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/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* gtksecurememory.c - API for allocating memory that is non-pageable
Copyright 2007 Stefan Walter
Copyright 2020 GNOME Foundation
SPDX-License-Identifier: LGPL-2.0-or-later
The Gnome Keyring Library 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.
The Gnome Keyring Library 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 the Gnome Library; see the file COPYING.LIB. If not,
see <http://www.gnu.org/licenses/>.
Author: Stef Walter <stef@memberwebs.com>
*/
/*
* IMPORTANT: This is pure vanila standard C, no glib. We need this
* because certain consumers of this protocol need to be built
* without linking in any special libraries. ie: the PKCS#11 module.
*/
#include "config.h"
#include "gtksecurememoryprivate.h"
#include <sys/types.h>
#if defined(HAVE_SYS_MMAN_H)
#include <sys/mman.h>
#endif
#include <stddef.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <assert.h>
#ifdef WITH_VALGRIND
#include <valgrind/valgrind.h>
#include <valgrind/memcheck.h>
#endif
#define DEBUG_SECURE_MEMORY 0
#if DEBUG_SECURE_MEMORY
#define DEBUG_ALLOC(msg, n) fprintf(stderr, "%s %lu bytes\n", msg, n);
#else
#define DEBUG_ALLOC(msg, n)
#endif
#define DEFAULT_BLOCK_SIZE 16384
#define DO_LOCK() \
GTK_SECURE_GLOBALS.lock ();
#define DO_UNLOCK() \
GTK_SECURE_GLOBALS.unlock ();
typedef struct {
void (* lock) (void);
void (* unlock) (void);
void * (* fallback_alloc) (void *pointer,
size_t length);
void (* fallback_free) (void *pointer);
void * pool_data;
const char * pool_version;
} GtkSecureGlob;
#include <glib.h>
#ifdef G_OS_WIN32
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
# include <dpapi.h> /* for CryptProtectMemory() */
#endif
#define GTK_SECURE_POOL_VER_STR "1.0"
static int show_warning = 1;
static int gtk_secure_warnings = 1;
static GMutex memory_mutex;
static void
gtk_memory_lock (void)
{
g_mutex_lock (&memory_mutex);
}
static void
gtk_memory_unlock (void)
{
g_mutex_unlock (&memory_mutex);
}
static GtkSecureGlob GTK_SECURE_GLOBALS = {
.lock = gtk_memory_lock,
.unlock = gtk_memory_unlock,
.fallback_alloc = g_realloc,
.fallback_free = g_free,
.pool_data = NULL,
.pool_version = GTK_SECURE_POOL_VER_STR,
};
/*
* We allocate all memory in units of sizeof(void*). This
* is our definition of 'word'.
*/
typedef void* word_t;
/* The amount of extra words we can allocate */
#define WASTE 4
/*
* Track allocated memory or a free block. This structure is not stored
* in the secure memory area. It is allocated from a pool of other
* memory. See meta_pool_xxx ().
*/
typedef struct _Cell {
word_t *words; /* Pointer to secure memory */
size_t n_words; /* Amount of secure memory in words */
size_t requested; /* Amount actually requested by app, in bytes, 0 if unused */
const char *tag; /* Tag which describes the allocation */
struct _Cell *next; /* Next in memory ring */
struct _Cell *prev; /* Previous in memory ring */
} Cell;
/*
* A block of secure memory. This structure is the header in that block.
*/
typedef struct _Block {
word_t *words; /* Actual memory hangs off here */
size_t n_words; /* Number of words in block */
size_t n_used; /* Number of used allocations */
struct _Cell* used_cells; /* Ring of used allocations */
struct _Cell* unused_cells; /* Ring of unused allocations */
struct _Block *next; /* Next block in list */
} Block;
/* -----------------------------------------------------------------------------
* UNUSED STACK
*/
static inline void
unused_push (void **stack, void *ptr)
{
g_assert (ptr);
g_assert (stack);
*((void**)ptr) = *stack;
*stack = ptr;
}
static inline void*
unused_pop (void **stack)
{
void *ptr;
g_assert (stack);
ptr = *stack;
*stack = *(void**)ptr;
return ptr;
}
static inline void*
unused_peek (void **stack)
{
g_assert (stack);
return *stack;
}
/* -----------------------------------------------------------------------------
* POOL META DATA ALLOCATION
*
* A pool for memory meta data. We allocate fixed size blocks. There are actually
* two different structures stored in this pool: Cell and Block. Cell is allocated
* way more often, and is bigger so we just allocate that size for both.
