softraid_crypto.c malloc failure case

[Michael W. Bombardieri]

Hi,

In sr_crypto_change_maskkey() p was being checked for NULL
twice, once after malloc() and once at goto label.
I think malloc() failure would be the only case where p doesn't
need to be freed, so add a special goto label for this.
Sorry if I got it wrong.

- Michael


Index: softraid_crypto.c
===================================================================
RCS file: /cvs/src/sys/dev/softraid_crypto.c,v
retrieving revision 1.131
diff -u -p -u -r1.131 softraid_crypto.c
--- softraid_crypto.c   8 Sep 2016 17:39:08 -0000       1.131
+++ softraid_crypto.c   17 Jan 2017 04:34:57 -0000
@@ -548,7 +548,7 @@ sr_crypto_change_maskkey(struct sr_disci
        ksz = sizeof(sd->mds.mdd_crypto.scr_key);
        p = malloc(ksz, M_DEVBUF, M_WAITOK | M_CANFAIL | M_ZERO);
        if (p == NULL)
-               goto out;
+               goto out_nomem;
 
        if (sr_crypto_decrypt(c, p, kdfinfo1->maskkey, ksz,
            sd->mds.mdd_crypto.scr_meta->scm_mask_alg) == -1)
@@ -597,11 +597,10 @@ sr_crypto_change_maskkey(struct sr_disci
        rv = 0; /* Success */
 
 out:
-       if (p) {
-               explicit_bzero(p, ksz);
-               free(p, M_DEVBUF, ksz);
-       }
+       explicit_bzero(p, ksz);
+       free(p, M_DEVBUF, ksz);
 
+out_nomem:
        explicit_bzero(check_digest, sizeof(check_digest));
        explicit_bzero(&kdfinfo1->maskkey, sizeof(kdfinfo1->maskkey));
        explicit_bzero(&kdfinfo2->maskkey, sizeof(kdfinfo2->maskkey));