3 files changed, 30 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 6380726f7538..9b7f3c477730 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -119,6 +119,10 @@ int libata_noacpi = 0;
 module_param_named(noacpi, libata_noacpi, int, 0444);
 MODULE_PARM_DESC(noacpi, "Disables the use of ACPI in probe/suspend/resume when set");
 
+int libata_allow_tpm = 0;
+module_param_named(allow_tpm, libata_allow_tpm, int, 0444);
+MODULE_PARM_DESC(allow_tpm, "Permit the use of TPM commands");
+
 MODULE_AUTHOR("Jeff Garzik");
 MODULE_DESCRIPTION("Library module for ATA devices");
 MODULE_LICENSE("GPL");
@@ -2161,8 +2165,14 @@ int ata_dev_configure(struct ata_device *dev)
                                                "supports DRM functions and may "
                                                "not be fully accessable.\n");
                         snprintf(revbuf, 7, "CFA");
-                } else
+                } else {
                         snprintf(revbuf, 7, "ATA-%d", ata_id_major_version(id));
+                        /* Warn the user if the device has TPM extensions */
+                        if (ata_id_has_tpm(id))
+                                ata_dev_printk(dev, KERN_WARNING,
+                                               "supports DRM functions and may "
+                                               "not be fully accessable.\n");
+                }
 
                 dev->n_sectors = ata_id_n_sectors(id);
 
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 14daf4848f09..f802dbce41ae 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2690,6 +2690,24 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
         if ((tf->protocol = ata_scsi_map_proto(cdb[1])) == ATA_PROT_UNKNOWN)
                 goto invalid_fld;
 
+        /*
+         * Filter TPM commands by default. These provide an
+         * essentially uncontrolled encrypted "back door" between
+         * applications and the disk. Set libata.allow_tpm=1 if you
+         * have a real reason for wanting to use them. This ensures
+         * that installed software cannot easily mess stuff up without
+         * user intent. DVR type users will probably ship with this enabled
+         * for movie content management.
+         *
+         * Note that for ATA8 we can issue a DCS change and DCS freeze lock
+         * for this and should do in future but that it is not sufficient as
+         * DCS is an optional feature set. Thus we also do the software filter
+         * so that we comply with the TC consortium stated goal that the user
+         * can turn off TC features of their system.
+         */
+        if (tf->command >= 0x5C && tf->command <= 0x5F && !libata_allow_tpm)
+                goto invalid_fld;
+
         /* We may not issue DMA commands if no DMA mode is set */
         if (tf->protocol == ATA_PROT_DMA && dev->dma_mode == 0)
                 goto invalid_fld;
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index bbe59c2fd1e2..048e26cfb339 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -60,6 +60,7 @@ extern int atapi_dmadir;
 extern int atapi_passthru16;
 extern int libata_fua;
 extern int libata_noacpi;
+extern int libata_allow_tpm;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
 extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
                            u64 block, u32 n_block, unsigned int tf_flags,