diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d9ea7ada1378..f918a998a087 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -384,6 +384,7 @@ struct smb_version_operations {
int (*clone_range)(const unsigned int, struct cifsFileInfo *src_file,
struct cifsFileInfo *target_file, u64 src_off, u64 len,
u64 dest_off);
+ int (*validate_negotiate)(const unsigned int, struct cifs_tcon *);
};
struct smb_version_values {
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index a3968eeb6fac..757da3e54d3d 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1319,6 +1319,7 @@ struct smb_version_operations smb30_operations = {
.create_lease_buf = smb3_create_lease_buf,
.parse_lease_buf = smb3_parse_lease_buf,
.clone_range = smb2_clone_range,
+ .validate_negotiate = smb3_validate_negotiate,
};
struct smb_version_values smb20_values = {
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1e136eee3ea6..2013234b73ad 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -454,6 +454,81 @@ neg_exit:
return rc;
}
+int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
+{
+ int rc = 0;
+ struct validate_negotiate_info_req vneg_inbuf;
+ struct validate_negotiate_info_rsp *pneg_rsp;
+ u32 rsplen;
+
+ cifs_dbg(FYI, "validate negotiate\n");
+
+ /*
+ * validation ioctl must be signed, so no point sending this if we
+ * can not sign it. We could eventually change this to selectively
+ * sign just this, the first and only signed request on a connection.
+ * This is good enough for now since a user who wants better security
+ * would also enable signing on the mount. Having validation of
+ * negotiate info for signed connections helps reduce attack vectors
+ */
+ if (tcon->ses->server->sign == false)
+ return 0; /* validation requires signing */
+
+ vneg_inbuf.Capabilities =
+ cpu_to_le32(tcon->ses->server->vals->req_capabilities);
+ memcpy(vneg_inbuf.Guid, cifs_client_guid, SMB2_CLIENT_GUID_SIZE);
+
+ if (tcon->ses->sign)
+ vneg_inbuf.SecurityMode =
+ cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
+ else if (global_secflags & CIFSSEC_MAY_SIGN)
+ vneg_inbuf.SecurityMode =
+ cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
+ else
+ vneg_inbuf.SecurityMode = 0;
+
+ vneg_inbuf.DialectCount = cpu_to_le16(1);
+ vneg_inbuf.Dialects[0] =
+ cpu_to_le16(tcon->ses->server->vals->protocol_id);
+
+ rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
+ FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
+ (char *)&vneg_inbuf, sizeof(struct validate_negotiate_info_req),
+ (char **)&pneg_rsp, &rsplen);
+
+ if (rc != 0) {
+ cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
+ return -EIO;
+ }
+
+ if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
+ cifs_dbg(VFS, "invalid size of protocol negotiate response\n");
+ return -EIO;
+ }
+
+ /* check validate negotiate info response matches what we got earlier */
+ if (pneg_rsp->Dialect !=
+ cpu_to_le16(tcon->ses->server->vals->protocol_id))
+ goto vneg_out;
+
+ if (pneg_rsp->SecurityMode != cpu_to_le16(tcon->ses->server->sec_mode))
+ goto vneg_out;
+
+ /* do not validate server guid because not saved at negprot time yet */
+
+ if ((le32_to_cpu(pneg_rsp->Capabilities) | SMB2_NT_FIND |
+ SMB2_LARGE_FILES) != tcon->ses->server->capabilities)
+ goto vneg_out;
+
+ /* validate negotiate successful */
+ cifs_dbg(FYI, "validate negotiate info successful\n");
+ return 0;
+
+vneg_out:
+ cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
+ return -EIO;
+}
+
int
SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_cp)
@@ -829,6 +904,8 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
((tcon->share_flags & SHI1005_FLAGS_DFS) == 0))
cifs_dbg(VFS, "DFS capability contradicts DFS flag\n");
init_copy_chunk_defaults(tcon);
+ if (tcon->ses->server->ops->validate_negotiate)
+ rc = tcon->ses->server->ops->validate_negotiate(xid, tcon);
tcon_exit:
free_rsp_buf(resp_buftype, rsp);
kfree(unc_path);
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index f88320bbb477..2022c542ea3a 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -577,13 +577,19 @@ struct copychunk_ioctl_rsp {
__le32 TotalBytesWritten;
} __packed;
-/* Response and Request are the same format */
-struct validate_negotiate_info {
+struct validate_negotiate_info_req {
__le32 Capabilities;
__u8 Guid[SMB2_CLIENT_GUID_SIZE];
__le16 SecurityMode;
__le16 DialectCount;
- __le16 Dialect[1];
+ __le16 Dialects[1]; /* dialect (someday maybe list) client asked for */
+} __packed;
+
+struct validate_negotiate_info_rsp {
+ __le32 Capabilities;
+ __u8 Guid[SMB2_CLIENT_GUID_SIZE];
+ __le16 SecurityMode;
+ __le16 Dialect; /* Dialect in use for the connection */
} __packed;
#define RSS_CAPABLE 0x00000001
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index b4eea105b08c..93adc64666f3 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -162,5 +162,6 @@ extern int smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon,
struct smb2_lock_element *buf);
extern int SMB2_lease_break(const unsigned int xid, struct cifs_tcon *tcon,
__u8 *lease_key, const __le32 lease_state);
+extern int smb3_validate_negotiate(const unsigned int, struct cifs_tcon *);
#endif /* _SMB2PROTO_H */
diff --git a/fs/cifs/smbfsctl.h b/fs/cifs/smbfsctl.h
index a4b2391fe66e..0e538b5c9622 100644
--- a/fs/cifs/smbfsctl.h
+++ b/fs/cifs/smbfsctl.h
@@ -90,7 +90,7 @@
#define FSCTL_LMR_REQUEST_RESILIENCY 0x001401D4 /* BB add struct */
#define FSCTL_LMR_GET_LINK_TRACK_INF 0x001400E8 /* BB add struct */
#define FSCTL_LMR_SET_LINK_TRACK_INF 0x001400EC /* BB add struct */
-#define FSCTL_VALIDATE_NEGOTIATE_INFO 0x00140204 /* BB add struct */
+#define FSCTL_VALIDATE_NEGOTIATE_INFO 0x00140204
/* Perform server-side data movement */
#define FSCTL_SRV_COPYCHUNK 0x001440F2
#define FSCTL_SRV_COPYCHUNK_WRITE 0x001480F2