsa_op
> + * @n: pointer to the rsa_op to be printed
> + * @how: true to print canonicalized
> + */
> +void rsa_op_print(rsa_op *n, bool how)
> +{
> + int i, j;
> + u32 limb;
> + u8 byte;
> + bool started = false;
> +
> + printk("Operand @ 0x%x, %d limbs in size, %d limbs allocated, value = ",
> + (u32)n, n->size, n->limbs);
> +
> + /* Print the sign */
> + printk("%s", (n->sign)? "-": " ");
> +
> + /* Print the hex value */
> + for (i = n->size - 1; i >= 0; i--) {
> + limb = n->data[i];
> +
> + /* Ignore leading zero limbs if canonicalization is selected */
> + if (!limb && !started && how)
> + continue;
> +
> + /*
> + * Print each limb as though each of its nibbles was a character
> + * from the set '0' to '9' and 'a' to 'f'
> + */
> + for (j = 28; j >= 0; j -= 4) {
> + byte = (u8)((limb >> j) & 0x0F);
> +
> + /*
> + * Ignore leading zero bytes if canonicalization
> + * is selected
> + */
> + if (!byte && !started && how)
> + continue;
> +
> + started = true;
> + byte += (byte <= 0x09)? '0': 'a' - 0x0A;
> + printk("%c", byte);
> + }
> + }
> +
> + if(!started)

space after "if"

> + printk("0");
> + printk("\n");


and then there's the introduction of a new typedef in a world
where we srongly try to limit new typedefs...

+typedef struct rsa_op {
+ u32 *data;
+ int sign;
+ int size;
+ int limbs;
+} rsa_op;

---
~Randy
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