Commit d978216d authored by Nick Mathewson's avatar Nick Mathewson 🦀
Browse files

Fix parsing bug with unecognized token at EOS 

In get_token(), we could read one byte past the end of the
region. This is only a big problem in the case where the region
itself is (a) potentially hostile, and (b) not explicitly
nul-terminated.

This patch fixes the underlying bug, and also makes sure that the
one remaining case of not-NUL-terminated potentially hostile data
gets NUL-terminated.

Fix for bug 21018, TROVE-2016-12-002, and CVE-2016-1254
parent 9db47e79

changes/bug21018

0 → 100644
+11 −0
Original line number Diff line number Diff line 
  o Major bugfixes (parsing, security):



    - Fix a bug in parsing that could cause clients to read a single

      byte past the end of an allocated region. This bug could be

      used to cause hardened clients (built with

      --enable-expensive-hardening) to crash if they tried to visit

      a hostile hidden service.  Non-hardened clients are only

      affected depending on the details of their platform's memory

      allocator. Fixes bug 21018; bugfix on 0.2.0.8-alpha. Found by

      using libFuzzer. Also tracked as TROVE-2016-12-002 and as

      CVE-2016-1254.

src/or/routerparse.c

+3 −3
Original line number Diff line number Diff line
@@ -3857,7 +3857,7 @@ get_next_token(memarea_t *area, 


  if (tok->tp == ERR_) {

    /* No keyword matched; call it an "K_opt" or "A_unrecognized" */

    if (**s == '@')

    if (*s < eol && **s == '@')

      tok->tp = A_UNKNOWN_;

    else

      tok->tp = K_OPT;
@@ -4863,7 +4863,7 @@ rend_decrypt_introduction_points(char **ipos_decrypted, 
        crypto_cipher_free(cipher);



        len = ipos_encrypted_size - 2 - client_entries_len - CIPHER_IV_LEN;

        dec = tor_malloc(len);

        dec = tor_malloc_zero(len + 1);

        declen = crypto_cipher_decrypt_with_iv(session_key, dec, len,

            ipos_encrypted + 2 + client_entries_len,

            ipos_encrypted_size - 2 - client_entries_len);
@@ -4895,7 +4895,7 @@ rend_decrypt_introduction_points(char **ipos_decrypted, 
                        "small.");

      return -1;

    }

    dec = tor_malloc_zero(ipos_encrypted_size - CIPHER_IV_LEN - 1);

    dec = tor_malloc_zero(ipos_encrypted_size - CIPHER_IV_LEN - 1 + 1);



    declen = crypto_cipher_decrypt_with_iv(descriptor_cookie, dec,

                                           ipos_encrypted_size -