105 lines
1.9 KiB
C
105 lines
1.9 KiB
C
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/*
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* Copyright (c) 2019 Yubico AB. All rights reserved.
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* Use of this source code is governed by a BSD-style
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* license that can be found in the LICENSE file.
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*/
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/*
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* cc -fPIC -D_GNU_SOURCE -shared -o preload-fuzz.so preload-fuzz.c
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* LD_PRELOAD=$(realpath preload-fuzz.so)
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <dlfcn.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#define FUZZ_DEV_PREFIX "nodev"
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static int fd_fuzz = -1;
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static int (*open_f)(const char *, int, mode_t);
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static int (*close_f)(int);
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static ssize_t (*write_f)(int, const void *, size_t);
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int
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open(const char *path, int flags, ...)
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{
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va_list ap;
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mode_t mode;
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va_start(ap, flags);
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mode = va_arg(ap, mode_t);
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va_end(ap);
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if (open_f == NULL) {
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open_f = dlsym(RTLD_NEXT, "open");
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if (open_f == NULL) {
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warnx("%s: dlsym", __func__);
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errno = EACCES;
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return (-1);
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}
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}
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if (strncmp(path, FUZZ_DEV_PREFIX, strlen(FUZZ_DEV_PREFIX)) != 0)
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return (open_f(path, flags, mode));
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if (fd_fuzz != -1) {
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warnx("%s: fd_fuzz != -1", __func__);
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errno = EACCES;
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return (-1);
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}
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if ((fd_fuzz = dup(STDIN_FILENO)) < 0) {
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warn("%s: dup", __func__);
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errno = EACCES;
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return (-1);
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}
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return (fd_fuzz);
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}
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int
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close(int fd)
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{
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if (close_f == NULL) {
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close_f = dlsym(RTLD_NEXT, "close");
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if (close_f == NULL) {
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warnx("%s: dlsym", __func__);
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errno = EACCES;
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return (-1);
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}
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}
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if (fd == fd_fuzz)
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fd_fuzz = -1;
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return (close_f(fd));
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}
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ssize_t
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write(int fd, const void *buf, size_t nbytes)
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{
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if (write_f == NULL) {
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write_f = dlsym(RTLD_NEXT, "write");
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if (write_f == NULL) {
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warnx("%s: dlsym", __func__);
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errno = EBADF;
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return (-1);
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}
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}
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if (fd != fd_fuzz)
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return (write_f(fd, buf, nbytes));
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return (nbytes);
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}
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