*/
/* Pool allocates this data type */
typedef union _Item {
Cell cell;
Block block;
} Item;
typedef struct _Pool {
struct _Pool *next; /* Next pool in list */
size_t length; /* Length in bytes of the pool */
size_t used; /* Number of cells used in pool */
void *unused; /* Unused stack of unused stuff */
size_t n_items; /* Total number of items in pool */
Item items[1]; /* Actual items hang off here */
} Pool;
static int
check_pool_version (void)
{
if (GTK_SECURE_GLOBALS.pool_version == NULL ||
strcmp (GTK_SECURE_GLOBALS.pool_version, GTK_SECURE_POOL_VER_STR) != 0) {
return 0;
}
return 1;
}
static void *
pool_alloc (void)
{
if (!check_pool_version ()) {
if (show_warning && gtk_secure_warnings)
fprintf (stderr, "the secure memory pool version does not match the code '%s' != '%s'\n",
GTK_SECURE_GLOBALS.pool_version ? GTK_SECURE_GLOBALS.pool_version : "(null)",
GTK_SECURE_POOL_VER_STR);
show_warning = 0;
return NULL;
}
#if defined(HAVE_MMAP) && defined(HAVE_GETPAGESIZE)
/* A pool with an available item */
Pool *pool = NULL;
for (pool = GTK_SECURE_GLOBALS.pool_data; pool != NULL; pool = pool->next) {
if (unused_peek (&pool->unused))
break;
}
void *item = NULL;
/* Create a new pool */
if (pool == NULL) {
size_t len = getpagesize () * 2;
void *pages = mmap (0, len, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (pages == MAP_FAILED)
return NULL;
/* Fill in the block header, and include in block list */
pool = pages;
pool->next = GTK_SECURE_GLOBALS.pool_data;
GTK_SECURE_GLOBALS.pool_data = pool;
pool->length = len;
pool->used = 0;
pool->unused = NULL;
/* Fill block with unused items */
pool->n_items = (len - sizeof (Pool)) / sizeof (Item);
for (size_t i = 0; i < pool->n_items; ++i)
unused_push (&pool->unused, pool->items + i);
#ifdef WITH_VALGRIND
VALGRIND_CREATE_MEMPOOL(pool, 0, 0);
#endif
}
++pool->used;
g_assert (unused_peek (&pool->unused));
item = unused_pop (&pool->unused);
#ifdef WITH_VALGRIND
VALGRIND_MEMPOOL_ALLOC (pool, item, sizeof (Item));
#endif
return memset (item, 0, sizeof (Item));
#else /* HAVE_MMAP */
return NULL;
#endif
}
static void
pool_free (void* item)
{
#ifdef HAVE_MMAP
Pool *pool, **at;
char *ptr, *beg, *end;
ptr = item;
/* Find which block this one belongs to */
for (at = (Pool **)&GTK_SECURE_GLOBALS.pool_data, pool = *at;
pool != NULL; at = &pool->next, pool = *at) {
beg = (char*)pool->items;
end = (char*)pool + pool->length - sizeof (Item);
if (ptr >= beg && ptr <= end) {
g_assert ((ptr - beg) % sizeof (Item) == 0);
break;
}
}
/* Otherwise invalid meta */
g_assert (at);
g_assert (pool);
g_assert (pool->used > 0);
/* No more meta cells used in this block, remove from list, destroy */
if (pool->used == 1) {
*at = pool->next;
#ifdef WITH_VALGRIND
VALGRIND_DESTROY_MEMPOOL (pool);
#endif
munmap (pool, pool->length);
return;
}
#ifdef WITH_VALGRIND
VALGRIND_MEMPOOL_FREE (pool, item);
VALGRIND_MAKE_MEM_UNDEFINED (item, sizeof (Item));
#endif
--pool->used;
memset (item, 0xCD, sizeof (Item));
unused_push (&pool->unused, item);
#endif /* HAVE_MMAP */
}
#ifndef G_DISABLE_ASSERT
static int
pool_valid (void* item)
{
Pool *pool;
char *ptr, *beg, *end;
ptr = item;
/* Find which block this one belongs to */
for (pool = GTK_SECURE_GLOBALS.pool_data; pool; pool = pool->next) {
beg = (char*)pool->items;
end = (char*)pool + pool->length - sizeof (Item);
if (ptr >= beg && ptr <= end)
return (pool->used && (ptr - beg) % sizeof (Item) == 0);
}
return 0;
}
#endif /* G_DISABLE_g_assert */
/* -----------------------------------------------------------------------------
* SEC ALLOCATION
*
* Each memory cell begins and ends with a pointer to its metadata. These are also
* used as guards or red zones. Since they're treated as redzones by valgrind we
* have to jump through a few hoops before reading and/or writing them.
