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secmem.c
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/* secmem.c - memory allocation from a secure heap
* Copyright (C) 1998, 1999, 2000, 2001, 2002,
* 2003, 2007 Free Software Foundation, Inc.
* Copyright (C) 2013, 2016 g10 Code GmbH
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#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
"g10lib.h"
#include
"secmem.h"
#if defined (MAP_ANON) && ! defined (MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
#endif
#define MINIMUM_POOL_SIZE 16384
#define STANDARD_POOL_SIZE 32768
#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)
/* An object describing a memory pool. */
typedef
struct
pooldesc_s
{
/* A link to the next pool. This is used to connect the overflow
* pools. */
struct
pooldesc_s
*
volatile
next
;
/* A memory buffer used as allocation pool. */
void
*
mem
;
/* The allocated size of MEM. */
size_t
size
;
/* Flag indicating that this memory pool is ready for use. May be
* checked in an atexit function. */
volatile
int
okay
;
/* Flag indicating whether MEM is mmapped. */
volatile
int
is_mmapped
;
/* The number of allocated bytes and the number of used blocks in
* this pool. */
unsigned
int
cur_alloced
,
cur_blocks
;
}
pooldesc_t
;
/* The pool of secure memory. This is the head of a linked list with
* the first element being the standard mlock-ed pool and the
* following elements being the overflow pools. */
static
pooldesc_t
mainpool
;
/* A couple of flags with some being set early. */
static
int
disable_secmem
;
static
int
show_warning
;
static
int
not_locked
;
static
int
no_warning
;
static
int
suspend_warning
;
static
int
no_mlock
;
static
int
no_priv_drop
;
static
unsigned
int
auto_expand
;
/* Lock protecting accesses to the memory pools. */
GPGRT_LOCK_DEFINE
(
secmem_lock
);
/* Convenient macros. */
#define SECMEM_LOCK gpgrt_lock_lock (&secmem_lock)
#define SECMEM_UNLOCK gpgrt_lock_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 *) (void *) ((char *) addr - BLOCK_HEAD_SIZE)
/* Prototypes. */
static
void
secmem_dump_stats_internal
(
int
extended
);
/*
* Functions
*/
/* Memory barrier */
static
inline
void
memory_barrier
(
void
)
{
#ifdef HAVE_SYNC_SYNCHRONIZE
#ifdef HAVE_GCC_ASM_VOLATILE_MEMORY
asm
volatile
(
""
:::
"memory"
);
#endif
/* Use GCC / clang intrinsic for memory barrier. */
__sync_synchronize
();
#else
/* Slow portable alternative, implement memory barrier by using mutex. */
gpgrt_lock_t
tmp
;
memset
(
&
tmp
,
0
,
sizeof
(
tmp
));
gpgrt_lock_init
(
&
tmp
);
gpgrt_lock_lock
(
&
tmp
);
gpgrt_lock_unlock
(
&
tmp
);
gpgrt_lock_destroy
(
&
tmp
);
#endif
}
/* Check whether P points into POOL. */
static
inline
int
ptr_into_pool_p
(
pooldesc_t
*
pool
,
const
void
*
p
)
{
/* We need to convert pointers to addresses. This is required by
C-99 6.5.8 to avoid undefined behaviour. See also
http://lists.gnupg.org/pipermail/gcrypt-devel/2007-February/001102.html
*/
uintptr_t
p_addr
=
(
uintptr_t
)
p
;
uintptr_t
pool_addr
=
(
uintptr_t
)
pool
->
mem
;
return
p_addr
>=
pool_addr
&&
p_addr
<
pool_addr
+
pool
->
size
;
}
/* Update the stats. */
static
void
stats_update
(
pooldesc_t
*
pool
,
size_t
add
,
size_t
sub
)
{
if
(
add
)
{
pool
->
cur_alloced
+=
add
;
pool
->
cur_blocks
++
;
}
if
(
sub
)
{
pool
->
cur_alloced
-=
sub
;
pool
->
cur_blocks
--
;
}
}
/* Return the block following MB or NULL, if MB is the last block. */
static
memblock_t
*
mb_get_next
(
pooldesc_t
*
pool
,
memblock_t
*
mb
)
{
memblock_t
*
mb_next
;
mb_next
=
(
memblock_t
*
)
(
void
*
)
((
char
*
)
mb
+
BLOCK_HEAD_SIZE
+
mb
->
size
);
if
(
!
