/src/gs_fuzzlib.h

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/*
# Copyright 2019 The Chromium OS Authors.
#
# 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.
#
################################################################################
*/

#include <base/gserrors.h>
#include <psi/iapi.h>

#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>

static const unsigned char *g_data;
static size_t g_size;

int fuzz_gs_device(
  const unsigned char *buf,
  size_t size,
  int color_scheme,
  const char *device_target,
  const char *output_file,
  int do_interpolation
);

#define min(x, y) ((x) < (y) ? (x) : (y))

static int gs_stdin(void *inst, char *buf, int len)
{
  size_t to_copy = min(len, g_size);
  to_copy = min(INT_MAX, to_copy);

  memcpy(buf, g_data, to_copy);

  g_data += to_copy;
  g_size -= to_copy;

  return to_copy;
}

static int gs_stdnull(void *inst, const char *buf, int len)
{
  /* Just discard everything. */
  return len;
}

int gs_to_raster_fuzz(
  const unsigned char *buf,
  size_t size,
  int color_scheme
)
{
  return fuzz_gs_device(buf, size, color_scheme, "cups", "/dev/null", 0);
}

int fuzz_gs_device(
  const unsigned char *buf,
  size_t size,
  int color_scheme,
  const char *device_target,
  const char *output_file,
  int do_interpolation
)
{
  int ret;
  void *gs = NULL;
  char color_space[50];
  char gs_device[50];
  char gs_o[100];
  char opt_interpolation[50];
  /*
   * We are expecting color_scheme to be in the [0:62] interval.
   * This corresponds to the color schemes defined here:
   * https://github.com/ArtifexSoftware/ghostpdl/blob/8c97d5adce0040ac38a1fb4d7954499c65f582ff/cups/libs/cups/raster.h#L102
   */
  sprintf(color_space, "-dcupsColorSpace=%d", color_scheme);
  sprintf(gs_device, "-sDEVICE=%s", device_target);
  sprintf(gs_o, "-sOutputFile=%s", output_file);
  if (do_interpolation) {
    sprintf(opt_interpolation, "-dDOINTERPOLATE");
  }
  else {
    sprintf(opt_interpolation, "-dNOINTERPOLATE");
  }
  /* Mostly stolen from cups-filters gstoraster. */
  char *args[] = {
    "gs",
    "-K1048576",
    "-r200x200",
    "-sBandListStorage=memory",
    "-dMaxBitmap=0",
    "-dBufferSpace=450k",
    "-dMediaPosition=1",
    color_space,
    "-dQUIET",
    "-dSAFER",
    "-dNOPAUSE",
    "-dBATCH",
    opt_interpolation,
    "-dNOMEDIAATTRS",
    "-sstdout=%%stderr",
    gs_o,
    gs_device,
    "-_",
  };
  int argc = sizeof(args) / sizeof(args[0]);

  /* Stash buffers globally, for gs_stdin(). */
  g_data = buf;
  g_size = size;

  ret = gsapi_new_instance(&gs, NULL);
  if (ret < 0) {
    fprintf(stderr, "gsapi_new_instance: error %d\n", ret);
    return ret;
  }

  gsapi_set_stdio(gs, gs_stdin, gs_stdnull, gs_stdnull);
  ret = gsapi_set_arg_encoding(gs, GS_ARG_ENCODING_UTF8);
  if (ret < 0) {
    fprintf(stderr, "gsapi_set_arg_encoding: error %d\n", ret);
    gsapi_delete_instance(gs);
    return ret;
  }

  ret = gsapi_init_with_args(gs, argc, args);
  if (ret && ret != gs_error_Quit)
    /* Just keep going, to cleanup. */
    fprintf(stderr, "gsapi_init_with_args: error %d\n", ret);

  ret = gsapi_exit(gs);
  if (ret < 0 && ret != gs_error_Quit) {
    fprintf(stderr, "gsapi_exit: error %d\n", ret);
    return ret;
  }

  gsapi_delete_instance(gs);

  return 0;
}

Coverage Report

Created: 2025-06-24 07:01