*/
static inline size_t
sec_size_to_words (size_t length)
{
return (length % sizeof (void*) ? 1 : 0) + (length / sizeof (void*));
}
static inline void
sec_write_guards (Cell *cell)
{
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_UNDEFINED (cell->words, sizeof (word_t));
VALGRIND_MAKE_MEM_UNDEFINED (cell->words + cell->n_words - 1, sizeof (word_t));
#endif
((void**)cell->words)[0] = (void*)cell;
((void**)cell->words)[cell->n_words - 1] = (void*)cell;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_NOACCESS (cell->words, sizeof (word_t));
VALGRIND_MAKE_MEM_NOACCESS (cell->words + cell->n_words - 1, sizeof (word_t));
#endif
}
static inline void
sec_check_guards (Cell *cell)
{
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (cell->words, sizeof (word_t));
VALGRIND_MAKE_MEM_DEFINED (cell->words + cell->n_words - 1, sizeof (word_t));
#endif
g_assert(((void**)cell->words)[0] == (void*)cell);
g_assert(((void**)cell->words)[cell->n_words - 1] == (void*)cell);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_NOACCESS (cell->words, sizeof (word_t));
VALGRIND_MAKE_MEM_NOACCESS (cell->words + cell->n_words - 1, sizeof (word_t));
#endif
}
static void
sec_insert_cell_ring (Cell **ring, Cell *cell)
{
g_assert (ring);
g_assert (cell);
g_assert (cell != *ring);
g_assert (cell->next == NULL);
g_assert (cell->prev == NULL);
/* Insert back into the mix of available memory */
if (*ring) {
cell->next = (*ring)->next;
cell->prev = *ring;
cell->next->prev = cell;
cell->prev->next = cell;
} else {
cell->next = cell;
cell->prev = cell;
}
*ring = cell;
g_assert (cell->next->prev == cell);
g_assert (cell->prev->next == cell);
}
static void
sec_remove_cell_ring (Cell **ring, Cell *cell)
{
g_assert (ring);
g_assert (*ring);
g_assert (cell->next);
g_assert (cell->prev);
g_assert (cell->next->prev == cell);
g_assert (cell->prev->next == cell);
if (cell == *ring) {
/* The last meta? */
if (cell->next == cell) {
g_assert (cell->prev == cell);
*ring = NULL;
/* Just pointing to this meta */
} else {
g_assert (cell->prev != cell);
*ring = cell->next;
}
}
cell->next->prev = cell->prev;
cell->prev->next = cell->next;
cell->next = cell->prev = NULL;
g_assert (*ring != cell);
}
static inline void*
sec_cell_to_memory (Cell *cell)
{
return cell->words + 1;
}
static inline int
sec_is_valid_word (Block *block, word_t *word)
{
return (word >= block->words && word < block->words + block->n_words);
}
static inline void
sec_clear_undefined (void *memory,
size_t from,
size_t to)
{
char *ptr = memory;
g_assert (from <= to);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_UNDEFINED (ptr + from, to - from);
#endif
memset (ptr + from, 0, to - from);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_UNDEFINED (ptr + from, to - from);
#endif
}
static inline void
sec_clear_noaccess (void *memory, size_t from, size_t to)
{
char *ptr = memory;
g_assert (from <= to);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_UNDEFINED (ptr + from, to - from);
#endif
memset (ptr + from, 0, to - from);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_NOACCESS (ptr + from, to - from);
#endif
}
static Cell*
sec_neighbor_before (Block *block, Cell *cell)
{
word_t *word;
g_assert (cell);
g_assert (block);
word = cell->words - 1;
if (!sec_is_valid_word (block, word))
return NULL;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (word, sizeof (word_t));
#endif
cell = *word;
sec_check_guards (cell);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_NOACCESS (word, sizeof (word_t));
#endif
return cell;
}
static Cell*
sec_neighbor_after (Block *block, Cell *cell)
{
word_t *word;
g_assert (cell);
g_assert (block);
word = cell->words + cell->n_words;
if (!sec_is_valid_word (block, word))
return NULL;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (word, sizeof (word_t));
#endif
cell = *word;
sec_check_guards (cell);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_NOACCESS (word, sizeof (word_t));
#endif
return cell;
}
static void*
sec_alloc (Block *block,
const char *tag,
size_t length)
{
Cell *cell, *other;
size_t n_words;
void *memory;
g_assert (block);
g_assert (length);
g_assert (tag);
if (!block->unused_cells)
return NULL;
/*
* Each memory allocation is aligned to a pointer size, and
* then, sandwidched between two pointers to its meta data.
