Use zfree() instead of explicit_bzero() and free().

In addition to reducing lines of code, this also ensures that the full
allocation is always zeroed avoiding possible bugs with incorrect
lengths passed to explicit_bzero().

Suggested by:	cem
Reviewed by:	cem, delphij
Approved by:	csprng (cem)
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D25435

sys/crypto/aesni/aesni.c

@@ -808,18 +808,12 @@ aesni_cipher_crypt(struct aesni_session *ses, struct cryptop *crp,
 		    crp->crp_payload_length, outbuf);
 
 out:
-	if (allocated) {
-		explicit_bzero(buf, crp->crp_payload_length);
-		free(buf, M_AESNI);
-	}
-	if (authallocated) {
-		explicit_bzero(authbuf, crp->crp_aad_length);
-		free(authbuf, M_AESNI);
-	}
-	if (outallocated) {
-		explicit_bzero(outbuf, crp->crp_payload_length);
-		free(outbuf, M_AESNI);
-	}
+	if (allocated)
+		zfree(buf, M_AESNI);
+	if (authallocated)
+		zfree(authbuf, M_AESNI);
+	if (outallocated)
+		zfree(outbuf, M_AESNI);
 	explicit_bzero(iv, sizeof(iv));
 	explicit_bzero(tag, sizeof(tag));
 	return (error);

sys/crypto/via/padlock_cipher.c

@@ -234,8 +234,7 @@ padlock_cipher_process(struct padlock_session *ses, struct cryptop *crp,
 		crypto_copyback(crp, crp->crp_payload_start,
 		    crp->crp_payload_length, abuf);
 
-		explicit_bzero(buf, crp->crp_payload_length + 16);
-		free(buf, M_PADLOCK);
+		zfree(buf, M_PADLOCK);
 	}
 	return (0);
 }

sys/dev/cxgbe/crypto/t4_kern_tls.c

@@ -2337,8 +2337,7 @@ cxgbe_tls_tag_free(struct m_snd_tag *mst)
 	if (tlsp->tx_key_addr >= 0)
 		free_keyid(tlsp, tlsp->tx_key_addr);
 
-	explicit_bzero(&tlsp->keyctx, sizeof(&tlsp->keyctx));
-	free(tlsp, M_CXGBE);
+	zfree(tlsp, M_CXGBE);
 }
 
 void

sys/dev/random/randomdev.c

@@ -241,8 +241,7 @@ int
 	if (error == ERESTART || error == EINTR)
 		error = 0;
 
-	explicit_bzero(random_buf, bufsize);
-	free(random_buf, M_ENTROPY);
+	zfree(random_buf, M_ENTROPY);
 	return (error);
 }
 

sys/geom/eli/g_eli.c

@@ -388,10 +388,7 @@ g_eli_resize(struct g_consumer *cp)
 		}
 iofail:
 		explicit_bzero(&md, sizeof(md));
-		if (sector != NULL) {
-			explicit_bzero(sector, pp->sectorsize);
-			free(sector, M_ELI);
-		}
+		zfree(sector, M_ELI);
 	}
 
 	oldsize = sc->sc_mediasize;

sys/geom/eli/g_eli_ctl.c

@@ -655,8 +655,7 @@ g_eli_ctl_configure(struct gctl_req *req, struct g_class *mp)
 			    prov, error);
 		}
 		explicit_bzero(&md, sizeof(md));
-		explicit_bzero(sector, pp->sectorsize);
-		free(sector, M_ELI);
+		zfree(sector, M_ELI);
 	}
 }
 
