[U-Boot] [PATCH v3 8/8] tools, fit_check_sign: verify a signed fit image

Heiko Schocher
2014-03-03T11:19:30Z

add host tool "fit_check_sign" which verifies, if a fit image is
signed correct.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>

---
- changes for v2:
- fixed compile error for sandbox
- add fit_check_sign test to test/vboot/vboot_test.sh

- changes for v3:
- add comment from Marek Vasut:
- do not use unlink
- add comment from Simon Glass:
- get_blob not weak, rename it to image_get_host_blob()
- use getopt
- as we not write the file, get rid of some unneccessary checks
- move fdtdec_get_int() from lib/libfdt/fdt_wip.c to
lib/fdtdec.c for HOSTCC compiles
- rebased against current head eeb72e67619b98d2502fe634a3a5d9953de92ad0
-> Makefile adaptions necessary introduced from kbuild changes
---
common/image-sig.c | 18 +++++-----
doc/uImage.FIT/signature.txt | 6 ++++
include/fdt_support.h | 5 +++
include/image.h | 17 +++++----
lib/fdtdec.c | 20 +++++++++++
lib/rsa/rsa-checksum.c | 10 ++++--
lib/rsa/rsa-sign.c | 2 +-
lib/rsa/rsa-verify.c | 18 +++++++---
test/vboot/vboot_test.sh | 20 +++++++++++
tools/.gitignore | 1 +
tools/Makefile | 7 ++--
tools/fdt_host.h | 2 ++
tools/fdtdec.c | 1 +
tools/fit_check_sign.c | 85 ++++++++++++++++++++++++++++++++++++++++++++
tools/image-host.c | 15 ++++++++
tools/rsa-checksum.c | 1 +
tools/rsa-verify.c | 1 +
17 files changed, 204 insertions(+), 25 deletions(-)
create mode 100644 tools/fdtdec.c
create mode 100644 tools/fit_check_sign.c
create mode 100644 tools/rsa-checksum.c
create mode 100644 tools/rsa-verify.c

diff --git a/common/image-sig.c b/common/image-sig.c
index 763960a..72284eb 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -19,9 +19,14 @@ DECLARE_GLOBAL_DATA_PTR;
#define IMAGE_MAX_HASHED_NODES 100

#ifdef USE_HOSTCC
-__attribute__((weak)) void *get_blob(void)
+void *host_blob;
+void image_set_host_blob(void *blob)
{
- return NULL;
+ host_blob = blob;
+}
+void *image_get_host_blob(void)
+{
+ return host_blob;
}
#endif

@@ -32,10 +37,9 @@ struct checksum_algo checksum_algos[] = {
RSA2048_BYTES,
#if IMAGE_ENABLE_SIGN
EVP_sha1,
-#else
+#endif
sha1_calculate,
padding_sha1_rsa2048,
-#endif
},
{
"sha256",
@@ -43,10 +47,9 @@ struct checksum_algo checksum_algos[] = {
RSA2048_BYTES,
#if IMAGE_ENABLE_SIGN
EVP_sha256,
-#else
+#endif
sha256_calculate,
padding_sha256_rsa2048,
-#endif
},
{
"sha256",
@@ -54,10 +57,9 @@ struct checksum_algo checksum_algos[] = {
RSA4096_BYTES,
#if IMAGE_ENABLE_SIGN
EVP_sha256,
-#else
+#endif
sha256_calculate,
padding_sha256_rsa4096,
-#endif
}

};
diff --git a/doc/uImage.FIT/signature.txt b/doc/uImage.FIT/signature.txt
index 71f8b6c..9502037 100644
--- a/doc/uImage.FIT/signature.txt
+++ b/doc/uImage.FIT/signature.txt
@@ -357,6 +357,9 @@ Build FIT with signed configuration
Test Verified Boot Run: unsigned config: OK
Sign images
Test Verified Boot Run: signed config: OK
+check signed config on the host
+OK
+Test Verified Boot Run: signed config: OK
Test Verified Boot Run: signed config with bad hash: OK
do sha256 test
Build FIT with signed images
@@ -367,6 +370,9 @@ Build FIT with signed configuration
Test Verified Boot Run: unsigned config: OK
Sign images
Test Verified Boot Run: signed config: OK
+check signed config on the host
+OK
+Test Verified Boot Run: signed config: OK
Test Verified Boot Run: signed config with bad hash: OK

