Diffstat (limited to 'pwmanager/libcrypt/crypt/secmem.c') (more/less context) (ignore whitespace changes)
| -rw-r--r-- | pwmanager/libcrypt/crypt/secmem.c | 653 |
1 files changed, 653 insertions, 0 deletions
diff --git a/pwmanager/libcrypt/crypt/secmem.c b/pwmanager/libcrypt/crypt/secmem.c new file mode 100644 index 0000000..163bf20 --- a/dev/null +++ b/pwmanager/libcrypt/crypt/secmem.c @@ -0,0 +1,653 @@ +/* secmem.c - memory allocation from a secure heap + * Copyright (C) 1998, 1999, 2000, 2001, 2002, + * 2003 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser general Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt 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 Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <stdarg.h> +#include <unistd.h> +#include <stddef.h> + +#if defined(HAVE_MLOCK) || defined(HAVE_MMAP) +#include <sys/mman.h> +#include <sys/types.h> +#include <fcntl.h> +#ifdef USE_CAPABILITIES +#include <sys/capability.h> +#endif +#endif + +#include "ath.h" +#include "g10lib.h" +#include "secmem.h" + +#if defined (MAP_ANON) && ! defined (MAP_ANONYMOUS) +#define MAP_ANONYMOUS MAP_ANON +#endif + +#define DEFAULT_POOL_SIZE 16384 +#define DEFAULT_PAGE_SIZE 4096 + +typedef struct memblock +{ + unsigned size; /* Size of the memory available to the + user. */ + int flags; /* See below. */ + PROPERLY_ALIGNED_TYPE aligned; +} memblock_t; + +/* This flag specifies that the memory block is in use. */ +#define MB_FLAG_ACTIVE 1 << 0 + +/* The pool of secure memory. */ +static void *pool; + +/* Size of POOL in bytes. */ +static size_t pool_size; + +/* True, if the memory pool is ready for use. May be checked in an + atexit function. */ +static volatile int pool_okay; + +/* True, if the memory pool is mmapped. */ +static volatile int pool_is_mmapped; + +/* FIXME? */ +static int disable_secmem; +static int show_warning; +static int no_warning; +static int suspend_warning; + +/* Stats. */ +static unsigned int cur_alloced, cur_blocks; + +/* Lock protecting accesses to the memory pool. */ +static ath_mutex_t secmem_lock; + +/* Convenient macros. */ +#define SECMEM_LOCK ath_mutex_lock (&secmem_lock) +#define SECMEM_UNLOCK ath_mutex_unlock (&secmem_lock) + +/* The size of the memblock structure; this does not include the + memory that is available to the user. */ +#define BLOCK_HEAD_SIZE \ + offsetof (memblock_t, aligned) + +/* Convert an address into the according memory block structure. */ +#define ADDR_TO_BLOCK(addr) \ + (memblock_t *) ((char *) addr - BLOCK_HEAD_SIZE) + +/* Check wether MB is a valid block. */ +#define BLOCK_VALID(mb) \ + (((char *) mb - (char *) pool) < pool_size) + +/* Update the stats. */ +static void +stats_update (size_t add, size_t sub) +{ + if (add) + { + cur_alloced += add; + cur_blocks++; + } + if (sub) + { + cur_alloced -= sub; + cur_blocks--; + } +} + +/* Return the block following MB or NULL, if MB is the last block. */ +static memblock_t * +mb_get_next (memblock_t *mb) +{ + memblock_t *mb_next; + + mb_next = (memblock_t *) ((char *) mb + BLOCK_HEAD_SIZE + mb->size); + + if (! BLOCK_VALID (mb_next)) + mb_next = NULL; + + return mb_next; +} + +/* Return the block preceeding MB or NULL, if MB is the first + block. */ +static memblock_t * +mb_get_prev (memblock_t *mb) +{ + memblock_t *mb_prev, *mb_next; + + if (mb == pool) + mb_prev = NULL; + else + { + mb_prev = (memblock_t *) pool; + while (1) + { + mb_next = mb_get_next (mb_prev); + if (mb_next == mb) + break; + else + mb_prev = mb_next; + } + } + + return mb_prev; +} + +/* If the preceeding block of MB and/or the following block of MB + exist and are not active, merge them to form a bigger block. */ +static void +mb_merge (memblock_t *mb) +{ + memblock_t *mb_prev, *mb_next; + + mb_prev = mb_get_prev (mb); + mb_next = mb_get_next (mb); + + if (mb_prev && (! (mb_prev->flags & MB_FLAG_ACTIVE))) + { + mb_prev->size += BLOCK_HEAD_SIZE + mb->size; + mb = mb_prev; + } + if (mb_next && (! (mb_next->flags & MB_FLAG_ACTIVE))) + mb->size += BLOCK_HEAD_SIZE + mb_next->size; +} + +/* Return a new block, which can hold SIZE bytes. */ +static memblock_t * +mb_get_new (memblock_t *block, size_t size) +{ + memblock_t *mb, *mb_split; + + for (mb = block; BLOCK_VALID (mb); mb = mb_get_next (mb)) + if (! (mb->flags & MB_FLAG_ACTIVE) && mb->size >= size) + { + /* Found a free block. */ + mb->flags |= MB_FLAG_ACTIVE; + + if (mb->size - size > BLOCK_HEAD_SIZE) + { + /* Split block. */ + + mb_split = (memblock_t *) (((char *) mb) + BLOCK_HEAD_SIZE + size); + mb_split->size = mb->size - size - BLOCK_HEAD_SIZE; + mb_split->flags = 0; + + mb->size = size; + + mb_merge (mb_split); + + } + + break; + } + + if (! BLOCK_VALID (mb)) + mb = NULL; + + return mb; +} + +/* Print a warning message. */ +static void +print_warn (void) +{ + if (!no_warning) + log_info (_("Warning: using insecure memory!\n")); +} + +/* Lock the memory pages into core and drop privileges. */ +static void +lock_pool (void *p, size_t n) +{ +#if defined(USE_CAPABILITIES) && defined(HAVE_MLOCK) + int err; + + cap_set_proc (cap_from_text ("cap_ipc_lock+ep")); + err = mlock (p, n); + if (err && errno) + err = errno; + cap_set_proc (cap_from_text ("cap_ipc_lock+p")); + + if (err) + { + if (errno != EPERM +#ifdef EAGAIN /* OpenBSD returns this */ + && errno != EAGAIN +#endif +#ifdef ENOSYS /* Some SCOs return this (function not implemented) */ + && errno != ENOSYS +#endif +#ifdef ENOMEM /* Linux might return this. */ + && errno != ENOMEM +#endif + ) + log_error ("can't lock memory: %s\n", strerror (err)); + show_warning = 1; + } + +#elif defined(HAVE_MLOCK) + uid_t uid; + int err; + + uid = getuid (); + +#ifdef HAVE_BROKEN_MLOCK + /* Under HP/UX mlock segfaults if called by non-root. Note, we have + noch checked whether mlock does really work under AIX where we + also detected a broken nlock. Note further, that using plock () + is not a good idea under AIX. */ + if (uid) + { + errno = EPERM; + err = errno; + } + else + { + err = mlock (p, n); + if (err && errno) + err = errno; + } +#else /* !HAVE_BROKEN_MLOCK */ + err = mlock (p, n); + if (err && errno) + err = errno; +#endif /* !HAVE_BROKEN_MLOCK */ + + if (uid && ! geteuid ()) + { + /* check that we really dropped the privs. + * Note: setuid(0) should always fail */ + if (setuid (uid) || getuid () != geteuid () || !setuid (0)) + log_fatal ("failed to reset uid: %s\n", strerror (errno)); + } + + if (err) + { + if (errno != EPERM +#ifdef EAGAIN /* OpenBSD returns this. */ + && errno != EAGAIN +#endif +#ifdef ENOSYS /* Some SCOs return this (function not implemented). */ + && errno != ENOSYS +#endif +#ifdef ENOMEM /* Linux might return this. */ + && errno != ENOMEM +#endif + ) + log_error ("can't lock memory: %s\n", strerror (err)); + show_warning = 1; + } + +#elif defined ( __QNX__ ) + /* QNX does not page at all, so the whole secure memory stuff does + * not make much sense. However it is still of use because it + * wipes out the memory on a free(). + * Therefore it is sufficient to suppress the warning + */ +#elif defined (HAVE_DOSISH_SYSTEM) || defined (__CYGWIN__) + /* It does not make sense to print such a warning, given the fact that + * this whole Windows !