From 31a75745443a4e07aa55b743aa6ccf99cc473f2f Mon Sep 17 00:00:00 2001 From: Emmanuele Bassi Date: Tue, 8 Sep 2020 17:40:32 +0100 Subject: [PATCH] Import egg-secure-memory allocator from gcr We can re-use the code inside gcr, as we know that it's working, tested, and license compatible. --- gtk/gtksecurememory.c | 1434 ++++++++++++++++++++++++++++++++++ gtk/gtksecurememoryprivate.h | 95 +++ gtk/meson.build | 1 + 3 files changed, 1530 insertions(+) create mode 100644 gtk/gtksecurememory.c create mode 100644 gtk/gtksecurememoryprivate.h diff --git a/gtk/gtksecurememory.c b/gtk/gtksecurememory.c new file mode 100644 index 0000000000..55db84398b --- /dev/null +++ b/gtk/gtksecurememory.c @@ -0,0 +1,1434 @@ +/* -*- 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 . + + Author: Stef Walter +*/ + +/* + * 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 + +#if defined(HAVE_MLOCK) +#include +#endif + +#include +#include +#include +#include +#include +#include +#include + +#ifdef WITH_VALGRIND +#include +#include +#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 + +#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; + } + +#ifdef HAVE_MMAP + /* 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 inlude 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 **)>K_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) + /* 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); + + show_warning = 1; + return pages; + +#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) + 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); + +#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 actualy 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); +} diff --git a/gtk/gtksecurememoryprivate.h b/gtk/gtksecurememoryprivate.h new file mode 100644 index 0000000000..0209d4fc11 --- /dev/null +++ b/gtk/gtksecurememoryprivate.h @@ -0,0 +1,95 @@ +/* gtksecurememoryprivate.h - Allocator for non-pageable memory + + 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 . + + Author: Stef Walter +*/ + +#pragma once + +#include + +/* + * Main functionality + * + * Allocations return NULL on failure. + */ + +#define GTK_SECURE_USE_FALLBACK 0x0001 + +void * gtk_secure_alloc_full (const char *tag, + size_t length, + int options); + +void * gtk_secure_realloc_full (const char *tag, + void *p, + size_t length, + int options); + +void gtk_secure_free (void *p); + +void gtk_secure_free_full (void *p, + int fallback); + +void gtk_secure_clear (void *p, + size_t length); + +int gtk_secure_check (const void *p); + +void gtk_secure_validate (void); + +char * gtk_secure_strdup_full (const char *tag, + const char *str, + int options); + +char * gtk_secure_strndup_full (const char *tag, + const char *str, + size_t length, + int options); + +void gtk_secure_strclear (char *str); + +void gtk_secure_strfree (char *str); + +/* Simple wrappers */ + +static inline void *gtk_secure_alloc (size_t length) { + return gtk_secure_alloc_full ("gtk", length, GTK_SECURE_USE_FALLBACK); +} + +static inline void *gtk_secure_realloc (void *p, size_t length) { + return gtk_secure_realloc_full ("gtk", p, length, GTK_SECURE_USE_FALLBACK); +} + +static inline void *gtk_secure_strdup (const char *str) { + return gtk_secure_strdup_full ("gtk", str, GTK_SECURE_USE_FALLBACK); +} + +static inline void *gtk_secure_strndup (const char *str, size_t length) { + return gtk_secure_strndup_full ("gtk", str, length, GTK_SECURE_USE_FALLBACK); +} + +typedef struct { + const char *tag; + size_t request_length; + size_t block_length; +} gtk_secure_rec; + +gtk_secure_rec * gtk_secure_records (unsigned int *count); diff --git a/gtk/meson.build b/gtk/meson.build index 13bdd71d61..c644ac9696 100644 --- a/gtk/meson.build +++ b/gtk/meson.build @@ -134,6 +134,7 @@ gtk_private_sources = files([ 'gtkscaler.c', 'gtksearchengine.c', 'gtksearchenginemodel.c', + 'gtksecurememory.c', 'gtksizerequestcache.c', 'gtksortkeys.c', 'gtkstyleanimation.c',