The CAAM can be used to protect user-defined data across system reboot:
- When the system is fused and boots into secure state, the master
key is a unique never-disclosed device-specific key
- random key is encrypted by key derived from master key
- data is encrypted using the random key
- encrypted data and its encrypted random key are stored alongside
- This blob can now be safely stored in non-volatile memory
On next power-on:
- blob is loaded into CAAM
- CAAM writes decrypted data either into memory or key register
Add functions to realize encrypting and decrypting into memory alongside
the CAAM driver.
They will be used in a later commit as a source for the trusted key
seal/unseal mechanism.
Signed-off-by: Steffen Trumtrar <[email protected]>
Signed-off-by: Ahmad Fatoum <[email protected]>
---
To: "Horia Geantă" <[email protected]>
To: Aymen Sghaier <[email protected]>
To: Herbert Xu <[email protected]>
To: "David S. Miller" <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jarkko Sakkinen <[email protected]>
Cc: Mimi Zohar <[email protected]>
Cc: David Howells <[email protected]>
Cc: James Morris <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: Udit Agarwal <[email protected]>
Cc: Jan Luebbe <[email protected]>
Cc: David Gstir <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Franck LENORMAND <[email protected]>
Cc: Sumit Garg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
drivers/crypto/caam/Kconfig | 3 +-
drivers/crypto/caam/Makefile | 1 +-
drivers/crypto/caam/blob_gen.c | 230 ++++++++++++++++++++++++++++++++++-
include/soc/fsl/caam-blob.h | 56 ++++++++-
4 files changed, 290 insertions(+)
create mode 100644 drivers/crypto/caam/blob_gen.c
create mode 100644 include/soc/fsl/caam-blob.h
diff --git a/drivers/crypto/caam/Kconfig b/drivers/crypto/caam/Kconfig
index 84ea7cba5ee5..ea9f8b1ae981 100644
--- a/drivers/crypto/caam/Kconfig
+++ b/drivers/crypto/caam/Kconfig
@@ -151,6 +151,9 @@ config CRYPTO_DEV_FSL_CAAM_RNG_API
Selecting this will register the SEC4 hardware rng to
the hw_random API for supplying the kernel entropy pool.
+config CRYPTO_DEV_FSL_CAAM_BLOB_GEN
+ bool
+
endif # CRYPTO_DEV_FSL_CAAM_JR
endif # CRYPTO_DEV_FSL_CAAM
diff --git a/drivers/crypto/caam/Makefile b/drivers/crypto/caam/Makefile
index 3570286eb9ce..25f7ae5a4642 100644
--- a/drivers/crypto/caam/Makefile
+++ b/drivers/crypto/caam/Makefile
@@ -21,6 +21,7 @@ caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI) += caamalg_qi.o
caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_AHASH_API) += caamhash.o
caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API) += caamrng.o
caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_PKC_API) += caampkc.o pkc_desc.o
+caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_BLOB_GEN) += blob_gen.o
caam-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI) += qi.o
ifneq ($(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI),)
diff --git a/drivers/crypto/caam/blob_gen.c b/drivers/crypto/caam/blob_gen.c
new file mode 100644
index 000000000000..513d3f90e438
--- /dev/null
+++ b/drivers/crypto/caam/blob_gen.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 Pengutronix, Steffen Trumtrar <[email protected]>
+ * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <[email protected]>
+ */
+
+#include <linux/device.h>
+#include <soc/fsl/caam-blob.h>
+
+#include "compat.h"
+#include "desc_constr.h"
+#include "desc.h"
+#include "error.h"
+#include "intern.h"
+#include "jr.h"
+#include "regs.h"
+
+struct caam_blob_priv {
+ struct device jrdev;
+};
+
+struct caam_blob_job_result {
+ int err;
+ struct completion completion;
+};
+
+static void caam_blob_job_done(struct device *dev, u32 *desc, u32 err, void *context)
+{
+ struct caam_blob_job_result *res = context;
+ int ecode = 0;
+
+ dev_dbg(dev, "%s %d: err 0x%x\n", __func__, __LINE__, err);
+
+ if (err)
+ ecode = caam_jr_strstatus(dev, err);
+
+ res->err = ecode;
+
+ /*
+ * Upon completion, desc points to a buffer containing a CAAM job
+ * descriptor which encapsulates data into an externally-storable
+ * blob.
