Hi Ruchika,
On 6 January 2015 at 02:37, Ruchika Gupta ruchika.gupta@freescale.com wrote:
Hi Simon,
-----Original Message----- From: sjg@google.com [mailto:sjg@google.com] On Behalf Of Simon Glass Sent: Saturday, January 03, 2015 3:54 AM To: Gupta Ruchika-R66431 Cc: U-Boot Mailing List; Sun York-R58495 Subject: Re: [PATCH 3/9] [v4] DM: crypto/rsa: Add rsa Modular
Exponentiation
DM driver
Hi Ruchika,
On 30 December 2014 at 02:30, Ruchika Gupta <ruchika.gupta@freescale.com
wrote:
Add a new rsa uclass for performing modular exponentiation and implement the software driver basing on this uclass.
Signed-off-by: Ruchika Gupta ruchika.gupta@freescale.com CC: Simon Glass sjg@chromium.org
Changes in v4: Removed Kconfig option for DM_RSA Corrected driver name for sw rsa driver Updated the rsa_mod_exp operation to have output length
Changes in v3: New patch with driver model for RSA UCLASS
drivers/crypto/Makefile | 1 + drivers/crypto/rsa/Makefile | 7 +++++++ drivers/crypto/rsa/rsa_sw.c | 39
+++++++++++++++++++++++++++++++++++++++
drivers/crypto/rsa/rsa_uclass.c | 31 +++++++++++++++++++++++++++++++ include/dm/uclass-id.h | 1 + include/u-boot/rsa-mod-exp.h | 37
+++++++++++++++++++++++++++++++++++++
6 files changed, 116 insertions(+) create mode 100644 drivers/crypto/rsa/Makefile create mode 100644 drivers/crypto/rsa/rsa_sw.c create mode 100644 drivers/crypto/rsa/rsa_uclass.c
Again I'm a bit worried we are going off into the weeds.
Is this an RSA driver or a modular exponentiation driver? It seems like
the
latter to me. If so, the uclass should be UCLASS_MOD_EXP, not
UCLASS_RSA, and
the files and directories should be renames also. Some hardware will implement the entire RSA algorithm, which would be a true RSA uclass.
Here I
think you are only doing part of it.
I did this to introduce a generic class for RSA which has mod_exp implementation for now and can be extended to have sign or any other algo added later.For now I will change it to UCLASS_MOD_EXP as you have suggested.
From what I understand the RSA API consists of two functions:
rsa_sign() rsa_verify()
These are defined in rsa.h.
So if you are planning to implement an RSA uclass it should support these two. In your case it seems like you are implementing a part of RSA, i.e. lower-level functionality. That's why I'm saying it doesn't look like an RSA uclass to me.
Other than that rename the code looks fine.
Minor point: again I don't see the value of returning the same value as sig_len, so you may as well drop those last two args to mod_exp() -
unless I
am missing something.
I will do that and revert back to earlier implementation with uint8_t *out.
diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile index 7b79237..a2f30fc 100644 --- a/drivers/crypto/Makefile +++ b/drivers/crypto/Makefile @@ -6,4 +6,5 @@ #
obj-$(CONFIG_EXYNOS_ACE_SHA) += ace_sha.o +obj-y += rsa/ obj-y += fsl/ diff --git a/drivers/crypto/rsa/Makefile b/drivers/crypto/rsa/Makefile new file mode 100644 index 0000000..927c5bd --- /dev/null +++ b/drivers/crypto/rsa/Makefile @@ -0,0 +1,7 @@ +# +# (C) Copyright 2014 Freescale Semiconductor, Inc. +# +# SPDX-License-Identifier: GPL-2.0+ +#
+obj-$(CONFIG_RSA) += rsa_uclass.o rsa_sw.o diff --git a/drivers/crypto/rsa/rsa_sw.c b/drivers/crypto/rsa/rsa_sw.c new file mode 100644 index 0000000..3dcd512 --- /dev/null +++ b/drivers/crypto/rsa/rsa_sw.c @@ -0,0 +1,39 @@ +/*
- (C) Copyright 2014 Freescale Semiconductor, Inc.
