lib/digsig: checks for NULL return value

mpi_read_from_buffer() return value must not be NULL.

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, 6 insertions, 2 deletions

diff --git a/lib/digsig.c b/lib/digsig.c
index b67e82c024b3..286d558033e2 100644
--- a/lib/digsig.c
+++ b/lib/digsig.c
@@ -109,9 +109,13 @@ static int digsig_verify_rsa(struct key *key,
         datap = pkh->mpi;
         endp = ukp->data + ukp->datalen;
 
+        err = -ENOMEM;
+
         for (i = 0; i < pkh->nmpi; i++) {
                 unsigned int remaining = endp - datap;
                 pkey[i] = mpi_read_from_buffer(datap, &remaining);
+                if (!pkey[i])
+                        goto err;
                 datap += remaining;
         }
 
@@ -168,8 +172,8 @@ err:
         mpi_free(res);
         kfree(out1);
         kfree(out2);
-        mpi_free(pkey[0]);
-        mpi_free(pkey[1]);
+        while (--i >= 0)
+                mpi_free(pkey[i]);
 err1:
         up_read(&key->sem);