ptr_into_pool_p
(
pool
,
mb_next
))
mb_next
=
NULL
;
return
mb_next
;
}
/* Return the block preceding MB or NULL, if MB is the first
block. */
static
memblock_t
*
mb_get_prev
(
pooldesc_t
*
pool
,
memblock_t
*
mb
)
{
memblock_t
*
mb_prev
,
*
mb_next
;
if
(
mb
==
pool
->
mem
)
mb_prev
=
NULL
;
else
{
mb_prev
=
(
memblock_t
*
)
pool
->
mem
;
while
(
1
)
{
mb_next
=
mb_get_next
(
pool
,
mb_prev
);
if
(
mb_next
==
mb
)
break
;
else
mb_prev
=
mb_next
;
}
}
return
mb_prev
;
}
/* If the preceding 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
(
pooldesc_t
*
pool
,
memblock_t
*
mb
)
{
memblock_t
*
mb_prev
,
*
mb_next
;
mb_prev
=
mb_get_prev
(
pool
,
mb
);
mb_next
=
mb_get_next
(
pool
,
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
(
pooldesc_t
*
pool
,
memblock_t
*
block
,
size_t
size
)
{
memblock_t
*
mb
,
*
mb_split
;
for
(
mb
=
block
;
ptr_into_pool_p
(
pool
,
mb
);
mb
=
mb_get_next
(
pool
,
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
*
)
(
void
*
)
(((
char
*
)
mb
)
+
BLOCK_HEAD_SIZE
+
size
);
mb_split
->
size
=
mb
->
size
-
size
-
BLOCK_HEAD_SIZE
;
mb_split
->
flags
=
0
;
mb
->
size
=
size
;
mb_merge
(
pool
,
mb_split
);
}
break
;
}
if
(
!
ptr_into_pool_p
(
pool
,
mb
))
{
gpg_err_set_errno
(
ENOMEM
);
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 of pool P of size N into core and drop
* privileges. */
static
void
lock_pool_pages
(
void
*
p
,
size_t
n
)
{
#if 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
=
-1
;
}
else
{
err
=
no_mlock
?
0
:
mlock
(
p
,
n
);
}
#else
/* !HAVE_BROKEN_MLOCK */
err
=
no_mlock
?
0
:
mlock
(
p
,
n
);
#endif
/* !HAVE_BROKEN_MLOCK */
/* Test whether we are running setuid(0). */
if
(
uid
&&
!
geteuid
())
{
/* Yes, we are. */
if
(
!
no_priv_drop
)
{
/* 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
/* BSD and also Linux may return 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
(
errno
));
show_warning
=
1
;
not_locked
=
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. */
(
void
)
p
;
(
void
)
n
;
#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. */
(
void
)
p
;
(
void
)
n
;
#else
(
void
)
p
;
(
void
)
n
;
if
(
!
no_mlock
)
log_info
(
"Please note that you don't have secure memory on this system
\n
"
);
#endif
}
/* Initialize POOL. */
static
void
init_pool
(
pooldesc_t
*
pool
,
size_t
n
)
{
memblock_t
*
mb
;
pool
->
size
=
n
;
if
(
disable_secmem
)
log_bug
(
"secure memory is disabled"
);
#if HAVE_MMAP
{
size_t
pgsize
;
long
int
pgsize_val
;
# if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
pgsize_val
=
sysconf
(
_SC_PAGESIZE
);
# elif defined(HAVE_GETPAGESIZE)
pgsize_val
=
getpagesize
();
# else
pgsize_val
=
-1
;
# endif
pgsize
=
(
pgsize_val
>
0
)
?
pgsize_val
:
DEFAULT_PAGE_SIZE
;
pool
->
size
=
(
pool
->
size
+
pgsize
-
1
)
&
~
(
pgsize
-
1
);
# ifdef MAP_ANONYMOUS
pool
->
mem
=
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
->
mem
=
(
void
*
)
-1
;
}
else
{
pool
->
mem
=
mmap
(
0
,
pool
->
size
,
(
PROT_READ
|
PROT_WRITE
),
MAP_PRIVATE
,
fd
,
0
);
close
(
fd
);
}
}
# endif
if
(
pool
->
mem
==
(
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
/*HAVE_MMAP*/
if
(
!
