diff options
Diffstat (limited to 'hmac/libkeccak_hmac_unmarshal.c')
-rw-r--r-- | hmac/libkeccak_hmac_unmarshal.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/hmac/libkeccak_hmac_unmarshal.c b/hmac/libkeccak_hmac_unmarshal.c new file mode 100644 index 0000000..ddada17 --- /dev/null +++ b/hmac/libkeccak_hmac_unmarshal.c @@ -0,0 +1,59 @@ +/* See LICENSE file for copyright and license details. */ +#include "../common.h" + +#if defined(__clang__) +# pragma clang diagnostic ignored "-Wcast-align" +#endif + + +/** + * Unmarshal a `struct libkeccak_hmac_state` from a buffer + * + * @param state The slot for the unmarshalled state, must not be + * initialised (memory leak otherwise), can be `NULL` + * @param data_ The input buffer + * @return The number of bytes read from `data`, 0 on error + */ +size_t +libkeccak_hmac_unmarshal(struct libkeccak_hmac_state *restrict state, const void *restrict data_) +{ + const unsigned char *restrict data = data_; + size_t parsed, size, i; + + state->key_opad = NULL; + state->key_ipad = NULL; + + parsed = libkeccak_state_unmarshal(state ? &state->sponge : NULL, data); + if (!parsed) + return 0; + data += parsed; + + __builtin_memcpy(&size, data, sizeof(size)); + data += sizeof(size_t); + if (state) + size = state->key_length; + size = (state->key_length + 7) >> 3; + + if (state) { + state->key_opad = malloc(2 * size); + if (!state->key_opad) { + libkeccak_state_destroy(&state->sponge); + return 0; + } + memcpy(state->key_opad, data, size); + data += size; + + if (data[0]) { + state->key_ipad = &state->key_opad[size]; + memcpy(state->key_ipad, state->key_opad, size); + for (i = 0; i < size; i++) + state->key_ipad[i] ^= (char)(HMAC_OUTER_PAD ^ HMAC_INNER_PAD); + } + + state->leftover = data[1]; + state->buffer = NULL; + state->buffer_size = 0; + } + + return parsed + sizeof(size_t) + size + 2 * sizeof(char); +} |