From: Christian Schoenebeck <qemu_oss@crudebyte.com>
To: qemu-devel@nongnu.org
Cc: Vitaly Chikunov <vt@altlinux.org>, Greg Kurz <groug@kaod.org>,
qemu-stable@nongnu.org, "Dmitry V . Levin" <ldv@altlinux.org>
Subject: Re: [PATCH v5] 9pfs: Fix segfault in do_readdir_many caused by struct dirent overread
Date: Thu, 17 Feb 2022 17:30:11 +0100 [thread overview]
Message-ID: <2135244.TdAzAAGDzu@silver> (raw)
In-Reply-To: <20220216181821.3481527-1-vt@altlinux.org>
On Mittwoch, 16. Februar 2022 19:18:21 CET Vitaly Chikunov wrote:
> `struct dirent' returned from readdir(3) could be shorter (or longer)
> than `sizeof(struct dirent)', thus memcpy of sizeof length will overread
> into unallocated page causing SIGSEGV. Example stack trace:
>
> #0 0x00005555559ebeed v9fs_co_readdir_many (/usr/bin/qemu-system-x86_64 +
> 0x497eed) #1 0x00005555559ec2e9 v9fs_readdir (/usr/bin/qemu-system-x86_64
> + 0x4982e9) #2 0x0000555555eb7983 coroutine_trampoline
> (/usr/bin/qemu-system-x86_64 + 0x963983) #3 0x00007ffff73e0be0 n/a (n/a +
> 0x0)
>
> While fixing this, provide a helper for any future `struct dirent' cloning.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/841
> Cc: qemu-stable@nongnu.org
> Co-authored-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
> Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> ---
Queued on 9p.next:
https://github.com/cschoenebeck/qemu/commits/9p.next
Thanks! I prepare a new PR now.
Best regards,
Christian Schoenebeck
prev parent reply other threads:[~2022-02-17 16:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-16 18:18 [PATCH v5] 9pfs: Fix segfault in do_readdir_many caused by struct dirent overread Vitaly Chikunov
2022-02-17 9:26 ` Christian Schoenebeck
2022-02-17 13:06 ` Vitaly Chikunov
2022-02-17 12:35 ` Greg Kurz
2022-02-17 16:30 ` Christian Schoenebeck [this message]
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=2135244.TdAzAAGDzu@silver \
--to=qemu_oss@crudebyte.com \
--cc=groug@kaod.org \
--cc=ldv@altlinux.org \
--cc=qemu-devel@nongnu.org \
--cc=qemu-stable@nongnu.org \
--cc=vt@altlinux.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.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.