1 files changed, 401 insertions, 0 deletions
diff --git a/sshbuf.c b/sshbuf.c
new file mode 100644
index 0000000..368ba79
--- /dev/null
+++ b/sshbuf.c
@@ -0,0 +1,401 @@
+/*	$OpenBSD: sshbuf.c,v 1.15 2020/02/26 13:40:09 jsg Exp $	*/
+/*
+ * Copyright (c) 2011 Damien Miller
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#define SSHBUF_INTERNAL
+#include "includes.h"
+
+#include <sys/types.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "ssherr.h"
+#include "sshbuf.h"
+#include "misc.h"
+
+static inline int
+sshbuf_check_sanity(const struct sshbuf *buf)
+{
+	SSHBUF_TELL("sanity");
+	if (__predict_false(buf == NULL ||
+	    (!buf->readonly && buf->d != buf->cd) ||
+	    buf->refcount < 1 || buf->refcount > SSHBUF_REFS_MAX ||
+	    buf->cd == NULL ||
+	    buf->max_size > SSHBUF_SIZE_MAX ||
+	    buf->alloc > buf->max_size ||
+	    buf->size > buf->alloc ||
+	    buf->off > buf->size)) {
+		/* Do not try to recover from corrupted buffer internals */
+		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+		ssh_signal(SIGSEGV, SIG_DFL);
+		raise(SIGSEGV);
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	return 0;
+}
+
+static void
+sshbuf_maybe_pack(struct sshbuf *buf, int force)
+{
+	SSHBUF_DBG(("force %d", force));
+	SSHBUF_TELL("pre-pack");
+	if (buf->off == 0 || buf->readonly || buf->refcount > 1)
+		return;
+	if (force ||
+	    (buf->off >= SSHBUF_PACK_MIN && buf->off >= buf->size / 2)) {
+		memmove(buf->d, buf->d + buf->off, buf->size - buf->off);
+		buf->size -= buf->off;
+		buf->off = 0;
+		SSHBUF_TELL("packed");
+	}
+}
+
+struct sshbuf *
+sshbuf_new(void)
+{
+	struct sshbuf *ret;
+
+	if ((ret = calloc(sizeof(*ret), 1)) == NULL)
+		return NULL;
+	ret->alloc = SSHBUF_SIZE_INIT;
+	ret->max_size = SSHBUF_SIZE_MAX;
+	ret->readonly = 0;
+	ret->refcount = 1;
+	ret->parent = NULL;
+	if ((ret->cd = ret->d = calloc(1, ret->alloc)) == NULL) {
+		free(ret);
+		return NULL;
+	}
+	return ret;
+}
+
+struct sshbuf *
+sshbuf_from(const void *blob, size_t len)
+{
+	struct sshbuf *ret;
+
+	if (blob == NULL || len > SSHBUF_SIZE_MAX ||
+	    (ret = calloc(sizeof(*ret), 1)) == NULL)
+		return NULL;
+	ret->alloc = ret->size = ret->max_size = len;
+	ret->readonly = 1;
+	ret->refcount = 1;
+	ret->parent = NULL;
+	ret->cd = blob;
+	ret->d = NULL;
+	return ret;
+}
+
+int
+sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent)
+{
+	int r;
+
+	if ((r = sshbuf_check_sanity(child)) != 0 ||
+	    (r = sshbuf_check_sanity(parent)) != 0)
+		return r;
+	child->parent = parent;
+	child->parent->refcount++;
+	return 0;
+}
+
+struct sshbuf *
+sshbuf_fromb(struct sshbuf *buf)
+{
+	struct sshbuf *ret;
+
+	if (sshbuf_check_sanity(buf) != 0)
+		return NULL;
+	if ((ret = sshbuf_from(sshbuf_ptr(buf), sshbuf_len(buf))) == NULL)
+		return NULL;
+	if (sshbuf_set_parent(ret, buf) != 0) {
+		sshbuf_free(ret);
+		return NULL;
+	}
+	return ret;
+}
+
+void
+sshbuf_free(struct sshbuf *buf)
+{
+	if (buf == NULL)
+		return;
+	/*
+	 * The following will leak on insane buffers, but this is the safest
+	 * course of action - an invalid pointer or already-freed pointer may
+	 * have been passed to us and continuing to scribble over memory would
+	 * be bad.
