libppd: Added NULL checks when "libppd" extension not present

The functions ppdFilterExternalCUPS(), ppdFilterEmitJCL(), and
ppdFilterUniversal() get the PPD file via the "libppd" extension for
the filter data. There was no NULL check when the extension was not
present, without extension there was simply a crash, a hang, or other
unexpected behavior.

This commit adds NULL checks so that if the extension is missing, the
functions simply do what they can do without PPD file, but do not
cause a crash.

diff --git a/ppd/ppd-filter.c b/ppd/ppd-filter.c
index 516602af52d6ba5bc1da56ee88dacaf67d7f96ab..a53af8f8f5660a474503b736eeabab1e53c9e2c8 100644 (file)
--- a/ppd/ppd-filter.c
+++ b/ppd/ppd-filter.c
@@ -1284,7 +1284,7 @@ ppdFilterExternalCUPS(int inputfd,      /* I - File descriptor input stream */
       add_env_var("PRINTER", "Unknown", &envp);
 
     /* PPD file path/name from filter data, required for most CUPS filters */
-    if (filter_data_ext->ppdfile)
+    if (filter_data_ext && filter_data_ext->ppdfile)
       add_env_var("PPD", filter_data_ext->ppdfile, &envp);
 
     /* Device URI from parameters */
@@ -1844,14 +1844,18 @@ ppdFilterEmitJCL(int inputfd,         /* I - File descriptor input stream */
   */
 
   fp = fdopen(outputfd, "w");
-  ppdEmit(filter_data_ext->ppd, fp, PPD_ORDER_EXIT);
-  ppdEmitJCLPDF(filter_data_ext->ppd, fp,
-               data->job_id, data->job_user, data->job_title,
-               hw_copies, hw_collate);
+  if (filter_data_ext)
+  {
+    ppdEmit(filter_data_ext->ppd, fp, PPD_ORDER_EXIT);
+    ppdEmitJCLPDF(filter_data_ext->ppd, fp,
+                 data->job_id, data->job_user, data->job_title,
+                 hw_copies, hw_collate);
+  }
   while ((bytes = read(outfds[0], buf, sizeof(buf))) > 0)
     fwrite(buf, 1, bytes, fp);
   close(outfds[0]);
-  ppdEmitJCLEnd(filter_data_ext->ppd, fp);
+  if (filter_data_ext)
+    ppdEmitJCLEnd(filter_data_ext->ppd, fp);
   fclose(fp);
 
   if (!streaming)
@@ -1948,7 +1952,7 @@ ppdFilterUniversal(int inputfd,         /* I - File descriptor input stream */
   char *final_output;
   char output[256];
   cf_filter_universal_parameter_t universal_parameters;
-  ppd_file_t *ppd;
+  ppd_file_t *ppd = NULL;
   ppd_cache_t *cache;
   cups_array_t *filter_chain;
   cf_filter_filter_in_chain_t extra_filter, universal_filter;
@@ -1978,12 +1982,13 @@ ppdFilterUniversal(int inputfd,         /* I - File descriptor input stream */
     }
   }
 
-  ppd = filter_data_ext->ppd;
+  if (filter_data_ext)
+    ppd = filter_data_ext->ppd;
 
   if (universal_parameters.actual_output_type)
     strncpy(output, universal_parameters.actual_output_type,
            sizeof(output) - 1);
-  else if(ppd)
+  else if (ppd)
   {
     strncpy(output, data->final_content_type, sizeof(output) - 1);