diff options
Diffstat (limited to 'kernel/lib/mpi')
| -rw-r--r-- | kernel/lib/mpi/mpi-pow.c | 7 | ||||
| -rw-r--r-- | kernel/lib/mpi/mpicoder.c | 60 |
2 files changed, 36 insertions, 31 deletions
diff --git a/kernel/lib/mpi/mpi-pow.c b/kernel/lib/mpi/mpi-pow.c index 5464c8744..e24388a86 100644 --- a/kernel/lib/mpi/mpi-pow.c +++ b/kernel/lib/mpi/mpi-pow.c @@ -64,8 +64,13 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod) if (!esize) { /* Exponent is zero, result is 1 mod MOD, i.e., 1 or 0 * depending on if MOD equals 1. */ - rp[0] = 1; res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1; + if (res->nlimbs) { + if (mpi_resize(res, 1) < 0) + goto enomem; + rp = res->d; + rp[0] = 1; + } res->sign = 0; goto leave; } diff --git a/kernel/lib/mpi/mpicoder.c b/kernel/lib/mpi/mpicoder.c index 3db76b8c1..e37dbf53e 100644 --- a/kernel/lib/mpi/mpicoder.c +++ b/kernel/lib/mpi/mpicoder.c @@ -128,6 +128,23 @@ leave: } EXPORT_SYMBOL_GPL(mpi_read_from_buffer); +static int count_lzeros(MPI a) +{ + mpi_limb_t alimb; + int i, lzeros = 0; + + for (i = a->nlimbs - 1; i >= 0; i--) { + alimb = a->d[i]; + if (alimb == 0) { + lzeros += sizeof(mpi_limb_t); + } else { + lzeros += count_leading_zeros(alimb) / 8; + break; + } + } + return lzeros; +} + /** * mpi_read_buffer() - read MPI to a bufer provided by user (msb first) * @@ -146,7 +163,7 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, uint8_t *p; mpi_limb_t alimb; unsigned int n = mpi_get_size(a); - int i, lzeros = 0; + int i, lzeros; if (buf_len < n || !buf || !nbytes) return -EINVAL; @@ -154,14 +171,7 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, if (sign) *sign = a->sign; - p = (void *)&a->d[a->nlimbs] - 1; - - for (i = a->nlimbs * sizeof(alimb) - 1; i >= 0; i--, p--) { - if (!*p) - lzeros++; - else - break; - } + lzeros = count_lzeros(a); p = buf; *nbytes = n - lzeros; @@ -343,7 +353,7 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes, u8 *p, *p2; mpi_limb_t alimb, alimb2; unsigned int n = mpi_get_size(a); - int i, x, y = 0, lzeros = 0, buf_len; + int i, x, y = 0, lzeros, buf_len; if (!nbytes || *nbytes < n) return -EINVAL; @@ -351,20 +361,15 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes, if (sign) *sign = a->sign; - p = (void *)&a->d[a->nlimbs] - 1; - - for (i = a->nlimbs * sizeof(alimb) - 1; i >= 0; i--, p--) { - if (!*p) - lzeros++; - else - break; - } + lzeros = count_lzeros(a); *nbytes = n - lzeros; buf_len = sgl->length; p2 = sg_virt(sgl); - for (i = a->nlimbs - 1; i >= 0; i--) { + for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB, + lzeros %= BYTES_PER_MPI_LIMB; + i >= 0; i--) { alimb = a->d[i]; p = (u8 *)&alimb2; #if BYTES_PER_MPI_LIMB == 4 @@ -385,17 +390,12 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes, #error please implement for this limb size. #endif if (lzeros > 0) { - if (lzeros >= sizeof(alimb)) { - p -= sizeof(alimb); - continue; - } else { - mpi_limb_t *limb1 = (void *)p - sizeof(alimb); - mpi_limb_t *limb2 = (void *)p - sizeof(alimb) - + lzeros; - *limb1 = *limb2; - p -= lzeros; - y = lzeros; - } + mpi_limb_t *limb1 = (void *)p - sizeof(alimb); + mpi_limb_t *limb2 = (void *)p - sizeof(alimb) + + lzeros; + *limb1 = *limb2; + p -= lzeros; + y = lzeros; lzeros -= sizeof(alimb); } |