+ */
+ complete(&res->completion);
+}
+
+static u32 *caam_blob_alloc_desc(size_t keymod_len)
+{
+ size_t len;
+
+ /* header + (key mod immediate) + 2x pointers + op */
+ len = 4 + (4 + ALIGN(keymod_len, 4)) + 2*(4 + 4 + CAAM_PTR_SZ_MAX) + 4;
+
+ if (len > CAAM_DESC_BYTES_MAX)
+ return NULL;
+
+ return kzalloc(len, GFP_KERNEL | GFP_DMA);
+}
+
+int caam_encap_blob(struct caam_blob_priv *priv, const char *keymod,
+ void *input, void *output, size_t length)
+{
+ u32 *desc;
+ struct device *jrdev = &priv->jrdev;
+ dma_addr_t dma_in, dma_out;
+ struct caam_blob_job_result testres;
+ size_t keymod_len = strlen(keymod);
+ int ret;
+
+ if (length <= CAAM_BLOB_OVERHEAD || keymod_len > CAAM_BLOB_KEYMOD_LENGTH)
+ return -EINVAL;
+
+ desc = caam_blob_alloc_desc(keymod_len);
+ if (!desc) {
+ dev_err(jrdev, "unable to allocate desc\n");
+ return -ENOMEM;
+ }
+
+ dma_in = dma_map_single(jrdev, input, length - CAAM_BLOB_OVERHEAD, DMA_TO_DEVICE);
+ if (dma_mapping_error(jrdev, dma_in)) {
+ dev_err(jrdev, "unable to map input DMA buffer\n");
+ ret = -ENOMEM;
+ goto out_free;
+ }
+
+ dma_out = dma_map_single(jrdev, output, length, DMA_FROM_DEVICE);
+ if (dma_mapping_error(jrdev, dma_out)) {
+ dev_err(jrdev, "unable to map output DMA buffer\n");
+ ret = -ENOMEM;
+ goto out_unmap_in;
+ }
+
+ /*
+ * 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
+ * initial counter (Ctr0) are generated automatically and stored in
+ * Class 1 Context DWords 0+1+2+3. The random BK is stored in the
+ * Class 1 Key Register. Operation Mode is set to AES-CCM.
+ */
+
+ init_job_desc(desc, 0);
+ append_key_as_imm(desc, keymod, keymod_len, keymod_len,
+ CLASS_2 | KEY_DEST_CLASS_REG);
+ append_seq_in_ptr_intlen(desc, dma_in, length - CAAM_BLOB_OVERHEAD, 0);
+ append_seq_out_ptr_intlen(desc, dma_out, length, 0);
+ append_operation(desc, OP_TYPE_ENCAP_PROTOCOL | OP_PCLID_BLOB);
+
+ print_hex_dump_debug("data@"__stringify(__LINE__)": ",
+ DUMP_PREFIX_ADDRESS, 16, 1, input,
+ length - CAAM_BLOB_OVERHEAD, false);
+ print_hex_dump_debug("jobdesc@"__stringify(__LINE__)": ",
+ DUMP_PREFIX_ADDRESS, 16, 1, desc,
+ desc_bytes(desc), false);
+
+ testres.err = 0;
+ init_completion(&testres.completion);
+
+ ret = caam_jr_enqueue(jrdev, desc, caam_blob_job_done, &testres);
+ if (ret == -EINPROGRESS) {
+ wait_for_completion(&testres.completion);
+ ret = testres.err;
+ print_hex_dump_debug("output@"__stringify(__LINE__)": ",
+ DUMP_PREFIX_ADDRESS, 16, 1, output,
+ length, false);
+ }
+
+ dma_unmap_single(jrdev, dma_out, length, DMA_FROM_DEVICE);
+out_unmap_in:
+ dma_unmap_single(jrdev, dma_in, length - CAAM_BLOB_OVERHEAD, DMA_TO_DEVICE);
+out_free:
+ kfree(desc);
+
+ return ret;
+}
+EXPORT_SYMBOL(caam_encap_blob);
+
+int caam_decap_blob(struct caam_blob_priv *priv, const char *keymod,
+ void *input, void *output, size_t length)
+{
+ u32 *desc;
+ struct device *jrdev = &priv->jrdev;
+ dma_addr_t dma_in, dma_out;
+ struct caam_blob_job_result testres;
+ size_t keymod_len = strlen(keymod);
+ int ret;
+
+ if (length <= CAAM_BLOB_OVERHEAD || keymod_len > CAAM_BLOB_KEYMOD_LENGTH)
+ return -EINVAL;
+
+ desc = caam_blob_alloc_desc(keymod_len);
+ if (!desc) {
+ dev_err(jrdev, "unable to allocate desc\n");
+ return -ENOMEM;
+ }
+
