[28323] in CVS-changelog-for-Kerberos-V5
krb5 commit: Add k5-input.h
daemon@ATHENA.MIT.EDU (Greg Hudson)
Sat May 17 19:54:33 2014
Date: Sat, 17 May 2014 19:54:28 -0400
From: Greg Hudson <ghudson@mit.edu>
Message-Id: <201405172354.s4HNsSB9025013@drugstore.mit.edu>
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https://github.com/krb5/krb5/commit/1263ed281d1f50b97399137b90344a75e991129c
commit 1263ed281d1f50b97399137b90344a75e991129c
Author: Greg Hudson <ghudson@mit.edu>
Date: Mon May 5 00:05:54 2014 -0400
Add k5-input.h
Add a header containing a declaration for struct k5input and static
inline functions to use it. A k5input structure can be used to safely
extract bytes and integers from a fixed-sized input buffer without
overrunning the buffer. It supports deferred error checking (similar
to k5buf) by returning dummy values and storing a status value in the
input structure.
src/include/k5-input.h | 143 ++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 143 insertions(+), 0 deletions(-)
diff --git a/src/include/k5-input.h b/src/include/k5-input.h
new file mode 100644
index 0000000..d42ebce
--- /dev/null
+++ b/src/include/k5-input.h
@@ -0,0 +1,143 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/* include/k5-input.h - k5input helper functions */
+/*
+ * Copyright (C) 2014 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef K5_INPUT_H
+#define K5_INPUT_H
+
+#include "k5-int.h"
+
+/*
+ * The k5input module defines helpers for safely consuming a fixed-sized block
+ * of memory. If an overrun or allocation failure occurs at any step,
+ * subsequent functions will return default values until the error is detected
+ * by looking at the status field.
+ */
+
+struct k5input {
+ const unsigned char *ptr;
+ size_t len;
+ krb5_error_code status;
+};
+
+static inline void
+k5_input_init(struct k5input *in, const void *ptr, size_t len)
+{
+ in->ptr = ptr;
+ in->len = len;
+ in->status = 0;
+}
+
+/* Only set the status value of in if it hasn't already been set, so status
+ * reflects the first thing to go wrong. */
+static inline void
+k5_input_set_status(struct k5input *in, krb5_error_code status)
+{
+ if (!in->status)
+ in->status = status;
+}
+
+static inline const unsigned char *
+k5_input_get_bytes(struct k5input *in, size_t len)
+{
+ if (in->len < len)
+ k5_input_set_status(in, EINVAL);
+ if (in->status)
+ return NULL;
+ in->len -= len;
+ in->ptr += len;
+ return in->ptr - len;
+}
+
+static inline unsigned char
+k5_input_get_byte(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 1);
+ return (ptr == NULL) ? '\0' : *ptr;
+}
+
+static inline uint16_t
+k5_input_get_uint16_be(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 2);
+ return (ptr == NULL) ? 0 : load_16_be(ptr);
+}
+
+static inline uint16_t
+k5_input_get_uint16_le(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 2);
+ return (ptr == NULL) ? 0 : load_16_le(ptr);
+}
+
+static inline uint16_t
+k5_input_get_uint16_n(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 2);
+ return (ptr == NULL) ? 0 : load_16_n(ptr);
+}
+
+static inline uint32_t
+k5_input_get_uint32_be(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 4);
+ return (ptr == NULL) ? 0 : load_32_be(ptr);
+}
+
+static inline uint32_t
+k5_input_get_uint32_le(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 4);
+ return (ptr == NULL) ? 0 : load_32_le(ptr);
+}
+
+static inline uint32_t
+k5_input_get_uint32_n(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 4);
+ return (ptr == NULL) ? 0 : load_32_n(ptr);
+}
+
+static inline uint64_t
+k5_input_get_uint64_be(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 8);
+ return (ptr == NULL) ? 0 : load_64_be(ptr);
+}
+
+static inline uint64_t
+k5_input_get_uint64_le(struct k5input *in)
+{
+ const unsigned char *ptr = k5_input_get_bytes(in, 8);
+ return (ptr == NULL) ? 0 : load_64_le(ptr);
+}
+
+#endif /* K5_BUF_H */
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