From: Bruno Haible <bruno@clisp.org>
To: 62039@debbugs.gnu.org
Subject: bug#62039: Emacs crashes while parsing a long Emacs Lisp string
Date: Tue, 07 Mar 2023 22:51:58 +0100 [thread overview]
Message-ID: <5401235.PpUMLH0tvb@nimes> (raw)
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When parsing a particular long Emacs Lisp string, Emacs crashes.
How to reproduce:
$ emacs -Q -batch -f batch-byte-compile foo.el
Segmentation fault
Find attached the compressed file foo.el.
Emacs version: 27.1
Platform: x86_64-linux-gnu
$ ulimit -a | grep stack
stack size (kbytes, -s) 8192
According to the documentation
https://www.gnu.org/software/emacs/manual/html_node/emacs/Bug-Criteria.html
any segmentation fault is a bug.
I haven't analyzed the security impact of this bug, but it is quite possible
that emacs receives a string through the network, and even though the string
is not meant to be evaluated, simply parsing it causes a denial-of-service
to the emacs user.
The cause of the bug is that in emacs/src/lread.c the function read_escape()
is recursive, and no bound on the recursion depth is enforced.
[-- Attachment #2: foo.el.gz --]
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next reply other threads:[~2023-03-07 21:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-07 21:51 Bruno Haible [this message]
2023-03-08 9:39 ` bug#62039: Emacs crashes while parsing a long Emacs Lisp string Mattias Engdegård
2023-03-11 9:25 ` Mattias Engdegård
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