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polarssl/library/memory_buffer_alloc.c

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/*
* Buffer-based memory allocator
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
#include "mbedtls/memory_buffer_alloc.h"
/* No need for the header guard as MBEDTLS_MEMORY_BUFFER_ALLOC_C
is dependent upon MBEDTLS_PLATFORM_C */
#include "mbedtls/platform.h"
#include "mbedtls/platform_util.h"
#include <string.h>
#if defined(MBEDTLS_MEMORY_BACKTRACE)
#include <execinfo.h>
#endif
#if defined(MBEDTLS_THREADING_C)
#include "mbedtls/threading.h"
#endif
#define MAGIC1 0xFF00AA55
#define MAGIC2 0xEE119966
#define MAX_BT 20
typedef struct _memory_header memory_header;
struct _memory_header
{
size_t magic1;
size_t size;
size_t alloc;
memory_header *prev;
memory_header *next;
memory_header *prev_free;
memory_header *next_free;
#if defined(MBEDTLS_MEMORY_BACKTRACE)
char **trace;
size_t trace_count;
#endif
size_t magic2;
};
typedef struct
{
unsigned char *buf;
size_t len;
memory_header *first;
memory_header *first_free;
int verify;
#if defined(MBEDTLS_MEMORY_DEBUG)
size_t alloc_count;
size_t free_count;
size_t total_used;
size_t maximum_used;
size_t header_count;
size_t maximum_header_count;
#endif
#if defined(MBEDTLS_THREADING_C)
mbedtls_threading_mutex_t mutex;
#endif
}
buffer_alloc_ctx;
static buffer_alloc_ctx heap;
#if defined(MBEDTLS_MEMORY_DEBUG)
static void debug_header( memory_header *hdr )
{
#if defined(MBEDTLS_MEMORY_BACKTRACE)
size_t i;
#endif
mbedtls_fprintf( stderr, "HDR: PTR(%10zu), PREV(%10zu), NEXT(%10zu), "
"ALLOC(%zu), SIZE(%10zu)\n",
(size_t) hdr, (size_t) hdr->prev, (size_t) hdr->next,
hdr->alloc, hdr->size );
mbedtls_fprintf( stderr, " FPREV(%10zu), FNEXT(%10zu)\n",
(size_t) hdr->prev_free, (size_t) hdr->next_free );
#if defined(MBEDTLS_MEMORY_BACKTRACE)
mbedtls_fprintf( stderr, "TRACE: \n" );
for( i = 0; i < hdr->trace_count; i++ )
mbedtls_fprintf( stderr, "%s\n", hdr->trace[i] );
mbedtls_fprintf( stderr, "\n" );
#endif
}
static void debug_chain( void )
{
memory_header *cur = heap.first;
mbedtls_fprintf( stderr, "\nBlock list\n" );
while( cur != NULL )
{
debug_header( cur );
cur = cur->next;
}
mbedtls_fprintf( stderr, "Free list\n" );
cur = heap.first_free;
while( cur != NULL )
{
debug_header( cur );
cur = cur->next_free;
}
}
#endif /* MBEDTLS_MEMORY_DEBUG */
static int verify_header( memory_header *hdr )
{
if( hdr->magic1 != MAGIC1 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: MAGIC1 mismatch\n" );
#endif
return( 1 );
}
if( hdr->magic2 != MAGIC2 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: MAGIC2 mismatch\n" );
#endif
return( 1 );
}
if( hdr->alloc > 1 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: alloc has illegal value\n" );
#endif
return( 1 );
}
if( hdr->prev != NULL && hdr->prev == hdr->next )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: prev == next\n" );
#endif
return( 1 );
}
if( hdr->prev_free != NULL && hdr->prev_free == hdr->next_free )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: prev_free == next_free\n" );
#endif
return( 1 );
}
return( 0 );
}
static int verify_chain( void )
{
memory_header *prv = heap.first, *cur;
if( prv == NULL || verify_header( prv ) != 0 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: verification of first header "
"failed\n" );
#endif
return( 1 );
}
if( heap.first->prev != NULL )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: verification failed: "
"first->prev != NULL\n" );
#endif
return( 1 );
}
cur = heap.first->next;
while( cur != NULL )
{
if( verify_header( cur ) != 0 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: verification of header "
"failed\n" );
#endif
return( 1 );
}
if( cur->prev != prv )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: verification failed: "
"cur->prev != prv\n" );
