[PATCH v2] cifs: move large array from stack to heap

[Aurelien Aptel <aaptel@xxxxxxxx>]

Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
---

Changes since v1:
* alloc MAX_TREE_SIZE instead of MAX_TREE_SIZE+1 as null is already
  taken into account in the definition of it and snprintf always
  NULL-terminates within the size param.

fs/cifs/cifssmb.c | 23 ++++++++++++++++-------
 fs/cifs/smb2pdu.c | 23 ++++++++++++++++-------
 2 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index b1f49c1c543a..332f88d753d1 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -128,24 +128,31 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
 	int rc;
 	struct dfs_cache_tgt_list tl;
 	struct dfs_cache_tgt_iterator *it = NULL;
-	char tree[MAX_TREE_SIZE + 1];
+	char *tree;
 	const char *tcp_host;
 	size_t tcp_host_len;
 	const char *dfs_host;
 	size_t dfs_host_len;

+	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
+	if (!tree)
+		return -ENOMEM;
+
 	if (tcon->ipc) {
-		snprintf(tree, sizeof(tree), "\\\\%s\\IPC$",
+		snprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
 			 tcon->ses->server->hostname);
-		return CIFSTCon(0, tcon->ses, tree, tcon, nlsc);
+		rc = CIFSTCon(0, tcon->ses, tree, tcon, nlsc);
+		goto out;
 	}

-	if (!tcon->dfs_path)
-		return CIFSTCon(0, tcon->ses, tcon->treeName, tcon, nlsc);
+	if (!tcon->dfs_path) {
+		rc = CIFSTCon(0, tcon->ses, tcon->treeName, tcon, nlsc);
+		goto out;
+	}

 	rc = dfs_cache_noreq_find(tcon->dfs_path + 1, NULL, &tl);
 	if (rc)
-		return rc;
+		goto out;

 	extract_unc_hostname(tcon->ses->server->hostname, &tcp_host,
 			     &tcp_host_len);
@@ -165,7 +172,7 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
 			continue;
 		}

-		snprintf(tree, sizeof(tree), "\\%s", tgt);
+		snprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);

 		rc = CIFSTCon(0, tcon->ses, tree, tcon, nlsc);
 		if (!rc)
@@ -182,6 +189,8 @@ static int __cifs_reconnect_tcon(const struct nls_table *nlsc,
 			rc = -ENOENT;
 	}
 	dfs_cache_free_tgts(&tl);
+out:
+	kfree(tree);
 	return rc;
 }
 #else
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index e283590955cd..9a7a51cd07ac 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -162,24 +162,31 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
 	int rc;
 	struct dfs_cache_tgt_list tl;
 	struct dfs_cache_tgt_iterator *it = NULL;
-	char tree[MAX_TREE_SIZE + 1];
+	char *tree;
 	const char *tcp_host;
 	size_t tcp_host_len;
 	const char *dfs_host;
 	size_t dfs_host_len;

+	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
+	if (!tree)
+		return -ENOMEM;
+
 	if (tcon->ipc) {
-		snprintf(tree, sizeof(tree), "\\\\%s\\IPC$",
+		snprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$",
 			 tcon->ses->server->hostname);
-		return SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
+		rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
+		goto out;
 	}

-	if (!tcon->dfs_path)
-		return SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nlsc);
+	if (!tcon->dfs_path) {
+		rc = SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nlsc);
+		goto out;
+	}

 	rc = dfs_cache_noreq_find(tcon->dfs_path + 1, NULL, &tl);
 	if (rc)
-		return rc;
+		goto out;

 	extract_unc_hostname(tcon->ses->server->hostname, &tcp_host,
 			     &tcp_host_len);
@@ -199,7 +206,7 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
 			continue;
 		}

-		snprintf(tree, sizeof(tree), "\\%s", tgt);
+		snprintf(tree, MAX_TREE_SIZE, "\\%s", tgt);

 		rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);
 		if (!rc)
@@ -216,6 +223,8 @@ static int __smb2_reconnect(const struct nls_table *nlsc,
 			rc = -ENOENT;
 	}
 	dfs_cache_free_tgts(&tl);
+out:
+	kfree(tree);
 	return rc;
 }
 #else
--
2.16.4