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

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
......@@ -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 */
......@@ -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);
......
......@@ -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);
......
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