@@ -759,8 +758,7 @@ g_eli_ctl_setkey(struct gctl_req *req, struct g_class *mp)
 	explicit_bzero(&md, sizeof(md));
 	error = g_write_data(cp, pp->mediasize - pp->sectorsize, sector,
 	    pp->sectorsize);
-	explicit_bzero(sector, pp->sectorsize);
-	free(sector, M_ELI);
+	zfree(sector, M_ELI);
 	if (error != 0) {
 		gctl_error(req, "Cannot store metadata on %s (error=%d).",
 		    pp->name, error);
@@ -875,8 +873,7 @@ g_eli_ctl_delkey(struct gctl_req *req, struct g_class *mp)
 		(void)g_io_flush(cp);
 	}
 	explicit_bzero(&md, sizeof(md));
-	explicit_bzero(sector, pp->sectorsize);
-	free(sector, M_ELI);
+	zfree(sector, M_ELI);
 	if (*all)
 		G_ELI_DEBUG(1, "All keys removed from %s.", pp->name);
 	else

sys/geom/eli/g_eli_key_cache.c

@@ -118,8 +118,7 @@ g_eli_key_allocate(struct g_eli_softc *sc, uint64_t keyno)
 	keysearch.gek_keyno = keyno;
 	ekey = RB_FIND(g_eli_key_tree, &sc->sc_ekeys_tree, &keysearch);
 	if (ekey != NULL) {
-		explicit_bzero(key, sizeof(*key));
-		free(key, M_ELI);
+		zfree(key, M_ELI);
 		key = ekey;
 		TAILQ_REMOVE(&sc->sc_ekeys_queue, key, gek_next);
 	} else {
@@ -175,8 +174,7 @@ g_eli_key_remove(struct g_eli_softc *sc, struct g_eli_key *key)
 	RB_REMOVE(g_eli_key_tree, &sc->sc_ekeys_tree, key);
 	TAILQ_REMOVE(&sc->sc_ekeys_queue, key, gek_next);
 	sc->sc_ekeys_allocated--;
-	explicit_bzero(key, sizeof(*key));
-	free(key, M_ELI);
+	zfree(key, M_ELI);
 }
 
 void

sys/geom/geom_dev.c

@@ -614,10 +614,7 @@ g_dev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread
 			kda->kda_encryptedkey = encryptedkey;
 			error = g_dev_setdumpdev(dev, kda);
 		}
-		if (encryptedkey != NULL) {
-			explicit_bzero(encryptedkey, kda->kda_encryptedkeysize);
-			free(encryptedkey, M_TEMP);
-		}
+		zfree(encryptedkey, M_TEMP);
 		explicit_bzero(kda, sizeof(*kda));
 		break;
 	    }

sys/kern/kern_environment.c

@@ -607,8 +607,7 @@ kern_unsetenv(const char *name)
 			kenvp[i++] = kenvp[j];
 		kenvp[i] = NULL;
 		mtx_unlock(&kenv_lock);
-		explicit_bzero(oldenv, strlen(oldenv));
-		free(oldenv, M_KENV);
+		zfree(oldenv, M_KENV);
 		return (0);
 	}
 	mtx_unlock(&kenv_lock);

sys/kern/kern_shutdown.c

@@ -1058,8 +1058,7 @@ kerneldumpcrypto_create(size_t blocksize, uint8_t encryption,
 
 	return (kdc);
 failed:
-	explicit_bzero(kdc, sizeof(*kdc) + dumpkeysize);
-	free(kdc, M_EKCD);
+	zfree(kdc, M_EKCD);
 	return (NULL);
 }
 
@@ -1156,8 +1155,7 @@ kerneldumpcomp_destroy(struct dumperinfo *di)
 	if (kdcomp == NULL)
 		return;
 	compressor_fini(kdcomp->kdc_stream);
-	explicit_bzero(kdcomp->kdc_buf, di->maxiosize);
-	free(kdcomp->kdc_buf, M_DUMPER);
+	zfree(kdcomp->kdc_buf, M_DUMPER);
 	free(kdcomp, M_DUMPER);
 }
 
@@ -1171,23 +1169,14 @@ free_single_dumper(struct dumperinfo *di)
 	if (di == NULL)
 		return;
 
-	if (di->blockbuf != NULL) {
-		explicit_bzero(di->blockbuf, di->blocksize);
-		free(di->blockbuf, M_DUMPER);
-	}
+	zfree(di->blockbuf, M_DUMPER);
 
 	kerneldumpcomp_destroy(di);
 
