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Subject: Re: [PATCH 03/13] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED
 enum
To:     Kees Cook <keescook@chromium.org>
Cc:     stable@vger.kernel.org, Mimi Zohar <zohar@linux.ibm.com>,
        Matthew Wilcox <willy@infradead.org>,
        James Morris <jmorris@namei.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Jessica Yu <jeyu@kernel.org>,
        Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Casey Schaufler <casey@schaufler-ca.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Matthew Garrett <matthewgarrett@google.com>,
        David Howells <dhowells@redhat.com>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Joel Fernandes (Google)" <joel@joelfernandes.org>,
        KP Singh <kpsingh@google.com>, Dave Olsthoorn <dave@bewaar.me>,
        Hans de Goede <hdegoede@redhat.com>,
        Peter Jones <pjones@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        linux-security-module@vger.kernel.org,
        linux-integrity@vger.kernel.org, selinux@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, kexec@lists.infradead.org,
        linux-kernel@vger.kernel.org
References: <20200717174309.1164575-1-keescook@chromium.org>
 <20200717174309.1164575-4-keescook@chromium.org>
From:   Scott Branden <scott.branden@broadcom.com>
Message-ID: <8ee5f0f1-8eae-510a-a3bb-7420a3fca001@broadcom.com>
Date:   Fri, 17 Jul 2020 12:10:15 -0700
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On 2020-07-17 10:42 a.m., Kees Cook wrote:
> The "FIRMWARE_EFI_EMBEDDED" enum is a "where", not a "what". It
> should not be distinguished separately from just "FIRMWARE", as this
> confuses the LSMs about what is being loaded. Additionally, there was
> no actual validation of the firmware contents happening.
>
> Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firmware_request_platform()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Scott Branden <scott.branden@broadcom.com>
> ---
> To aid in backporting, this change is made before moving
> kernel_read_file() to separate header/source files.
> ---
>   drivers/base/firmware_loader/fallback_platform.c | 2 +-
>   include/linux/fs.h                               | 3 +--
>   2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
> index 685edb7dd05a..6958ab1a8059 100644
> --- a/drivers/base/firmware_loader/fallback_platform.c
> +++ b/drivers/base/firmware_loader/fallback_platform.c
> @@ -17,7 +17,7 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
>   	if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))
>   		return -ENOENT;
>   
> -	rc = security_kernel_load_data(LOADING_FIRMWARE_EFI_EMBEDDED);
> +	rc = security_kernel_load_data(LOADING_FIRMWARE);
>   	if (rc)
>   		return rc;
>   
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 95fc775ed937..f50a35d54a61 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2993,11 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode)
>   #endif
>   extern int do_pipe_flags(int *, int);
>   
> -/* This is a list of *what* is being read, not *how*. */
> +/* This is a list of *what* is being read, not *how* nor *where*. */
>   #define __kernel_read_file_id(id) \
>   	id(UNKNOWN, unknown)		\
>   	id(FIRMWARE, firmware)		\
> -	id(FIRMWARE_EFI_EMBEDDED, firmware)	\
>   	id(MODULE, kernel-module)		\
>   	id(KEXEC_IMAGE, kexec-image)		\
>   	id(KEXEC_INITRAMFS, kexec-initramfs)	\