Introduce the new function to get the number of bits and bytes from an MPI.
Signed-off-by: Roberto Sassu <[email protected]> --- include/linux/mpi.h | 2 ++ lib/mpi/mpicoder.c | 33 ++++++++++++++++++++++++++------- 2 files changed, 28 insertions(+), 7 deletions(-) diff --git a/include/linux/mpi.h b/include/linux/mpi.h index 7cd1473c64a4..56187bb57c78 100644 --- a/include/linux/mpi.h +++ b/include/linux/mpi.h @@ -61,6 +61,8 @@ int mpi_resize(MPI a, unsigned nlimbs); /*-- mpicoder.c --*/ MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes); +int mpi_key_length(const void *xbuffer, unsigned int ret_nread, + unsigned int *nbits_arg, unsigned int *nbytes_arg); MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread); MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len); void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign); diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c index eead4b339466..207cb3b91a51 100644 --- a/lib/mpi/mpicoder.c +++ b/lib/mpi/mpicoder.c @@ -78,22 +78,41 @@ MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes) } EXPORT_SYMBOL_GPL(mpi_read_raw_data); -MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread) +int mpi_key_length(const void *xbuffer, unsigned int ret_nread, + unsigned int *nbits_arg, unsigned int *nbytes_arg) { const uint8_t *buffer = xbuffer; - unsigned int nbits, nbytes; - MPI val; + unsigned int nbits; - if (*ret_nread < 2) - return ERR_PTR(-EINVAL); + if (ret_nread < 2) + return -EINVAL; nbits = buffer[0] << 8 | buffer[1]; if (nbits > MAX_EXTERN_MPI_BITS) { pr_info("MPI: mpi too large (%u bits)\n", nbits); - return ERR_PTR(-EINVAL); + return -EINVAL; } - nbytes = DIV_ROUND_UP(nbits, 8); + if (nbits_arg) + *nbits_arg = nbits; + if (nbytes_arg) + *nbytes_arg = DIV_ROUND_UP(nbits, 8); + + return 0; +} +EXPORT_SYMBOL_GPL(mpi_key_length); + +MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread) +{ + const uint8_t *buffer = xbuffer; + unsigned int nbytes; + MPI val; + int ret; + + ret = mpi_key_length(xbuffer, *ret_nread, NULL, &nbytes); + if (ret < 0) + return ERR_PTR(ret); + if (nbytes + 2 > *ret_nread) { pr_info("MPI: mpi larger than buffer nbytes=%u ret_nread=%u\n", nbytes, *ret_nread); -- 2.17.1