+ dma_in = dma_map_single(jrdev, input, length, DMA_TO_DEVICE);
+ if (dma_mapping_error(jrdev, dma_in)) {
+ dev_err(jrdev, "unable to map input DMA buffer\n");
+ ret = -ENOMEM;
+ goto out_free;
+ }
+
+ dma_out = dma_map_single(jrdev, output, length - CAAM_BLOB_OVERHEAD, DMA_FROM_DEVICE);
+ if (dma_mapping_error(jrdev, dma_out)) {
+ dev_err(jrdev, "unable to map output DMA buffer\n");
+ ret = -ENOMEM;
+ goto out_unmap_in;
+ }
+
+ /*
+ * 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
+ * initial counter (Ctr0) are generated automatically and stored in
+ * Class 1 Context DWords 0+1+2+3. The random BK is stored in the
+ * Class 1 Key Register. Operation Mode is set to AES-CCM.
+ */
+
+ init_job_desc(desc, 0);
+ append_key_as_imm(desc, keymod, keymod_len, keymod_len,
+ CLASS_2 | KEY_DEST_CLASS_REG);
+ append_seq_in_ptr(desc, dma_in, length, 0);
+ append_seq_out_ptr(desc, dma_out, length - CAAM_BLOB_OVERHEAD, 0);
+ append_operation(desc, OP_TYPE_DECAP_PROTOCOL | OP_PCLID_BLOB);
+
+ print_hex_dump_debug("data@"__stringify(__LINE__)": ",
+ DUMP_PREFIX_ADDRESS, 16, 1, input,
+ length, false);
+ print_hex_dump_debug("jobdesc@"__stringify(__LINE__)": ",
+ DUMP_PREFIX_ADDRESS, 16, 1, desc,
+ desc_bytes(desc), false);
+
+ testres.err = 0;
+ init_completion(&testres.completion);
+
+ ret = caam_jr_enqueue(jrdev, desc, caam_blob_job_done, &testres);
+ if (ret == -EINPROGRESS) {
+ wait_for_completion(&testres.completion);
+ ret = testres.err;
+ print_hex_dump_debug("output@"__stringify(__LINE__)": ",
+ DUMP_PREFIX_ADDRESS, 16, 1, output,
+ length - CAAM_BLOB_OVERHEAD, false);
+ }
+
+ dma_unmap_single(jrdev, dma_out, length - CAAM_BLOB_OVERHEAD, DMA_FROM_DEVICE);
+out_unmap_in:
+ dma_unmap_single(jrdev, dma_in, length, DMA_TO_DEVICE);
+out_free:
+ kfree(desc);
+
+ return ret;
+}
+EXPORT_SYMBOL(caam_decap_blob);
+
+struct caam_blob_priv *caam_blob_gen_init(void)
+{
+ struct device *jrdev;
+
+ jrdev = caam_jr_alloc();
+ if (IS_ERR(jrdev))
+ return ERR_CAST(jrdev);
+
+ return container_of(jrdev, struct caam_blob_priv, jrdev);
+}
+EXPORT_SYMBOL(caam_blob_gen_init);
+
+void caam_blob_gen_exit(struct caam_blob_priv *priv)
+{
+ caam_jr_free(&priv->jrdev);
+}
+EXPORT_SYMBOL(caam_blob_gen_exit);
diff --git a/include/soc/fsl/caam-blob.h b/include/soc/fsl/caam-blob.h
new file mode 100644
index 000000000000..aebbc9335f64
--- /dev/null
+++ b/include/soc/fsl/caam-blob.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Pengutronix, Ahmad Fatoum <[email protected]>
+ */
+
+#ifndef __CAAM_BLOB_GEN
+#define __CAAM_BLOB_GEN
+
+#include <linux/types.h>
+
+#define CAAM_BLOB_KEYMOD_LENGTH 16
+#define CAAM_BLOB_OVERHEAD (32 + 16)
+#define CAAM_BLOB_MAX_LEN 4096
+
+struct caam_blob_priv;
+
+/** caam_blob_gen_init - initialize blob generation
+ *
+ * returns either pointer to new caam_blob_priv instance
+ * or error pointer
+ */
+struct caam_blob_priv *caam_blob_gen_init(void);
+
+/** caam_blob_gen_init - free blob generation resources
+ *
+ * @priv: instance returned by caam_blob_gen_init
+ */
+void caam_blob_gen_exit(struct caam_blob_priv *priv);
+
+/** caam_encap_blob - encapsulate blob
+ *
+ * @priv: instance returned by caam_blob_gen_init
+ * @keymod: string to use as key modifier for blob encapsulation
+ * can't be longer than CAAM_BLOB_KEYMOD_LENGTH