 #ifdef EKCD
-	if (di->kdcrypto != NULL) {
-		explicit_bzero(di->kdcrypto, sizeof(*di->kdcrypto) +
-		    di->kdcrypto->kdc_dumpkeysize);
-		free(di->kdcrypto, M_EKCD);
-	}
+	zfree(di->kdcrypto, M_EKCD);
 #endif
-
-	explicit_bzero(di, sizeof(*di));
-	free(di, M_DUMPER);
+	zfree(di, M_DUMPER);
 }
 
 /* Registration of dumpers */

sys/kern/uipc_ktls.c

@@ -682,15 +682,12 @@ ktls_cleanup(struct ktls_session *tls)
 #endif
 	}
 	if (tls->params.auth_key != NULL) {
-		explicit_bzero(tls->params.auth_key, tls->params.auth_key_len);
-		free(tls->params.auth_key, M_KTLS);
+		zfree(tls->params.auth_key, M_KTLS);
 		tls->params.auth_key = NULL;
 		tls->params.auth_key_len = 0;
 	}
 	if (tls->params.cipher_key != NULL) {
-		explicit_bzero(tls->params.cipher_key,
-		    tls->params.cipher_key_len);
-		free(tls->params.cipher_key, M_KTLS);
+		zfree(tls->params.cipher_key, M_KTLS);
 		tls->params.cipher_key = NULL;
 		tls->params.cipher_key_len = 0;
 	}

sys/netinet/netdump/netdump_client.c

@@ -642,11 +642,7 @@ netdump_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr,
 		dumper.mediasize = 0;
 
 		error = dumper_insert(&dumper, conf->kda_iface, conf);
-		if (encryptedkey != NULL) {
-			explicit_bzero(encryptedkey,
-			    conf->kda_encryptedkeysize);
-			free(encryptedkey, M_TEMP);
-		}
+		zfree(encryptedkey, M_TEMP);
 		if (error != 0)
 			netdump_unconfigure();
 		break;

sys/opencrypto/crypto.c

@@ -897,8 +897,7 @@ crypto_deletesession(crypto_session_t cses)
 
 	cap = cses->cap;
 
-	explicit_bzero(cses->softc, cap->cc_session_size);
-	free(cses->softc, M_CRYPTO_DATA);
+	zfree(cses->softc, M_CRYPTO_DATA);
 	uma_zfree(cryptoses_zone, cses);
 
 	CRYPTO_DRIVER_LOCK();

sys/opencrypto/cryptosoft.c

@@ -1428,27 +1428,14 @@ static void
 swcr_freesession(device_t dev, crypto_session_t cses)
 {
 	struct swcr_session *ses;
-	struct swcr_auth *swa;
-	struct auth_hash *axf;
 
 	ses = crypto_get_driver_session(cses);
 
 	mtx_destroy(&ses->swcr_lock);
 
 	zfree(ses->swcr_encdec.sw_kschedule, M_CRYPTO_DATA);
-
-	axf = ses->swcr_auth.sw_axf;
-	if (axf != NULL) {
-		swa = &ses->swcr_auth;
-		if (swa->sw_ictx != NULL) {
-			explicit_bzero(swa->sw_ictx, axf->ctxsize);
-			free(swa->sw_ictx, M_CRYPTO_DATA);
-		}
-		if (swa->sw_octx != NULL) {
-			explicit_bzero(swa->sw_octx, axf->ctxsize);
-			free(swa->sw_octx, M_CRYPTO_DATA);
-		}
-	}
+	zfree(ses->swcr_auth.sw_ictx, M_CRYPTO_DATA);
+	zfree(ses->swcr_auth.sw_octx, M_CRYPTO_DATA);
 }
 
 /*

sys/opencrypto/ktls_ocf.c

@@ -343,8 +343,7 @@ ktls_ocf_free(struct ktls_session *tls)
 	os = tls->cipher;
 	crypto_freesession(os->sid);
 	mtx_destroy(&os->lock);
-	explicit_bzero(os, sizeof(*os));
-	free(os, M_KTLS_OCF);
+	zfree(os, M_KTLS_OCF);
 }
 
 static int