mirror of https://github.com/sudo-project/sudo.git
161 lines
3.8 KiB
C
161 lines
3.8 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
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* Copyright (c) 2022 Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <errno.h>
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#include <limits.h>
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#include <string.h>
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#if defined(HAVE_STDINT_H)
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# include <stdint.h>
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#elif defined(HAVE_INTTYPES_H)
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# include <inttypes.h>
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#endif
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#include <sudo_compat.h>
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#include <sudo_util.h>
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#if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
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# define MAP_ANON MAP_ANONYMOUS
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#endif
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#ifndef MAP_FAILED
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# define MAP_FAILED ((void *)-1)
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#endif
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/*
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* This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
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* if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
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*/
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#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
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/*
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* Allocate "size" bytes via mmap().
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* Space is allocated to store the size for later unmapping.
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*/
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void *
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sudo_mmap_alloc_v1(size_t size)
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{
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void *ptr;
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unsigned long *ulp;
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#ifndef MAP_ANON
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int fd;
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/* SunOS-style mmap allocation using /dev/zero. */
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if ((fd = open("/dev/zero", O_RDWR)) == -1)
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return NULL;
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size += sizeof(unsigned long);
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ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
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close(fd);
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#else
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size += sizeof(unsigned long);
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ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
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#endif
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if (ptr == MAP_FAILED) {
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errno = ENOMEM;
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return NULL;
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}
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/* Store size before the actual data. */
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ulp = (unsigned long *)ptr;
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ulp[0] = size;
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return (void *)&ulp[1];
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}
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/*
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* Allocate "nmemb" elements of "size" bytes via mmap().
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* If overflow would occur, errno is set to ENOMEM and
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* NULL is returned.
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*/
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void *
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sudo_mmap_allocarray_v1(size_t nmemb, size_t size)
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{
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if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
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nmemb > 0 && SIZE_MAX / nmemb < size) {
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errno = ENOMEM;
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return NULL;
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}
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return sudo_mmap_alloc_v1(nmemb * size);
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}
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/*
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* Make a copy of "str" via mmap() and return it.
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*/
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char *
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sudo_mmap_strdup_v1(const char *str)
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{
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size_t len = strlen(str);
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char *newstr;
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if (len == SIZE_MAX) {
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errno = ENOMEM;
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return NULL;
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}
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newstr = sudo_mmap_alloc_v1(len + 1);
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if (newstr != NULL) {
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memcpy(newstr, str, len);
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newstr[len] = '\0';
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}
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return newstr;
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}
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/*
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* Set the page permissions for the allocation represented by "ptr" to
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* read-only. Returns 0 on success, -1 on failure.
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*/
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int
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sudo_mmap_protect_v1(void *ptr)
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{
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if (ptr != NULL) {
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unsigned long *ulp = ptr;
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const unsigned long size = ulp[-1];
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return mprotect((void *)&ulp[-1], size, PROT_READ);
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}
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/* Can't protect NULL. */
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errno = EINVAL;
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return -1;
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}
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/*
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* Free "ptr" allocated by sudo_mmap_alloc().
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* The allocated size is stored (as unsigned long) in ptr[-1].
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*/
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void
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sudo_mmap_free_v1(void *ptr)
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{
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if (ptr != NULL) {
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unsigned long *ulp = (unsigned long *)ptr - 1;
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const unsigned long size = ulp[0];
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int saved_errno = errno;
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(void)munmap((void *)ulp, size);
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errno = saved_errno;
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}
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}
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