zsh-5.8 (CVE-2019-20044)

[Bruce Dubbs]

New minor version.

[Xi Ruoyao]

Changes since 5.7.1-test-3
--------------------------

CVE-2019-20044: When unsetting the PRIVILEGED option, the shell sets its
effective user and group IDs to match their respective real IDs. On some
platforms (including Linux and macOS, but not FreeBSD), when the RUID and
EUID were both non-zero, it was possible to regain the shell's former
privileges by e.g. assigning to the EUID or EGID parameter. In the course
of investigating this issue, it was also found that the setopt built-in
did not correctly report errors when unsetting the option, which
prevented users from handling them as the documentation recommended.
setopt now returns non-zero if it is unable to safely drop privileges.
[ Reported by Sam Foxman <samfoxman320@gmail.com>. ]

Changes from 5.7.1 to 5.7.1-test-3
----------------------------------

The zsh/zutil module's zparseopts builtin learnt an -F option to abort
parsing when an unrecognised option-like parameter is encountered.

The zsh/files module gained a chmod builtin.

Several changes have been made to the way completion functions track
'precommands' (such as `command` and `env`) and determine whether the
command being completed for is a shell builtin. Developers of completion
functions may wish to familiarise themselves with `_normal -p` and
`_pick_variant -b`.

The option CD_SILENT was added to suppress all output from cd (whether
explicit or implicit with AUTO_CD). It is disabled by default.

The compadd builtin's -o option now takes an optional argument to
specify the order of completion matches. This affects the display
of candidate matches and the order in which they are selected when
cycling between them using menu completion.

The :h and :t modifiers in parameter expansion (if braces are present),
glob qualifiers and history expansion may take following decimal digit
arguments in order to keep that many leading or trailing path components
instead of the defaults of all but one (:h) and one (:t).  In an absolute
path the leading '/' counts as one component.

The functions builtin gained a -c option to efficiently copy functions.

The zshmisc(1) manual page incorrectly stated that when 'exit' is used
in a `try' block inside a function, the corresponding `always' block will
be executed.  The manual page has been corrected.  The shell's behaviour
has not changed, but code such as the following:
.
    f() { { exit } always { echo Hello world } }
.
should be changed either to use 'return' instead of 'exit', or to have
the try/always block outside of any function.

[Bruce Dubbs]

Fixed at revision 22719.