zsh-workers
 help / color / mirror / code / Atom feed
From: Stephane Chazelas <stephane.chazelas@gmail.com>
To: Daniel Shahaf <d.s@daniel.shahaf.name>
Cc: zsh-workers@zsh.org
Subject: Re: [PATCH] Re: regexp-replace and ^, word boundary or look-behind operators
Date: Wed, 18 Dec 2019 08:31:55 +0000	[thread overview]
Message-ID: <20191218083155.6si7sejaqorbynpd@chaz.gmail.com> (raw)
In-Reply-To: <2ea6feb3-a686-4d83-ab27-6a582424487c@www.fastmail.com>

2019-12-18 00:22:53 +0000, Daniel Shahaf:
[...]
> > +eval $1=\$5
> 
> How about «: ${(P)1::="$5"}» to avoid eval?

I suppose that would work but would not prevent code injection
vulnerabilities if $1 was not guaranteed to contain a valid
variable name:

$ 1='a[`uname>&2`]'
$ : ${(P)1::="$5"}
Linux
zsh: bad math expression: empty string
Linux
zsh: bad math expression: empty string

Note that uname was run twice suggesting it's potentially less
efficient than using eval (IIRC, that was already discussed
here. possibly that was fixed in a newer version).

Here, I'd say it's the caller's responsibility to make sure they
pass a valid lvalue as first argument.

-- 
Stephane

  reply	other threads:[~2019-12-18  8:32 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16 21:10 Stephane Chazelas
2019-12-16 21:27 ` Stephane Chazelas
2019-12-17  7:38   ` Stephane Chazelas
2019-12-17 11:11     ` [PATCH] " Stephane Chazelas
2019-12-18  0:22       ` Daniel Shahaf
2019-12-18  8:31         ` Stephane Chazelas [this message]
2020-01-01 14:03         ` [PATCH v2] " Stephane Chazelas
2021-04-30  6:11           ` Stephane Chazelas
2021-04-30 23:13             ` Bart Schaefer
2021-05-05 11:45               ` [PATCH v3] regexp-replace and ^, word boundary or look-behind operators (and more) Stephane Chazelas
2021-05-31  0:58                 ` Lawrence Velázquez
2021-05-31 18:18                 ` Bart Schaefer
2021-05-31 21:37                   ` [PATCH] (?) typeset array[position=index]=value Bart Schaefer
2021-06-01  5:32                     ` Stephane Chazelas
2021-06-01 16:05                       ` Bart Schaefer
2021-06-02  2:51                         ` [PATCH] (take two?) typeset array[position=index]=value / unset hash[$stuff] Bart Schaefer
2021-06-02 10:06                           ` Stephane Chazelas
2021-06-02 14:52                             ` Bart Schaefer
2021-06-02 16:02                               ` Stephane Chazelas
2021-06-02  9:11                         ` [PATCH] (?) typeset array[position=index]=value Stephane Chazelas
2021-06-02 13:34                           ` Daniel Shahaf
2021-06-02 14:20                             ` Stephane Chazelas
2021-06-02 15:59                               ` Bart Schaefer
2021-06-03  2:04                                 ` [PATCH (not final)] (take three?) unset "array[$anything]" Bart Schaefer
2021-06-03  2:42                                   ` Bart Schaefer
2021-06-03  6:12                                     ` Bart Schaefer
2021-06-03  8:54                                       ` Peter Stephenson
2021-06-03 13:13                                         ` Stephane Chazelas
2021-06-03 14:41                                           ` Peter Stephenson
2021-06-04 19:25                                             ` Bart Schaefer
2021-06-05 18:18                                               ` Peter Stephenson
2021-06-09 23:31                                                 ` Bart Schaefer
2021-06-13 16:51                                                   ` Peter Stephenson
2021-06-13 18:04                                                     ` Bart Schaefer
2021-06-13 19:48                                                       ` Peter Stephenson
2021-06-13 21:44                                                         ` Bart Schaefer
2021-06-14  7:19                                                           ` Stephane Chazelas
2021-06-03 18:12                                           ` Bart Schaefer
2021-06-04  8:02                                             ` Stephane Chazelas
2021-06-04 18:36                                               ` Bart Schaefer
2021-06-04 20:21                                                 ` Stephane Chazelas
2021-06-05  0:20                                                   ` Bart Schaefer
2021-06-05 17:05                                                     ` Stephane Chazelas
2021-06-10  0:14                                                       ` Square brackets in command position Bart Schaefer
2021-06-03  6:05                                   ` [PATCH (not final)] (take three?) unset "array[$anything]" Stephane Chazelas
2021-06-03  6:43                                     ` Bart Schaefer
2021-06-03  7:31                                       ` Stephane Chazelas
2021-06-10  0:21                         ` [PATCH] (?) typeset array[position=index]=value Bart Schaefer
2021-06-05  4:29                     ` Mikael Magnusson
2021-06-05  5:49                       ` Bart Schaefer
2021-06-05 11:06                         ` Mikael Magnusson
2021-06-05 16:22                           ` Bart Schaefer
2021-06-18 10:53                         ` Mikael Magnusson
2024-03-08 15:30                 ` [PATCH v3] regexp-replace and ^, word boundary or look-behind operators (and more) Stephane Chazelas
2024-03-09  8:41                   ` [PATCH v5] " Stephane Chazelas
2024-03-09  9:21                     ` MBEGIN when =~ finds bytes inside characters (Was: [PATCH v5] regexp-replace and ^, word boundary or look-behind operators (and more).) Stephane Chazelas
2024-03-09 13:03                   ` [PATCH v3] regexp-replace and ^, word boundary or look-behind operators (and more) Stephane Chazelas
2024-03-10 19:52                     ` [PATCH v6] " Stephane Chazelas

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191218083155.6si7sejaqorbynpd@chaz.gmail.com \
    --to=stephane.chazelas@gmail.com \
    --cc=d.s@daniel.shahaf.name \
    --cc=zsh-workers@zsh.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/zsh/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).