diff options
Diffstat (limited to 'mpi')
| -rw-r--r-- | mpi/mpiutil.c | 43 |
1 files changed, 31 insertions, 12 deletions
diff --git a/mpi/mpiutil.c b/mpi/mpiutil.c index 3ae84c30..9dde37fb 100644 --- a/mpi/mpiutil.c +++ b/mpi/mpiutil.c @@ -28,6 +28,21 @@ #include "mpi-internal.h" #include "mod-source-info.h" + +#if SIZEOF_UNSIGNED_INT == 2 +# define MY_UINT_MAX 0xffff +/* (visual check: 0123 ) */ +#elif SIZEOF_UNSIGNED_INT == 4 +# define MY_UINT_MAX 0xffffffff +/* (visual check: 01234567 ) */ +#elif SIZEOF_UNSIGNED_INT == 8 +# define MY_UINT_MAX 0xffffffffffffffff +/* (visual check: 0123456789abcdef ) */ +#else +# error Need MY_UINT_MAX for this limb size +#endif + + /* Constants allocated right away at startup. */ static gcry_mpi_t constants[MPI_NUMBER_OF_CONSTANTS]; @@ -539,23 +554,27 @@ _gcry_mpi_set_ui (gcry_mpi_t w, unsigned long u) return w; } +/* If U is non-negative and small enough store it as an unsigned int + * at W. If the value does not fit into an unsigned int or is + * negative return GPG_ERR_ERANGE. Note that we return an unsigned + * int so that the value can be used with the bit test functions; in + * contrast the other _ui functions take an unsigned long so that on + * some platforms they may accept a larger value. On error the value + * at U is not changed. */ gcry_err_code_t -_gcry_mpi_get_ui (gcry_mpi_t w, unsigned long *u) +_gcry_mpi_get_ui (unsigned int *w, gcry_mpi_t u) { - gcry_err_code_t err = GPG_ERR_NO_ERROR; - unsigned long x = 0; + mpi_limb_t x; - if (w->nlimbs > 1) - err = GPG_ERR_TOO_LARGE; - else if (w->nlimbs == 1) - x = w->d[0]; - else - x = 0; + if (u->nlimbs > 1 || u->sign) + return GPG_ERR_ERANGE; - if (! err) - *u = x; + x = (u->nlimbs == 1) ? u->d[0] : 0; + if (sizeof (x) > sizeof (unsigned int) && x > MY_UINT_MAX) + return GPG_ERR_ERANGE; - return err; + *w = x; + return 0; } |