lib/mpi: checks for zero divisor length

Divisor length should not be 0.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Reviewed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/mpi/mpi-div.c b/lib/mpi/mpi-div.c
index c3087d1390ce..8a45717bd001 100644
--- a/lib/mpi/mpi-div.c
+++ b/lib/mpi/mpi-div.c
@@ -149,6 +149,9 @@ int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
         mpi_ptr_t marker[5];
         int markidx = 0;
 
+        if (!dsize)
+                return -EINVAL;
+
         memset(marker, 0, sizeof(marker));
 
         /* Ensure space is enough for quotient and remainder.