pool
->
okay
)
{
pool
->
mem
=
malloc
(
pool
->
size
);
if
(
!
pool
->
mem
)
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
->
mem
;
mb
->
size
=
pool
->
size
-
BLOCK_HEAD_SIZE
;
mb
->
flags
=
0
;
}
/* Enable overflow pool allocation in all cases. CHUNKSIZE is a hint
* on how large to allocate overflow pools. */
void
_gcry_secmem_set_auto_expand
(
unsigned
int
chunksize
)
{
/* Round up to a multiple of the STANDARD_POOL_SIZE. */
chunksize
=
((
chunksize
+
(
2
*
STANDARD_POOL_SIZE
)
-
1
)
/
STANDARD_POOL_SIZE
)
*
STANDARD_POOL_SIZE
;
if
(
chunksize
<
STANDARD_POOL_SIZE
)
/* In case of overflow. */
chunksize
=
STANDARD_POOL_SIZE
;
SECMEM_LOCK
;
auto_expand
=
chunksize
;
SECMEM_UNLOCK
;
}
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
;
no_mlock
=
flags
&
GCRY_SECMEM_FLAG_NO_MLOCK
;
no_priv_drop
=
flags
&
GCRY_SECMEM_FLAG_NO_PRIV_DROP
;
/* 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
int
_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
;
flags
|=
not_locked
?
GCRY_SECMEM_FLAG_NOT_LOCKED
:
0
;
flags
|=
no_mlock
?
GCRY_SECMEM_FLAG_NO_MLOCK
:
0
;
flags
|=
no_priv_drop
?
GCRY_SECMEM_FLAG_NO_PRIV_DROP
:
0
;
SECMEM_UNLOCK
;
return
flags
;
}
/* This function initializes the main memory pool MAINPOOL. It is
* expected to be called with the secmem lock held. */
static
void
_gcry_secmem_init_internal
(
size_t
n
)
{
pooldesc_t
*
pool
;
pool
=
&
mainpool
;
if
(
!
n
)
{
#ifdef USE_CAPABILITIES
/* drop all capabilities */
if
(
!
no_priv_drop
)
{
cap_t
cap
;
cap
=
cap_from_text
(
"all-eip"
);
cap_set_proc
(
cap
);
cap_free
(
cap
);
}
#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
<
MINIMUM_POOL_SIZE
)
n
=
MINIMUM_POOL_SIZE
;
if
(
!
pool
->
okay
)
{
init_pool
(
pool
,
n
);
lock_pool_pages
(
pool
->
mem
,
n
);
}
else
log_error
(
"Oops, secure memory pool already initialized
\n
"
);
}
}
/* 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
;
_gcry_secmem_init_internal
(
n
);
SECMEM_UNLOCK
;
}
gcry_err_code_t
_gcry_secmem_module_init
(
void
)
{
/* Not anymore needed. */
return
0
;
}
static
void
*
_gcry_secmem_malloc_internal
(
size_t
size
,
int
xhint
)
{
pooldesc_t
*
pool
;
memblock_t
*
mb
;
pool
=
&
mainpool
;
if
(
!
pool
->
okay
)
{
/* Try to initialize the pool if the user forgot about it. */
_gcry_secmem_init_internal
(
STANDARD_POOL_SIZE
);
if
(
!
pool
->
okay
)
{
log_info
(
_
(
"operation is not possible without "
"initialized secure memory
\n
"
));
gpg_err_set_errno
(
ENOMEM
);
return
NULL
;
}
}
if
(
not_locked
&&
fips_mode
())
{
log_info
(
_
(
"secure memory pool is not locked while in FIPS mode
\n
"
));
gpg_err_set_errno
(
ENOMEM
);
return
NULL
;
}
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
(
pool
,
(
memblock_t
*
)
pool
->
mem
,
size
);
if
(
mb
)
{
stats_update
(
pool
,
mb
->
size
,
0
);
return
&
mb
->
aligned
.
c
;
}
/* If we are called from xmalloc style functions resort to the
* overflow pools to return memory. We don't do this in FIPS mode,
* though. If the auto-expand option is active we do the expanding
* also for the standard malloc functions.