+ * @input: buffer which CAAM will DMA from
+ * @output: buffer which CAAM will DMA to
+ * @length: buffer length including blob overhead
+ * CAAM_BLOB_OVERHEAD < length <= CAAM_BLOB_MAX_LEN
+ */
+int caam_encap_blob(struct caam_blob_priv *priv, const char *keymod,
+ void *input, void *output, size_t length);
+
+/** caam_decap_blob - decapsulate blob
+ *
+ * @priv: instance returned by caam_blob_gen_init
+ * @keymod: string to use as key modifier for blob decapsulation
+ * can't be longer than CAAM_BLOB_KEYMOD_LENGTH
+ * @input: buffer which CAAM will DMA from
+ * @output: buffer which CAAM will DMA to
+ * @length: buffer length including blob overhead
+ * CAAM_BLOB_OVERHEAD < length <= CAAM_BLOB_MAX_LEN
+ */
+int caam_decap_blob(struct caam_blob_priv *priv, const char *keymod,
+ void *input, void *output, size_t length);
+
+#endif
--
git-series 0.9.1
Hi Ahmad,
> On 21.07.2021, at 18:48, Ahmad Fatoum <[email protected]> wrote:
[...]
> diff --git a/drivers/crypto/caam/blob_gen.c b/drivers/crypto/caam/blob_gen.c
> new file mode 100644
> index 000000000000..513d3f90e438
> --- /dev/null
> +++ b/drivers/crypto/caam/blob_gen.c
> @@ -0,0 +1,230 @@
[...]
> +
> +int caam_encap_blob(struct caam_blob_priv *priv, const char *keymod,
> + void *input, void *output, size_t length)
> +{
> + u32 *desc;
> + struct device *jrdev = &priv->jrdev;
> + dma_addr_t dma_in, dma_out;
> + struct caam_blob_job_result testres;
> + size_t keymod_len = strlen(keymod);
> + int ret;
> +
> + if (length <= CAAM_BLOB_OVERHEAD || keymod_len > CAAM_BLOB_KEYMOD_LENGTH)
The docs for this function mention the length <= CAAM_BLOB_MAX_LEN
restriction. This is not checked here. Is this intended?
Since you already assert that MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN
in security/keys/trusted-keys/trusted_caam.c, this will never
be an issue for CAAM-based trusted-keys though.
> + return -EINVAL;
> +
> + desc = caam_blob_alloc_desc(keymod_len);
> + if (!desc) {
> + dev_err(jrdev, "unable to allocate desc\n");
> + return -ENOMEM;
> + }
> +
[...]
> diff --git a/include/soc/fsl/caam-blob.h b/include/soc/fsl/caam-blob.h
> new file mode 100644
> index 000000000000..aebbc9335f64
> --- /dev/null
> +++ b/include/soc/fsl/caam-blob.h
> @@ -0,0 +1,56 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2020 Pengutronix, Ahmad Fatoum <[email protected]>
> + */
> +
> +#ifndef __CAAM_BLOB_GEN
> +#define __CAAM_BLOB_GEN
> +
> +#include <linux/types.h>
> +
> +#define CAAM_BLOB_KEYMOD_LENGTH 16
> +#define CAAM_BLOB_OVERHEAD (32 + 16)
> +#define CAAM_BLOB_MAX_LEN 4096
> +
> +struct caam_blob_priv;
> +
> +/** caam_blob_gen_init - initialize blob generation
> + *
> + * returns either pointer to new caam_blob_priv instance
> + * or error pointer
> + */
> +struct caam_blob_priv *caam_blob_gen_init(void);
> +
> +/** caam_blob_gen_init - free blob generation resources
s/init/exit/
> + *
> + * @priv: instance returned by caam_blob_gen_init
> + */
> +void caam_blob_gen_exit(struct caam_blob_priv *priv);
Except these minor things, I noticed no issues with this whole series:
Reviewed-by: David Gstir <[email protected]>
On 10.08.21 13:29, David Gstir wrote:
> Hi Ahmad,
>
>> On 21.07.2021, at 18:48, Ahmad Fatoum <[email protected]> wrote:
>
>
> [...]