@#$% and their user base are inherently insecure + */ +#elif defined (__riscos__) + /* no virtual memory on RISC OS, so no pages are swapped to disc, + * besides we don't have mmap, so we don't use it! ;-) + * But don't complain, as explained above. + */ +#else + log_info ("Please note that you don't have secure memory on this system\n"); +#endif +} + +/* Initialize POOL. */ +static void +init_pool (size_t n) +{ + size_t pgsize; + memblock_t *mb; + + pool_size = n; + + if (disable_secmem) + log_bug ("secure memory is disabled"); + +#ifdef HAVE_GETPAGESIZE + pgsize = getpagesize (); +#else + pgsize = DEFAULT_PAGE_SIZE; +#endif + +#if HAVE_MMAP + pool_size = (pool_size + pgsize - 1) & ~(pgsize - 1); +#ifdef MAP_ANONYMOUS + pool = mmap (0, pool_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); +#else /* map /dev/zero instead */ + { + int fd; + + fd = open ("/dev/zero", O_RDWR); + if (fd == -1) + { + log_error ("can't open /dev/zero: %s\n", strerror (errno)); + pool = (void *) -1; + } + else + { + pool = mmap (0, pool_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + } + } +#endif + if (pool == (void *) -1) + log_info ("can't mmap pool of %u bytes: %s - using malloc\n", + (unsigned) pool_size, strerror (errno)); + else + { + pool_is_mmapped = 1; + pool_okay = 1; + } + +#endif + if (!pool_okay) + { + pool = malloc (pool_size); + if (!pool) + log_fatal ("can't allocate memory pool of %u bytes\n", + (unsigned) pool_size); + else + pool_okay = 1; + } + + /* Initialize first memory block. */ + mb = (memblock_t *) pool; + mb->size = pool_size; + mb->flags = 0; +} + +void +_gcry_secmem_set_flags (unsigned flags) +{ + int was_susp; + + SECMEM_LOCK; + + was_susp = suspend_warning; + no_warning = flags & GCRY_SECMEM_FLAG_NO_WARNING; + suspend_warning = flags & GCRY_SECMEM_FLAG_SUSPEND_WARNING; + + /* and now issue the warning if it is not longer suspended */ + if (was_susp && !suspend_warning && show_warning) + { + show_warning = 0; + print_warn (); + } + + SECMEM_UNLOCK; +} + +unsigned +_gcry_secmem_get_flags (void) +{ + unsigned flags; + + SECMEM_LOCK; + + flags = no_warning ? GCRY_SECMEM_FLAG_NO_WARNING : 0; + flags |= suspend_warning ? GCRY_SECMEM_FLAG_SUSPEND_WARNING : 0; + + SECMEM_UNLOCK; + + return flags; +} + +/* Initialize the secure memory system. If running with the necessary + privileges, the secure memory pool will be locked into the core in + order to prevent page-outs of the data. Furthermore allocated + secure memory will be wiped out when released. */ +void +_gcry_secmem_init (size_t n) +{ + SECMEM_LOCK; + + if (!n) + { +#ifdef USE_CAPABILITIES + /* drop all capabilities */ + cap_set_proc (cap_from_text ("all-eip")); + +#elif !defined(HAVE_DOSISH_SYSTEM) + uid_t uid; + + disable_secmem = 1; + uid = getuid (); + if (uid != geteuid ()) + { + if (setuid (uid) || getuid () != geteuid () || !setuid (0)) + log_fatal ("failed to drop setuid\n"); + } +#endif + } + else + { + if (n < DEFAULT_POOL_SIZE) + n = DEFAULT_POOL_SIZE; + if (! pool_okay) + { + init_pool (n); + if (! geteuid ()) + lock_pool (pool, n); + else if (!no_warning) + log_info ("Secure memory is