* These pointers also act as guards.
*
* We allocate memory in units of sizeof (void*)
*/
n_words = sec_size_to_words (length) + 2;
/* Look for a cell of at least our required size */
cell = block->unused_cells;
while (cell->n_words < n_words) {
cell = cell->next;
if (cell == block->unused_cells) {
cell = NULL;
break;
}
}
if (!cell)
return NULL;
g_assert (cell->tag == NULL);
g_assert (cell->requested == 0);
g_assert (cell->prev);
g_assert (cell->words);
sec_check_guards (cell);
/* Steal from the cell if it's too long */
if (cell->n_words > n_words + WASTE) {
other = pool_alloc ();
if (!other)
return NULL;
other->n_words = n_words;
other->words = cell->words;
cell->n_words -= n_words;
cell->words += n_words;
sec_write_guards (other);
sec_write_guards (cell);
cell = other;
}
if (cell->next)
sec_remove_cell_ring (&block->unused_cells, cell);
++block->n_used;
cell->tag = tag;
cell->requested = length;
sec_insert_cell_ring (&block->used_cells, cell);
memory = sec_cell_to_memory (cell);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_UNDEFINED (memory, length);
#endif
return memset (memory, 0, length);
}
static void*
sec_free (Block *block, void *memory)
{
Cell *cell, *other;
word_t *word;
g_assert (block);
g_assert (memory);
word = memory;
--word;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (word, sizeof (word_t));
#endif
/* Lookup the meta for this memory block (using guard pointer) */
g_assert (sec_is_valid_word (block, word));
g_assert (pool_valid (*word));
cell = *word;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (cell->words, cell->n_words * sizeof (word_t));
#endif
sec_check_guards (cell);
sec_clear_noaccess (memory, 0, cell->requested);
sec_check_guards (cell);
g_assert (cell->requested > 0);
g_assert (cell->tag != NULL);
/* Remove from the used cell ring */
sec_remove_cell_ring (&block->used_cells, cell);
/* Find previous unallocated neighbor, and merge if possible */
other = sec_neighbor_before (block, cell);
if (other && other->requested == 0) {
g_assert (other->tag == NULL);
g_assert (other->next && other->prev);
other->n_words += cell->n_words;
sec_write_guards (other);
pool_free (cell);
cell = other;
}
/* Find next unallocated neighbor, and merge if possible */
other = sec_neighbor_after (block, cell);
if (other && other->requested == 0) {
g_assert (other->tag == NULL);
g_assert (other->next && other->prev);
other->n_words += cell->n_words;
other->words = cell->words;
if (cell->next)
sec_remove_cell_ring (&block->unused_cells, cell);
sec_write_guards (other);
pool_free (cell);
cell = other;
}
/* Add to the unused list if not already there */
if (!cell->next)
sec_insert_cell_ring (&block->unused_cells, cell);
cell->tag = NULL;
cell->requested = 0;
--block->n_used;
return NULL;
}
static void
memcpy_with_vbits (void *dest,
void *src,
size_t length)
{
#ifdef WITH_VALGRIND
int vbits_setup = 0;
void *vbits = NULL;
if (RUNNING_ON_VALGRIND) {
vbits = malloc (length);
if (vbits != NULL)
vbits_setup = VALGRIND_GET_VBITS (src, vbits, length);
VALGRIND_MAKE_MEM_DEFINED (src, length);
}
#endif
memcpy (dest, src, length);
#ifdef WITH_VALGRIND
if (vbits_setup == 1) {
VALGRIND_SET_VBITS (dest, vbits, length);
VALGRIND_SET_VBITS (src, vbits, length);
}
free (vbits);
#endif
}
static void*
sec_realloc (Block *block,
const char *tag,
void *memory,
size_t length)
{
Cell *cell, *other;
word_t *word;
size_t n_words;
size_t valid;
void *alloc;
/* Standard realloc behavior, should have been handled elsewhere */
g_assert (memory != NULL);
g_assert (length > 0);
g_assert (tag != NULL);
/* Dig out where the meta should be */
word = memory;
--word;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (word, sizeof (word_t));
#endif
g_assert (sec_is_valid_word (block, word));
g_assert (pool_valid (*word));
cell = *word;
/* Validate that it's actually for real */
sec_check_guards (cell);
g_assert (cell->requested > 0);
g_assert (cell->tag != NULL);
/* The amount of valid data */
valid = cell->requested;
/* How many words we actually want */
n_words = sec_size_to_words (length) + 2;
/* Less memory is required than is in the cell */
if (n_words <= cell->n_words) {
/* TODO: No shrinking behavior yet */
cell->requested = length;
alloc = sec_cell_to_memory (cell);
/*
* Even though we may be reusing the same cell, that doesn't
* mean that the allocation is shrinking. It could have shrunk
* and is now expanding back some.
