src/java.desktop/share/native/libsplashscreen/giflib/openbsd-reallocarray.c - master - githubmirror/panama-vector

src/java.desktop/share/native/libsplashscreen/giflib/openbsd-reallocarray.c
97 строк4 KB
Damon Nguyen
8379256: Update GIFlib to 6.1.1
11 мар 2026, 03:22
11 мар 2026, 03:228b8bb43
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * SPDX-FileCopyrightText: Copyright (C) 2008 Otto Moerbeek <otto@drijf.net>
 * SPDX-License-Identifier: MIT
 */

#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>

#ifndef SIZE_MAX
#define SIZE_MAX UINTPTR_MAX
#endif

/*
 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
 */
#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))

void *openbsd_reallocarray(void *optr, size_t nmemb, size_t size) {
        if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
            nmemb > 0 && SIZE_MAX / nmemb < size) {
                errno = ENOMEM;
                return NULL;
        }
        /*
         * Head off variations in realloc behavior on different
         * platforms (reported by MarkR <mrogers6@users.sf.net>)
         *
         * The behaviour of reallocarray is implementation-defined if
         * nmemb or size is zero. It can return NULL or non-NULL
         * depending on the platform.
         * https://www.securecoding.cert.org/confluence/display/c/MEM04-C.Beware+of+zero-lengthallocations
         *
         * Here are some extracts from realloc man pages on different platforms.
         *
         * void realloc( void memblock, size_t size );
         *
         * Windows:
         *
         * If there is not enough available memory to expand the block
         * to the given size, the original block is left unchanged,
         * and NULL is returned.  If size is zero, then the block
         * pointed to by memblock is freed; the return value is NULL,
         * and memblock is left pointing at a freed block.
         *
         * OpenBSD:
         *
         * If size or nmemb is equal to 0, a unique pointer to an
         * access protected, zero sized object is returned. Access via
         * this pointer will generate a SIGSEGV exception.
         *
         * Linux:
         *
         * If size was equal to 0, either NULL or a pointer suitable
         * to be passed to free() is returned.
         *
         * OS X:
         *
         * If size is zero and ptr is not NULL, a new, minimum sized
         * object is allocated and the original object is freed.
         *
         * It looks like images with zero width or height can trigger
         * this, and fuzzing behaviour will differ by platform, so
         * fuzzing on one platform may not detect zero-size allocation
         * problems on other platforms.
         */
        if (size == 0 || nmemb == 0) {
                return NULL;
        }
        return realloc(optr, size * nmemb);
}