>
>> diff --git a/drivers/crypto/caam/blob_gen.c b/drivers/crypto/caam/blob_gen.c
>> new file mode 100644
>> index 000000000000..513d3f90e438
>> --- /dev/null
>> +++ b/drivers/crypto/caam/blob_gen.c
>> @@ -0,0 +1,230 @@
>
> [...]
>
>> +
>> +int caam_encap_blob(struct caam_blob_priv *priv, const char *keymod,
>> + void *input, void *output, size_t length)
>> +{
>> + u32 *desc;
>> + struct device *jrdev = &priv->jrdev;
>> + dma_addr_t dma_in, dma_out;
>> + struct caam_blob_job_result testres;
>> + size_t keymod_len = strlen(keymod);
>> + int ret;
>> +
>> + if (length <= CAAM_BLOB_OVERHEAD || keymod_len > CAAM_BLOB_KEYMOD_LENGTH)
>
> The docs for this function mention the length <= CAAM_BLOB_MAX_LEN
> restriction. This is not checked here. Is this intended?
Yes.
> Since you already assert that MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN
> in security/keys/trusted-keys/trusted_caam.c, this will never
> be an issue for CAAM-based trusted-keys though.
I omitted checks in code, which are verified at compile-time.
Would you prefer a runtime check to be added as well?
>> + return -EINVAL;
>> +
>> + desc = caam_blob_alloc_desc(keymod_len);
>> + if (!desc) {
>> + dev_err(jrdev, "unable to allocate desc\n");
>> + return -ENOMEM;
>> + }
>> +
>
> [...]
>
>> diff --git a/include/soc/fsl/caam-blob.h b/include/soc/fsl/caam-blob.h
>> new file mode 100644
>> index 000000000000..aebbc9335f64
>> --- /dev/null
>> +++ b/include/soc/fsl/caam-blob.h
>> @@ -0,0 +1,56 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Copyright (C) 2020 Pengutronix, Ahmad Fatoum <[email protected]>
>> + */
>> +
>> +#ifndef __CAAM_BLOB_GEN
>> +#define __CAAM_BLOB_GEN
>> +
>> +#include <linux/types.h>
>> +
>> +#define CAAM_BLOB_KEYMOD_LENGTH 16
>> +#define CAAM_BLOB_OVERHEAD (32 + 16)
>> +#define CAAM_BLOB_MAX_LEN 4096
>> +
>> +struct caam_blob_priv;
>> +
>> +/** caam_blob_gen_init - initialize blob generation
>> + *
>> + * returns either pointer to new caam_blob_priv instance
>> + * or error pointer
>> + */
>> +struct caam_blob_priv *caam_blob_gen_init(void);
>> +
>> +/** caam_blob_gen_init - free blob generation resources
>
> s/init/exit/
Oh, thanks for catching.
>> + *
>> + * @priv: instance returned by caam_blob_gen_init
>> + */
>> +void caam_blob_gen_exit(struct caam_blob_priv *priv);
>
>
> Except these minor things, I noticed no issues with this whole series:
>
> Reviewed-by: David Gstir <[email protected]>
Thanks! Will include it with the next iteration.
Cheers,
Ahmad
>
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
Hi Ahmad,
> On 11.08.2021, at 12:22, Ahmad Fatoum <[email protected]> wrote:
>
>> Since you already assert that MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN
>> in security/keys/trusted-keys/trusted_caam.c, this will never
>> be an issue for CAAM-based trusted-keys though.
> I omitted checks in code, which are verified at compile-time.
> Would you prefer a runtime check to be added as well?
I’d say the compile-time check suffices, unless this is intended
to be used outside of trusted-keys. But I don’t think this is very likely…
Cheers,
David