[PATCH 6.18 032/641] smb: client: fix potential UAF and double free in smb2_open_file()

[PATCH 6.18 032/641] smb: client: fix potential UAF and double free in smb2_open_file()

[Greg Kroah-Hartman]

6.18-stable review patch.  If anyone has any objections, please let me know.

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

From: Paulo Alcantara <pc@manguebit.org>

[ Upstream commit ebbbc4bfad4cb355d17c671223d0814ee3ef4eda ]

Zero out @err_iov and @err_buftype before retrying SMB2_open() to
prevent an UAF bug if @data != NULL, otherwise a double free.

Fixes: e3a43633023e ("smb/client: fix memory leak in smb2_open_file()")
Reported-by: David Howells <dhowells@redhat.com>
Closes: https://lore.kernel.org/r/2892312.1770306653@warthog.procyon.org.uk
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/smb2file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/smb/client/smb2file.c b/fs/smb/client/smb2file.c
index 03f90553d8319..e6cdf2efc7f4f 100644
--- a/fs/smb/client/smb2file.c
+++ b/fs/smb/client/smb2file.c
@@ -178,6 +178,8 @@ int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32
 		       &err_buftype);
 	if (rc == -EACCES && retry_without_read_attributes) {
 		free_rsp_buf(err_buftype, err_iov.iov_base);
+		memset(&err_iov, 0, sizeof(err_iov));
+		err_buftype = CIFS_NO_BUFFER;
 		oparms->desired_access &= ~FILE_READ_ATTRIBUTES;
 		rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
 			       &err_buftype);
-- 
2.51.0

[PATCH 6.18 325/641] smb: client: correct value for smbd_max_fragmented_recv_size

[Greg Kroah-Hartman]

6.18-stable review patch.  If anyone has any objections, please let me know.

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

From: Stefan Metzmacher <metze@samba.org>

[ Upstream commit 4a93d1ee2d0206970b6eb13fbffe07938cd95948 ]

When we download a file without rdma offload or get
a large directly enumeration from the server,
the server might want to send up to smbd_max_fragmented_recv_size
bytes, but if it is too large all our recv buffers
might already be moved to the recv_io.reassembly.list
and we're no longer able to grant recv credits.

The maximum fragmented upper-layer payload receive size supported

Assume max_payload_per_credit is
smbd_max_receive_size - 24 = 1340

The maximum number would be
smbd_receive_credit_max * max_payload_per_credit

                      1340 * 255 = 341700 (0x536C4)

The minimum value from the spec is 131072 (0x20000)

For now we use the logic we used in ksmbd before:
                (1364 * 255) / 2 = 173910 (0x2A756)

Fixes: 03bee01d6215 ("CIFS: SMBD: Add SMB Direct protocol initial values and constants")
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/smbdirect.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c
index 01d55bcc6d0f9..c8cef098d4806 100644
--- a/fs/smb/client/smbdirect.c
+++ b/fs/smb/client/smbdirect.c
@@ -101,8 +101,23 @@ int smbd_send_credit_target = 255;
 /* The maximum single message size can be sent to remote peer */
 int smbd_max_send_size = 1364;
 
-/*  The maximum fragmented upper-layer payload receive size supported */
-int smbd_max_fragmented_recv_size = 1024 * 1024;
+/*
+ * The maximum fragmented upper-layer payload receive size supported
+ *
+ * Assume max_payload_per_credit is
+ * smbd_max_receive_size - 24 = 1340
+ *
+ * The maximum number would be
+ * smbd_receive_credit_max * max_payload_per_credit
+ *
+ *                       1340 * 255 = 341700 (0x536C4)
+ *
+ * The minimum value from the spec is 131072 (0x20000)
+ *
+ * For now we use the logic we used in ksmbd before:
+ *                 (1364 * 255) / 2 = 173910 (0x2A756)
+ */
+int smbd_max_fragmented_recv_size = (1364 * 255) / 2;
 
 /*  The maximum single-message size which can be received */
 int smbd_max_receive_size = 1364;
-- 
2.51.0