From d37e296979ed1652aec6850e2d736bd0ebf0cdb1 Mon Sep 17 00:00:00 2001 From: Tadeusz Struk Date: Mon, 15 Jun 2015 13:18:36 -0700 Subject: 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: Tadeusz Struk Signed-off-by: Herbert Xu --- include/linux/mpi.h | 15 +++++++++ lib/mpi/mpicoder.c | 87 +++++++++++++++++++++++++++++++++++++++++------------ lib/mpi/mpiutil.c | 6 ++-- 3 files changed, 86 insertions(+), 22 deletions(-) diff --git a/include/linux/mpi.h b/include/linux/mpi.h index 5af1b81def49..641b7d6fd096 100644 --- a/include/linux/mpi.h +++ b/include/linux/mpi.h @@ -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 */ diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c index 4cc6442733f4..bc0a1da8afba 100644 --- a/lib/mpi/mpicoder.c +++ b/lib/mpi/mpicoder.c @@ -128,28 +128,36 @@ leave: } 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); diff --git a/lib/mpi/mpiutil.c b/lib/mpi/mpiutil.c index bf076d281d40..314f4dfa603e 100644 --- a/lib/mpi/mpiutil.c +++ b/lib/mpi/mpiutil.c @@ -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); -- cgit v1.2.1