1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngmem.c - stub functions for memory allocation
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Copyright (c) 2018 Cosmin Truta
33 * Copyright (c) 1998-2002,2004,2006-2014,2016 Glenn Randers-Pehrson
34 * Copyright (c) 1996-1997 Andreas Dilger
35 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 *
41 * This file provides a location for all memory allocation. Users who
42 * need special memory handling are expected to supply replacement
43 * functions for png_malloc() and png_free(), and to use
44 * png_create_read_struct_2() and png_create_write_struct_2() to
45 * identify the replacement functions.
46 */
47
48 #include "pngpriv.h"
49
50 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
51 /* Free a png_struct */
52 void /* PRIVATE */
53 png_destroy_png_struct(png_structrp png_ptr)
54 {
55 if (png_ptr != NULL)
56 {
57 /* png_free might call png_error and may certainly call
58 * png_get_mem_ptr, so fake a temporary png_struct to support this.
59 */
60 png_struct dummy_struct = *png_ptr;
61 memset(png_ptr, 0, (sizeof *png_ptr));
62 png_free(&dummy_struct, png_ptr);
63
64 # ifdef PNG_SETJMP_SUPPORTED
65 /* We may have a jmp_buf left to deallocate. */
66 png_free_jmpbuf(&dummy_struct);
67 # endif
68 }
69 }
70
71 /* Allocate memory. For reasonable files, size should never exceed
72 * 64K. However, zlib may allocate more than 64K if you don't tell
73 * it not to. See zconf.h and png.h for more information. zlib does
74 * need to allocate exactly 64K, so whatever you call here must
75 * have the ability to do that.
76 */
77 PNG_FUNCTION(png_voidp,PNGAPI
78 png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
79 {
80 png_voidp ret;
81
82 ret = png_malloc(png_ptr, size);
83
84 if (ret != NULL)
85 memset(ret, 0, size);
86
87 return ret;
88 }
89
90 /* png_malloc_base, an internal function added at libpng 1.6.0, does the work of
91 * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED.
92 * Checking and error handling must happen outside this routine; it returns NULL
93 * if the allocation cannot be done (for any reason.)
94 */
95 PNG_FUNCTION(png_voidp /* PRIVATE */,
96 png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),
97 PNG_ALLOCATED)
98 {
99 /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS
100 * allocators have also been removed in 1.6.0, so any 16-bit system now has
101 * to implement a user memory handler. This checks to be sure it isn't
102 * called with big numbers.
103 */
104 #ifndef PNG_USER_MEM_SUPPORTED
105 PNG_UNUSED(png_ptr)
106 #endif
107
108 /* Some compilers complain that this is always true. However, it
109 * can be false when integer overflow happens.
110 */
111 if (size > 0 && size <= PNG_SIZE_MAX
112 # ifdef PNG_MAX_MALLOC_64K
113 && size <= 65536U
114 # endif
115 )
116 {
117 #ifdef PNG_USER_MEM_SUPPORTED
118 if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
119 return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);
120
121 else
122 #endif
123 return malloc((size_t)size); /* checked for truncation above */
124 }
125
126 else
127 return NULL;
128 }
129
130 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
131 defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
132 /* This is really here only to work round a spurious warning in GCC 4.6 and 4.7
133 * that arises because of the checks in png_realloc_array that are repeated in
134 * png_malloc_array.
135 */
136 static png_voidp
137 png_malloc_array_checked(png_const_structrp png_ptr, int nelements,
138 size_t element_size)
139 {
140 png_alloc_size_t req = (png_alloc_size_t)nelements; /* known to be > 0 */
141
142 if (req <= PNG_SIZE_MAX/element_size)
143 return png_malloc_base(png_ptr, req * element_size);
144
145 /* The failure case when the request is too large */
146 return NULL;
147 }
148
149 PNG_FUNCTION(png_voidp /* PRIVATE */,
150 png_malloc_array,(png_const_structrp png_ptr, int nelements,
151 size_t element_size),PNG_ALLOCATED)
152 {
153 if (nelements <= 0 || element_size == 0)
154 png_error(png_ptr, "internal error: array alloc");
155
156 return png_malloc_array_checked(png_ptr, nelements, element_size);
157 }
158
159 PNG_FUNCTION(png_voidp /* PRIVATE */,
160 png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
161 int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
162 {
163 /* These are internal errors: */
164 if (add_elements <= 0 || element_size == 0 || old_elements < 0 ||
165 (old_array == NULL && old_elements > 0))
166 png_error(png_ptr, "internal error: array realloc");
167
168 /* Check for overflow on the elements count (so the caller does not have to
169 * check.)