Test passed
diff --git a/include/fdt_support.h b/include/fdt_support.h
index 9871e2f..76c9b2e 100644
--- a/include/fdt_support.h
+++ b/include/fdt_support.h
@@ -115,4 +115,9 @@ static inline int fdt_status_disabled_by_alias(void *fdt, const char* alias)
}

#endif /* ifdef CONFIG_OF_LIBFDT */
+
+#ifdef USE_HOSTCC
+int fdtdec_get_int(const void *blob, int node, const char *prop_name,
+ int default_val);
+#endif
#endif /* ifndef __FDT_SUPPORT_H */
diff --git a/include/image.h b/include/image.h
index 540afaa..2508d7d 100644
--- a/include/image.h
+++ b/include/image.h
@@ -832,7 +832,7 @@ int calculate_hash(const void *data, int data_len, const char *algo,
#if defined(CONFIG_FIT_SIGNATURE)
# ifdef USE_HOSTCC
# define IMAGE_ENABLE_SIGN 1
-# define IMAGE_ENABLE_VERIFY 0
+# define IMAGE_ENABLE_VERIFY 1
# include <openssl/evp.h>
#else
# define IMAGE_ENABLE_SIGN 0
@@ -844,7 +844,9 @@ int calculate_hash(const void *data, int data_len, const char *algo,
#endif

#ifdef USE_HOSTCC
-# define gd_fdt_blob() NULL
+void *image_get_host_blob(void);
+void image_set_host_blob(void *host_blob);
+# define gd_fdt_blob() image_get_host_blob()
#else
# define gd_fdt_blob() (gd->fdt_blob)
#endif
@@ -881,14 +883,11 @@ struct checksum_algo {
const int checksum_len;
const int pad_len;
#if IMAGE_ENABLE_SIGN
- const EVP_MD *(*calculate)(void);
-#else
-#if IMAGE_ENABLE_VERIFY
+ const EVP_MD *(*calculate_sign)(void);
+#endif
void (*calculate)(const struct image_region region[],
int region_count, uint8_t *checksum);
const uint8_t *rsa_padding;
-#endif
-#endif
};

struct image_sig_algo {
@@ -1009,7 +1008,11 @@ struct image_region *fit_region_make_list(const void *fit,

static inline int fit_image_check_target_arch(const void *fdt, int node)
{
+#ifndef USE_HOSTCC
return fit_image_check_arch(fdt, node, IH_ARCH_DEFAULT);
+#else
+ return 0;
+#endif
}

#ifdef CONFIG_FIT_VERBOSE
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 1fecab3..42b74bc 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -3,6 +3,7 @@
* SPDX-License-Identifier: GPL-2.0+
*/

+#ifndef USE_HOSTCC
#include <common.h>
#include <serial.h>
#include <libfdt.h>
@@ -617,3 +618,22 @@ int fdtdec_decode_region(const void *blob, int node,
debug("%s: size=%zx\n", __func__, *size);
return 0;
}
+#else
+#include "libfdt.h"
+#include "fdt_support.h"
+
+int fdtdec_get_int(const void *blob, int node, const char *prop_name,
+ int default_val)
+{
+ const int *cell;
+ int len;
+
+ cell = fdt_getprop_w((void *)blob, node, prop_name, &len);
+ if (cell && len >= sizeof(int)) {
+ int val = fdt32_to_cpu(cell[0]);
+
+ return val;
+ }
+ return default_val;
+}
+#endif
diff --git a/lib/rsa/rsa-checksum.c b/lib/rsa/rsa-checksum.c
index a9d096d..32d6602 100644
--- a/lib/rsa/rsa-checksum.c
+++ b/lib/rsa/rsa-checksum.c
@@ -4,14 +4,18 @@
* SPDX-License-Identifier: GPL-2.0+
*/

