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!"
> +
> /*
> * 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.
> u32 status; /* CSTA - CAAM Status */
> u64 rsvd3;
>
Cheers,
Ahmad
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