170 */
171 if (add_elements <= INT_MAX - old_elements)
172 {
173 png_voidp new_array = png_malloc_array_checked(png_ptr,
174 old_elements+add_elements, element_size);
175
176 if (new_array != NULL)
177 {
178 /* Because png_malloc_array worked the size calculations below cannot
179 * overflow.
180 */
181 if (old_elements > 0)
182 memcpy(new_array, old_array, element_size*(unsigned)old_elements);
183
184 memset((char*)new_array + element_size*(unsigned)old_elements, 0,
185 element_size*(unsigned)add_elements);
186
187 return new_array;
188 }
189 }
190
191 return NULL; /* error */
192 }
193 #endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
194
195 /* Various functions that have different error handling are derived from this.
196 * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate
197 * function png_malloc_default is also provided.
198 */
199 PNG_FUNCTION(png_voidp,PNGAPI
200 png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
201 {
202 png_voidp ret;
203
204 if (png_ptr == NULL)
205 return NULL;
206
207 ret = png_malloc_base(png_ptr, size);
208
209 if (ret == NULL)
210 png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */
211
212 return ret;
213 }
214
215 #ifdef PNG_USER_MEM_SUPPORTED
216 PNG_FUNCTION(png_voidp,PNGAPI
217 png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
218 PNG_ALLOCATED PNG_DEPRECATED)
219 {
220 png_voidp ret;
221
222 if (png_ptr == NULL)
223 return NULL;
224
225 /* Passing 'NULL' here bypasses the application provided memory handler. */
226 ret = png_malloc_base(NULL/*use malloc*/, size);
227
228 if (ret == NULL)
229 png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
230
231 return ret;
232 }
233 #endif /* USER_MEM */
234
235 /* This function was added at libpng version 1.2.3. The png_malloc_warn()
236 * function will issue a png_warning and return NULL instead of issuing a
237 * png_error, if it fails to allocate the requested memory.
238 */
239 PNG_FUNCTION(png_voidp,PNGAPI
240 png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size),
241 PNG_ALLOCATED)
242 {
243 if (png_ptr != NULL)
244 {
245 png_voidp ret = png_malloc_base(png_ptr, size);
246
247 if (ret != NULL)
248 return ret;
249
250 png_warning(png_ptr, "Out of memory");
251 }
252
253 return NULL;
254 }
255
256 /* Free a pointer allocated by png_malloc(). If ptr is NULL, return
257 * without taking any action.
258 */
259 void PNGAPI
260 png_free(png_const_structrp png_ptr, png_voidp ptr)
261 {
262 if (png_ptr == NULL || ptr == NULL)
263 return;
264
265 #ifdef PNG_USER_MEM_SUPPORTED
266 if (png_ptr->free_fn != NULL)
267 png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);
268
269 else
270 png_free_default(png_ptr, ptr);
271 }
272
273 PNG_FUNCTION(void,PNGAPI
274 png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
275 {
276 if (png_ptr == NULL || ptr == NULL)
277 return;
278 #endif /* USER_MEM */
279
280 free(ptr);
281 }
282
283 #ifdef PNG_USER_MEM_SUPPORTED
284 /* This function is called when the application wants to use another method
285 * of allocating and freeing memory.
286 */
287 void PNGAPI
288 png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr
289 malloc_fn, png_free_ptr free_fn)
290 {
291 if (png_ptr != NULL)
292 {
293 png_ptr->mem_ptr = mem_ptr;
294 png_ptr->malloc_fn = malloc_fn;
295 png_ptr->free_fn = free_fn;
296 }
297 }
298
299 /* This function returns a pointer to the mem_ptr associated with the user
300 * functions. The application should free any memory associated with this
301 * pointer before png_write_destroy and png_read_destroy are called.
302 */
303 png_voidp PNGAPI
304 png_get_mem_ptr(png_const_structrp png_ptr)
305 {
306 if (png_ptr == NULL)
307 return NULL;
308
309 return png_ptr->mem_ptr;
310 }
311 #endif /* USER_MEM */
312 #endif /* READ || WRITE */