On Fri, 4 Nov 2022, Ahmad Fatoum wrote:
Hello Nikolaus,
On 19.10.22 14:44, Nikolaus Voss wrote:
If CAAM is not in "trusted" or "secure" state, a fixed non-volatile key
is used instead of the unique device key. This is the default mode of
operation without secure boot (HAB). In this scenario, CAAM encrypted
blobs should be used only for testing but not in a production
environment, so issue a warning.
Thanks for your patch.
Signed-off-by: Nikolaus Voss <nikolaus.voss@xxxxxxxxxxxxxxx>
---
drivers/crypto/caam/blob_gen.c | 8 ++++++++
drivers/crypto/caam/regs.h | 3 +++
2 files changed, 11 insertions(+)
diff --git a/drivers/crypto/caam/blob_gen.c b/drivers/crypto/caam/blob_gen.c
index 6345c7269eb0..f3e741393f65 100644
--- a/drivers/crypto/caam/blob_gen.c
+++ b/drivers/crypto/caam/blob_gen.c
@@ -6,6 +6,7 @@
#define pr_fmt(fmt) "caam blob_gen: " fmt
+#include <linux/bitfield.h>
#include <linux/device.h>
#include <soc/fsl/caam-blob.h>
@@ -62,11 +63,13 @@ int caam_process_blob(struct caam_blob_priv *priv,
struct caam_blob_info *info, bool encap)
I agree with Herbert that this may not be the best place. I think
a single warning during caam_blob_gen_init() would suffice.
{
struct caam_blob_job_result testres;
+ const struct caam_drv_private *ctrlpriv;
struct device *jrdev = &priv->jrdev;
dma_addr_t dma_in, dma_out;
int op = OP_PCLID_BLOB;
size_t output_len;
u32 *desc;
+ u32 moo;
int ret;
if (info->key_mod_len > CAAM_BLOB_KEYMOD_LENGTH)
@@ -100,6 +103,11 @@ int caam_process_blob(struct caam_blob_priv *priv,
goto out_unmap_in;
}
+ ctrlpriv = dev_get_drvdata(jrdev->parent);
+ moo = FIELD_GET(CSTA_MOO, ctrlpriv->ctrl->perfmon.status);
+ if (moo != CSTA_MOO_SECURE && moo != CSTA_MOO_TRUSTED)
+ dev_warn(jrdev, "using insecure test key!\n");
I'd make the warning a bit more verbose, e.g.
"device not configured for trusted/secure mode: using insecure test key!"
I agree.
+
/*
* A data blob is encrypted using a blob key (BK); a random number.
* The BK is used as an AES-CCM key. The initial block (B0) and the
diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h
index 66d6dad841bb..b7de5fb5e056 100644
--- a/drivers/crypto/caam/regs.h
+++ b/drivers/crypto/caam/regs.h
@@ -426,6 +426,9 @@ struct caam_perfmon {
u32 rsvd2;
#define CSTA_PLEND BIT(10)
#define CSTA_ALT_PLEND BIT(18)
+#define CSTA_MOO GENMASK(9, 8)
+#define CSTA_MOO_SECURE 1
+#define CSTA_MOO_TRUSTED 3
I just checked the i.MX6 and LS1046 security reference manuals and both
have Trusted as 2 (10b). 3 is fail. Does you SoC differ? Either way, please
note what SoC you were testing on in the commit message.
You're right, I will correct that.
Niko
