CIFS: refactor crypto shash/sdesc allocation&free

shash and sdesc and always allocated and freed together.
* abstract this in new functions cifs_alloc_hash() and cifs_free_hash().
* make smb2/3 crypto allocation independent from each other.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>

fs/cifs/cifsencrypt.c

@@ -36,37 +36,6 @@
 #include <crypto/skcipher.h>
 #include <crypto/aead.h>
 
-static int
-cifs_crypto_shash_md5_allocate(struct TCP_Server_Info *server)
-{
-	int rc;
-	unsigned int size;
-
-	if (server->secmech.sdescmd5 != NULL)
-		return 0; /* already allocated */
-
-	server->secmech.md5 = crypto_alloc_shash("md5", 0, 0);
-	if (IS_ERR(server->secmech.md5)) {
-		cifs_dbg(VFS, "could not allocate crypto md5\n");
-		rc = PTR_ERR(server->secmech.md5);
-		server->secmech.md5 = NULL;
-		return rc;
-	}
-
-	size = sizeof(struct shash_desc) +
-			crypto_shash_descsize(server->secmech.md5);
-	server->secmech.sdescmd5 = kmalloc(size, GFP_KERNEL);
-	if (!server->secmech.sdescmd5) {
-		crypto_free_shash(server->secmech.md5);
-		server->secmech.md5 = NULL;
-		return -ENOMEM;
-	}
-	server->secmech.sdescmd5->shash.tfm = server->secmech.md5;
-	server->secmech.sdescmd5->shash.flags = 0x0;
-
-	return 0;
-}
-
 int __cifs_calc_signature(struct smb_rqst *rqst,
 			struct TCP_Server_Info *server, char *signature,
 			struct shash_desc *shash)
@@ -132,13 +101,10 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
 	if (!rqst->rq_iov || !signature || !server)
 		return -EINVAL;
 
-	if (!server->secmech.sdescmd5) {
-		rc = cifs_crypto_shash_md5_allocate(server);
-		if (rc) {
-			cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
+	rc = cifs_alloc_hash("md5", &server->secmech.md5,
+			     &server->secmech.sdescmd5);
+	if (rc)
 		return -1;
-		}
-	}
 
 	rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
 	if (rc) {
@@ -663,37 +629,6 @@ CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
 	return rc;
 }
 
-static int crypto_hmacmd5_alloc(struct TCP_Server_Info *server)
-{
-	int rc;
-	unsigned int size;
-
-	/* check if already allocated */
-	if (server->secmech.sdeschmacmd5)
-		return 0;
-
-	server->secmech.hmacmd5 = crypto_alloc_shash("hmac(md5)", 0, 0);
-	if (IS_ERR(server->secmech.hmacmd5)) {
-		cifs_dbg(VFS, "could not allocate crypto hmacmd5\n");
-		rc = PTR_ERR(server->secmech.hmacmd5);
-		server->secmech.hmacmd5 = NULL;
-		return rc;
-	}
-
-	size = sizeof(struct shash_desc) +
-			crypto_shash_descsize(server->secmech.hmacmd5);
-	server->secmech.sdeschmacmd5 = kmalloc(size, GFP_KERNEL);
-	if (!server->secmech.sdeschmacmd5) {
-		crypto_free_shash(server->secmech.hmacmd5);
-		server->secmech.hmacmd5 = NULL;
-		return -ENOMEM;
-	}
-	server->secmech.sdeschmacmd5->shash.tfm = server->secmech.hmacmd5;
-	server->secmech.sdeschmacmd5->shash.flags = 0x0;
-
-	return 0;
-}
-
 int
 setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 {
@@ -757,9 +692,10 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 
 	mutex_lock(&ses->server->srv_mutex);
 