*/
if (length < valid)
sec_clear_undefined (alloc, length, valid);
return alloc;
}
/* Need braaaaaiiiiiinsss... */
while (cell->n_words < n_words) {
/* See if we have a neighbor who can give us some memory */
other = sec_neighbor_after (block, cell);
if (!other || other->requested != 0)
break;
/* Eat the whole neighbor if not too big */
if (n_words - cell->n_words + WASTE >= other->n_words) {
cell->n_words += other->n_words;
sec_write_guards (cell);
sec_remove_cell_ring (&block->unused_cells, other);
pool_free (other);
/* Steal from the neighbor */
} else {
other->words += n_words - cell->n_words;
other->n_words -= n_words - cell->n_words;
sec_write_guards (other);
cell->n_words = n_words;
sec_write_guards (cell);
}
}
if (cell->n_words >= n_words) {
cell->requested = length;
cell->tag = tag;
alloc = sec_cell_to_memory (cell);
sec_clear_undefined (alloc, valid, length);
return alloc;
}
/* That didn't work, try alloc/free */
alloc = sec_alloc (block, tag, length);
if (alloc) {
memcpy_with_vbits (alloc, memory, valid);
sec_free (block, memory);
}
return alloc;
}
static size_t
sec_allocated (Block *block, void *memory)
{
Cell *cell;
word_t *word;
g_assert (block);
g_assert (memory);
word = memory;
--word;
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (word, sizeof (word_t));
#endif
/* Lookup the meta for this memory block (using guard pointer) */
g_assert (sec_is_valid_word (block, word));
g_assert (pool_valid (*word));
cell = *word;
sec_check_guards (cell);
g_assert (cell->requested > 0);
g_assert (cell->tag != NULL);
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_NOACCESS (word, sizeof (word_t));
#endif
return cell->requested;
}
static void
sec_validate (Block *block)
{
Cell *cell;
word_t *word, *last;
#ifdef WITH_VALGRIND
if (RUNNING_ON_VALGRIND)
return;
#endif
word = block->words;
last = word + block->n_words;
for (;;) {
g_assert (word < last);
g_assert (sec_is_valid_word (block, word));
g_assert (pool_valid (*word));
cell = *word;
/* Validate that it's actually for real */
sec_check_guards (cell);
/* Is it an allocated block? */
if (cell->requested > 0) {
g_assert (cell->tag != NULL);
g_assert (cell->next != NULL);
g_assert (cell->prev != NULL);
g_assert (cell->next->prev == cell);
g_assert (cell->prev->next == cell);
g_assert (cell->requested <= (cell->n_words - 2) * sizeof (word_t));
/* An unused block */
} else {
g_assert (cell->tag == NULL);
g_assert (cell->next != NULL);
g_assert (cell->prev != NULL);
g_assert (cell->next->prev == cell);
g_assert (cell->prev->next == cell);
}
word += cell->n_words;
if (word == last)
break;
}
}
/* -----------------------------------------------------------------------------
* LOCKED MEMORY
*/
static void*
sec_acquire_pages (size_t *sz,
const char *during_tag)
{
g_assert (sz);
g_assert (*sz);
g_assert (during_tag);
#if defined(HAVE_MLOCK) && defined(HAVE_MMAP) && defined(HAVE_GETPAGESIZE)
/* Make sure sz is a multiple of the page size */
unsigned long pgsize = getpagesize ();
*sz = (*sz + pgsize -1) & ~(pgsize - 1);
void *pages = mmap (0, *sz, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (pages == MAP_FAILED) {
if (show_warning && gtk_secure_warnings)
fprintf (stderr, "couldn't map %lu bytes of memory (%s): %s\n",
(unsigned long)*sz, during_tag, strerror (errno));
show_warning = 0;
return NULL;
}
if (mlock (pages, *sz) < 0) {
if (show_warning && gtk_secure_warnings && errno != EPERM) {
fprintf (stderr, "couldn't lock %lu bytes of memory (%s): %s\n",
