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Diffstat (limited to 'circuitpython/shared-bindings/aesio/aes.c')
| -rw-r--r-- | circuitpython/shared-bindings/aesio/aes.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/circuitpython/shared-bindings/aesio/aes.c b/circuitpython/shared-bindings/aesio/aes.c new file mode 100644 index 0000000..bb72b10 --- /dev/null +++ b/circuitpython/shared-bindings/aesio/aes.c @@ -0,0 +1,268 @@ +#include <stdint.h> +#include <string.h> + +#include "py/obj.h" +#include "py/objproperty.h" +#include "py/runtime.h" + +#include "shared-bindings/aesio/__init__.h" + +// Defined at the end of this file + +//| MODE_ECB: int +//| MODE_CBC: int +//| MODE_CTR: int +//| +//| class AES: +//| """Encrypt and decrypt AES streams""" +//| +//| def __init__(self, key: ReadableBuffer, mode: int = 0, iv: Optional[ReadableBuffer] = None, segment_size: int = 8) -> None: +//| """Create a new AES state with the given key. +//| +//| :param ~circuitpython_typing.ReadableBuffer key: A 16-, 24-, or 32-byte key +//| :param int mode: AES mode to use. One of: `MODE_ECB`, `MODE_CBC`, or +//| `MODE_CTR` +//| :param ~circuitpython_typing.ReadableBuffer iv: Initialization vector to use for CBC or CTR mode +//| +//| Additional arguments are supported for legacy reasons. +//| +//| Encrypting a string:: +//| +//| import aesio +//| from binascii import hexlify +//| +//| key = b'Sixteen byte key' +//| inp = b'CircuitPython!!!' # Note: 16-bytes long +//| outp = bytearray(len(inp)) +//| cipher = aesio.AES(key, aesio.MODE_ECB) +//| cipher.encrypt_into(inp, outp) +//| hexlify(outp)""" +//| ... +//| + +STATIC mp_obj_t aesio_aes_make_new(const mp_obj_type_t *type, size_t n_args, + size_t n_kw, const mp_obj_t *all_args) { + (void)type; + enum { ARG_key, ARG_mode, ARG_IV, ARG_counter, ARG_segment_size }; + static const mp_arg_t allowed_args[] = { + {MP_QSTR_key, MP_ARG_OBJ | MP_ARG_REQUIRED, {.u_obj = MP_OBJ_NULL} }, + {MP_QSTR_mode, MP_ARG_INT, {.u_int = AES_MODE_ECB} }, + {MP_QSTR_IV, MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} }, + {MP_QSTR_counter, MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} }, + {MP_QSTR_segment_size, MP_ARG_INT, {.u_int = 8}}, + }; + mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)]; + + mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), + allowed_args, args); + + aesio_aes_obj_t *self = m_new_obj(aesio_aes_obj_t); + self->base.type = &aesio_aes_type; + + mp_buffer_info_t bufinfo; + + const uint8_t *key = NULL; + uint32_t key_length = 0; + if (mp_get_buffer(args[ARG_key].u_obj, &bufinfo, MP_BUFFER_READ)) { + if ((bufinfo.len != 16) && (bufinfo.len != 24) && (bufinfo.len != 32)) { + mp_raise_TypeError(translate("Key must be 16, 24, or 32 bytes long")); + } + key = bufinfo.buf; + key_length = bufinfo.len; + } else { + mp_raise_TypeError(translate("No key was specified")); + } + + int mode = args[ARG_mode].u_int; + switch (args[ARG_mode].u_int) { + case AES_MODE_CBC: + case AES_MODE_ECB: + case AES_MODE_CTR: + break; + default: + mp_raise_TypeError(translate("Requested AES mode is unsupported")); + } + + // IV is required for CBC mode and is ignored for other modes. + const uint8_t *iv = NULL; + if (args[ARG_IV].u_obj != NULL && + mp_get_buffer(args[ARG_IV].u_obj, &bufinfo, MP_BUFFER_READ)) { + if (bufinfo.len != AES_BLOCKLEN) { + mp_raise_TypeError_varg(translate("IV must be %d bytes long"), + AES_BLOCKLEN); + } + iv = bufinfo.buf; + } + + common_hal_aesio_aes_construct(self, key, key_length, iv, mode, + args[ARG_counter].u_int); + return MP_OBJ_FROM_PTR(self); +} + +STATIC mp_obj_t aesio_aes_rekey(size_t n_args, const mp_obj_t *pos_args) { + aesio_aes_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]); + + mp_buffer_info_t bufinfo; + mp_get_buffer_raise(pos_args[1], &bufinfo, MP_BUFFER_READ); + const uint8_t *key = bufinfo.buf; + size_t key_length = bufinfo.len; + if (key == NULL) { + mp_raise_ValueError(translate("No key was specified")); + } + if ((key_length != 16) && (key_length != 24) && (key_length != 32)) { + mp_raise_TypeError(translate("Key must be 16, 24, or 32 bytes long")); + } + + const uint8_t *iv = NULL; + if (n_args > 2) { + mp_get_buffer_raise(pos_args[2], &bufinfo, MP_BUFFER_READ); + size_t iv_length = bufinfo.len; + iv = (const uint8_t *)bufinfo.buf; + if (iv_length != AES_BLOCKLEN) { + mp_raise_TypeError_varg(translate("IV must be %d bytes long"), + AES_BLOCKLEN); + } + } + + common_hal_aesio_aes_rekey(self, key, key_length, iv); + return mp_const_none; +} + +MP_DEFINE_CONST_FUN_OBJ_VAR(aesio_aes_rekey_obj, 2, aesio_aes_rekey); + +STATIC void validate_length(aesio_aes_obj_t *self, size_t src_length, + size_t dest_length) { + if (src_length != dest_length) { + mp_raise_ValueError( + translate("Source and destination buffers must be the same length")); + } + + switch (self->mode) { + case AES_MODE_ECB: + if (src_length != 16) { + mp_raise_msg(&mp_type_ValueError, + translate("ECB only operates on 16 bytes at a time")); + } + break; + case AES_MODE_CBC: + if ((src_length & 15) != 0) { + mp_raise_msg(&mp_type_ValueError, + translate("CBC blocks must be multiples of 16 bytes")); + } + break; + case AES_MODE_CTR: + break; + } +} + +//| def encrypt_into(self, src: ReadableBuffer, dest: WriteableBuffer) -> None: +//| """Encrypt the buffer from ``src`` into ``dest``. +//| +//| For ECB mode, the buffers must be 16 bytes long. For CBC mode, the +//| buffers must be a multiple of 16 bytes, and must be equal length. For +//| CTX mode, there are no restrictions.""" +//| ... +//| +STATIC mp_obj_t aesio_aes_encrypt_into(mp_obj_t aesio_obj, mp_obj_t src, + mp_obj_t dest) { + if (!mp_obj_is_type(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + // Convert parameters into expected types. + aesio_aes_obj_t *aes = MP_OBJ_TO_PTR(aesio_obj); + + mp_buffer_info_t srcbufinfo, destbufinfo; + mp_get_buffer_raise(src, &srcbufinfo, MP_BUFFER_READ); + mp_get_buffer_raise(dest, &destbufinfo, MP_BUFFER_WRITE); + validate_length(aes, srcbufinfo.len, destbufinfo.len); + + memcpy(destbufinfo.buf, srcbufinfo.buf, srcbufinfo.len); + + common_hal_aesio_aes_encrypt(aes, (uint8_t *)destbufinfo.buf, + destbufinfo.len); + return mp_const_none; +} + +STATIC MP_DEFINE_CONST_FUN_OBJ_3(aesio_aes_encrypt_into_obj, + aesio_aes_encrypt_into); + +//| def decrypt_into(self, src: ReadableBuffer, dest: WriteableBuffer) -> None: +//| """Decrypt the buffer from ``src`` into ``dest``. +//| For ECB mode, the buffers must be 16 bytes long. For CBC mode, the +//| buffers must be a multiple of 16 bytes, and must be equal length. For +//| CTX mode, there are no restrictions.""" +//| ... +//| +STATIC mp_obj_t aesio_aes_decrypt_into(mp_obj_t aesio_obj, mp_obj_t src, + mp_obj_t dest) { + if (!mp_obj_is_type(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + // Convert parameters into expected types. + aesio_aes_obj_t *aes = MP_OBJ_TO_PTR(aesio_obj); + + mp_buffer_info_t srcbufinfo, destbufinfo; + mp_get_buffer_raise(src, &srcbufinfo, MP_BUFFER_READ); + mp_get_buffer_raise(dest, &destbufinfo, MP_BUFFER_WRITE); + validate_length(aes, srcbufinfo.len, destbufinfo.len); + + memcpy(destbufinfo.buf, srcbufinfo.buf, srcbufinfo.len); + + common_hal_aesio_aes_decrypt(aes, (uint8_t *)destbufinfo.buf, + destbufinfo.len); + return mp_const_none; +} + +STATIC MP_DEFINE_CONST_FUN_OBJ_3(aesio_aes_decrypt_into_obj, + aesio_aes_decrypt_into); + +STATIC mp_obj_t aesio_aes_get_mode(mp_obj_t aesio_obj) { + if (!mp_obj_is_type(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + aesio_aes_obj_t *self = MP_OBJ_TO_PTR(aesio_obj); + return MP_OBJ_NEW_SMALL_INT(self->mode); +} +MP_DEFINE_CONST_FUN_OBJ_1(aesio_aes_get_mode_obj, aesio_aes_get_mode); + +STATIC mp_obj_t aesio_aes_set_mode(mp_obj_t aesio_obj, mp_obj_t mode_obj) { + if (!mp_obj_is_type(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + aesio_aes_obj_t *self = MP_OBJ_TO_PTR(aesio_obj); + + int mode = mp_obj_get_int(mode_obj); + switch (mode) { + case AES_MODE_CBC: + case AES_MODE_ECB: + case AES_MODE_CTR: + break; + default: + mp_raise_TypeError(translate("Requested AES mode is unsupported")); + } + + common_hal_aesio_aes_set_mode(self, mode); + return mp_const_none; +} +MP_DEFINE_CONST_FUN_OBJ_2(aesio_aes_set_mode_obj, aesio_aes_set_mode); + +MP_PROPERTY_GETSET(aesio_aes_mode_obj, + (mp_obj_t)&aesio_aes_get_mode_obj, + (mp_obj_t)&aesio_aes_set_mode_obj); + +STATIC const mp_rom_map_elem_t aesio_locals_dict_table[] = { + // Methods + {MP_ROM_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_AES)}, + {MP_ROM_QSTR(MP_QSTR_encrypt_into), (mp_obj_t)&aesio_aes_encrypt_into_obj}, + {MP_ROM_QSTR(MP_QSTR_decrypt_into), (mp_obj_t)&aesio_aes_decrypt_into_obj}, + {MP_ROM_QSTR(MP_QSTR_rekey), (mp_obj_t)&aesio_aes_rekey_obj}, + {MP_ROM_QSTR(MP_QSTR_mode), (mp_obj_t)&aesio_aes_mode_obj}, +}; +STATIC MP_DEFINE_CONST_DICT(aesio_locals_dict, aesio_locals_dict_table); + +const mp_obj_type_t aesio_aes_type = { + {&mp_type_type}, + .name = MP_QSTR_AES, + .make_new = aesio_aes_make_new, + .locals_dict = (mp_obj_dict_t *)&aesio_locals_dict, +}; |