not locked into core\n"); + } + else + log_error ("Oops, secure memory pool already initialized\n"); + } + + SECMEM_UNLOCK; +} + + +static void * +_gcry_secmem_malloc_internal (size_t size) +{ + memblock_t *mb; + + if (!pool_okay) + { + log_info (_ + ("operation is not possible without initialized secure memory\n")); + exit (2); + } + if (show_warning && !suspend_warning) + { + show_warning = 0; + print_warn (); + } + + /* Blocks are always a multiple of 32. */ + size = ((size + 31) / 32) * 32; + + mb = mb_get_new ((memblock_t *) pool, size); + if (mb) + stats_update (size, 0); + + return mb ? &mb->aligned.c : NULL; +} + +void * +_gcry_secmem_malloc (size_t size) +{ + void *p; + + SECMEM_LOCK; + p = _gcry_secmem_malloc_internal (size); + SECMEM_UNLOCK; + + return p; +} + +static void +_gcry_secmem_free_internal (void *a) +{ + memblock_t *mb; + int size; + + if (!a) + return; + + mb = ADDR_TO_BLOCK (a); + size = mb->size; + + /* This does not make much sense: probably this memory is held in the + * cache. We do it anyway: */ +#define MB_WIPE_OUT(byte) \ + memset ((memblock_t *) ((char *) mb + BLOCK_HEAD_SIZE), (byte), size); + + MB_WIPE_OUT (0xff); + MB_WIPE_OUT (0xaa); + MB_WIPE_OUT (0x55); + MB_WIPE_OUT (0x00); + + stats_update (0, size); + + mb->flags &= ~MB_FLAG_ACTIVE; + + /* Update stats. */ + + mb_merge (mb); +} + +/* Wipe out and release memory. */ +void +_gcry_secmem_free (void *a) +{ + SECMEM_LOCK; + _gcry_secmem_free_internal (a); + SECMEM_UNLOCK; +} + +/* Realloc memory. */ +void * +_gcry_secmem_realloc (void *p, size_t newsize) +{ + memblock_t *mb; + size_t size; + void *a; + + SECMEM_LOCK; + + mb = (memblock_t *) ((char *) p - ((size_t) &((memblock_t *) 0)->aligned.c)); + size = mb->size; + if (newsize < size) + { + /* It is easier to not shrink the memory. */ + a = p; + } + else + { + a = _gcry_secmem_malloc_internal (newsize); + if (a) + { + memcpy (a, p, size); + memset ((char *) a + size, 0, newsize - size); + _gcry_secmem_free_internal (p); + } + } + + SECMEM_UNLOCK; + + return a; +} + +int +_gcry_private_is_secure (const void *p) +{ + int ret = 0; + + SECMEM_LOCK; + + if (pool_okay && BLOCK_VALID (ADDR_TO_BLOCK (p))) + ret = 1; + + SECMEM_UNLOCK; + + return ret; +} + + +/**************** + * Warning: This code might be called by an interrupt handler + * and frankly, there should really be such a handler, + * to make sure that the memory is wiped out. + * We hope that the OS wipes out mlocked memory after + * receiving a SIGKILL - it really should do so, otherwise + * there is no chance to get the secure memory cleaned. + */ +void +_gcry_secmem_term () +{ + if (!pool_okay) + return; + + wipememory2 (pool, 0xff, pool_size); + wipememory2 (pool, 0xaa, pool_size); + wipememory2 (pool, 0x55, pool_size); + wipememory2 (pool, 0x00, pool_size); +#if HAVE_MMAP + if (pool_is_mmapped) + munmap (pool, pool_size); +#endif + pool = NULL; + pool_okay = 0; + pool_size = 0; +} + + +void +_gcry_secmem_dump_stats () +{ +#if 1 + SECMEM_LOCK; + + if (pool_okay) + log_info ("secmem usage: %u/%lu bytes in %u blocks\n", + cur_alloced, (unsigned long)pool_size, cur_blocks); + SECMEM_UNLOCK; +#else + memblock_t *mb; + int i; + + SECMEM_LOCK; + + for (i = 0, mb = (memblock_t *) pool; + BLOCK_VALID (mb); + mb = mb_get_next (mb), i++) + log_info ("SECMEM: [%s] block: %i; size: %i\n", + (mb->flags & MB_FLAG_ACTIVE) ? "used" : "free", + i, + mb->size); + SECMEM_UNLOCK; +#endif +} |