- Author: Ruchika Gupta ruchika.gupta@freescale.com
- SPDX-License-Identifier: GPL-2.0+
- */
+#include <config.h> +#include <common.h> +#include <dm.h> +#include <u-boot/rsa-mod-exp.h>
+int mod_exp_sw(struct udevice *dev, const uint8_t *sig, uint32_t
sig_len,
struct key_prop *prop, uint8_t **outp, uint32_t+*out_len) {
int ret = 0;ret = rsa_mod_exp_sw(sig, sig_len, prop, outp, out_len);if (ret) {debug("%s: RSA failed to verify: %d\n", __func__, ret);return ret;}return 0;+}
+static const struct rsa_ops rsa_ops_sw = {
.mod_exp = mod_exp_sw,+};
+U_BOOT_DRIVER(rsa_sw) = {
.name = "rsa_sw",.id = UCLASS_RSA,.ops = &rsa_ops_sw,+};
+U_BOOT_DEVICE(rsa_sw) = {
.name = "rsa_sw",+}; diff --git a/drivers/crypto/rsa/rsa_uclass.c b/drivers/crypto/rsa/rsa_uclass.c new file mode 100644 index 0000000..4d52dcc --- /dev/null +++ b/drivers/crypto/rsa/rsa_uclass.c @@ -0,0 +1,31 @@ +/*
- (C) Copyright 2014 Freescale Semiconductor, Inc
- Author: Ruchika Gupta ruchika.gupta@freescale.com
- SPDX-License-Identifier: GPL-2.0+
- */
+#include <common.h> +#include <dm.h> +#include <u-boot/rsa-mod-exp.h> +#include <errno.h> +#include <fdtdec.h> +#include <malloc.h> +#include <asm/io.h> +#include <linux/list.h>
+int rsa_mod_exp(struct udevice *dev, const uint8_t *sig, uint32_t
sig_len,
struct key_prop *node, uint8_t **out, uint32_t+*out_len) {
const struct rsa_ops *ops = device_get_ops(dev);if (!ops->mod_exp)return -ENOSYS;return ops->mod_exp(dev, sig, sig_len, node, out, out_len); }+UCLASS_DRIVER(rsa) = {
.id = UCLASS_RSA,.name = "rsa",+}; diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h index f17c3c2..823e43c 100644 --- a/include/dm/uclass-id.h +++ b/include/dm/uclass-id.h @@ -33,6 +33,7 @@ enum uclass_id { UCLASS_I2C, /* I2C bus */ UCLASS_I2C_GENERIC, /* Generic I2C device */ UCLASS_I2C_EEPROM, /* I2C EEPROM device */
UCLASS_RSA, /* RSA Mod Exp device */ UCLASS_COUNT, UCLASS_INVALID = -1,diff --git a/include/u-boot/rsa-mod-exp.h b/include/u-boot/rsa-mod-exp.h index 7b74f3c..417e468 100644 --- a/include/u-boot/rsa-mod-exp.h +++ b/include/u-boot/rsa-mod-exp.h @@ -46,4 +46,41 @@ struct key_prop { int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len, struct key_prop *node, uint8_t **outp, uint32_t *out_len);
+int rsa_mod_exp(struct udevice *dev, const uint8_t *sig, uint32_t
sig_len,
struct key_prop *node, uint8_t **outp, uint32_t+*out_len);
+/**
- struct struct rsa_ops - Driver model for RSA operations
- The uclass interface is implemented by all crypto devices which
+use
- driver model.
- */
+struct rsa_ops {
/*** Perform Modular Exponentiation** Operation: out[] = sig ^ exponent % modulus** @dev: RSA Device* @sig: RSA PKCS1.5 signature* @sig_len: Length of signature in number of bytes* @node: Node with RSA key elements like modulus,exponent,
* R^2, n0inv* @outp: Set to an allocated buffer holding the outputhash
* @out_len: Set to length of hash(outp) calculated after* exponentiation.** This computes exponentiation over the signature. Resulting* hash value is placed in an allocated buffer, the pointer is* returned as *outp. The length of calulated hash is returnedvia
* the out_len pointer argument. The caller should free *outp** Returns: 0 if exponentiation is successful, or a negativevalue
* if it wasn't.*/int (*mod_exp)(struct udevice *dev, const uint8_t *sig,uint32_t sig_len, struct key_prop *node,uint8_t **outp, uint32_t *len); };#endif
1.8.1.4
Regards, Ruchika
Regards, Simon