*
* The idea of using them by default only for the xmalloc function
* is so that a user can control whether memory will be allocated in
* the initial created mlock protected secmem area or may also be
* allocated from the overflow pools. */
if
((
xhint
||
auto_expand
)
&&
!
fips_mode
())
{
/* Check whether we can allocate from the overflow pools. */
for
(
pool
=
pool
->
next
;
pool
;
pool
=
pool
->
next
)
{
mb
=
mb_get_new
(
pool
,
(
memblock_t
*
)
pool
->
mem
,
size
);
if
(
mb
)
{
stats_update
(
pool
,
mb
->
size
,
0
);
return
&
mb
->
aligned
.
c
;
}
}
/* Allocate a new overflow pool. We put a new pool right after
* the mainpool so that the next allocation will happen in that
* pool and not in one of the older pools. When this new pool
* gets full we will try to find space in the older pools. */
pool
=
calloc
(
1
,
sizeof
*
pool
);
if
(
!
pool
)
return
NULL
;
/* Not enough memory for a new pool descriptor. */
pool
->
size
=
auto_expand
?
auto_expand
:
STANDARD_POOL_SIZE
;
pool
->
mem
=
malloc
(
pool
->
size
);
if
(
!
pool
->
mem
)
{
free
(
pool
);
return
NULL
;
/* Not enough memory available for a new pool. */
}
/* Initialize first memory block. */
mb
=
(
memblock_t
*
)
pool
->
mem
;
mb
->
size
=
pool
->
size
-
BLOCK_HEAD_SIZE
;
mb
->
flags
=
0
;
pool
->
okay
=
1
;
/* Take care: in _gcry_private_is_secure we do not lock and thus
* we assume that the second assignment below is atomic. Memory
* barrier prevents reordering of stores to new pool structure after
* MAINPOOL.NEXT assigment and prevents _gcry_private_is_secure seeing
* non-initialized POOL->NEXT pointers. */
pool
->
next
=
mainpool
.
next
;
memory_barrier
();
mainpool
.
next
=
pool
;
/* After the first time we allocated an overflow pool, print a
* warning. */
if
(
!
pool
->
next
)
print_warn
();
/* Allocate. */
mb
=
mb_get_new
(
pool
,
(
memblock_t
*
)
pool
->
mem
,
size
);
if
(
mb
)
{
stats_update
(
pool
,
mb
->
size
,
0
);
return
&
mb
->
aligned
.
c
;
}
}
return
NULL
;
}
/* Allocate a block from the secmem of SIZE. With XHINT set assume
* that the caller is a xmalloc style function. */
void
*
_gcry_secmem_malloc
(
size_t
size
,
int
xhint
)
{
void
*
p
;
SECMEM_LOCK
;
p
=
_gcry_secmem_malloc_internal
(
size
,
xhint
);
SECMEM_UNLOCK
;
return
p
;
}
static
int
_gcry_secmem_free_internal
(
void
*
a
)
{
pooldesc_t
*
pool
;
memblock_t
*
mb
;
int
size
;
for
(
pool
=
&
mainpool
;
pool
;
pool
=
pool
->
next
)
if
(
pool
->
okay
&&
ptr_into_pool_p
(
pool
,
a
))
break
;
if
(
!
pool
)
return
0
;
/* A does not belong to use. */
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) \
wipememory2 (((char *) mb + BLOCK_HEAD_SIZE), (byte), size)
MB_WIPE_OUT
(
0xff
);
MB_WIPE_OUT
(
0xaa
);
MB_WIPE_OUT
(
0x55
);
MB_WIPE_OUT
(
0x00
);
/* Update stats. */
stats_update
(
pool
,
0
,
size
);
mb
->
flags
&=
~
MB_FLAG_ACTIVE
;
mb_merge
(
pool
,
mb
);
return
1
;
/* Freed. */
}
/* Wipe out and release memory. Returns true if this function
* actually released A. */
int
_gcry_secmem_free
(
void
*
a
)
{
int
mine
;
if
(
!
