[U-Boot] [PATCH v1 3/3] lib: rsa: add rsa_verify_with_pkey()

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Wed, Oct 09, 2019 at 07:56:04PM +0200, Heinrich Schuchardt wrote:
> On 10/9/19 7:30 AM, AKASHI Takahiro wrote:
> >This function, and hence rsa_verify(), will perform RSA verification
> >with two essential parameters for a RSA public key in contract of
> >rsa_verify_with_keynode(), which requires additional three parameters
> >stored in FIT image.
> >
> >It will be used in implementing UEFI secure boot, i.e. image authentication
> >and variable authentication.
> >
> >Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> 
> Is this code tested by test/py/tests/test_vboot.py? Or is there another
> unit test?

I haven't run vboot test yet.
For rsa_verify_with_pkey(), as with vtest for FIT signature,
we can test it with my "UEFI secure boot" pytest.

> >---
> >  lib/rsa/Kconfig      |  7 -----
> >  lib/rsa/Makefile     |  1 -
> >  lib/rsa/rsa-verify.c | 63 ++++++++++++++++++++++++++++++++++++++------
> >  3 files changed, 55 insertions(+), 16 deletions(-)
> >
> >diff --git a/lib/rsa/Kconfig b/lib/rsa/Kconfig
> >index d1743d7a4c47..62b7ab9c5e5c 100644
> >--- a/lib/rsa/Kconfig
> >+++ b/lib/rsa/Kconfig
> >@@ -30,13 +30,6 @@ config RSA_VERIFY
> >  	help
> >  	  Add RSA signature verification support.
> >
> >-config RSA_VERIFY_WITH_PKEY
> >-	bool "Execute RSA verification without key parameters from FDT"
> >-	depends on RSA
> >-	help
> >-	  This options enables RSA signature verification without
> >-	  using public key parameters which is embedded control FDT.
> >-
> >  config RSA_SOFTWARE_EXP
> >  	bool "Enable driver for RSA Modular Exponentiation in software"
> >  	depends on DM
> >diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile
> >index 14ed3cb4012b..c07305188e0c 100644
> >--- a/lib/rsa/Makefile
> >+++ b/lib/rsa/Makefile
> >@@ -6,5 +6,4 @@
> >  # Wolfgang Denk, DENX Software Engineering, wd at denx.de.
> >
> >  obj-$(CONFIG_$(SPL_)RSA_VERIFY) += rsa-verify.o rsa-checksum.o
> >-obj-$(CONFIG_RSA_VERIFY_WITH_PKEY) += rsa-keyprop.o
> >  obj-$(CONFIG_RSA_SOFTWARE_EXP) += rsa-mod-exp.o
> >diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
> >index 1df42f28c64a..ce79984b30f9 100644
> >--- a/lib/rsa/rsa-verify.c
> >+++ b/lib/rsa/rsa-verify.c
> >@@ -17,9 +17,14 @@
> >  #include "mkimage.h"
> >  #include <fdt_support.h>
> >  #endif
> >+#include <linux/kconfig.h>
> >  #include <u-boot/rsa-mod-exp.h>
> >  #include <u-boot/rsa.h>
> >
> >+#ifndef __UBOOT__ /* for host tools */
> >+#undef CONFIG_RSA_VERIFY_WITH_PKEY
> 
> Where should it have been defined?

defined in patch#2

> >+#endif
> >+
> >  /* Default public exponent for backward compatibility */
> >  #define RSA_DEFAULT_PUBEXP	65537
> >
> >@@ -344,6 +349,34 @@ static int rsa_verify_key(struct image_sign_info *info,
> >  }
> >  #endif
> >
> >+#ifdef CONFIG_RSA_VERIFY_WITH_PKEY
> 
> Where would CONFIG_RSA_VERIFY_WITH_PKEY be defined? You just a removed
> it from Kconfig.

Because rsa-keyprop.c be compiled only under CONFIG_RSA_VERIFY_WITH_PKEY
per Simon's comment.

> >+/**
> >+ * rsa_verify_with_pkey()
> 
> The short text for the function is missing.
> 
> >+ *
> 
> Please, describe the parameters.

Sure.

-Takahiro Akashi

> >+ */
> >+static int rsa_verify_with_pkey(struct image_sign_info *info,
> >+				const void *hash, uint8_t *sig, uint sig_len)
> >+{
> >+	struct key_prop *prop;
> >+	int ret;
> >+
> >+	/* Public key is self-described to fill key_prop */
> >+	prop = rsa_gen_key_prop(info->key, info->keylen);
> >+	if (!prop) {
> >+		debug("Generating necessary parameter for decoding failed\n");
> >+		return -EACCES;
> >+	}
> >+
> >+	ret = rsa_verify_key(info, prop, sig, sig_len, hash,
> >+			     info->crypto->key_len);
> >+
> >+	rsa_free_key_prop(prop);
> >+
> >+	return ret;
> >+}
> >+#endif
> >+
> >+#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
> >  /**
> >   * rsa_verify_with_keynode() - Verify a signature against some data using
> >   * information in node with prperties of RSA Key like modulus, exponent etc.
> >@@ -397,18 +430,21 @@ static int rsa_verify_with_keynode(struct image_sign_info *info,
> >
> >  	return ret;
> >  }
> >+#endif
> >
> >  int rsa_verify(struct image_sign_info *info,
> >  	       const struct image_region region[], int region_count,
> >  	       uint8_t *sig, uint sig_len)
> >  {
> >-	const void *blob = info->fdt_blob;
> >  	/* Reserve memory for maximum checksum-length */
> >  	uint8_t hash[info->crypto->key_len];
> >+	int ret = -EACCES;
> >+#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
> >+	const void *blob = info->fdt_blob;
> >  	int ndepth, noffset;
> >  	int sig_node, node;
> >  	char name[100];
> >-	int ret;
> >+#endif
> >
> >  	/*
> >  	 * Verify that the checksum-length does not exceed the
> >@@ -421,12 +457,6 @@ int rsa_verify(struct image_sign_info *info,
> >  		return -EINVAL;
> >  	}
> >
> >-	sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
> >-	if (sig_node < 0) {
> >-		debug("%s: No signature node found\n", __func__);
> >-		return -ENOENT;
> >-	}
> >-
> >  	/* Calculate checksum with checksum-algorithm */
> >  	ret = info->checksum->calculate(info->checksum->name,
> >  					region, region_count, hash);
> >@@ -435,6 +465,22 @@ int rsa_verify(struct image_sign_info *info,
> >  		return -EINVAL;
> >  	}
> >
> >+#ifdef CONFIG_RSA_VERIFY_WITH_PKEY
> 
> Where should this have been defined?
> 
> Best regards
> 
> Heinrich
> 
> >+	if (!info->fdt_blob) {
> >+		/* don't rely on fdt properties */
> >+		ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
> >+
> >+		return ret;
> >+	}
> >+#endif
> >+
> >+#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
> >+	sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
> >+	if (sig_node < 0) {
> >+		debug("%s: No signature node found\n", __func__);
> >+		return -ENOENT;
> >+	}
> >+
> >  	/* See if we must use a particular key */
> >  	if (info->required_keynode != -1) {
> >  		ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
> >@@ -461,6 +507,7 @@ int rsa_verify(struct image_sign_info *info,
> >  				break;
> >  		}
> >  	}
> >+#endif
> >
> >  	return ret;
> >  }
> >
>