Binaries may be encrypted in a FIT image with AES. This algo needs a key and an IV (Initialization Vector). The IV is provided in a file (pointer by iv-name-hint in the ITS file) when building the ITB file.

This commits adds provide an alternative way to manage the IV. If the property iv-name-hint is not provided in the ITS file, the tool mkimage will generate an random IV and store it in the FIT image.

Signed-off-by: Philippe Reynes philippe.reynes@softathome.com --- include/image.h | 2 +- include/u-boot/aes.h | 6 +++-- lib/aes/aes-encrypt.c | 22 +++++++++++++++---- tools/image-host.c | 61 +++++++++++++++++++++++++++++++++++++++++---------- 4 files changed, 72 insertions(+), 19 deletions(-)

diff --git a/include/image.h b/include/image.h index 9a5a87d..10995b8 100644 --- a/include/image.h +++ b/include/image.h @@ -1463,7 +1463,7 @@ struct cipher_algo { unsigned char **cipher, int *cipher_len);

int (*add_cipher_data)(struct image_cipher_info *info, - void *keydest); + void *keydest, void *fit, int node_noffset);

int (*decrypt)(struct image_cipher_info *info, const void *cipher, size_t cipher_len, diff --git a/include/u-boot/aes.h b/include/u-boot/aes.h index 3228104..acbc50b 100644 --- a/include/u-boot/aes.h +++ b/include/u-boot/aes.h @@ -13,7 +13,8 @@ int image_aes_encrypt(struct image_cipher_info *info, const unsigned char *data, int size, unsigned char **cipher, int *cipher_len); -int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest); +int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest, + void *fit, int node_noffset); #else int image_aes_encrypt(struct image_cipher_info *info, const unsigned char *data, int size, @@ -22,7 +23,8 @@ int image_aes_encrypt(struct image_cipher_info *info, return -ENXIO; }

-int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest) +int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest, + void *fit, int node_noffset) { return -ENXIO; } diff --git a/lib/aes/aes-encrypt.c b/lib/aes/aes-encrypt.c index de00a83..a6d1720 100644 --- a/lib/aes/aes-encrypt.c +++ b/lib/aes/aes-encrypt.c @@ -74,7 +74,8 @@ int image_aes_encrypt(struct image_cipher_info *info, return ret; }

-int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest) +int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest, + void *fit, int node_noffset) { int parent, node; char name[128]; @@ -97,8 +98,13 @@ int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest) goto done;

/* Either create or overwrite the named key node */ - snprintf(name, sizeof(name), "key-%s-%s-%s", - info->name, info->keyname, info->ivname); + if (info->ivname) + snprintf(name, sizeof(name), "key-%s-%s-%s", + info->name, info->keyname, info->ivname); + else + snprintf(name, sizeof(name), "key-%s-%s", + info->name, info->keyname); + node = fdt_subnode_offset(keydest, parent, name); if (node == -FDT_ERR_NOTFOUND) { node = fdt_add_subnode(keydest, parent, name); @@ -116,9 +122,17 @@ int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest) ret = node; }

- if (!ret) + if (ret) + goto done; + + if (info->ivname) + /* Store the IV in the u-boot device tree */ ret = fdt_setprop(keydest, node, "iv", info->iv, info->cipher->iv_len); + else + /* Store the IV in the FIT image */ + ret = fdt_setprop(fit, node_noffset, "iv", + info->iv, info->cipher->iv_len);

if (!ret) ret = fdt_setprop(keydest, node, "key", diff --git a/tools/image-host.c b/tools/image-host.c index 3d52593..8886bef 100644 --- a/tools/image-host.c +++ b/tools/image-host.c @@ -320,6 +320,36 @@ err: return ret; }

+static int get_random_data(void *data, int size) +{ + unsigned char *tmp = data; + struct timespec date; + int i, ret = 0; + + if (!tmp) { + printf("%s: pointer data is NULL\n", __func__); + ret = -1; + goto out; + } + + ret = clock_gettime(CLOCK_MONOTONIC, &date); + if (ret < 0) { + printf("%s: clock_gettime has failed (err=%d, str=%s)\n", + __func__, ret, strerror(ret)); + goto out; + } + + srand(date.tv_nsec); + + for (i = 0; i < size; i++) { + *tmp = rand() & 0xff; + tmp++; + } + + out: + return ret; +} + static int fit_image_setup_cipher(struct image_cipher_info *info, const char *keydir, void *fit, const char *image_name, int image_noffset, @@ -345,13 +375,13 @@ static int fit_image_setup_cipher(struct image_cipher_info *info, goto out; }

- /* Read the IV name */ + /* + * Read the IV name + * + * If this property is not provided then mkimage will generate + * a random IV and store it in the FIT image + */ info->ivname = fdt_getprop(fit, noffset, "iv-name-hint", NULL); - if (!info->ivname) { - printf("Can't get iv name for cipher in image '%s'\n", - image_name); - goto out; - }

info->fit = fit; info->node_noffset = noffset; @@ -377,17 +407,23 @@ static int fit_image_setup_cipher(struct image_cipher_info *info, if (ret < 0) goto out;

- /* Read the IV in the file */ - snprintf(filename, sizeof(filename), "%s/%s%s", - info->keydir, info->ivname, ".bin"); info->iv = malloc(info->cipher->iv_len); if (!info->iv) { printf("Can't allocate memory for iv\n"); ret = -1; goto out; } - ret = fit_image_read_data(filename, (unsigned char *)info->iv, - info->cipher->iv_len); + + if (info->ivname) { + /* Read the IV in the file */ + snprintf(filename, sizeof(filename), "%s/%s%s", + info->keydir, info->ivname, ".bin"); + ret = fit_image_read_data(filename, (unsigned char *)info->iv, + info->cipher->iv_len); + } else { + /* Generate an ramdom IV */ + ret = get_random_data((void *)info->iv, info->cipher->iv_len); + }

out: return ret; @@ -453,9 +489,10 @@ fit_image_process_cipher(const char *keydir, void *keydest, void *fit, * Write the public key into the supplied FDT file; this might fail * several times, since we try signing with successively increasing * size values + * And, if needed, write the iv in the FIT file */ if (keydest) { - ret = info.cipher->add_cipher_data(&info, keydest); + ret = info.cipher->add_cipher_data(&info, keydest, fit, node_noffset); if (ret) { printf("Failed to add verification data for cipher '%s' in image '%s'\n", info.keyname, image_name);