Commit f8be737d authored by Patrick Monnerat's avatar Patrick Monnerat
Browse files

content_encoding: accept up to 4 unknown trailer bytes after raw deflate data 

Some servers issue raw deflate data that may be followed by an undocumented
trailer. This commit makes curl tolerate such a trailer of up to 4 bytes
before considering the data is in error.

Reported-by: clbr on github
Fixes #2719
parent 5b511b09

lib/content_encoding.c

+15 −11
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.

 * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms
@@ -73,9 +73,9 @@ 
typedef enum {

  ZLIB_UNINIT,               /* uninitialized */

  ZLIB_INIT,                 /* initialized */

  ZLIB_INFLATING,       /* Inflating started. */

  ZLIB_INFLATING,            /* inflating started. */

  ZLIB_EXTERNAL_TRAILER,     /* reading external trailer */

  ZLIB_GZIP_HEADER,          /* reading gzip header */

  ZLIB_GZIP_TRAILER,    /* reading gzip trailer */

  ZLIB_GZIP_INFLATING,       /* inflating gzip stream */

  ZLIB_INIT_GZIP             /* initialized in transparent gzip mode */

} zlibInitState;
@@ -150,8 +150,8 @@ static CURLcode process_trailer(struct connectdata *conn, zlib_params *zp) 
  if(result || !zp->trailerlen)

    result = exit_zlib(conn, z, &zp->zlib_init, result);

  else {

    /* Only occurs for gzip with zlib < 1.2.0.4. */

    zp->zlib_init = ZLIB_GZIP_TRAILER;

    /* Only occurs for gzip with zlib < 1.2.0.4 or raw deflate. */

    zp->zlib_init = ZLIB_EXTERNAL_TRAILER;

  }

  return result;

}
@@ -233,6 +233,7 @@ static CURLcode inflate_stream(struct connectdata *conn, 
          z->next_in = orig_in;

          z->avail_in = nread;

          zp->zlib_init = ZLIB_INFLATING;

          zp->trailerlen = 4; /* Tolerate up to 4 unknown trailer bytes. */

          done = FALSE;

          break;

        }
@@ -287,6 +288,9 @@ static CURLcode deflate_unencode_write(struct connectdata *conn, 
  z->next_in = (Bytef *) buf;

  z->avail_in = (uInt) nbytes;



  if(zp->zlib_init == ZLIB_EXTERNAL_TRAILER)

    return process_trailer(conn, zp);



  /* Now uncompress the data */

  return inflate_stream(conn, writer, ZLIB_INFLATING);

}
@@ -532,7 +536,7 @@ static CURLcode gzip_unencode_write(struct connectdata *conn, 
  }

  break;



  case ZLIB_GZIP_TRAILER:

  case ZLIB_EXTERNAL_TRAILER:

    z->next_in = (Bytef *) buf;

    z->avail_in = (uInt) nbytes;

    return process_trailer(conn, zp);