MPI: Fix mpi_read_buffer
Change mpi_read_buffer to return a number without leading zeros
so that mpi_read_buffer and mpi_get_buffer return the same thing.
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index bc0a1da..95c52a9 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -146,18 +146,25 @@
uint8_t *p;
mpi_limb_t alimb;
unsigned int n = mpi_get_size(a);
- int i;
+ int i, lzeros = 0;
- if (buf_len < n || !buf)
+ if (buf_len < n || !buf || !nbytes)
return -EINVAL;
if (sign)
*sign = a->sign;
- if (nbytes)
- *nbytes = n;
+ p = (void *)&a->d[a->nlimbs] - 1;
+
+ for (i = a->nlimbs * sizeof(alimb) - 1; i >= 0; i--, p--) {
+ if (!*p)
+ lzeros++;
+ else
+ break;
+ }
p = buf;
+ *nbytes = n - lzeros;
for (i = a->nlimbs - 1; i >= 0; i--) {
alimb = a->d[i];
@@ -178,6 +185,19 @@
#else
#error please implement for this limb size.
#endif
+
+ if (lzeros > 0) {
+ if (lzeros >= sizeof(alimb)) {
+ p -= sizeof(alimb);
+ } else {
+ mpi_limb_t *limb1 = (void *)p - sizeof(alimb);
+ mpi_limb_t *limb2 = (void *)p - sizeof(alimb)
+ + lzeros;
+ *limb1 = *limb2;
+ p -= lzeros;
+ }
+ lzeros -= sizeof(alimb);
+ }
}
return 0;
}
@@ -197,7 +217,7 @@
*/
void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign)
{
- uint8_t *buf, *p;
+ uint8_t *buf;
unsigned int n;
int ret;
@@ -220,14 +240,6 @@
kfree(buf);
return NULL;
}
-
- /* this is sub-optimal but we need to do the shift operation
- * because the caller has to free the returned buffer */
- for (p = buf; !*p && *nbytes; p++, --*nbytes)
- ;
- if (p != buf)
- memmove(buf, p, *nbytes);
-
return buf;
}
EXPORT_SYMBOL_GPL(mpi_get_buffer);