#endif
return( 1 );
}
prv = cur;
cur = cur->next;
}
return( 0 );
}
static void *buffer_alloc_calloc( size_t n, size_t size )
{
memory_header *new, *cur = heap.first_free;
unsigned char *p;
void *ret;
size_t original_len, len;
#if defined(MBEDTLS_MEMORY_BACKTRACE)
void *trace_buffer[MAX_BT];
size_t trace_cnt;
#endif
if( heap.buf == NULL || heap.first == NULL )
return( NULL );
original_len = len = n * size;
if( n == 0 || size == 0 || len / n != size )
return( NULL );
else if( len > (size_t)-MBEDTLS_MEMORY_ALIGN_MULTIPLE )
return( NULL );
if( len % MBEDTLS_MEMORY_ALIGN_MULTIPLE )
{
len -= len % MBEDTLS_MEMORY_ALIGN_MULTIPLE;
len += MBEDTLS_MEMORY_ALIGN_MULTIPLE;
}
// Find block that fits
//
while( cur != NULL )
{
if( cur->size >= len )
break;
cur = cur->next_free;
}
if( cur == NULL )
return( NULL );
if( cur->alloc != 0 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: block in free_list but allocated "
"data\n" );
#endif
mbedtls_exit( 1 );
}
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.alloc_count++;
#endif
// Found location, split block if > memory_header + 4 room left
//
if( cur->size - len < sizeof(memory_header) +
MBEDTLS_MEMORY_ALIGN_MULTIPLE )
{
cur->alloc = 1;
// Remove from free_list
//
if( cur->prev_free != NULL )
cur->prev_free->next_free = cur->next_free;
else
heap.first_free = cur->next_free;
if( cur->next_free != NULL )
cur->next_free->prev_free = cur->prev_free;
cur->prev_free = NULL;
cur->next_free = NULL;
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.total_used += cur->size;
if( heap.total_used > heap.maximum_used )
heap.maximum_used = heap.total_used;
#endif
#if defined(MBEDTLS_MEMORY_BACKTRACE)
trace_cnt = backtrace( trace_buffer, MAX_BT );
cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
cur->trace_count = trace_cnt;
#endif
if( ( heap.verify & MBEDTLS_MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
mbedtls_exit( 1 );
ret = (unsigned char *) cur + sizeof( memory_header );
memset( ret, 0, original_len );
return( ret );
}
p = ( (unsigned char *) cur ) + sizeof(memory_header) + len;
new = (memory_header *) p;
new->size = cur->size - len - sizeof(memory_header);
new->alloc = 0;
new->prev = cur;
new->next = cur->next;
#if defined(MBEDTLS_MEMORY_BACKTRACE)
new->trace = NULL;
new->trace_count = 0;
#endif
new->magic1 = MAGIC1;
new->magic2 = MAGIC2;
if( new->next != NULL )
new->next->prev = new;
// Replace cur with new in free_list
//
new->prev_free = cur->prev_free;
new->next_free = cur->next_free;
if( new->prev_free != NULL )
new->prev_free->next_free = new;
else
heap.first_free = new;
if( new->next_free != NULL )
new->next_free->prev_free = new;
cur->alloc = 1;
cur->size = len;
cur->next = new;
cur->prev_free = NULL;
cur->next_free = NULL;
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.header_count++;
if( heap.header_count > heap.maximum_header_count )
heap.maximum_header_count = heap.header_count;
heap.total_used += cur->size;
if( heap.total_used > heap.maximum_used )
heap.maximum_used = heap.total_used;
#endif
#if defined(MBEDTLS_MEMORY_BACKTRACE)
trace_cnt = backtrace( trace_buffer, MAX_BT );
cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
cur->trace_count = trace_cnt;
#endif
if( ( heap.verify & MBEDTLS_MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
mbedtls_exit( 1 );
ret = (unsigned char *) cur + sizeof( memory_header );
memset( ret, 0, original_len );
return( ret );
}
static void buffer_alloc_free( void *ptr )
{
memory_header *hdr, *old = NULL;
unsigned char *p = (unsigned char *) ptr;
if( ptr == NULL || heap.buf == NULL || heap.first == NULL )
return;
if( p < heap.buf || p >= heap.buf + heap.len )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: mbedtls_free() outside of managed "
"space\n" );
#endif
mbedtls_exit( 1 );
}
p -= sizeof(memory_header);
hdr = (memory_header *) p;