+#ifndef USE_HOSTCC
#include <common.h>
#include <fdtdec.h>
-#include <rsa.h>
-#include <sha1.h>
-#include <sha256.h>
#include <asm/byteorder.h>
#include <asm/errno.h>
#include <asm/unaligned.h>
+#else
+#include "fdt_host.h"
+#endif
+#include <rsa.h>
+#include <sha1.h>
+#include <sha256.h>

/* PKCS 1.5 paddings as described in the RSA PKCS#1 v2.1 standard. */

diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 0fe6e9f..ca8c120 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -193,7 +193,7 @@ static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
goto err_create;
}
EVP_MD_CTX_init(context);
- if (!EVP_SignInit(context, checksum_algo->calculate())) {
+ if (!EVP_SignInit(context, checksum_algo->calculate_sign())) {
ret = rsa_err("Signer setup failed");
goto err_sign;
}
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 09268ca..587da5b 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -4,17 +4,28 @@
* SPDX-License-Identifier: GPL-2.0+
*/

+#ifndef USE_HOSTCC
#include <common.h>
#include <fdtdec.h>
-#include <rsa.h>
-#include <sha1.h>
-#include <sha256.h>
+#include <asm/types.h>
#include <asm/byteorder.h>
#include <asm/errno.h>
+#include <asm/types.h>
#include <asm/unaligned.h>
+#else
+#include "fdt_host.h"
+#include "mkimage.h"
+#include <fdt_support.h>
+#endif
+#include <rsa.h>
+#include <sha1.h>
+#include <sha256.h>

#define UINT64_MULT32(v, multby) (((uint64_t)(v)) * ((uint32_t)(multby)))

+#define get_unaligned_be32(a) fdt32_to_cpu(*(uint32_t *)a)
+#define put_unaligned_be32(a, b) (*(uint32_t *)(b) = cpu_to_fdt32(a))
+
/**
* subtract_modulus() - subtract modulus from the given value
*
@@ -150,7 +161,6 @@ static int pow_mod(const struct rsa_public_key *key, uint32_t *inout)
/* Convert to bigendian byte array */
for (i = key->len - 1, ptr = inout; (int)i >= 0; i--, ptr++)
put_unaligned_be32(result[i], ptr);
-
return 0;
}

diff --git a/test/vboot/vboot_test.sh b/test/vboot/vboot_test.sh
index 3e2856e..3c6efa7 100755
--- a/test/vboot/vboot_test.sh
+++ b/test/vboot/vboot_test.sh
@@ -47,6 +47,7 @@ O=$(readlink -f ${O})
dtc="-I dts -O dtb -p 2000"
uboot="${O}/u-boot"
mkimage="${O}/tools/mkimage"
+fit_check_sign="${O}/tools/fit_check_sign"
keys="${dir}/dev-keys"
echo ${mkimage} -D "${dtc}"

@@ -99,6 +100,25 @@ function do_test {

run_uboot "signed config" "dev+"

+ echo check signed config on the host
+ if ! ${fit_check_sign} -f test.fit -k sandbox-u-boot.dtb >${tmp}; then
+ echo
+ echo "Verified boot key check on host failed, output follows:"
+ cat ${tmp}
+ false
+ else
+ if ! grep -q "dev+" ${tmp}; then
+ echo
+ echo "Verified boot key check failed, output follows:"
+ cat ${tmp}
+ false
+ else
+ echo "OK"
+ fi
+ fi
+
+ run_uboot "signed config" "dev+"
+
# Increment the first byte of the signature, which should cause failure
sig=$(fdtget -t bx test.fit /configurations/conf at 1/signature at 1 value)
newbyte=$(printf %x $((0x${sig:0:2} + 1)))
diff --git a/tools/.gitignore b/tools/.gitignore
index 2f6ecc7..b1e997f 100644
--- a/tools/.gitignore
+++ b/tools/.gitignore
@@ -1,5 +1,6 @@
/bmp_logo
/envcrc
+/fit_check_sign
/fit_info
/gen_eth_addr
/img2srec
diff --git a/tools/Makefile b/tools/Makefile
index c54d738..8d25ecc 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -61,13 +61,13 @@ mkenvimage$(SFX)-objs := crc32.o mkenvimage.o os_support.o

