From: Stefan Kangas <stefankangas@gmail.com>
To: lux <lx@shellcodes.org>
Cc: 59544 <59544@debbugs.gnu.org>, Eli Zaretskii <eliz@gnu.org>
Subject: bug#59544: [PATCH] Fixed lib-src/etags.c command execute vulnerability
Date: Thu, 24 Nov 2022 23:53:46 -0800 [thread overview]
Message-ID: <CADwFkmmsMSHOzgcPpke46iiGfg=y6QiQvMW2GvrLroCADrsHaA@mail.gmail.com> (raw)
In-Reply-To: <tencent_BA67F66A766B02EE74E407C2D58269381B09@qq.com> (lux's message of "Fri, 25 Nov 2022 14:41:56 +0800")
"lux" <lx@shellcodes.org> writes:
> I rewrote this code, not use system(1).
Thanks.
> From d6bc71f8640efe7caa2657a75c5aa4d8b4f0532c Mon Sep 17 00:00:00 2001
> From: lu4nx <lx@shellcodes.org>
> Date: Fri, 25 Nov 2022 14:38:29 +0800
> Subject: [PATCH] * Fixed lib-src/etags.c command execute vulnerability
>
> ---
> lib-src/etags.c | 44 +++++++++++++++++++++++++++++++-------------
> 1 file changed, 31 insertions(+), 13 deletions(-)
>
> diff --git a/lib-src/etags.c b/lib-src/etags.c
> index f665f35fa6..1bb352f565 100644
> --- a/lib-src/etags.c
> +++ b/lib-src/etags.c
> @@ -1387,9 +1387,11 @@ main (int argc, char **argv)
> /* From here on, we are in (CTAGS && !cxref_style) */
> if (update)
> {
> - char *cmd =
> - xmalloc (strlen (tagfile) + whatlen_max +
> - sizeof "mv..OTAGS;grep -Fv '\t\t' OTAGS >;rm OTAGS");
> + FILE *otags_f, *tag_f;
> + int buf_len;
> + char *buf;
> + char line[512];
Hmm, I'm not sure about the hard-coded 512 character line limit here.
ISTR that some people use much longer lines than that.
Could we do without it?
(As a matter of style, I would just declare the types at first use,
which limits their scope and makes the code easier to read. But it's up
to you.)
> +
> for (i = 0; i < current_arg; ++i)
> {
> switch (argbuffer[i].arg_type)
> @@ -1400,17 +1402,33 @@ main (int argc, char **argv)
> default:
> continue; /* the for loop */
> }
> - char *z = stpcpy (cmd, "mv ");
> - z = stpcpy (z, tagfile);
> - z = stpcpy (z, " OTAGS;grep -Fv '\t");
> - z = stpcpy (z, argbuffer[i].what);
> - z = stpcpy (z, "\t' OTAGS >");
> - z = stpcpy (z, tagfile);
> - strcpy (z, ";rm OTAGS");
> - if (system (cmd) != EXIT_SUCCESS)
> - fatal ("failed to execute shell command");
> +
> + otags_f = fopen ("OTAGS", "w");
> + tag_f = fopen (tagfile, "r");
> +
> + if (otags_f == NULL)
> + pfatal ("OTAGS");
> +
> + if (tag_f == NULL)
> + pfatal (tagfile);
> +
> + buf_len = strlen (argbuffer[i].what) + sizeof ("\t\t ") + 1;
> + buf = xmalloc (buf_len);
> + snprintf (buf, buf_len, "\t%s\t", argbuffer[i].what);
> +
> + while (fgets (line, sizeof (line), tag_f) != NULL)
We should check ferror(tag_f), too and croak if there is a problem.
> + {
> + if (strstr (line, buf) == NULL)
> + fputs (line, otags_f);
Missing error handling for fputs.
> + }
> +
> + fclose (otags_f);
> + fclose (tag_f);
Should be:
if (fclose (otags_f) == EOF)
pfatal (otags_f);
if (fclose (tag_f) == EOF)
pfatal (tag_f);
> +
> + rename ("OTAGS", tagfile);
> + unlink ("OTAGS");
Please add error handling for both of these.
> }
> - free (cmd);
> +
Nit: I don't think the empty line helps here?
> append_to_tagfile = true;
> }
next prev parent reply other threads:[~2022-11-25 7:53 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-24 15:27 bug#59544: [PATCH] Fixed lib-src/etags.c command execute vulnerability lux
2022-11-24 18:01 ` Eli Zaretskii
2022-11-24 18:12 ` Stefan Kangas
2022-11-24 18:38 ` Eli Zaretskii
2022-11-25 3:45 ` lux
2022-11-25 6:41 ` lux
2022-11-25 7:53 ` Stefan Kangas [this message]
2022-11-25 8:38 ` lux
2022-11-25 8:56 ` Stefan Kangas
2022-11-25 12:19 ` Eli Zaretskii
2022-11-25 12:18 ` Eli Zaretskii
2022-11-25 16:02 ` lux
2022-11-26 0:43 ` Stefan Kangas
2022-11-26 2:30 ` lux
2022-11-26 3:09 ` lux
2022-11-26 9:47 ` Stefan Kangas
2022-11-26 10:14 ` Eli Zaretskii
[not found] ` <tencent_A9399566146BF66A0CEFAEE4B3C285839109@qq.com>
2022-11-26 12:28 ` Eli Zaretskii
2022-11-26 13:03 ` Stefan Kangas
2022-11-26 14:15 ` Eli Zaretskii
[not found] ` <tencent_F5BD82AD38AB67E06AB86AE8EE5EE577C309@qq.com>
2022-11-26 14:30 ` Eli Zaretskii
2022-11-26 13:21 ` Eli Zaretskii
[not found] ` <tencent_63F9E4F0AB6043CE8C198E1AAA9AD9BB1A07@qq.com>
2022-11-26 14:17 ` Eli Zaretskii
[not found] ` <tencent_0B66566A766A94EE00E45DC327831B387709@qq.com>
2022-11-26 14:49 ` Eli Zaretskii
[not found] ` <tencent_B9EE8C5FCD5A8DCF9D8AFC56787AF00AE706@qq.com>
2022-11-26 17:11 ` Eli Zaretskii
2022-11-27 3:05 ` lux
2022-11-27 6:35 ` lux
2022-11-27 14:15 ` Eli Zaretskii
2022-11-27 14:31 ` Eli Zaretskii
[not found] ` <tencent_67B00527E64C548D4ECDF55D977C75B84B06@qq.com>
2022-11-27 18:07 ` Eli Zaretskii
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
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CADwFkmmsMSHOzgcPpke46iiGfg=y6QiQvMW2GvrLroCADrsHaA@mail.gmail.com' \
--to=stefankangas@gmail.com \
--cc=59544@debbugs.gnu.org \
--cc=eliz@gnu.org \
--cc=lx@shellcodes.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.savannah.gnu.org/cgit/emacs.git
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 read-only IMAP folder(s) and NNTP newsgroup(s).