(unsigned long)*sz, during_tag, strerror (errno));
show_warning = 0;
}
munmap (pages, *sz);
return NULL;
}
DEBUG_ALLOC ("gtk-secure-memory: new block ", *sz);
#if defined(HAVE_MADVISE) && defined(MADV_DONTDUMP)
if (madvise (pages, *sz, MADV_DONTDUMP) < 0) {
if (show_warning && gtk_secure_warnings) {
/*
* Not fatal - this was added in Linux 3.4 and older
* kernels will legitimately fail this at runtime
*/
fprintf (stderr, "couldn't MADV_DONTDUMP %lu bytes of memory (%s): %s\n",
(unsigned long)*sz, during_tag, strerror (errno));
}
}
#endif
show_warning = 1;
return pages;
#elif defined G_OS_WIN32
/* Make sure sz is a multiple of CRYPTPROTECTMEMORY_BLOCK_SIZE in wincrypt.h */
*sz = (*sz + CRYPTPROTECTMEMORY_BLOCK_SIZE - 1) & ~(CRYPTPROTECTMEMORY_BLOCK_SIZE - 1);
void *data = (void *) LocalAlloc (LPTR, *sz);
if (data == NULL) {
if (show_warning && gtk_secure_warnings)
fprintf (stderr, "couldn't allocate %lu bytes of memory (%s): %#010lX\n",
(unsigned long)*sz, during_tag, GetLastError ());
show_warning = 0;
return NULL;
}
if (!CryptProtectMemory (data, *sz, CRYPTPROTECTMEMORY_SAME_PROCESS)) {
if (show_warning && gtk_secure_warnings)
fprintf (stderr, "couldn't encrypt %lu bytes of memory (%s): %#010lX\n",
(unsigned long)*sz, during_tag, GetLastError ());
show_warning = 0;
return NULL;
}
DEBUG_ALLOC ("gtk-secure-memory: new block ", *sz);
show_warning = 1;
return data;
#else
if (show_warning && gtk_secure_warnings)
fprintf (stderr, "your system does not support private memory");
show_warning = 0;
return NULL;
#endif
}
static void
sec_release_pages (void *pages, size_t sz)
{
g_assert (pages);
#if defined(HAVE_MLOCK) && defined(HAVE_GETPAGESIZE)
g_assert (sz % getpagesize () == 0);
if (munlock (pages, sz) < 0 && gtk_secure_warnings)
fprintf (stderr, "couldn't unlock private memory: %s\n", strerror (errno));
if (munmap (pages, sz) < 0 && gtk_secure_warnings)
fprintf (stderr, "couldn't unmap private anonymous memory: %s\n", strerror (errno));
DEBUG_ALLOC ("gtk-secure-memory: freed block ", sz);
#elif defined G_OS_WIN32
g_assert (sz % CRYPTPROTECTMEMORY_BLOCK_SIZE == 0);
if (!CryptUnprotectMemory (pages, sz, CRYPTPROTECTMEMORY_SAME_PROCESS))
fprintf (stderr, "couldn't decrypt private memory: %#010lX\n", GetLastError ());
if (LocalFree (pages) != NULL)
fprintf (stderr, "couldn't free private anonymous memory: %#010lX\n", GetLastError ());
DEBUG_ALLOC ("gtk-secure-memory: freed block ", sz);
#else
g_assert (FALSE);
#endif
}
/* -----------------------------------------------------------------------------
* MANAGE DIFFERENT BLOCKS
*/
static Block *all_blocks = NULL;
static Block*
sec_block_create (size_t size,
const char *during_tag)
{
Block *block;
Cell *cell;
g_assert (during_tag);
/* We can force all all memory to be malloced */
if (getenv ("SECMEM_FORCE_FALLBACK"))
return NULL;
block = pool_alloc ();
if (!block)
return NULL;
cell = pool_alloc ();
if (!cell) {
pool_free (block);
return NULL;
}
/* The size above is a minimum, we're free to go bigger */
if (size < DEFAULT_BLOCK_SIZE)
size = DEFAULT_BLOCK_SIZE;
block->words = sec_acquire_pages (&size, during_tag);
block->n_words = size / sizeof (word_t);
if (!block->words) {
pool_free (block);
pool_free (cell);
return NULL;
}
#ifdef WITH_VALGRIND
VALGRIND_MAKE_MEM_DEFINED (block->words, size);
#endif
/* The first cell to allocate from */
cell->words = block->words;
cell->n_words = block->n_words;
cell->requested = 0;