-	rc = crypto_hmacmd5_alloc(ses->server);
+	rc = cifs_alloc_hash("hmac(md5)",
+			     &ses->server->secmech.hmacmd5,
+			     &ses->server->secmech.sdeschmacmd5);
 	if (rc) {
-		cifs_dbg(VFS, "could not crypto alloc hmacmd5 rc %d\n", rc);
 		goto unlock;
 	}
 

fs/cifs/cifsproto.h

@@ -542,4 +542,9 @@ enum securityEnum cifs_select_sectype(struct TCP_Server_Info *,
 struct cifs_aio_ctx *cifs_aio_ctx_alloc(void);
 void cifs_aio_ctx_release(struct kref *refcount);
 int setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw);
+
+int cifs_alloc_hash(const char *name, struct crypto_shash **shash,
+		    struct sdesc **sdesc);
+void cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc);
+
 #endif			/* _CIFSPROTO_H */

fs/cifs/link.c

@@ -50,25 +50,12 @@ static int
 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
 {
 	int rc;
-	unsigned int size;
-	struct crypto_shash *md5;
-	struct sdesc *sdescmd5;
-
-	md5 = crypto_alloc_shash("md5", 0, 0);
-	if (IS_ERR(md5)) {
-		rc = PTR_ERR(md5);
-		cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
-			 __func__, rc);
-		return rc;
-	}
-	size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
-	sdescmd5 = kmalloc(size, GFP_KERNEL);
-	if (!sdescmd5) {
-		rc = -ENOMEM;
+	struct crypto_shash *md5 = NULL;
+	struct sdesc *sdescmd5 = NULL;
+
+	rc = cifs_alloc_hash("md5", &md5, &sdescmd5);
+	if (rc)
 		goto symlink_hash_err;
-	}
-	sdescmd5->shash.tfm = md5;
-	sdescmd5->shash.flags = 0x0;
 
 	rc = crypto_shash_init(&sdescmd5->shash);
 	if (rc) {
@@ -85,9 +72,7 @@ symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
 		cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
 
 symlink_hash_err:
-	crypto_free_shash(md5);
-	kfree(sdescmd5);
-
+	cifs_free_hash(&md5, &sdescmd5);
 	return rc;
 }
 

fs/cifs/misc.c

@@ -848,3 +848,57 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 	iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
 	return 0;
 }
+
+/**
+ * cifs_alloc_hash - allocate hash and hash context together
+ *
+ * The caller has to make sure @sdesc is initialized to either NULL or
+ * a valid context. Both can be freed via cifs_free_hash().
+ */
+int
+cifs_alloc_hash(const char *name,
+		struct crypto_shash **shash, struct sdesc **sdesc)
+{
+	int rc = 0;
+	size_t size;
+
+	if (*sdesc != NULL)
+		return 0;
+
+	*shash = crypto_alloc_shash(name, 0, 0);
+	if (IS_ERR(*shash)) {
+		cifs_dbg(VFS, "could not allocate crypto %s\n", name);
+		rc = PTR_ERR(*shash);
+		*shash = NULL;
+		*sdesc = NULL;
+		return rc;
+	}
+
+	size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
+	*sdesc = kmalloc(size, GFP_KERNEL);
+	if (*sdesc == NULL) {
+		cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
+		crypto_free_shash(*shash);
+		*shash = NULL;
+		return -ENOMEM;
+	}
+
+	(*sdesc)->shash.tfm = *shash;
+	(*sdesc)->shash.flags = 0x0;
+	return 0;
+}
+
+/**
+ * cifs_free_hash - free hash and hash context together
+ *
+ * Freeing a NULL hash or context is safe.
+ */
+void
+cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
+{
+	kfree(*sdesc);
+	*sdesc = NULL;
+	if (*shash)
+		crypto_free_shash(*shash);
+	*shash = NULL;
+}

fs/cifs/smb2transport.c

@@ -43,76 +43,31 @@
 static int
 smb2_crypto_shash_allocate(struct TCP_Server_Info *server)
 {
-	int rc;
-	unsigned int size;
-
-	if (server->secmech.sdeschmacsha256 != NULL)
-		return 0; /* already allocated */
-
-	server->secmech.hmacsha256 = crypto_alloc_shash("hmac(sha256)", 0, 0);
-	if (IS_ERR(server->secmech.hmacsha256)) {
-		cifs_dbg(VFS, "could not allocate crypto hmacsha256\n");
-		rc = PTR_ERR(server->secmech.hmacsha256);
-		server->secmech.hmacsha256 = NULL;
-		return rc;
-	}
-
-	size = sizeof(struct shash_desc) +
-			crypto_shash_descsize(server->secmech.hmacsha256);
-	server->secmech.sdeschmacsha256 = kmalloc(size, GFP_KERNEL);
-	if (!server->secmech.sdeschmacsha256) {
-		crypto_free_shash(server->secmech.hmacsha256);
-		server->secmech.hmacsha256 = NULL;
-		return -ENOMEM;
-	}
-	server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;
-	server->secmech.sdeschmacsha256->shash.flags = 0x0;
-
-	return 0;
+	return cifs_alloc_hash("hmac(sha256)",
+			       &server->secmech.hmacsha256,
+			       &server->secmech.sdeschmacsha256);
 }
 
 static int
 smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
 {
-	unsigned int size;
+	struct cifs_secmech *p = &server->secmech;
 	int rc;
 