+	 */
+	if (sshbuf_check_sanity(buf) != 0)
+		return;
+
+	/*
+	 * If we are a parent with still-extant children, then don't free just
+	 * yet. The last child's call to sshbuf_free should decrement our
+	 * refcount to 0 and trigger the actual free.
+	 */
+	buf->refcount--;
+	if (buf->refcount > 0)
+		return;
+
+	/*
+	 * If we are a child, the free our parent to decrement its reference
+	 * count and possibly free it.
+	 */
+	sshbuf_free(buf->parent);
+	buf->parent = NULL;
+
+	if (!buf->readonly) {
+		explicit_bzero(buf->d, buf->alloc);
+		free(buf->d);
+	}
+	freezero(buf, sizeof(*buf));
+}
+
+void
+sshbuf_reset(struct sshbuf *buf)
+{
+	u_char *d;
+
+	if (buf->readonly || buf->refcount > 1) {
+		/* Nonsensical. Just make buffer appear empty */
+		buf->off = buf->size;
+		return;
+	}
+	(void) sshbuf_check_sanity(buf);
+	buf->off = buf->size = 0;
+	if (buf->alloc != SSHBUF_SIZE_INIT) {
+		if ((d = recallocarray(buf->d, buf->alloc, SSHBUF_SIZE_INIT,
+		    1)) != NULL) {
+			buf->cd = buf->d = d;
+			buf->alloc = SSHBUF_SIZE_INIT;
+		}
+	}
+	explicit_bzero(buf->d, SSHBUF_SIZE_INIT);
+}
+
+size_t
+sshbuf_max_size(const struct sshbuf *buf)
+{
+	return buf->max_size;
+}
+
+size_t
+sshbuf_alloc(const struct sshbuf *buf)
+{
+	return buf->alloc;
+}
+
+const struct sshbuf *
+sshbuf_parent(const struct sshbuf *buf)
+{
+	return buf->parent;
+}
+
+u_int
+sshbuf_refcount(const struct sshbuf *buf)
+{
+	return buf->refcount;
+}
+
+int
+sshbuf_set_max_size(struct sshbuf *buf, size_t max_size)
+{
+	size_t rlen;
+	u_char *dp;
+	int r;
+
+	SSHBUF_DBG(("set max buf = %p len = %zu", buf, max_size));
+	if ((r = sshbuf_check_sanity(buf)) != 0)
+		return r;
+	if (max_size == buf->max_size)
+		return 0;
+	if (buf->readonly || buf->refcount > 1)
+		return SSH_ERR_BUFFER_READ_ONLY;
+	if (max_size > SSHBUF_SIZE_MAX)
+		return SSH_ERR_NO_BUFFER_SPACE;
+	/* pack and realloc if necessary */
+	sshbuf_maybe_pack(buf, max_size < buf->size);
+	if (max_size < buf->alloc && max_size > buf->size) {
+		if (buf->size < SSHBUF_SIZE_INIT)
+			rlen = SSHBUF_SIZE_INIT;
+		else
+			rlen = ROUNDUP(buf->size, SSHBUF_SIZE_INC);
+		if (rlen > max_size)
+			rlen = max_size;
+		SSHBUF_DBG(("new alloc = %zu", rlen));
+		if ((dp = recallocarray(buf->d, buf->alloc, rlen, 1)) == NULL)
+			return SSH_ERR_ALLOC_FAIL;
+		buf->cd = buf->d = dp;
+		buf->alloc = rlen;
+	}
+	SSHBUF_TELL("new-max");
+	if (max_size < buf->alloc)
+		return SSH_ERR_NO_BUFFER_SPACE;
+	buf->max_size = max_size;
+	return 0;
+}
+
+size_t
+sshbuf_len(const struct sshbuf *buf)
+{
+	if (sshbuf_check_sanity(buf) != 0)
+		return 0;
+	return buf->size - buf->off;
+}
+
+size_t
+sshbuf_avail(const struct sshbuf *buf)
+{
+	if (sshbuf_check_sanity(buf) != 0 || buf->readonly || buf->refcount > 1)
+		return 0;
+	return buf->max_size - (buf->size - buf->off);
+}
+
+const u_char *
+sshbuf_ptr(const struct sshbuf *buf)
+{
+	if (sshbuf_check_sanity(buf) != 0)