if( verify_header( hdr ) != 0 )
mbedtls_exit( 1 );
if( hdr->alloc != 1 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
mbedtls_fprintf( stderr, "FATAL: mbedtls_free() on unallocated "
"data\n" );
#endif
mbedtls_exit( 1 );
}
hdr->alloc = 0;
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.free_count++;
heap.total_used -= hdr->size;
#endif
#if defined(MBEDTLS_MEMORY_BACKTRACE)
free( hdr->trace );
hdr->trace = NULL;
hdr->trace_count = 0;
#endif
// Regroup with block before
//
if( hdr->prev != NULL && hdr->prev->alloc == 0 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.header_count--;
#endif
hdr->prev->size += sizeof(memory_header) + hdr->size;
hdr->prev->next = hdr->next;
old = hdr;
hdr = hdr->prev;
if( hdr->next != NULL )
hdr->next->prev = hdr;
memset( old, 0, sizeof(memory_header) );
}
// Regroup with block after
//
if( hdr->next != NULL && hdr->next->alloc == 0 )
{
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.header_count--;
#endif
hdr->size += sizeof(memory_header) + hdr->next->size;
old = hdr->next;
hdr->next = hdr->next->next;
if( hdr->prev_free != NULL || hdr->next_free != NULL )
{
if( hdr->prev_free != NULL )
hdr->prev_free->next_free = hdr->next_free;
else
heap.first_free = hdr->next_free;
if( hdr->next_free != NULL )
hdr->next_free->prev_free = hdr->prev_free;
}
hdr->prev_free = old->prev_free;
hdr->next_free = old->next_free;
if( hdr->prev_free != NULL )
hdr->prev_free->next_free = hdr;
else
heap.first_free = hdr;
if( hdr->next_free != NULL )
hdr->next_free->prev_free = hdr;
if( hdr->next != NULL )
hdr->next->prev = hdr;
memset( old, 0, sizeof(memory_header) );
}
// Prepend to free_list if we have not merged
// (Does not have to stay in same order as prev / next list)
//
if( old == NULL )
{
hdr->next_free = heap.first_free;
if( heap.first_free != NULL )
heap.first_free->prev_free = hdr;
heap.first_free = hdr;
}
if( ( heap.verify & MBEDTLS_MEMORY_VERIFY_FREE ) && verify_chain() != 0 )
mbedtls_exit( 1 );
}
void mbedtls_memory_buffer_set_verify( int verify )
{
heap.verify = verify;
}
int mbedtls_memory_buffer_alloc_verify( void )
{
return verify_chain();
}
#if defined(MBEDTLS_MEMORY_DEBUG)
void mbedtls_memory_buffer_alloc_status( void )
{
mbedtls_fprintf( stderr,
"Current use: %zu blocks / %zu bytes, max: %zu blocks / "
"%zu bytes (total %zu bytes), alloc / free: %zu / %zu\n",
heap.header_count, heap.total_used,
heap.maximum_header_count, heap.maximum_used,
heap.maximum_header_count * sizeof( memory_header )
+ heap.maximum_used,
heap.alloc_count, heap.free_count );
if( heap.first->next == NULL )
{
mbedtls_fprintf( stderr, "All memory de-allocated in stack buffer\n" );
}
else
{
mbedtls_fprintf( stderr, "Memory currently allocated:\n" );
debug_chain();
}
}
void mbedtls_memory_buffer_alloc_max_get( size_t *max_used, size_t *max_blocks )
{
*max_used = heap.maximum_used;
*max_blocks = heap.maximum_header_count;
}
void mbedtls_memory_buffer_alloc_max_reset( void )
{
heap.maximum_used = 0;
heap.maximum_header_count = 0;
}
void mbedtls_memory_buffer_alloc_cur_get( size_t *cur_used, size_t *cur_blocks )
{
*cur_used = heap.total_used;
*cur_blocks = heap.header_count;
}
#endif /* MBEDTLS_MEMORY_DEBUG */
#if defined(MBEDTLS_THREADING_C)
static void *buffer_alloc_calloc_mutexed( size_t n, size_t size )
{
void *buf;
if( mbedtls_mutex_lock( &heap.mutex ) != 0 )
return( NULL );
buf = buffer_alloc_calloc( n, size );
if( mbedtls_mutex_unlock( &heap.mutex ) )
return( NULL );
return( buf );
}
static void buffer_alloc_free_mutexed( void *ptr )
{
/* We have to good option here, but corrupting the heap seems
* worse than loosing memory. */
if( mbedtls_mutex_lock( &heap.mutex ) )
return;
buffer_alloc_free( ptr );
(void) mbedtls_mutex_unlock( &heap.mutex );
}
#endif /* MBEDTLS_THREADING_C */
void mbedtls_memory_buffer_alloc_init( unsigned char *buf, size_t len )