sec_write_guards (cell);
sec_insert_cell_ring (&block->unused_cells, cell);
block->next = all_blocks;
all_blocks = block;
return block;
}
static void
sec_block_destroy (Block *block)
{
Block *bl, **at;
Cell *cell;
g_assert (block);
g_assert (block->words);
g_assert (block->n_used == 0);
/* Remove from the list */
for (at = &all_blocks, bl = *at; bl; at = &bl->next, bl = *at) {
if (bl == block) {
*at = block->next;
break;
}
}
/* Must have been found */
g_assert (bl == block);
g_assert (block->used_cells == NULL);
/* Release all the meta data cells */
while (block->unused_cells) {
cell = block->unused_cells;
sec_remove_cell_ring (&block->unused_cells, cell);
pool_free (cell);
}
/* Release all pages of secure memory */
sec_release_pages (block->words, block->n_words * sizeof (word_t));
pool_free (block);
}
/* ------------------------------------------------------------------------
* PUBLIC FUNCTIONALITY
*/
void*
gtk_secure_alloc_full (const char *tag,
size_t length,
int flags)
{
Block *block;
void *memory = NULL;
if (tag == NULL)
tag = "?";
if (length > 0xFFFFFFFF / 2) {
if (gtk_secure_warnings)
fprintf (stderr, "tried to allocate an insane amount of memory: %lu\n",
(unsigned long)length);
return NULL;
}
/* Can't allocate zero bytes */
if (length == 0)
return NULL;
DO_LOCK ();
for (block = all_blocks; block; block = block->next) {
memory = sec_alloc (block, tag, length);
if (memory)
break;
}
/* None of the current blocks have space, allocate new */
if (!memory) {
block = sec_block_create (length, tag);
if (block)
memory = sec_alloc (block, tag, length);
}
#ifdef WITH_VALGRIND
if (memory != NULL)
VALGRIND_MALLOCLIKE_BLOCK (memory, length, sizeof (void*), 1);
#endif
DO_UNLOCK ();
if (!memory && (flags & GTK_SECURE_USE_FALLBACK) && GTK_SECURE_GLOBALS.fallback_alloc != NULL) {
memory = GTK_SECURE_GLOBALS.fallback_alloc (NULL, length);
if (memory) /* Our returned memory is always zeroed */
memset (memory, 0, length);
}
if (!memory)
errno = ENOMEM;
return memory;
}
void*
gtk_secure_realloc_full (const char *tag,
void *memory,
size_t length,
int flags)
{
Block *block = NULL;
size_t previous = 0;
int donew = 0;
void *alloc = NULL;
if (tag == NULL)
tag = "?";
if (length > 0xFFFFFFFF / 2) {
if (gtk_secure_warnings)
fprintf (stderr, "tried to allocate an excessive amount of memory: %lu\n",
(unsigned long)length);
return NULL;
}
if (memory == NULL)
return gtk_secure_alloc_full (tag, length, flags);
if (!length) {
gtk_secure_free_full (memory, flags);
return NULL;
}
DO_LOCK ();
/* Find out where it belongs to */
for (block = all_blocks; block; block = block->next) {
if (sec_is_valid_word (block, memory)) {
previous = sec_allocated (block, memory);
#ifdef WITH_VALGRIND
/* Let valgrind think we are unallocating so that it'll validate */
VALGRIND_FREELIKE_BLOCK (memory, sizeof (word_t));
#endif
alloc = sec_realloc (block, tag, memory, length);
#ifdef WITH_VALGRIND
/* Now tell valgrind about either the new block or old one */
VALGRIND_MALLOCLIKE_BLOCK (alloc ? alloc : memory,
alloc ? length : previous,
sizeof (word_t), 1);
#endif
break;
}
}
/* If it didn't work we may need to allocate a new block */
if (block && !alloc)
donew = 1;
if (block && block->n_used == 0)
sec_block_destroy (block);
DO_UNLOCK ();
if (!block) {
if ((flags & GTK_SECURE_USE_FALLBACK) && GTK_SECURE_GLOBALS.fallback_alloc) {
/*
* In this case we can't zero the returned memory,
* because we don't know what the block size was.
