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Commit d37e2969 authored by Tadeusz Struk's avatar Tadeusz Struk Committed by Herbert Xu
Browse files

MPILIB: add mpi_read_buf() and mpi_get_size() helpers 



Added a mpi_read_buf() helper function to export MPI to a buf provided by
the user, and a mpi_get_size() helper, that tells the user how big the buf is.
Changed mpi_free to use kzfree instead of kfree because it is used to free
crypto keys.

Signed-off-by: default avatarTadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 4beb1060

include/linux/mpi.h

+15 −0
Original line number Diff line number Diff line
@@ -81,6 +81,8 @@ MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread); 
int mpi_fromstr(MPI val, const char *str);

u32 mpi_get_keyid(MPI a, u32 *keyid);

void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);

int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,

		    int *sign);

void *mpi_get_secure_buffer(MPI a, unsigned *nbytes, int *sign);

int mpi_set_buffer(MPI a, const void *buffer, unsigned nbytes, int sign);
@@ -142,4 +144,17 @@ int mpi_rshift(MPI x, MPI a, unsigned n); 
/*-- mpi-inv.c --*/

int mpi_invm(MPI x, MPI u, MPI v);



/* inline functions */



/**

 * mpi_get_size() - returns max size required to store the number

 *

 * @a:	A multi precision integer for which we want to allocate a bufer

 *

 * Return: size required to store the number

 */

static inline unsigned int mpi_get_size(MPI a)

{

	return a->nlimbs * BYTES_PER_MPI_LIMB;

}

#endif /*G10_MPI_H */

lib/mpi/mpicoder.c

+68 −19
Original line number Diff line number Diff line
@@ -128,28 +128,36 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread) 
}

EXPORT_SYMBOL_GPL(mpi_read_from_buffer);



/****************

 * Return an allocated buffer with the MPI (msb first).

 * NBYTES receives the length of this buffer. Caller must free the

 * return string (This function does return a 0 byte buffer with NBYTES

 * set to zero if the value of A is zero. If sign is not NULL, it will

 * be set to the sign of the A.

/**

 * mpi_read_buffer() - read MPI to a bufer provided by user (msb first)

 *

 * @a:		a multi precision integer

 * @buf:	bufer to which the output will be written to. Needs to be at

 *		leaset mpi_get_size(a) long.

 * @buf_len:	size of the buf.

 * @nbytes:	receives the actual length of the data written.

 * @sign:	if not NULL, it will be set to the sign of a.

 *

 * Return:	0 on success or error code in case of error

 */

void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign)

int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,

		    int *sign)

{

	uint8_t *p, *buffer;

	uint8_t *p;

	mpi_limb_t alimb;

	unsigned int n = mpi_get_size(a);

	int i;

	unsigned int n;



	if (buf_len < n || !buf)

		return -EINVAL;



	if (sign)

		*sign = a->sign;

	*nbytes = n = a->nlimbs * BYTES_PER_MPI_LIMB;

	if (!n)

		n++;		/* avoid zero length allocation */

	p = buffer = kmalloc(n, GFP_KERNEL);

	if (!p)

		return NULL;



	if (nbytes)

		*nbytes = n;



	p = buf;



	for (i = a->nlimbs - 1; i >= 0; i--) {

		alimb = a->d[i];
@@ -171,15 +179,56 @@ void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign) 
#error please implement for this limb size.

#endif

	}

	return 0;

}

EXPORT_SYMBOL_GPL(mpi_read_buffer);



/*

 * mpi_get_buffer() - Returns an allocated buffer with the MPI (msb first).

 * Caller must free the return string.

 * This function does return a 0 byte buffer with nbytes set to zero if the

 * value of A is zero.

 *

 * @a:		a multi precision integer.

 * @nbytes:	receives the length of this buffer.

 * @sign:	if not NULL, it will be set to the sign of the a.

 *

 * Return:	Pointer to MPI buffer or NULL on error

 */

void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign)

{

	uint8_t *buf, *p;

	unsigned int n;

	int ret;



	if (!nbytes)

		return NULL;



	n = mpi_get_size(a);



	if (!n)

		n++;



	buf = kmalloc(n, GFP_KERNEL);



	if (!buf)

		return NULL;



	ret = mpi_read_buffer(a, buf, n, nbytes, sign);



	if (ret) {

		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 = buffer; !*p && *nbytes; p++, --*nbytes)

	for (p = buf; !*p && *nbytes; p++, --*nbytes)

		;

	if (p != buffer)

		memmove(buffer, p, *nbytes);

	if (p != buf)

		memmove(buf, p, *nbytes);



	return buffer;

	return buf;

}

EXPORT_SYMBOL_GPL(mpi_get_buffer);

lib/mpi/mpiutil.c

+3 −3
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ void mpi_free_limb_space(mpi_ptr_t a) 
	if (!a)

		return;



	kfree(a);

	kzfree(a);

}



void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
@@ -95,7 +95,7 @@ int mpi_resize(MPI a, unsigned nlimbs) 
		if (!p)

			return -ENOMEM;

		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));

		kfree(a->d);

		kzfree(a->d);

		a->d = p;

	} else {

		a->d = kzalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
@@ -112,7 +112,7 @@ void mpi_free(MPI a) 
		return;



	if (a->flags & 4)

		kfree(a->d);

		kzfree(a->d);

	else

		mpi_free_limb_space(a->d);