Linux-m68k Archive on lore.kernel.org
 help / color / Atom feed
From: Aleksa Sarai <cyphar@cyphar.com>
To: Al Viro <viro@zeniv.linux.org.uk>,
	Jeff Layton <jlayton@kernel.org>,
	"J. Bruce Fields" <bfields@fieldses.org>,
	Arnd Bergmann <arnd@arndb.de>,
	David Howells <dhowells@redhat.com>,
	Shuah Khan <shuah@kernel.org>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
	Jonathan Corbet <corbet@lwn.net>
Cc: Aleksa Sarai <cyphar@cyphar.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andy Lutomirski <luto@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
	Tycho Andersen <tycho@tycho.ws>,
	David Drysdale <drysdale@google.com>,
	Chanho Min <chanho.min@lge.com>, Oleg Nesterov <oleg@redhat.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Christian Brauner <christian@brauner.io>,
	Aleksa Sarai <asarai@suse.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	dev@opencontainers.org, containers@lists.linux-foundation.org,
	bpf@vger.kernel.org, netdev@vger.kernel.org,
	linux-alpha@vger.kernel.org, linux-api@vger.kernel.org,
	libc-alpha@sourceware.org, linux-arch@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
	linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
	linux-xtensa@linux-xtensa.org, sparclinux@vger.kernel.org
Subject: [PATCH RESEND v17 01/13] namei: only return -ECHILD from follow_dotdot_rcu()
Date: Wed, 20 Nov 2019 16:06:19 +1100
Message-ID: <20191120050631.12816-2-cyphar@cyphar.com> (raw)
In-Reply-To: <20191120050631.12816-1-cyphar@cyphar.com>

It's over-zealous to return hard errors under RCU-walk here, given that
a REF-walk will be triggered for all other cases handling ".." under
RCU.

The original purpose of this check was to ensure that if a rename occurs
such that a directory is moved outside of the bind-mount which the
resolution started in, it would be detected and blocked to avoid being
able to mess with paths outside of the bind-mount. However, triggering a
new REF-walk is just as effective a solution.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Fixes: 397d425dc26d ("vfs: Test for and handle paths that are unreachable from their mnt_root")
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 fs/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index 671c3c1a3425..5a47d9c09581 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1359,7 +1359,7 @@ static int follow_dotdot_rcu(struct nameidata *nd)
 			nd->path.dentry = parent;
 			nd->seq = seq;
 			if (unlikely(!path_connected(&nd->path)))
-				return -ENOENT;
+				return -ECHILD;
 			break;
 		} else {
 			struct mount *mnt = real_mount(nd->path.mnt);
-- 
2.24.0


  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-20  5:06 [PATCH RESEND v17 00/13] open: introduce openat2(2) syscall Aleksa Sarai
2019-11-20  5:06 ` Aleksa Sarai [this message]
2019-11-20  5:06 ` [PATCH RESEND v17 02/13] nsfs: clean-up ns_get_path() signature to return int Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 03/13] namei: allow nd_jump_link() to produce errors Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 04/13] namei: allow set_root() " Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 05/13] namei: LOOKUP_NO_SYMLINKS: block symlink resolution Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 06/13] namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 07/13] namei: LOOKUP_NO_XDEV: block mountpoint crossing Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 08/13] namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 09/13] namei: LOOKUP_IN_ROOT: chroot-like " Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 10/13] namei: LOOKUP_{IN_ROOT,BENEATH}: permit limited ".." resolution Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 11/13] open: introduce openat2(2) syscall Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 12/13] selftests: add openat2(2) selftests Aleksa Sarai
2019-11-20  5:06 ` [PATCH RESEND v17 13/13] Documentation: path-lookup: include new LOOKUP flags Aleksa Sarai

Reply instructions:

You may reply publically 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=20191120050631.12816-2-cyphar@cyphar.com \
    --to=cyphar@cyphar.com \
    --cc=akpm@linux-foundation.org \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=andriin@fb.com \
    --cc=arnd@arndb.de \
    --cc=asarai@suse.de \
    --cc=ast@kernel.org \
    --cc=bfields@fieldses.org \
    --cc=bpf@vger.kernel.org \
    --cc=chanho.min@lge.com \
    --cc=christian@brauner.io \
    --cc=containers@lists.linux-foundation.org \
    --cc=corbet@lwn.net \
    --cc=daniel@iogearbox.net \
    --cc=dev@opencontainers.org \
    --cc=dhowells@redhat.com \
    --cc=drysdale@google.com \
    --cc=ebiederm@xmission.com \
    --cc=jannh@google.com \
    --cc=jlayton@kernel.org \
    --cc=jolsa@redhat.com \
    --cc=kafai@fb.com \
    --cc=keescook@chromium.org \
    --cc=libc-alpha@sourceware.org \
    --cc=linux-alpha@vger.kernel.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-ia64@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-m68k@lists.linux-m68k.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=linux-parisc@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linux-sh@vger.kernel.org \
    --cc=linux-xtensa@linux-xtensa.org \
    --cc=linux@rasmusvillemoes.dk \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=oleg@redhat.com \
    --cc=peterz@infradead.org \
    --cc=shuah@kernel.org \
    --cc=skhan@linuxfoundation.org \
    --cc=songliubraving@fb.com \
    --cc=sparclinux@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    --cc=tycho@tycho.ws \
    --cc=viro@zeniv.linux.org.uk \
    --cc=yhs@fb.com \
    /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

Linux-m68k Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-m68k/0 linux-m68k/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-m68k linux-m68k/ https://lore.kernel.org/linux-m68k \
		linux-m68k@vger.kernel.org linux-m68k@lists.linux-m68k.org
	public-inbox-index linux-m68k

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-m68k


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git