a
)
return
1
;
/* Tell caller that we handled it. */
SECMEM_LOCK
;
mine
=
_gcry_secmem_free_internal
(
a
);
SECMEM_UNLOCK
;
return
mine
;
}
static
void
*
_gcry_secmem_realloc_internal
(
void
*
p
,
size_t
newsize
,
int
xhint
)
{
memblock_t
*
mb
;
size_t
size
;
void
*
a
;
mb
=
(
memblock_t
*
)
(
void
*
)
((
char
*
)
p
-
offsetof
(
memblock_t
,
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
,
xhint
);
if
(
a
)
{
memcpy
(
a
,
p
,
size
);
memset
((
char
*
)
a
+
size
,
0
,
newsize
-
size
);
_gcry_secmem_free_internal
(
p
);
}
}
return
a
;
}
/* Realloc memory. With XHINT set assume that the caller is a xmalloc
* style function. */
void
*
_gcry_secmem_realloc
(
void
*
p
,
size_t
newsize
,
int
xhint
)
{
void
*
a
;
SECMEM_LOCK
;
a
=
_gcry_secmem_realloc_internal
(
p
,
newsize
,
xhint
);
SECMEM_UNLOCK
;
return
a
;
}
/* Return true if P points into the secure memory areas. */
int
_gcry_private_is_secure
(
const
void
*
p
)
{
pooldesc_t
*
pool
;
/* We do no lock here because once a pool is allocated it will not
* be removed anymore (except for gcry_secmem_term). Further, as
* assigment of POOL->NEXT in new pool structure is visible in
* this thread before assigment of MAINPOOL.NEXT, pool list can be
* iterated locklessly. This visiblity is ensured by memory barrier
* between POOL->NEXT and MAINPOOL.NEXT assignments in
* _gcry_secmem_malloc_internal. */
for
(
pool
=
&
mainpool
;
pool
;
pool
=
pool
->
next
)
if
(
pool
->
okay
&&
ptr_into_pool_p
(
pool
,
p
))
return
1
;
return
0
;
}
/****************
* 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
(
void
)
{
pooldesc_t
*
pool
,
*
next
;
for
(
pool
=
&
mainpool
;
pool
;
pool
=
next
)
{
next
=
pool
->
next
;
if
(
!
pool
->
okay
)
continue
;
wipememory2
(
pool
->
mem
,
0xff
,
pool
->
size
);
wipememory2
(
pool
->
mem
,
0xaa
,
pool
->
size
);
wipememory2
(
pool
->
mem
,
0x55
,
pool
->
size
);
wipememory2
(
pool
->
mem
,
0x00
,
pool
->
size
);
if
(
0
)
;
#if HAVE_MMAP
else
if
(
pool
->
is_mmapped
)
munmap
(
pool
->
mem
,
pool
->
size
);
#endif
else
free
(
pool
->
mem
);
pool
->
mem
=
NULL
;
pool
->
okay
=
0
;
pool
->
size
=
0
;
if
(
pool
!=
&
mainpool
)
free
(
pool
);
}
mainpool
.
next
=
NULL
;
not_locked
=
0
;
}
/* Print stats of the secmem allocator. With EXTENDED passwed as true
* a detiled listing is returned (used for testing). */
void
_gcry_secmem_dump_stats
(
int
extended
)
{
SECMEM_LOCK
;
secmem_dump_stats_internal
(
extended
);
SECMEM_UNLOCK
;
}
static
void
secmem_dump_stats_internal
(
int
extended
)
{
pooldesc_t
*
pool
;
memblock_t
*
mb
;
int
i
,
poolno
;
for
(
pool
=
&
mainpool
,
poolno
=
0
;
pool
;
pool
=
pool
->
next
,
poolno
++
)
{
if
(
!
extended
)
{
if
(
pool
->
okay
)
log_info
(
"%-13s %u/%lu bytes in %u blocks
\n
"
,
pool
==
&
mainpool
?
"secmem usage:"
:
""
,
pool
->
cur_alloced
,
(
unsigned
long
)
pool
->
size
,
pool
->
cur_blocks
);
}
else
{
for
(
i
=
0
,
mb
=
(
memblock_t
*
)
pool
->
mem
;
ptr_into_pool_p
(
pool
,
mb
);
mb
=
mb_get_next
(
pool
,
mb
),
i
++
)
log_info
(
"SECMEM: pool %d %s block %i size %i
\n
"
,
poolno
,
(
mb
->
flags
&
MB_FLAG_ACTIVE
)
?
"used"
:
"free"
,
i
,
mb
->
size
);
}
}
}
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Expires
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