return NULL;
}
if (nbytes > 0)
- nbits -= count_leading_zeros(buffer[0]);
- else
- nbits = 0;
+ nbits -= count_leading_zeros(buffer[0]) - (BITS_PER_LONG - 8);
nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
val = mpi_alloc(nlimbs);
MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
{
const uint8_t *buffer = xbuffer;
- int i, j;
- unsigned nbits, nbytes, nlimbs, nread = 0;
- mpi_limb_t a;
- MPI val = NULL;
+ unsigned int nbits, nbytes;
+ MPI val;
if (*ret_nread < 2)
- goto leave;
+ return ERR_PTR(-EINVAL);
nbits = buffer[0] << 8 | buffer[1];
if (nbits > MAX_EXTERN_MPI_BITS) {
pr_info("MPI: mpi too large (%u bits)\n", nbits);
- goto leave;
+ return ERR_PTR(-EINVAL);
}
- buffer += 2;
- nread = 2;
nbytes = DIV_ROUND_UP(nbits, 8);
- nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
- val = mpi_alloc(nlimbs);
- if (!val)
- return NULL;
- i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
- i %= BYTES_PER_MPI_LIMB;
- val->nbits = nbits;
- j = val->nlimbs = nlimbs;
- val->sign = 0;
- for (; j > 0; j--) {
- a = 0;
- for (; i < BYTES_PER_MPI_LIMB; i++) {
- if (++nread > *ret_nread) {
- printk
- ("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
- nread, *ret_nread);
- goto leave;
- }
- a <<= 8;
- a |= *buffer++;
- }
- i = 0;
- val->d[j - 1] = a;
+ if (nbytes + 2 > *ret_nread) {
+ pr_info("MPI: mpi larger than buffer nbytes=%u ret_nread=%u\n",
+ nbytes, *ret_nread);
+ return ERR_PTR(-EINVAL);
}
-leave:
- *ret_nread = nread;
+ val = mpi_read_raw_data(buffer + 2, nbytes);
+ if (!val)
+ return ERR_PTR(-ENOMEM);
+
+ *ret_nread = nbytes + 2;
return val;
}
EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
}
EXPORT_SYMBOL_GPL(mpi_get_buffer);
-/****************
- * Use BUFFER to update MPI.
- */
-int mpi_set_buffer(MPI a, const void *xbuffer, unsigned nbytes, int sign)
-{
- const uint8_t *buffer = xbuffer, *p;
- mpi_limb_t alimb;
- int nlimbs;
- int i;
-
- nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
- if (RESIZE_IF_NEEDED(a, nlimbs) < 0)
- return -ENOMEM;
- a->sign = sign;
-
- for (i = 0, p = buffer + nbytes - 1; p >= buffer + BYTES_PER_MPI_LIMB;) {
-#if BYTES_PER_MPI_LIMB == 4
- alimb = (mpi_limb_t) *p--;
- alimb |= (mpi_limb_t) *p-- << 8;
- alimb |= (mpi_limb_t) *p-- << 16;
- alimb |= (mpi_limb_t) *p-- << 24;
-#elif BYTES_PER_MPI_LIMB == 8
- alimb = (mpi_limb_t) *p--;
- alimb |= (mpi_limb_t) *p-- << 8;
- alimb |= (mpi_limb_t) *p-- << 16;
- alimb |= (mpi_limb_t) *p-- << 24;
- alimb |= (mpi_limb_t) *p-- << 32;
- alimb |= (mpi_limb_t) *p-- << 40;
- alimb |= (mpi_limb_t) *p-- << 48;
- alimb |= (mpi_limb_t) *p-- << 56;
-#else
-#error please implement for this limb size.
-#endif
- a->d[i++] = alimb;
- }
- if (p >= buffer) {
-#if BYTES_PER_MPI_LIMB == 4
- alimb = *p--;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 8;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 16;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 24;
-#elif BYTES_PER_MPI_LIMB == 8
- alimb = (mpi_limb_t) *p--;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 8;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 16;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 24;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 32;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 40;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 48;
- if (p >= buffer)
- alimb |= (mpi_limb_t) *p-- << 56;
-#else
-#error please implement for this limb size.
-#endif
- a->d[i++] = alimb;
- }
- a->nlimbs = i;
-
- if (i != nlimbs) {
- pr_emerg("MPI: mpi_set_buffer: Assertion failed (%d != %d)", i,
- nlimbs);
- BUG();
- }
- return 0;
-}
-EXPORT_SYMBOL_GPL(mpi_set_buffer);
-
/**
* mpi_write_to_sgl() - Funnction exports MPI to an sgl (msb first)
*
* @a: a multi precision integer
* @sgl: scatterlist to write to. Needs to be at least
* mpi_get_size(a) long.
- * @nbytes: in/out param - it has the be set to the maximum number of
- * bytes that can be written to sgl. This has to be at least
- * the size of the integer a. On return it receives the actual
- * length of the data written on success or the data that would
- * be written if buffer was too small.
+ * @nbytes: the number of bytes to write. Leading bytes will be
+ * filled with zero.
* @sign: if not NULL, it will be set to the sign of a.
*
* Return: 0 on success or error code in case of error
*/
-int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes,
+int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned nbytes,
int *sign)
{
u8 *p, *p2;
#error please implement for this limb size.
#endif
unsigned int n = mpi_get_size(a);
- int i, x, y = 0, lzeros, buf_len;
-
- if (!nbytes)
- return -EINVAL;
+ int i, x, buf_len;
if (sign)
*sign = a->sign;
- lzeros = count_lzeros(a);
-
- if (*nbytes < n - lzeros) {
- *nbytes = n - lzeros;
+ if (nbytes < n)
return -EOVERFLOW;
- }
- *nbytes = n - lzeros;
buf_len = sgl->length;
p2 = sg_virt(sgl);
- for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB,
- lzeros %= BYTES_PER_MPI_LIMB;
- i >= 0; i--) {
+ while (nbytes > n) {
+ if (!buf_len) {
+ sgl = sg_next(sgl);
+ if (!sgl)
+ return -EINVAL;
+ buf_len = sgl->length;
+ p2 = sg_virt(sgl);
+ }
+
+ i = min_t(unsigned, nbytes - n, buf_len);
+ memset(p2, 0, i);
+ p2 += i;
+ buf_len -= i;
+ nbytes -= i;
+ }
+
+ for (i = a->nlimbs - 1; i >= 0; i--) {
#if BYTES_PER_MPI_LIMB == 4
- alimb = cpu_to_be32(a->d[i]);
+ alimb = a->d[i] ? cpu_to_be32(a->d[i]) : 0;
#elif BYTES_PER_MPI_LIMB == 8
- alimb = cpu_to_be64(a->d[i]);
+ alimb = a->d[i] ? cpu_to_be64(a->d[i]) : 0;
#else
#error please implement for this limb size.
#endif
- if (lzeros) {
- y = lzeros;
- lzeros = 0;
- }
-
- p = (u8 *)&alimb + y;
+ p = (u8 *)&alimb;
- for (x = 0; x < sizeof(alimb) - y; x++) {
+ for (x = 0; x < sizeof(alimb); x++) {
if (!buf_len) {
sgl = sg_next(sgl);
if (!sgl)
*p2++ = *p++;
buf_len--;
}
- y = 0;
}
return 0;
}
projects / cascardo / linux.git / blobdiff