Coverity 709056: Check return value on fputs in tor-gencert

changes/cov709056

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - Check return value of fputs() when writing authority certificate
+      file. Fixes Coverity issue 709056; bugfix on 0.2.0.1-alpha.
+

src/tools/tor-gencert.c

@@ -497,7 +497,12 @@ generate_certificate(void)
     return 1;
   }
 
-  fputs(buf, f);
+  if (fputs(buf, f) < 0) {
+    log_err(LD_GENERAL, "Couldn't write to %s: %s",
+            certificate_file, strerror(errno));
+    fclose(f);
+    return 1;
+  }
   fclose(f);
   return 0;
 }