-	if (server->secmech.sdesccmacaes != NULL)
-		return 0;  /* already allocated */
-
-	rc = smb2_crypto_shash_allocate(server);
+	rc = cifs_alloc_hash("hmac(sha256)",
+			     &p->hmacsha256,
+			     &p->sdeschmacsha256);
 	if (rc)
-		return rc;
-
-	server->secmech.cmacaes = crypto_alloc_shash("cmac(aes)", 0, 0);
-	if (IS_ERR(server->secmech.cmacaes)) {
-		cifs_dbg(VFS, "could not allocate crypto cmac-aes");
-		kfree(server->secmech.sdeschmacsha256);
-		server->secmech.sdeschmacsha256 = NULL;
-		crypto_free_shash(server->secmech.hmacsha256);
-		server->secmech.hmacsha256 = NULL;
-		rc = PTR_ERR(server->secmech.cmacaes);
-		server->secmech.cmacaes = NULL;
-		return rc;
-	}
+		goto err;
 
-	size = sizeof(struct shash_desc) +
-			crypto_shash_descsize(server->secmech.cmacaes);
-	server->secmech.sdesccmacaes = kmalloc(size, GFP_KERNEL);
-	if (!server->secmech.sdesccmacaes) {
-		cifs_dbg(VFS, "%s: Can't alloc cmacaes\n", __func__);
-		kfree(server->secmech.sdeschmacsha256);
-		server->secmech.sdeschmacsha256 = NULL;
-		crypto_free_shash(server->secmech.hmacsha256);
-		crypto_free_shash(server->secmech.cmacaes);
-		server->secmech.hmacsha256 = NULL;
-		server->secmech.cmacaes = NULL;
-		return -ENOMEM;
-	}
-	server->secmech.sdesccmacaes->shash.tfm = server->secmech.cmacaes;
-	server->secmech.sdesccmacaes->shash.flags = 0x0;
+	rc = cifs_alloc_hash("cmac(aes)", &p->cmacaes, &p->sdesccmacaes);
+	if (rc)
+		goto err;
 
 	return 0;
+err:
+	cifs_free_hash(&p->hmacsha256, &p->sdeschmacsha256);
+	return rc;
 }
 
 static struct cifs_ses *

fs/cifs/smbencrypt.c

@@ -121,25 +121,12 @@ int
 mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
 {
 	int rc;
-	unsigned int size;
-	struct crypto_shash *md4;
-	struct sdesc *sdescmd4;
-
-	md4 = crypto_alloc_shash("md4", 0, 0);
-	if (IS_ERR(md4)) {
-		rc = PTR_ERR(md4);
-		cifs_dbg(VFS, "%s: Crypto md4 allocation error %d\n",
-			 __func__, rc);
-		return rc;
-	}
-	size = sizeof(struct shash_desc) + crypto_shash_descsize(md4);
-	sdescmd4 = kmalloc(size, GFP_KERNEL);
-	if (!sdescmd4) {
-		rc = -ENOMEM;
+	struct crypto_shash *md4 = NULL;
+	struct sdesc *sdescmd4 = NULL;
+
+	rc = cifs_alloc_hash("md4", &md4, &sdescmd4);
+	if (rc)
 		goto mdfour_err;
-	}
-	sdescmd4->shash.tfm = md4;
-	sdescmd4->shash.flags = 0x0;
 
 	rc = crypto_shash_init(&sdescmd4->shash);
 	if (rc) {
@@ -156,9 +143,7 @@ mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
 		cifs_dbg(VFS, "%s: Could not generate md4 hash\n", __func__);
 
 mdfour_err:
-	crypto_free_shash(md4);
-	kfree(sdescmd4);
-
+	cifs_free_hash(&md4, &sdescmd4);
 	return rc;
 }