From: Al Viro <viro@zeniv.linux.org.uk>
To: Aleksa Sarai <cyphar@cyphar.com>
Cc: 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>,
Christian Brauner <christian@brauner.io>,
David Drysdale <drysdale@google.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Eric Biederman <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexei Starovoitov <ast@kernel.org>,
Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
Tycho Andersen <tycho@tycho.ws>, Chanho Min <chanho.min@lge.com>,
Oleg Nesterov <oleg@redhat.com>, Aleksa Sarai <asarai@suse.de>,
containers@lists.linux-foundation.org,
linux-alpha@vger.kernel.org, linux-api@vger.kernel.org,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.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: Re: [PATCH v9 05/10] namei: O_BENEATH-style path resolution flags
Date: Sun, 14 Jul 2019 15:36:23 +0100 [thread overview]
Message-ID: <20190714143623.GR17978@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190714070029.m53etvm3y4etidxt@yavin>
On Sun, Jul 14, 2019 at 05:00:29PM +1000, Aleksa Sarai wrote:
> The basic property being guaranteed by LOOKUP_IN_ROOT is that it will
> not result in resolution of a path component which was not inside the
> root of the dirfd tree at some point during resolution (and that all
> absolute symlink and ".." resolution will be done relative to the
> dirfd). This may smell slightly of chroot(2), because unfortunately it
> is a similar concept -- the reason for this is to allow for a more
> efficient way to safely resolve paths inside a rootfs than spawning a
> separate process to then pass back the fd to the caller.
IDGI... If attacker can modify your subtree, you have already lost -
after all, they can make anything appear inside that tree just before
your syscall is made and bring it back out immediately afterwards.
And if they can't, what is the race you are trying to protect against?
Confused...
next prev parent reply other threads:[~2019-07-14 14:36 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-06 14:57 [PATCH v9 00/10] namei: openat2(2) path resolution restrictions Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 01/10] namei: obey trailing magic-link DAC permissions Aleksa Sarai
2019-07-12 4:14 ` Al Viro
2019-07-12 6:36 ` Al Viro
2019-07-12 12:20 ` Aleksa Sarai
2019-07-12 13:10 ` Al Viro
2019-07-14 7:11 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 02/10] procfs: switch magic-link modes to be more sane Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 03/10] open: O_EMPTYPATH: procfs-less file descriptor re-opening Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 04/10] namei: split out nd->dfd handling to dirfd_path_init Aleksa Sarai
2019-07-12 4:20 ` Al Viro
2019-07-12 12:07 ` Aleksa Sarai
2019-07-12 12:12 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 05/10] namei: O_BENEATH-style path resolution flags Aleksa Sarai
2019-07-12 4:33 ` Al Viro
2019-07-12 10:57 ` Aleksa Sarai
2019-07-12 12:39 ` Al Viro
2019-07-12 12:55 ` Al Viro
2019-07-12 13:25 ` Al Viro
2019-07-12 15:00 ` Al Viro
2019-07-13 2:41 ` Al Viro
2019-07-14 3:58 ` Al Viro
2019-07-16 8:03 ` Aleksa Sarai
2019-07-14 7:00 ` Aleksa Sarai
2019-07-14 14:36 ` Al Viro [this message]
2019-07-18 3:17 ` Aleksa Sarai
2019-07-14 10:31 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 06/10] namei: LOOKUP_IN_ROOT: chroot-like path resolution Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 07/10] namei: aggressively check for nd->root escape on ".." resolution Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 08/10] open: openat2(2) syscall Aleksa Sarai
2019-07-18 14:48 ` Rasmus Villemoes
2019-07-18 15:21 ` Aleksa Sarai
2019-07-18 15:10 ` Arnd Bergmann
2019-07-18 16:12 ` Aleksa Sarai
2019-07-18 21:29 ` Arnd Bergmann
2019-07-19 2:12 ` Dmitry V. Levin
2019-07-19 10:29 ` Christian Brauner
2019-07-19 1:59 ` Dmitry V. Levin
2019-07-19 2:19 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 09/10] kselftest: save-and-restore errno to allow for %m formatting Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 10/10] selftests: add openat2(2) selftests Aleksa Sarai
2019-07-08 1:15 ` Michael Ellerman
2019-07-08 5:47 ` Aleksa Sarai
2019-07-12 15:11 ` [PATCH v9 00/10] namei: openat2(2) path resolution restrictions Al Viro
2019-07-12 15:32 ` Aleksa Sarai
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