+		return NULL;
+	return buf->cd + buf->off;
+}
+
+u_char *
+sshbuf_mutable_ptr(const struct sshbuf *buf)
+{
+	if (sshbuf_check_sanity(buf) != 0 || buf->readonly || buf->refcount > 1)
+		return NULL;
+	return buf->d + buf->off;
+}
+
+int
+sshbuf_check_reserve(const struct sshbuf *buf, size_t len)
+{
+	int r;
+
+	if ((r = sshbuf_check_sanity(buf)) != 0)
+		return r;
+	if (buf->readonly || buf->refcount > 1)
+		return SSH_ERR_BUFFER_READ_ONLY;
+	SSHBUF_TELL("check");
+	/* Check that len is reasonable and that max_size + available < len */
+	if (len > buf->max_size || buf->max_size - len < buf->size - buf->off)
+		return SSH_ERR_NO_BUFFER_SPACE;
+	return 0;
+}
+
+int
+sshbuf_allocate(struct sshbuf *buf, size_t len)
+{
+	size_t rlen, need;
+	u_char *dp;
+	int r;
+
+	SSHBUF_DBG(("allocate buf = %p len = %zu", buf, len));
+	if ((r = sshbuf_check_reserve(buf, len)) != 0)
+		return r;
+	/*
+	 * If the requested allocation appended would push us past max_size
+	 * then pack the buffer, zeroing buf->off.
+	 */
+	sshbuf_maybe_pack(buf, buf->size + len > buf->max_size);
+	SSHBUF_TELL("allocate");
+	if (len + buf->size <= buf->alloc)
+		return 0; /* already have it. */
+
+	/*
+	 * Prefer to alloc in SSHBUF_SIZE_INC units, but
+	 * allocate less if doing so would overflow max_size.
+	 */
+	need = len + buf->size - buf->alloc;
+	rlen = ROUNDUP(buf->alloc + need, SSHBUF_SIZE_INC);
+	SSHBUF_DBG(("need %zu initial rlen %zu", need, rlen));
+	if (rlen > buf->max_size)
+		rlen = buf->alloc + need;
+	SSHBUF_DBG(("adjusted rlen %zu", rlen));
+	if ((dp = recallocarray(buf->d, buf->alloc, rlen, 1)) == NULL) {
+		SSHBUF_DBG(("realloc fail"));
+		return SSH_ERR_ALLOC_FAIL;
+	}
+	buf->alloc = rlen;
+	buf->cd = buf->d = dp;
+	if ((r = sshbuf_check_reserve(buf, len)) < 0) {
+		/* shouldn't fail */
+		return r;
+	}
+	SSHBUF_TELL("done");
+	return 0;
+}
+
+int
+sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp)
+{
+	u_char *dp;
+	int r;
+
+	if (dpp != NULL)
+		*dpp = NULL;
+
+	SSHBUF_DBG(("reserve buf = %p len = %zu", buf, len));
+	if ((r = sshbuf_allocate(buf, len)) != 0)
+		return r;
+
+	dp = buf->d + buf->size;
+	buf->size += len;
+	if (dpp != NULL)
+		*dpp = dp;
+	return 0;
+}
+
+int
+sshbuf_consume(struct sshbuf *buf, size_t len)
+{
+	int r;
+
+	SSHBUF_DBG(("len = %zu", len));
+	if ((r = sshbuf_check_sanity(buf)) != 0)
+		return r;
+	if (len == 0)
+		return 0;
+	if (len > sshbuf_len(buf))
+		return SSH_ERR_MESSAGE_INCOMPLETE;
+	buf->off += len;
+	/* deal with empty buffer */
+	if (buf->off == buf->size)
+		buf->off = buf->size = 0;
+	SSHBUF_TELL("done");
+	return 0;
+}
+
+int
+sshbuf_consume_end(struct sshbuf *buf, size_t len)
+{
+	int r;
+
+	SSHBUF_DBG(("len = %zu", len));
+	if ((r = sshbuf_check_sanity(buf)) != 0)
+		return r;
+	if (len == 0)
+		return 0;
+	if (len > sshbuf_len(buf))
+		return SSH_ERR_MESSAGE_INCOMPLETE;
+	buf->size -= len;
+	SSHBUF_TELL("done");
+	return 0;
+}
+