linux-kernel - [PATCH 4.19 10/49] cifs: fix memory leak in smb2_copychunk

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Date:   Mon, 24 May 2021 17:25:21 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Aurelien Aptel <aaptel@...e.com>,
        Ronnie Sahlberg <lsahlber@...hat.com>,
        Steve French <stfrench@...rosoft.com>
Subject: [PATCH 4.19 10/49] cifs: fix memory leak in smb2_copychunk_range

From: Ronnie Sahlberg <lsahlber@...hat.com>

commit d201d7631ca170b038e7f8921120d05eec70d7c5 upstream.

When using smb2_copychunk_range() for large ranges we will
run through several iterations of a loop calling SMB2_ioctl()
but never actually free the returned buffer except for the final
iteration.
This leads to memory leaks everytime a large copychunk is requested.

Fixes: 9bf0c9cd4314 ("CIFS: Fix SMB2/SMB3 Copy offload support (refcopy) for large files")
Cc: <stable@...r.kernel.org>
Reviewed-by: Aurelien Aptel <aaptel@...e.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@...hat.com>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/cifs/smb2ops.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1174,6 +1174,8 @@ smb2_copychunk_range(const unsigned int
 			cpu_to_le32(min_t(u32, len, tcon->max_bytes_chunk));
 
 		/* Request server copy to target from src identified by key */
+		kfree(retbuf);
+		retbuf = NULL;
 		rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
 			trgtfile->fid.volatile_fid, FSCTL_SRV_COPYCHUNK_WRITE,
 			true /* is_fsctl */, (char *)pcchunk,