{
memset( &heap, 0, sizeof( buffer_alloc_ctx ) );
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init( &heap.mutex );
mbedtls_platform_set_calloc_free( buffer_alloc_calloc_mutexed,
buffer_alloc_free_mutexed );
#else
mbedtls_platform_set_calloc_free( buffer_alloc_calloc, buffer_alloc_free );
#endif
if( len < sizeof( memory_header ) + MBEDTLS_MEMORY_ALIGN_MULTIPLE )
return;
else if( (size_t)buf % MBEDTLS_MEMORY_ALIGN_MULTIPLE )
{
/* Adjust len first since buf is used in the computation */
len -= MBEDTLS_MEMORY_ALIGN_MULTIPLE
- (size_t)buf % MBEDTLS_MEMORY_ALIGN_MULTIPLE;
buf += MBEDTLS_MEMORY_ALIGN_MULTIPLE
- (size_t)buf % MBEDTLS_MEMORY_ALIGN_MULTIPLE;
}
memset( buf, 0, len );
heap.buf = buf;
heap.len = len;
heap.first = (memory_header *)buf;
heap.first->size = len - sizeof( memory_header );
heap.first->magic1 = MAGIC1;
heap.first->magic2 = MAGIC2;
heap.first_free = heap.first;
}
void mbedtls_memory_buffer_alloc_free( void )
{
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_free( &heap.mutex );
#endif
mbedtls_platform_zeroize( &heap, sizeof(buffer_alloc_ctx) );
}
#if defined(MBEDTLS_SELF_TEST)
static int check_pointer( void *p )
{
if( p == NULL )
return( -1 );
if( (size_t) p % MBEDTLS_MEMORY_ALIGN_MULTIPLE != 0 )
return( -1 );
return( 0 );
}
static int check_all_free( void )
{
if(
#if defined(MBEDTLS_MEMORY_DEBUG)
heap.total_used != 0 ||
#endif
heap.first != heap.first_free ||
(void *) heap.first != (void *) heap.buf )
{
return( -1 );
}
return( 0 );
}
#define TEST_ASSERT( condition ) \
if( ! (condition) ) \
{ \
if( verbose != 0 ) \
mbedtls_printf( "failed\n" ); \
\
ret = 1; \
goto cleanup; \
}
int mbedtls_memory_buffer_alloc_self_test( int verbose )
{
unsigned char buf[1024];
unsigned char *p, *q, *r, *end;
int ret = 0;
if( verbose != 0 )
mbedtls_printf( " MBA test #1 (basic alloc-free cycle): " );
mbedtls_memory_buffer_alloc_init( buf, sizeof( buf ) );
p = mbedtls_calloc( 1, 1 );
q = mbedtls_calloc( 1, 128 );
r = mbedtls_calloc( 1, 16 );
TEST_ASSERT( check_pointer( p ) == 0 &&
check_pointer( q ) == 0 &&
check_pointer( r ) == 0 );
mbedtls_free( r );
mbedtls_free( q );
mbedtls_free( p );
TEST_ASSERT( check_all_free( ) == 0 );
/* Memorize end to compare with the next test */
end = heap.buf + heap.len;
mbedtls_memory_buffer_alloc_free( );
if( verbose != 0 )
mbedtls_printf( "passed\n" );
if( verbose != 0 )
mbedtls_printf( " MBA test #2 (buf not aligned): " );
mbedtls_memory_buffer_alloc_init( buf + 1, sizeof( buf ) - 1 );
TEST_ASSERT( heap.buf + heap.len == end );
p = mbedtls_calloc( 1, 1 );
q = mbedtls_calloc( 1, 128 );
r = mbedtls_calloc( 1, 16 );
TEST_ASSERT( check_pointer( p ) == 0 &&
check_pointer( q ) == 0 &&
check_pointer( r ) == 0 );
mbedtls_free( r );
mbedtls_free( q );
mbedtls_free( p );
TEST_ASSERT( check_all_free( ) == 0 );
mbedtls_memory_buffer_alloc_free( );
if( verbose != 0 )
mbedtls_printf( "passed\n" );
if( verbose != 0 )
mbedtls_printf( " MBA test #3 (full): " );
mbedtls_memory_buffer_alloc_init( buf, sizeof( buf ) );
p = mbedtls_calloc( 1, sizeof( buf ) - sizeof( memory_header ) );
TEST_ASSERT( check_pointer( p ) == 0 );
TEST_ASSERT( mbedtls_calloc( 1, 1 ) == NULL );
mbedtls_free( p );
p = mbedtls_calloc( 1, sizeof( buf ) - 2 * sizeof( memory_header ) - 16 );
q = mbedtls_calloc( 1, 16 );
TEST_ASSERT( check_pointer( p ) == 0 && check_pointer( q ) == 0 );
TEST_ASSERT( mbedtls_calloc( 1, 1 ) == NULL );
mbedtls_free( q );
TEST_ASSERT( mbedtls_calloc( 1, 17 ) == NULL );
mbedtls_free( p );
TEST_ASSERT( check_all_free( ) == 0 );
mbedtls_memory_buffer_alloc_free( );
if( verbose != 0 )
mbedtls_printf( "passed\n" );
cleanup:
mbedtls_memory_buffer_alloc_free( );
return( ret );
}
#endif /* MBEDTLS_SELF_TEST */
#endif /* MBEDTLS_MEMORY_BUFFER_ALLOC_C */
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