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Date:   Wed, 8 Jul 2020 18:12:33 +0200
From:   Jessica Yu <jeyu@kernel.org>
To:     Kees Cook <keescook@chromium.org>
Cc:     Dominik Czarnota <dominik.czarnota@trailofbits.com>,
        stable@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.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 3/5] module: Do not expose section addresses to
 non-CAP_SYSLOG
Message-ID: <20200708161233.GB5609@linux-8ccs.fritz.box>
References: <20200702232638.2946421-1-keescook@chromium.org>
 <20200702232638.2946421-4-keescook@chromium.org>
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+++ Kees Cook [02/07/20 16:26 -0700]:
>The printing of section addresses in /sys/module/*/sections/* was not
>using the correct credentials to evaluate visibility.
>
>Before:
>
> # cat /sys/module/*/sections/.*text
> 0xffffffffc0458000
> ...
> # capsh --drop=CAP_SYSLOG -- -c "cat /sys/module/*/sections/.*text"
> 0xffffffffc0458000
> ...
>
>After:
>
> # cat /sys/module/*/sections/*.text
> 0xffffffffc0458000
> ...
> # capsh --drop=CAP_SYSLOG -- -c "cat /sys/module/*/sections/.*text"
> 0x0000000000000000
> ...
>
>Additionally replaces the existing (safe) /proc/modules check with
>file->f_cred for consistency.
>
>Cc: stable@vger.kernel.org
>Reported-by: Dominik Czarnota <dominik.czarnota@trailofbits.com>
>Fixes: be71eda5383f ("module: Fix display of wrong module .text address")
>Signed-off-by: Kees Cook <keescook@chromium.org>

Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>