[dovecot/core] 79454b: lib-mail: Fix read overflow / crash in message_hea...

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: 79454ba23ef6baf56997cd3cc23123eb69ae4f4c
      https://github.com/dovecot/core/commit/79454ba23ef6baf56997cd3cc23123eb69ae4f4c
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2017-03-24 (Fri, 24 Mar 2017)

  Changed paths:
    M src/lib-mail/message-header-decode.c
    M src/lib-mail/test-message-header-decode.c

  Log Message:
  -----------
  lib-mail: Fix read overflow / crash in message_header_decode()

If the input string was "=?charset?Q|B?text?", the code attempted to look up
the character after it. And if it was "=", the callback was called with
size=-1, which ends up in a crash.