*/
return GTK_SECURE_GLOBALS.fallback_alloc (memory, length);
} else {
if (gtk_secure_warnings)
fprintf (stderr, "memory does not belong to secure memory pool: 0x%08" G_GUINTPTR_FORMAT "x\n",
(guintptr) memory);
g_assert (0 && "memory does does not belong to secure memory pool");
return NULL;
}
}
if (donew) {
alloc = gtk_secure_alloc_full (tag, length, flags);
if (alloc) {
memcpy_with_vbits (alloc, memory, previous);
gtk_secure_free_full (memory, flags);
}
}
if (!alloc)
errno = ENOMEM;
return alloc;
}
void
gtk_secure_free (void *memory)
{
gtk_secure_free_full (memory, GTK_SECURE_USE_FALLBACK);
}
void
gtk_secure_free_full (void *memory, int flags)
{
Block *block = NULL;
if (memory == NULL)
return;
DO_LOCK ();
/* Find out where it belongs to */
for (block = all_blocks; block; block = block->next) {
if (sec_is_valid_word (block, memory))
break;
}
#ifdef WITH_VALGRIND
/* We like valgrind's warnings, so give it a first whack at checking for errors */
if (block != NULL || !(flags & GTK_SECURE_USE_FALLBACK))
VALGRIND_FREELIKE_BLOCK (memory, sizeof (word_t));
#endif
if (block != NULL) {
sec_free (block, memory);
if (block->n_used == 0)
sec_block_destroy (block);
}
DO_UNLOCK ();
if (!block) {
if ((flags & GTK_SECURE_USE_FALLBACK) && GTK_SECURE_GLOBALS.fallback_free) {
GTK_SECURE_GLOBALS.fallback_free (memory);
} else {
if (gtk_secure_warnings)
fprintf (stderr, "memory does not belong to secure memory pool: 0x%08" G_GUINTPTR_FORMAT "x\n",
(guintptr) memory);
g_assert (0 && "memory does does not belong to secure memory pool");
}
}
}
int
gtk_secure_check (const void *memory)
{
Block *block = NULL;
DO_LOCK ();
/* Find out where it belongs to */
for (block = all_blocks; block; block = block->next) {
if (sec_is_valid_word (block, (word_t*)memory))
break;
}
DO_UNLOCK ();
return block == NULL ? 0 : 1;
}
void
gtk_secure_validate (void)
{
Block *block = NULL;
DO_LOCK ();
for (block = all_blocks; block; block = block->next)
sec_validate (block);
DO_UNLOCK ();
}
static gtk_secure_rec *
records_for_ring (Cell *cell_ring,
gtk_secure_rec *records,
unsigned int *count,
unsigned int *total)
{
gtk_secure_rec *new_rec;
unsigned int allocated = *count;
Cell *cell;
cell = cell_ring;
do {
if (*count >= allocated) {
new_rec = realloc (records, sizeof (gtk_secure_rec) * (allocated + 32));
if (new_rec == NULL) {
*count = 0;
free (records);
return NULL;
} else {
records = new_rec;
allocated += 32;
}
}
if (cell != NULL) {
records[*count].request_length = cell->requested;
records[*count].block_length = cell->n_words * sizeof (word_t);
records[*count].tag = cell->tag;
(*count)++;
(*total) += cell->n_words;
cell = cell->next;
}
} while (cell != NULL && cell != cell_ring);
return records;
}
gtk_secure_rec *
gtk_secure_records (unsigned int *count)
{
gtk_secure_rec *records = NULL;
Block *block = NULL;
unsigned int total;
*count = 0;
DO_LOCK ();
for (block = all_blocks; block != NULL; block = block->next) {
total = 0;
records = records_for_ring (block->unused_cells, records, count, &total);
if (records == NULL)
break;
records = records_for_ring (block->used_cells, records, count, &total);
if (records == NULL)
break;
/* Make sure this actually accounts for all memory */
g_assert (total == block->n_words);
}
DO_UNLOCK ();
return records;
}
char*
gtk_secure_strdup_full (const char *tag,
const char *str,
int options)
{
size_t len;
char *res;
if (!str)
return NULL;
len = strlen (str) + 1;
res = (char *)gtk_secure_alloc_full (tag, len, options);
strcpy (res, str);
return res;
}
char *
gtk_secure_strndup_full (const char *tag,
const char *str,
size_t length,
int options)
{
size_t len;
char *res;
const char *end;
if (!str)
return NULL;
end = memchr (str, '\0', length);
if (end != NULL)
length = (end - str);
len = length + 1;
res = (char *)gtk_secure_alloc_full (tag, len, options);
memcpy (res, str, len);
return res;
}
void
gtk_secure_clear (void *p, size_t length)
{
volatile char *vp;
if (p == NULL)
return;
vp = (volatile char*)p;
while (length) {
*vp = 0xAA;
vp++;
length--;
}
}
void
gtk_secure_strclear (char *str)
{
if (!str)
return;
gtk_secure_clear ((unsigned char*)str, strlen (str));
}
void
gtk_secure_strfree (char *str)
{
/*
* If we're using unpageable 'secure' memory, then the free call
* should zero out the memory, but because on certain platforms
* we may be using normal memory, zero it out here just in case.
*/
gtk_secure_strclear (str);
gtk_secure_free_full (str, GTK_SECURE_USE_FALLBACK);
}
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