From 9d4bd0942daca7b705d73de7341834444567b457 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@kth.se>
Date: Sun, 10 Feb 2019 17:20:40 +0100
Subject: Add libsha2_hmac_[un]marshal
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Signed-off-by: Mattias Andrée <maandree@kth.se>
---
 Makefile         |  2 ++
 hmac_marshal.c   | 41 +++++++++++++++++++++++++++++++++++++++++
 hmac_unmarshal.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 libsha2.h        | 25 +++++++++++++++++++++++++
 4 files changed, 122 insertions(+)
 create mode 100644 hmac_marshal.c
 create mode 100644 hmac_unmarshal.c

diff --git a/Makefile b/Makefile
index 2df18be..dc7060e 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,8 @@ OBJ =\
 	digest.o\
 	hmac_digest.o\
 	hmac_init.o\
+	hmac_marshal.o\
+	hmac_unmarshal.o\
 	hmac_update.o\
 	init.o\
 	marshal.o\
diff --git a/hmac_marshal.c b/hmac_marshal.c
new file mode 100644
index 0000000..2cb0816
--- /dev/null
+++ b/hmac_marshal.c
@@ -0,0 +1,41 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Marshal an HMAC state into a buffer
+ * 
+ * @param   state  The state to marshal
+ * @param   buf    Output buffer, `NULL` to only return the required size
+ * @return         The number of bytes marshalled to `buf`
+ */
+size_t
+libsha2_hmac_marshal(const struct libsha2_hmac_state *restrict state, void *restrict buf_)
+{
+	char *restrict buf = buf_;
+	size_t off = 0;
+
+	if (buf)
+		*(int *)buf = 0; /* version */
+	off += sizeof(int);
+
+	off += libsha2_marshal(&state->sha2_state, buf ? &buf[off] : NULL);
+
+	if (buf)
+		*(size_t *)&buf[off] = state->outsize;
+	off += sizeof(size_t);
+
+	if (buf)
+		*(unsigned char *)&buf[off] = state->inited;
+	off += sizeof(unsigned char);
+
+	if (buf)
+		memcpy(&buf[off], state->ipad, state->sha2_state.chunk_size);
+	off += state->sha2_state.chunk_size;
+
+	if (buf)
+		memcpy(&buf[off], state->opad, state->sha2_state.chunk_size);
+	off += state->sha2_state.chunk_size;
+
+	return off;
+}
diff --git a/hmac_unmarshal.c b/hmac_unmarshal.c
new file mode 100644
index 0000000..cc62d5c
--- /dev/null
+++ b/hmac_unmarshal.c
@@ -0,0 +1,54 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Unmarshal an HMAC 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
+libsha2_hmac_unmarshal(struct libsha2_hmac_state *restrict state, const void *restrict buf_, size_t bufsize)
+{
+	const char *restrict buf = buf_;
+	size_t off = 0;
+	size_t r;
+
+	if (bufsize < sizeof(int)) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	if (*(const int *)buf) { /* version */
+		errno = EINVAL;
+		return 0;
+	}
+	off += sizeof(int);
+
+	r = libsha2_unmarshal(&state->sha2_state, &buf[off], bufsize - off);
+	if (!r)
+		return 0;
+	off += r;
+
+	if (bufsize - off < sizeof(size_t) + sizeof(unsigned char) + 2 * state->sha2_state.chunk_size) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	state->outsize = *(size_t *)&buf[off];
+	off += sizeof(size_t);
+
+	state->inited = *(unsigned char *)&buf[off];
+	off += sizeof(unsigned char);
+
+	memcpy(state->ipad, &buf[off], state->sha2_state.chunk_size);
+	off += state->sha2_state.chunk_size;
+
+	memcpy(state->opad, &buf[off], state->sha2_state.chunk_size);
+	off += state->sha2_state.chunk_size;
+
+	return off;
+}
diff --git a/libsha2.h b/libsha2.h
index d4d52bf..21e0b98 100644
--- a/libsha2.h
+++ b/libsha2.h
@@ -363,5 +363,30 @@ __attribute__((__leaf__, __nonnull__, __nothrow__))
 #endif
 int libsha2_hmac_digest(struct libsha2_hmac_state *restrict, const void *, size_t, void *);
 
+/**
+ * Marshal an HMAC state into a buffer
+ * 
+ * @param   state  The state to marshal
+ * @param   buf    Output buffer, `NULL` to only return the required size
+ * @return         The number of bytes marshalled to `buf`
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nonnull__(1), __nothrow__))
+#endif
+size_t libsha2_hmac_marshal(const struct libsha2_hmac_state *restrict, void *restrict);
+
+/**
+ * Unmarshal an HMAC 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
+ */
+#if defined(__GNUC__)
+__attribute__((__leaf__, __nonnull__, __nothrow__))
+#endif
+size_t libsha2_hmac_unmarshal(struct libsha2_hmac_state *restrict, const void *restrict, size_t);
+
 
 #endif
-- 
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