+++ /dev/null
-/* -*-c-*-
- *
- * $Id$
- *
- * Locked memory allocation (Unix-specific)
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include "config.h"
-
-#include <assert.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <sys/types.h>
-#include <unistd.h>
-
-#ifdef HAVE_MLOCK
-# include <sys/mman.h>
-#endif
-
-#include <mLib/arena.h>
-#include <mLib/dstr.h>
-#include <mLib/sub.h>
-
-#include "lmem.h"
-
-/*----- Arena operations --------------------------------------------------*/
-
-static void *aalloc(arena *a, size_t sz) { return l_alloc((lmem *)a, sz); }
-static void afree(arena *a, void *p) { l_free((lmem *)a, p); }
-static void apurge(arena *a) { l_purge((lmem *)a); }
-
-static const arena_ops l_ops = { aalloc, arena_fakerealloc, afree, apurge };
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @l_init@ --- *
- *
- * Arguments: @lmem *lm@ = pointer to locked memory descriptor
- * @size_t sz@ = size of locked memory area requested
- *
- * Returns: Zero if everything is fine, @+1@ if some insecure memory was
- * allocated, and @-1@ if everything went horribly wrong.
- *
- * Use: Initializes the locked memory manager. This function is safe
- * to call in a privileged program; privileges should usually be
- * dropped after allocating the locked memory block.
- *
- * You must call @sub_init@ before allocating locked memory
- * buffers.
- */
-
-int l_init(lmem *lm, size_t sz)
-{
- char *p;
- int rc = 0;
- l_node *l;
-
- /* --- Preliminaries --- */
-
- lm->a.ops = &l_ops;
- lm->err = 0;
- lm->f = 0;
-
- /* --- Try making a secure locked passphrase buffer --- *
- *
- * Drop privileges before emitting diagnostic messages.
- */
-
-#ifdef HAVE_MLOCK
-
- /* --- Memory-map a page from somewhere --- */
-
-# ifdef MAP_ANON
- p = mmap(0, sz, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
-# else
- {
- int fd;
- if ((fd = open("/dev/zero", O_RDWR)) >= 0) {
- p = mmap(0, sz, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
- close(fd);
- }
- }
-# endif
-
- /* --- Lock the page in memory --- *
- *
- * Why does @mmap@ return such a stupid result if it fails?
- */
-
- if (p == 0 || p == MAP_FAILED) {
- lm->emsg = "couldn't map locked memory area: %s";
- lm->err = errno;
- p = 0;
- } else if (mlock(p, sz)) {
- lm->emsg = "error locking memory area: %s";
- lm->err = errno;
- munmap(p, sz);
- p = 0;
- } else
- lm->f |= LF_LOCKED;
-
-#endif
-
- /* --- Make a standard passphrase buffer --- */
-
-#ifdef HAVE_MLOCK
- if (!p)
-#else
- lm->err = 0;
- lm->emsg = "locked memory not available on this system";
-#endif
- {
- if ((p = malloc(sz)) == 0) {
- lm->emsg = "not enough standard memory!";
- lm->err = ENOMEM;
- return (-1);
- }
- rc = +1;
- }
-
- /* --- Initialize the buffer --- */
-
- lm->sz = lm->free = sz;
- lm->p = p;
-
- /* --- Initialize the free list --- */
-
- l = CREATE(l_node);
- l->next = 0;
- l->p = p;
- l->sz = sz;
- l->f = 0;
- lm->l = l;
-
- /* --- Done --- */
-
- return (rc);
-}
-
-/* --- @l_alloc@ --- *
- *
- * Arguments: @lmem *lm@ = pointer to locked memory descriptor
- * @size_t sz@ = size requested
- *
- * Returns: Pointer to allocated memory.
- *
- * Use: Allocates @sz@ bytes of locked memory.
