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: linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
sparclinux@vger.kernel.org, linux-api@vger.kernel.org,
Jiri Olsa <jolsa@redhat.com>,
linux-arch@vger.kernel.org, linux-s390@vger.kernel.org,
Tycho Andersen <tycho@tycho.ws>, Aleksa Sarai <asarai@suse.de>,
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Jann Horn <jannh@google.com>,
linuxppc-dev@lists.ozlabs.org, dev@opencontainers.org,
Aleksa Sarai <cyphar@cyphar.com>,
Andy Lutomirski <luto@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
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Christian Brauner <christian@brauner.io>,
libc-alpha@sourceware.org, linux-parisc@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, netdev@vger.kernel.org,
Chanho Min <chanho.min@lge.com>, Oleg Nesterov <oleg@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org,
bpf@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
containers@lists.linux-foundation.org
Subject: [PATCH v18 01/13] namei: only return -ECHILD from follow_dotdot_rcu()
Date: Sat, 7 Dec 2019 01:13:26 +1100 [thread overview]
Message-ID: <20191206141338.23338-2-cyphar@cyphar.com> (raw)
In-Reply-To: <20191206141338.23338-1-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
next prev parent reply other threads:[~2019-12-06 14:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-06 14:13 [PATCH v18 00/13] open: introduce openat2(2) syscall Aleksa Sarai
2019-12-06 14:13 ` Aleksa Sarai [this message]
2019-12-06 14:13 ` [PATCH v18 02/13] nsfs: clean-up ns_get_path() signature to return int Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 03/13] namei: allow nd_jump_link() to produce errors Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 04/13] namei: allow set_root() " Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 05/13] namei: LOOKUP_NO_SYMLINKS: block symlink resolution Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 06/13] namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 07/13] namei: LOOKUP_NO_XDEV: block mountpoint crossing Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 08/13] namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 09/13] namei: LOOKUP_IN_ROOT: chroot-like " Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 10/13] namei: LOOKUP_{IN_ROOT, BENEATH}: permit limited ".." resolution Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 11/13] open: introduce openat2(2) syscall Aleksa Sarai
2019-12-16 19:20 ` Florian Weimer
2019-12-17 6:39 ` Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 12/13] selftests: add openat2(2) selftests Aleksa Sarai
2019-12-06 14:13 ` [PATCH v18 13/13] Documentation: path-lookup: include new LOOKUP flags Aleksa Sarai
2019-12-08 4:39 ` [PATCH v18 00/13] open: introduce openat2(2) syscall Al Viro
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