Commit 94479061 authored by Roberto Sassu's avatar Roberto Sassu Committed by Zheng Zengkai
Browse files

mpi: introduce mpi_key_length() 



hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

Introduce the new function to get the number of bits and bytes from an MPI.

Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: default avatarTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: default avatarJason Yan <yanaijie@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 9ce5f5ac

include/linux/mpi.h

+2 −0
Original line number Diff line number Diff line
@@ -90,6 +90,8 @@ enum gcry_mpi_format { 
};



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);

int mpi_fromstr(MPI val, const char *str);

MPI mpi_scanval(const char *string);

lib/mpi/mpicoder.c

+26 −7
Original line number Diff line number Diff line
@@ -79,22 +79,41 @@ 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);