- */
-
-void *l_alloc(lmem *lm, size_t sz)
-{
- l_node *l;
-
- sz = (sz + 3u) & ~3u;
- for (l = lm->l; l; l = l->next) {
- if (l->f & LF_ALLOC)
- continue;
- if (l->sz < sz)
- continue;
- l->f |= LF_ALLOC;
- if (l->sz > sz) {
- l_node *n = CREATE(l_node);
- n->next = l->next;
- n->p = l->p + sz;
- n->sz = l->sz - sz;
- l->sz = sz;
- n->f = 0;
- l->next = n;
- }
- assert(((void)"Locked buffer space has vanished", lm->free >= sz));
- lm->free -= sz;
- return (l->p);
- }
- return (0);
-}
-
-/* --- @l_free@ --- *
- *
- * Arguments: @lmem *lm@ = pointer to locked memory descriptor
- * @void *p@ = pointer to block
- *
- * Returns: ---
- *
- * Use: Releases a block of locked memory.
- */
-
-void l_free(lmem *lm, void *p)
-{
- l_node *l;
- l_node *ll = 0;
-
- for (l = lm->l; l; l = l->next) {
- size_t sz;
-
- /* --- If this isn't the block, skip it --- */
-
- if (l->p != p) {
- ll = l;
- continue;
- }
- assert(((void)"Block is already free", l->f & LF_ALLOC));
-
- /* --- Coalesce with adjacent free blocks --- */
-
- l->f &= ~LF_ALLOC;
- sz = l->sz;
- memset(p, 0, sz);
-
- if (ll && !(ll->f & LF_ALLOC)) {
- assert(((void)"Previous block doesn't fit", ll->p + ll->sz == p));
- ll->sz += sz;
- ll->next = l->next;
- DESTROY(l);
- l = ll;
- }
-
- ll = l->next;
- if (ll && !(ll->f & LF_ALLOC)) {
- assert(((void)"Next block doesn't fit", ll->p == l->p + l->sz));
- l->sz += ll->sz;
- l->next = ll->next;
- DESTROY(ll);
- }
-
- lm->free += sz;
- assert(((void)"Free lunch", lm->free <= lm->sz));
- return;
- }
- assert(((void)"Not a locked block", 0));
-}
-
-/* --- @l_purge@ --- *
- *
- * Arguments: @lmem *lm@ = pointer to locked memory descriptor
- *
- * Returns: ---
- *
- * Use: Purges all the free blocks in the buffer, and clears all of
- * the locked memory. Memory is not freed back to the system.
- */
-
-void l_purge(lmem *lm)
-{
- l_node *l;
-
- l = lm->l;
- while (l) {
- l_node *ll = l->next;
- DESTROY(l);
- l = ll;
- }
- memset(lm->p, 0, lm->sz);
- l = CREATE(l_node);
- l->next = 0;
- l->p = lm->p;
- l->sz = lm->sz;
- l->f = 0;
- lm->l = l;
- lm->free = l->sz;
-}
-
-/* --- @l_destroy@ --- *
- *
- * Arguments: @lmem *lm@ = pointer to locked memory descriptor
- *
- * Returns: ---
- *
- * Use: Disposes of a locked memory arena permanently.
- */
-
-void l_destroy(lmem *lm)
-{
- l_node *l;
-
- l = lm->l;
- while (l) {
- l_node *ll = l->next;
- DESTROY(l);
- l = ll;
- }
- memset(lm->p, 0, lm->sz);
-
-#ifdef HAVE_MLOCK
- if (lm->f & LF_LOCKED)
- munmap(lm->p, lm->sz);
- else
-#endif
- free(lm->p); /*sic*/
-}
-
-/* --- @l_report@ --- *
- *
- * Arguments: @lmem *lm@ = pointer to locked memory descriptor
- * @dstr *d@ = string to write the error message on
- *
- * Returns: Zero if the buffer is fine, @+1@ if there was a problem
- * getting locked memory but insecure stuff could be allocated,
- * and @-1@ if not even insecure memory could be found.
- *
- * Use: Returns a user-digestable explanation for the state of a
- * locked memory buffer. If the return code is zero, no message
- * is emitted to the string @d@.
- */
-
-int l_report(lmem *lm, dstr *d)
-{
- int rc;
- if (lm->err)
- dstr_putf(d, lm->emsg, strerror(lm->err));
- if (!lm->p)
- rc = -1;
- else if (lm->err)
- rc = +1;
- else
- rc = 0;
- return (rc);
-}
-
-/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff