From: Kees Cook <keescook@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dominik Czarnota <dominik.czarnota@trailofbits.com>,
stable@vger.kernel.org, Jessica Yu <jeyu@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.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>,
KP Singh <kpsingh@chromium.org>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Masami Hiramatsu <mhiramat@kernel.org>,
Jakub Kicinski <kuba@kernel.org>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Will Deacon <will@kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Marc Zyngier <maz@kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Matteo Croce <mcroce@redhat.com>,
Edward Cree <ecree@solarflare.com>,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
Alexander Lobakin <alobakin@dlink.ru>,
Thomas Richter <tmricht@linux.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] module: Refactor section attr into bin attribute
Date: Fri, 3 Jul 2020 08:29:43 -0700 [thread overview]
Message-ID: <202007030818.99013B6@keescook> (raw)
In-Reply-To: <20200703060207.GA6344@kroah.com>
On Fri, Jul 03, 2020 at 08:02:07AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Jul 02, 2020 at 04:26:35PM -0700, Kees Cook wrote:
> > + sattr->battr.size = 3 /* "0x", "\n" */ + (BITS_PER_LONG / 4);
>
> They get a correct "size" value now, nice!
Yeah, though I do have some concerns that switching to a bin attribute
changes the userspace behavior a bit. With seq_file-based "show", we
get a 4096 size, and seeking isn't possible (lseek to non-0 location
will fail). With the raw "read", we get the right size, but lseek()
is allowed (but I've got the "read" handler refuse reads starting from
non-zero). When I reviewed[1] potential readers (elftutils, systemtap,
kmod), they all seem to do normal things (fopen/fscanf/fclose), so I'm
hoping this won't be a problem in practice.
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Thanks!
[1] https://codesearch.debian.net/search?q=%2Fsys%2Fmodule.*sections&literal=0
--
Kees Cook
next prev parent reply other threads:[~2020-07-03 15:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 23:26 [PATCH 0/5] Refactor kallsyms_show_value() users for correct cred Kees Cook
2020-07-02 23:26 ` [PATCH 1/5] kallsyms: Refactor kallsyms_show_value() to take cred Kees Cook
2020-07-10 14:03 ` Sasha Levin
2020-07-10 15:57 ` Kees Cook
2020-07-11 16:07 ` Sasha Levin
2020-07-02 23:26 ` [PATCH 2/5] module: Refactor section attr into bin attribute Kees Cook
2020-07-03 6:02 ` Greg Kroah-Hartman
2020-07-03 15:29 ` Kees Cook [this message]
2020-07-08 16:10 ` Jessica Yu
2020-07-02 23:26 ` [PATCH 3/5] module: Do not expose section addresses to non-CAP_SYSLOG Kees Cook
2020-07-08 16:12 ` Jessica Yu
2020-07-02 23:26 ` [PATCH 4/5] kprobes: Do not expose probe " Kees Cook
2020-07-03 1:00 ` Linus Torvalds
2020-07-03 15:13 ` Kees Cook
2020-07-03 15:50 ` Kees Cook
2020-07-05 20:10 ` Linus Torvalds
2020-07-05 20:19 ` Kees Cook
2020-07-10 14:09 ` Masami Hiramatsu
2020-07-02 23:26 ` [PATCH 5/5] bpf: Check correct cred for CAP_SYSLOG in bpf_dump_raw_ok() Kees Cook
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