hostprogs-y += dumpimage$(SFX) mkimage$(SFX)
ifdef CONFIG_FIT_SIGNATURE
-hostprogs-y += fit_info$(SFX)
+hostprogs-y += fit_info$(SFX) fit_check_sign$(SFX)
endif

FIT_SIG_OBJS-$(CONFIG_FIT_SIGNATURE) := image-sig.o
# Flattened device tree objects
LIBFDT_OBJS := fdt.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_wip.o
-RSA_OBJS-$(CONFIG_FIT_SIGNATURE) := rsa-sign.o
+RSA_OBJS-$(CONFIG_FIT_SIGNATURE) := rsa-sign.o rsa-verify.o rsa-checksum.o

# common objs for dumpimage and mkimage
dumpimage-mkimage-objs := aisimage.o \
@@ -97,6 +97,7 @@ dumpimage-mkimage-objs := aisimage.o \
dumpimage$(SFX)-objs := $(dumpimage-mkimage-objs) dumpimage.o
mkimage$(SFX)-objs := $(dumpimage-mkimage-objs) mkimage.o
fit_info$(SFX)-objs := $(dumpimage-mkimage-objs) fit_info.o
+fit_check_sign$(SFX)-objs := $(dumpimage-mkimage-objs) fit_check_sign.o

# TODO(sjg at chromium.org): Is this correct on Mac OS?

@@ -105,6 +106,7 @@ ifneq ($(CONFIG_MX23)$(CONFIG_MX28),)
HOSTLOADLIBES_dumpimage$(SFX) := -lssl -lcrypto
HOSTLOADLIBES_mkimage$(SFX) := -lssl -lcrypto
HOSTLOADLIBES_fit_info$(SFX) := -lssl -lcrypto
+HOSTLOADLIBES_fit_check_sign$(SFX) := -lssl -lcrypto
# Add CONFIG_MXS into host CFLAGS, so we can check whether or not register
# the mxsimage support within tools/mxsimage.c .
HOSTCFLAGS_mxsimage.o += -DCONFIG_MXS
@@ -114,6 +116,7 @@ ifdef CONFIG_FIT_SIGNATURE
HOSTLOADLIBES_dumpimage$(SFX) := -lssl -lcrypto
HOSTLOADLIBES_mkimage$(SFX) := -lssl -lcrypto
HOSTLOADLIBES_fit_info$(SFX) := -lssl -lcrypto
+HOSTLOADLIBES_fit_check_sign$(SFX) := -lssl -lcrypto

# This affects include/image.h, but including the board config file
# is tricky, so manually define this options here.
diff --git a/tools/fdt_host.h b/tools/fdt_host.h
index c2b23c6..134d965 100644
--- a/tools/fdt_host.h
+++ b/tools/fdt_host.h
@@ -11,4 +11,6 @@
#include "../include/libfdt.h"
#include "../include/fdt_support.h"

