linux-kernel - [PATCH 3.16 183/192] Fix memory leaks in cifs_do

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Message-ID: <lsq.1507553065.113036804@decadent.org.uk>
Date:   Mon, 09 Oct 2017 13:44:25 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Aurelien Aptel" <aaptel@...e.com>,
        "Sachin Prabhu" <sprabhu@...hat.com>,
        "Steve French" <smfrench@...il.com>
Subject: [PATCH 3.16 183/192] Fix memory leaks in cifs_do_mount()

3.16.49-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sachin Prabhu <sprabhu@...hat.com>

commit 4214ebf4654798309364d0c678b799e402f38288 upstream.

Fix memory leaks introduced by the patch
fs/cifs: make share unaccessible at root level mountable

Also move allocation of cifs_sb->prepath to cifs_setup_cifs_sb().

Signed-off-by: Sachin Prabhu <sprabhu@...hat.com>
Tested-by: Aurelien Aptel <aaptel@...e.com>
Signed-off-by: Steve French <smfrench@...il.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/cifs/cifsfs.c    | 20 ++++++++------------
 fs/cifs/cifsproto.h |  2 +-
 fs/cifs/connect.c   | 10 +++++++++-
 3 files changed, 18 insertions(+), 14 deletions(-)

--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -663,26 +663,22 @@ cifs_do_mount(struct file_system_type *f
 	cifs_sb->mountdata = kstrndup(data, PAGE_SIZE, GFP_KERNEL);
 	if (cifs_sb->mountdata == NULL) {
 		root = ERR_PTR(-ENOMEM);
-		goto out_cifs_sb;
+		goto out_free;
 	}
 
-	if (volume_info->prepath) {
-		cifs_sb->prepath = kstrdup(volume_info->prepath, GFP_KERNEL);
-		if (cifs_sb->prepath == NULL) {
-			root = ERR_PTR(-ENOMEM);
-			goto out_cifs_sb;
-		}
+	rc = cifs_setup_cifs_sb(volume_info, cifs_sb);
+	if (rc) {
+		root = ERR_PTR(rc);
+		goto out_free;
 	}
 
-	cifs_setup_cifs_sb(volume_info, cifs_sb);
-
 	rc = cifs_mount(cifs_sb, volume_info);
 	if (rc) {
 		if (!(flags & MS_SILENT))
 			cifs_dbg(VFS, "cifs_mount failed w/return code = %d\n",
 				 rc);
 		root = ERR_PTR(rc);
-		goto out_mountdata;
+		goto out_free;
 	}
 
 	mnt_data.vol = volume_info;
@@ -729,9 +725,9 @@ out:
 	cifs_cleanup_volume_info(volume_info);
 	return root;
 
-out_mountdata:
+out_free:
+	kfree(cifs_sb->prepath);
 	kfree(cifs_sb->mountdata);
-out_cifs_sb:
 	kfree(cifs_sb);
 out_nls:
 	unload_nls(volume_info->local_nls);
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -183,7 +183,7 @@ extern int cifs_read_from_socket(struct
 extern int cifs_readv_from_socket(struct TCP_Server_Info *server,
 		struct kvec *iov_orig, unsigned int nr_segs,
 		unsigned int to_read);
-extern void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
+extern int cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 			       struct cifs_sb_info *cifs_sb);
 extern int cifs_match_super(struct super_block *, void *);
 extern void cifs_cleanup_volume_info(struct smb_vol *pvolume_info);
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3194,7 +3194,7 @@ void reset_cifs_unix_caps(unsigned int x
 	}
 }
 
-void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
+int cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 			struct cifs_sb_info *cifs_sb)
 {
 	INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
@@ -3276,6 +3276,14 @@ void cifs_setup_cifs_sb(struct smb_vol *
 
 	if ((pvolume_info->cifs_acl) && (pvolume_info->dynperm))
 		cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
+
+	if (pvolume_info->prepath) {
+		cifs_sb->prepath = kstrdup(pvolume_info->prepath, GFP_KERNEL);
+		if (cifs_sb->prepath == NULL)
+			return -ENOMEM;
+	}
+
+	return 0;
 }
 
 static void