FIT cipher support currently allocates the output buffer inside the AES helper. SPL often needs to decrypt directly into a caller-selected buffer, for example a load buffer or a scratch buffer used before decompression.
Add a decrypt_to callback to the FIT cipher algorithm and wire it up for AES. The existing allocating decrypt path becomes a wrapper around the new helper. When DM_AES is enabled, try the first UCLASS_AES provider before using the software AES fallback in U-Boot proper. Return AES device errors to the caller instead of hiding them with a software fallback after the device has accepted the operation. Signed-off-by: James Hilliard <[email protected]> --- boot/image-cipher.c | 38 +++++++++++++++-- boot/image-fit.c | 7 +++- include/image.h | 39 +++++++++++++++-- include/u-boot/aes.h | 10 +++++ lib/Makefile | 2 +- lib/aes/aes-decrypt.c | 98 ++++++++++++++++++++++++++++++++++++------- 6 files changed, 170 insertions(+), 24 deletions(-) diff --git a/boot/image-cipher.c b/boot/image-cipher.c index 9d389f26cea..93b3dd3c637 100644 --- a/boot/image-cipher.c +++ b/boot/image-cipher.c @@ -25,6 +25,7 @@ struct cipher_algo cipher_algos[] = { #endif .encrypt = image_aes_encrypt, .decrypt = image_aes_decrypt, + .decrypt_to = image_aes_decrypt_to, .add_cipher_data = image_aes_add_cipher_data }, { @@ -36,6 +37,7 @@ struct cipher_algo cipher_algos[] = { #endif .encrypt = image_aes_encrypt, .decrypt = image_aes_decrypt, + .decrypt_to = image_aes_decrypt_to, .add_cipher_data = image_aes_add_cipher_data }, { @@ -47,6 +49,7 @@ struct cipher_algo cipher_algos[] = { #endif .encrypt = image_aes_encrypt, .decrypt = image_aes_decrypt, + .decrypt_to = image_aes_decrypt_to, .add_cipher_data = image_aes_add_cipher_data } }; @@ -70,6 +73,7 @@ static int fit_image_setup_decrypt(struct image_cipher_info *info, int cipher_noffset) { const void *fdt = gd_fdt_blob(); + int key_len, iv_len; const char *node_name; char node_path[128]; int noffset; @@ -94,7 +98,7 @@ static int fit_image_setup_decrypt(struct image_cipher_info *info, return -1; } - info->iv = fdt_getprop(fit, cipher_noffset, "iv", NULL); + info->iv = fdt_getprop(fit, cipher_noffset, "iv", &iv_len); info->ivname = fdt_getprop(fit, cipher_noffset, "iv-name-hint", NULL); if (!info->iv && !info->ivname) { @@ -136,20 +140,28 @@ static int fit_image_setup_decrypt(struct image_cipher_info *info, } /* read key */ - info->key = fdt_getprop(fdt, noffset, "key", NULL); + info->key = fdt_getprop(fdt, noffset, "key", &key_len); if (!info->key) { printf("Can't get key in cipher node '%s'\n", node_path); return -1; } + if (key_len != info->cipher->key_len) { + printf("Bad key length in cipher node '%s'\n", node_path); + return -1; + } /* read iv */ if (!info->iv) { - info->iv = fdt_getprop(fdt, noffset, "iv", NULL); + info->iv = fdt_getprop(fdt, noffset, "iv", &iv_len); if (!info->iv) { printf("Can't get IV in cipher node '%s'\n", node_path); return -1; } } + if (iv_len != info->cipher->iv_len) { + printf("Bad IV length for cipher in image '%s'\n", node_name); + return -1; + } return 0; } @@ -173,3 +185,23 @@ int fit_image_decrypt_data(const void *fit, out: return ret; } + +int fit_image_decrypt_data_to(const void *fit, + int image_noffset, int cipher_noffset, + const void *data_ciphered, size_t size_ciphered, + void *data_unciphered, size_t *size_unciphered) +{ + struct image_cipher_info info; + int ret; + + ret = fit_image_setup_decrypt(&info, fit, image_noffset, + cipher_noffset); + if (ret < 0) + return ret; + + if (!info.cipher->decrypt_to) + return -ENOSYS; + + return info.cipher->decrypt_to(&info, data_ciphered, size_ciphered, + data_unciphered, size_unciphered); +} diff --git a/boot/image-fit.c b/boot/image-fit.c index 044a40e1910..dac8b35f338 100644 --- a/boot/image-fit.c +++ b/boot/image-fit.c @@ -1030,7 +1030,7 @@ int fit_image_get_data_size(const void *fit, int noffset, int *data_size) * * @fit: pointer to the FIT image header * @noffset: component image node offset - * @data_size: holds the data-size property + * @data_size: holds the data-size-unciphered property * * returns: * 0, on success @@ -1040,10 +1040,13 @@ int fit_image_get_data_size_unciphered(const void *fit, int noffset, size_t *data_size) { const fdt32_t *val; + int len; - val = fdt_getprop(fit, noffset, "data-size-unciphered", NULL); + val = fdt_getprop(fit, noffset, "data-size-unciphered", &len); if (!val) return -ENOENT; + if (len != sizeof(*val)) + return -EINVAL; *data_size = (size_t)fdt32_to_cpu(*val); diff --git a/include/image.h b/include/image.h index 9c8a746d576..5edbf8fdc33 100644 --- a/include/image.h +++ b/include/image.h @@ -1862,11 +1862,40 @@ int fit_image_check_sig(const void *fit, int noffset, const void *data, size_t size, const void *key_blob, int required_keynode, char **err_msgp); -int fit_image_decrypt_data(const void *fit, - int image_noffset, int cipher_noffset, - const void *data, size_t size, +/** + * fit_image_decrypt_data() - Decrypt a FIT image payload + * + * @fit: FIT image + * @image_noffset: Offset of the image node to decrypt + * @cipher_noffset: Offset of the cipher node for the image + * @data: Encrypted image payload + * @size: Size of encrypted image payload + * @data_unciphered: Returns allocated decrypted payload + * @size_unciphered: Returns size of decrypted payload + * Return: 0 on success, <0 on error + */ +int fit_image_decrypt_data(const void *fit, int image_noffset, + int cipher_noffset, const void *data, size_t size, void **data_unciphered, size_t *size_unciphered); +/** + * fit_image_decrypt_data_to() - Decrypt a FIT image payload to a buffer + * + * @fit: FIT image + * @image_noffset: Offset of the image node to decrypt + * @cipher_noffset: Offset of the cipher node for the image + * @data: Encrypted image payload + * @size: Size of encrypted image payload + * @data_unciphered: Destination buffer for decrypted payload. The caller + * must provide at least @size bytes. + * @size_unciphered: Returns size of decrypted payload + * Return: 0 on success, <0 on error + */ +int fit_image_decrypt_data_to(const void *fit, + int image_noffset, int cipher_noffset, + const void *data, size_t size, + void *data_unciphered, size_t *size_unciphered); + /** * fit_region_make_list() - Make a list of regions to hash * @@ -1960,6 +1989,10 @@ struct cipher_algo { int (*decrypt)(struct image_cipher_info *info, const void *cipher, size_t cipher_len, void **data, size_t *data_len); + + int (*decrypt_to)(struct image_cipher_info *info, + const void *cipher, size_t cipher_len, + void *data, size_t *data_len); }; int fit_image_cipher_get_algo(const void *fit, int noffset, char **algo); diff --git a/include/u-boot/aes.h b/include/u-boot/aes.h index acbc50b9e6f..6d81af3780d 100644 --- a/include/u-boot/aes.h +++ b/include/u-boot/aes.h @@ -34,6 +34,9 @@ int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest, int image_aes_decrypt(struct image_cipher_info *info, const void *cipher, size_t cipher_len, void **data, size_t *size); +int image_aes_decrypt_to(struct image_cipher_info *info, + const void *cipher, size_t cipher_len, + void *data, size_t *size); #else int image_aes_decrypt(struct image_cipher_info *info, const void *cipher, size_t cipher_len, @@ -41,6 +44,13 @@ int image_aes_decrypt(struct image_cipher_info *info, { return -ENXIO; } + +int image_aes_decrypt_to(struct image_cipher_info *info, + const void *cipher, size_t cipher_len, + void *data, size_t *size) +{ + return -ENXIO; +} #endif /* IMAGE_ENABLE_DECRYPT */ #endif diff --git a/lib/Makefile b/lib/Makefile index d0ffabc2b47..c69a928e6d8 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -19,7 +19,6 @@ obj-$(CONFIG_ARCH_AT91) += at91/ obj-$(CONFIG_OPTEE_LIB) += optee/ obj-$(CONFIG_AES) += aes.o -obj-$(CONFIG_AES) += aes/ obj-$(CONFIG_$(PHASE_)BINMAN_FDT) += binman.o obj-$(CONFIG_FW_LOADER) += fw_loader.o @@ -88,6 +87,7 @@ obj-$(CONFIG_$(PHASE_)ASN1_DECODER_LEGACY) += asn1_decoder.o obj-$(CONFIG_$(PHASE_)ZLIB) += zlib/ obj-$(CONFIG_$(PHASE_)ZSTD) += zstd/ +obj-$(CONFIG_$(PHASE_)FIT_CIPHER) += aes/ obj-$(CONFIG_$(PHASE_)GZIP) += gunzip.o obj-$(CONFIG_$(PHASE_)LZO) += lzo/ obj-$(CONFIG_$(PHASE_)LZMA) += lzma/ diff --git a/lib/aes/aes-decrypt.c b/lib/aes/aes-decrypt.c index 741102a4723..84e7a5bf3e5 100644 --- a/lib/aes/aes-decrypt.c +++ b/lib/aes/aes-decrypt.c @@ -4,37 +4,105 @@ */ #ifndef USE_HOSTCC +#include <dm.h> #include <malloc.h> #endif #include <image.h> #include <uboot_aes.h> +#ifndef USE_HOSTCC +static int image_aes_validate_lengths(struct image_cipher_info *info, + size_t cipher_len) +{ + if (!cipher_len || cipher_len % AES_BLOCK_LENGTH || + info->size_unciphered > cipher_len) + return -EINVAL; + + return 0; +} +#endif + +int image_aes_decrypt_to(struct image_cipher_info *info, + const void *cipher, size_t cipher_len, + void *data, size_t *size) +{ +#ifndef USE_HOSTCC + unsigned int aes_blocks, key_len = info->cipher->key_len; + int ret = -ENOSYS; + + ret = image_aes_validate_lengths(info, cipher_len); + if (ret) + return ret; + + *size = info->size_unciphered; + + if (CONFIG_IS_ENABLED(DM_AES)) { + struct udevice *dev; + + ret = uclass_first_device_err(UCLASS_AES, &dev); + if (!ret) { + ret = dm_aes_set_key_for_key_slot(dev, key_len * 8, + (u8 *)info->key, 0); + if (ret) + return ret; + + ret = dm_aes_select_key_slot(dev, key_len * 8, 0); + if (ret) + return ret; + + aes_blocks = cipher_len / AES_BLOCK_LENGTH; + + return dm_aes_cbc_decrypt(dev, (u8 *)info->iv, + (u8 *)cipher, data, + aes_blocks); + } + } + + if (!IS_ENABLED(CONFIG_XPL_BUILD)) { + unsigned char key_exp[AES256_EXPAND_KEY_LENGTH]; + + /* First we expand the key. */ + aes_expand_key((u8 *)info->key, key_len, key_exp); + + /* Calculate the number of AES blocks to decrypt. */ + aes_blocks = cipher_len / AES_BLOCK_LENGTH; + + aes_cbc_decrypt_blocks(key_len, key_exp, (u8 *)info->iv, + (u8 *)cipher, data, aes_blocks); + return 0; + } + + return ret; +#endif + + return 0; +} + int image_aes_decrypt(struct image_cipher_info *info, const void *cipher, size_t cipher_len, void **data, size_t *size) { -#ifndef USE_HOSTCC - unsigned char key_exp[AES256_EXPAND_KEY_LENGTH]; - unsigned int aes_blocks, key_len = info->cipher->key_len; +#ifdef USE_HOSTCC + return 0; +#else + int ret; + + ret = image_aes_validate_lengths(info, cipher_len); + if (ret) + return ret; *data = malloc(cipher_len); if (!*data) { printf("Can't allocate memory to decrypt\n"); return -ENOMEM; } - *size = info->size_unciphered; - memcpy(&key_exp[0], info->key, key_len); - - /* First we expand the key. */ - aes_expand_key((u8 *)info->key, key_len, key_exp); - - /* Calculate the number of AES blocks to encrypt. */ - aes_blocks = DIV_ROUND_UP(cipher_len, AES_BLOCK_LENGTH); + ret = image_aes_decrypt_to(info, cipher, cipher_len, *data, size); + if (ret) { + free(*data); + *data = NULL; + } - aes_cbc_decrypt_blocks(key_len, key_exp, (u8 *)info->iv, - (u8 *)cipher, *data, aes_blocks); + return ret; #endif - - return 0; } -- 2.53.0