+int fit_check_sign(const void *working_fdt, const void *key);
+
#endif /* __FDT_HOST_H__ */
diff --git a/tools/fdtdec.c b/tools/fdtdec.c
new file mode 100644
index 0000000..f1c2256
--- /dev/null
+++ b/tools/fdtdec.c
@@ -0,0 +1 @@
+#include "../lib/fdtdec.c"
diff --git a/tools/fit_check_sign.c b/tools/fit_check_sign.c
new file mode 100644
index 0000000..d6d9340
--- /dev/null
+++ b/tools/fit_check_sign.c
@@ -0,0 +1,85 @@
+/*
+ * (C) Copyright 2014
+ * DENX Software Engineering
+ * Heiko Schocher <hs@denx.de>
+ *
+ * Based on:
+ * (C) Copyright 2008 Semihalf
+ *
+ * (C) Copyright 2000-2004
+ * DENX Software Engineering
+ * Wolfgang Denk, wd at denx.de
+ *
+ * Updated-by: Prafulla Wadaskar <prafulla@marvell.com>
+ * FIT image specific code abstracted from mkimage.c
+ * some functions added to address abstraction
+ *
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include "mkimage.h"
+#include "fit_common.h"
+#include <image.h>
+#include <u-boot/crc.h>
+
+void usage(char *cmdname)
+{
+ fprintf(stderr, "Usage: %s -f fit file -k key file\n"
+ " -f ==> set fit file which should be checked'\n"
+ " -k ==> set key file which contains the key'\n",
+ cmdname);
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+ int ffd = -1;
+ int kfd = -1;
+ struct stat fsbuf;
+ struct stat ksbuf;
+ void *fit_blob;
+ char *fdtfile = NULL;
+ char *keyfile = NULL;
+ char cmdname[50];
+ int ret;
+ void *key_blob;
+ int c;
+
+ strcpy(cmdname, *argv);
+ while ((c = getopt(argc, argv, "f:k:")) != -1)
+ switch (c) {
+ case 'f':
+ fdtfile = optarg;
+ break;
+ case 'k':
+ keyfile = optarg;
+ break;
+ default:
+ usage(cmdname);
+ break;
+ }
+
+ ffd = mmap_fdt(cmdname, fdtfile, &fit_blob, &fsbuf, 0);
+ if (ffd < 0)
+ return EXIT_FAILURE;
+ kfd = mmap_fdt(cmdname, keyfile, &key_blob, &ksbuf, 0);
+ if (ffd < 0)
+ return EXIT_FAILURE;
+
+ image_set_host_blob(key_blob);
+ ret = fit_check_sign(fit_blob, key_blob);
+
+ if (ret)
+ ret = EXIT_SUCCESS;
+ else
+ ret = EXIT_FAILURE;
+
+ (void) munmap((void *)fit_blob, fsbuf.st_size);
+ (void) munmap((void *)key_blob, ksbuf.st_size);
+
+ close(ffd);
+ close(kfd);
+ exit(ret);
+}
diff --git a/tools/image-host.c b/tools/image-host.c
index 8e185ec..651f1c2 100644
--- a/tools/image-host.c
+++ b/tools/image-host.c
@@ -695,3 +695,18 @@ int fit_add_verification_data(const char *keydir, void *keydest, void *fit,

return 0;
}
+
+#ifdef CONFIG_FIT_SIGNATURE
+int fit_check_sign(const void *working_fdt, const void *key)
+{
+ int cfg_noffset;
+ int ret;
+
+ cfg_noffset = fit_conf_get_node(working_fdt, NULL);
+ if (!cfg_noffset)
+ return -1;
+
+ ret = fit_config_verify(working_fdt, cfg_noffset);
+ return ret;
+}
+#endif
diff --git a/tools/rsa-checksum.c b/tools/rsa-checksum.c
new file mode 100644
index 0000000..09033e6
--- /dev/null
+++ b/tools/rsa-checksum.c
@@ -0,0 +1 @@
+#include "../lib/rsa/rsa-checksum.c"
diff --git a/tools/rsa-verify.c b/tools/rsa-verify.c
new file mode 100644
index 0000000..bb662a1
--- /dev/null
+++ b/tools/rsa-verify.c
@@ -0,0 +1 @@
+#include "../lib/rsa/rsa-verify.c"
--
1.8.3.1