Make sure we call inflateEnd when there is an error reading or compar…

…ing the

stream CRC (Issue #91)

CHANGES.md

@@ -4,6 +4,7 @@ Changes in libcups
 libcups v3.0.0 (YYYY-MM-DD)
 ---------------------------
 
+- Fixed a compressed file error handling bug (Issue #91)
 - Fixed the default User-Agent string sent in requests.
 - Fixed a recursion issue in `ippReadIO`.
 

cups/file.c

@@ -1682,6 +1682,7 @@ cups_fill(cups_file_t *fp)		// I - CUPS file
 
 	if (fp->stream.avail_in > 0)
 	{
+	  // Get the first N trailer bytes from the inflate stream...
 	  if (fp->stream.avail_in > sizeof(trailer))
 	    tbytes = (ssize_t)sizeof(trailer);
 	  else
@@ -1692,6 +1693,12 @@ cups_fill(cups_file_t *fp)		// I - CUPS file
 	  fp->stream.avail_in -= (size_t)tbytes;
 	}
 
+        // Reset the compressed flag so that we re-read the file header...
+        inflateEnd(&fp->stream);
+
+	fp->compressed = false;
+
+        // Get any remaining trailer bytes...
         if (tbytes < (ssize_t)sizeof(trailer))
 	{
 	  if (read(fp->fd, trailer + tbytes, sizeof(trailer) - (size_t)tbytes) < ((ssize_t)sizeof(trailer) - tbytes))
@@ -1704,6 +1711,7 @@ cups_fill(cups_file_t *fp)		// I - CUPS file
 	  }
 	}
 
+        // Calculate and compare the CRC...
 	tcrc = ((((((uLong)trailer[3] << 8) | (uLong)trailer[2]) << 8) | (uLong)trailer[1]) << 8) | (uLong)trailer[0];
 
 	if (tcrc != fp->crc)
@@ -1714,11 +1722,6 @@ cups_fill(cups_file_t *fp)		// I - CUPS file
 
 	  return (-1);
 	}
-
-        // Otherwise, reset the compressed flag so that we re-read the file header...
-        inflateEnd(&fp->stream);
-
-	fp->compressed = false;
       }
       else if (status < Z_OK)
       {