b232508707
We already had nm_free_secret() to clear the secret out of a NUL terminated string. That works well for secrets which are strings, it can be used with a cleanup attribute (nm_auto_free_secret) and as a cleanup function for a GBytes. However, it does not work for secrets which are binary. For those, we must also track the length of the allocated data and clear it. Add two new structs NMSecretPtr and NMSecretBuf to help with that.
152 lines
3.9 KiB
C
152 lines
3.9 KiB
C
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
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/* NetworkManager -- Network link manager
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA.
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*
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* (C) Copyright 2018 Red Hat, Inc.
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*/
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#ifndef __NM_SECRET_UTILS_H__
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#define __NM_SECRET_UTILS_H__
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#include "nm-macros-internal.h"
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/*****************************************************************************/
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void nm_explicit_bzero (void *s, gsize n);
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/*****************************************************************************/
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char *nm_secret_strchomp (char *secret);
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/*****************************************************************************/
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static inline void
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nm_free_secret (char *secret)
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{
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if (secret) {
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nm_explicit_bzero (secret, strlen (secret));
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g_free (secret);
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}
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}
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NM_AUTO_DEFINE_FCN (char *, _nm_auto_free_secret, nm_free_secret)
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/**
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* nm_auto_free_secret:
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*
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* Call g_free() on a variable location when it goes out of scope.
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* Also, previously, calls memset(loc, 0, strlen(loc)) to clear out
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* the secret.
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*/
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#define nm_auto_free_secret nm_auto(_nm_auto_free_secret)
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/*****************************************************************************/
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GBytes *nm_secret_copy_to_gbytes (gconstpointer mem, gsize mem_len);
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/*****************************************************************************/
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/* NMSecretPtr is a pair of malloc'ed data pointer and the length of the
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* data. The purpose is to use it in combination with nm_auto_clear_secret_ptr
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* which ensures that the data pointer (with all len bytes) is cleared upon
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* cleanup. */
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typedef struct {
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gsize len;
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/* the data pointer. This pointer must be allocated with malloc (at least
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* when used with nm_secret_ptr_clear()). */
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union {
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char *str;
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void *ptr;
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guint8 *bin;
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};
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} NMSecretPtr;
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static inline void
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nm_secret_ptr_clear (NMSecretPtr *secret)
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{
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if (secret) {
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if (secret->len > 0) {
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if (secret->ptr)
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nm_explicit_bzero (secret->ptr, secret->len);
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secret->len = 0;
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}
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nm_clear_g_free (&secret->ptr);
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}
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}
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#define nm_auto_clear_secret_ptr nm_auto(nm_secret_ptr_clear)
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#define NM_SECRET_PTR_STATIC(_len) \
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((const NMSecretPtr) { \
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.len = _len, \
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.ptr = ((guint8 [_len]) { }), \
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})
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static inline void
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nm_secret_ptr_clear_static (const NMSecretPtr *secret)
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{
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if (secret) {
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if (secret->len > 0) {
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nm_assert (secret->ptr);
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nm_explicit_bzero (secret->ptr, secret->len);
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}
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}
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}
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#define nm_auto_clear_static_secret_ptr nm_auto(nm_secret_ptr_clear_static)
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static inline void
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nm_secret_ptr_move (NMSecretPtr *dst, NMSecretPtr *src)
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{
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if (dst && dst != src) {
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*dst = *src;
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src->len = 0;
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src->ptr = NULL;
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}
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}
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/*****************************************************************************/
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typedef struct {
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const gsize len;
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union {
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char str[0];
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guint8 bin[0];
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};
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} NMSecretBuf;
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static inline void
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_nm_auto_free_secret_buf (NMSecretBuf **ptr)
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{
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NMSecretBuf *b = *ptr;
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if (b) {
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nm_assert (b->len > 0);
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nm_explicit_bzero (b->bin, b->len);
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g_free (b);
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}
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}
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#define nm_auto_free_secret_buf nm_auto(_nm_auto_free_secret_buf)
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NMSecretBuf *nm_secret_buf_new (gsize len);
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GBytes *nm_secret_buf_to_gbytes_take (NMSecretBuf *secret, gssize actual_len);
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/*****************************************************************************/
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#endif /* __NM_SECRET_UTILS_H__ */
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