From ed0296b9055713df0d910e4e7528ffe6fc539514 Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Sun, 10 Feb 2019 20:21:19 +0100 Subject: First commit MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- unmarshal.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 unmarshal.c (limited to 'unmarshal.c') diff --git a/unmarshal.c b/unmarshal.c new file mode 100644 index 0000000..e89a8dd --- /dev/null +++ b/unmarshal.c @@ -0,0 +1,59 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" + + +/** + * Unmarshal a state from a buffer + * + * @param state Output parameter for the unmarshalled state + * @param buf The buffer from which the state shall be unmarshalled + * @param bufsize The maximum number of bytes that can be unmarshalled + * @return The number of read bytes, 0 on failure + */ +size_t +libsha1_unmarshal(struct libsha1_state *restrict state, const void *restrict buf_, size_t bufsize) +{ + const char *restrict buf = buf_; + size_t off = 0; + + if (bufsize < sizeof(int) + sizeof(enum libsha1_algorithm) + sizeof(size_t)) { + errno = EINVAL; + return 0; + } + + if (*(const int *)buf) { /* version */ + errno = EINVAL; + return 0; + } + off += sizeof(int); + + state->algorithm = *(const enum libsha1_algorithm *)&buf[off]; + off += sizeof(enum libsha1_algorithm); + state->message_size = *(const size_t *)&buf[off]; + off += sizeof(size_t); + + if (bufsize - off < sizeof(state->w) + sizeof(state->h)) { + errno = EINVAL; + return 0; + } + memcpy(state->w, &buf[off], sizeof(state->w)); + off += sizeof(state->w); + memcpy(state->h, &buf[off], sizeof(state->h)); + off += sizeof(state->h); + + if (bufsize - off < sizeof(size_t)) { + errno = EINVAL; + return 0; + } + state->chunk_size = *(const size_t *)&buf[off]; + off += sizeof(size_t); + + if (bufsize - off < (state->message_size / 8) % state->chunk_size) { + errno = EINVAL; + return 0; + } + memcpy(state->chunk, &buf[off], (state->message_size / 8) % state->chunk_size); + off += (state->message_size / 8) % state->chunk_size; + + return off; +} -- cgit v1.2.3-70-g09d2