[PATCH] cifs: fix memory leak in smb2_copychunk_range

From: Ronnie Sahlberg <lsahlber@redhat.com>
To: linux-cifs <linux-cifs@vger.kernel.org>
Cc: Steve French <smfrench@gmail.com>
Subject: [PATCH] cifs: fix memory leak in smb2_copychunk_range
Date: Wed, 19 May 2021 08:40:11 +1000	[thread overview]
Message-ID: <20210518224011.663856-1-lsahlber@redhat.com> (raw)

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: 9bf0c9cd431440a831e60c0a0fd0bc4f0e083e7f
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/smb2ops.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 19b8e5b5ab28..21ef51d338e0 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1861,6 +1861,8 @@ smb2_copychunk_range(const unsigned int xid,
 			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,
-- 
2.30.2

