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From: Kees Cook <keescook@chromium.org>
To: Takashi Iwai <tiwai@suse.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Scott Branden <scott.branden@broadcom.com>,
	Mimi Zohar <zohar@linux.ibm.com>, Jessica Yu <jeyu@kernel.org>,
	SeongJae Park <sjpark@amazon.de>, KP Singh <kpsingh@chromium.org>,
	linux-efi@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-integrity@vger.kernel.org, selinux@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 18/19] firmware: Add request_partial_firmware_into_buf()
Date: Wed, 29 Jul 2020 10:43:39 -0700
Message-ID: <202007291042.D43AA4AB37@keescook> (raw)
In-Reply-To: <s5ha6zig7s6.wl-tiwai@suse.de>

On Wed, Jul 29, 2020 at 08:22:17AM +0200, Takashi Iwai wrote:
> On Wed, 29 Jul 2020 03:17:39 +0200,
> Luis Chamberlain wrote:
> > 
> > Long ago Takashi had some points about this strategy breaking
> > compressed file use. Was that considered?
> 
> As long as I read the patch, it tries to skip both the compressed and
> the fallback loading when FW_OPT_PARTIAL is set, which is good.
> 
> However...
> 
> > > @@ -771,18 +805,20 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
> > >  	}
> > >  
> > >  	ret = _request_firmware_prepare(&fw, name, device, buf, size,
> > > -					opt_flags);
> > > +					offset, opt_flags);
> > >  	if (ret <= 0) /* error or already assigned */
> > >  		goto out;
> > >  
> > >  	ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL);
> > > -#ifdef CONFIG_FW_LOADER_COMPRESS
> > > -	if (ret == -ENOENT)
> > > +
> > > +	/* Only full reads can support decompression, platform, and sysfs. */
> > > +	if (!(opt_flags & FW_OPT_PARTIAL))
> > > +		nondirect = true;
> > > +
> > > +	if (ret == -ENOENT && nondirect)
> > >  		ret = fw_get_filesystem_firmware(device, fw->priv, ".xz",
> > >  						 fw_decompress_xz);
> > > -#endif
> 
> ... by dropping this ifdef, the fw loader would try to access *.xz
> file unnecessarily even if CONFIG_FW_LOADER_COMPRESS is disabled.

Ah, good point. I'd added the -ENOENT fw_decompress_xz, but I take your
point about the needless access. I will switch this back to an #ifdef.

-- 
Kees Cook

  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24 21:36 [PATCH v3 00/19] Introduce partial kernel_read_file() support Kees Cook
2020-07-24 21:36 ` [PATCH v3 01/19] test_firmware: Test platform fw loading on non-EFI systems Kees Cook
2020-07-24 21:36 ` [PATCH v3 02/19] selftest/firmware: Add selftest timeout in settings Kees Cook
2020-07-24 21:36 ` [PATCH v3 03/19] firmware_loader: EFI firmware loader must handle pre-allocated buffer Kees Cook
2020-07-25 10:07   ` Greg Kroah-Hartman
2020-07-25 15:50     ` Kees Cook
2020-07-25 17:20       ` Greg Kroah-Hartman
2020-07-24 21:36 ` [PATCH v3 04/19] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum Kees Cook
2020-07-27 13:35   ` Mimi Zohar
2020-07-24 21:36 ` [PATCH v3 05/19] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum Kees Cook
2020-07-24 21:36 ` [PATCH v3 06/19] fs/kernel_read_file: Split into separate include file Kees Cook
2020-07-27 14:41   ` Mimi Zohar
2020-07-24 21:36 ` [PATCH v3 07/19] fs/kernel_read_file: Split into separate source file Kees Cook
2020-07-27 14:53   ` Mimi Zohar
2020-07-24 21:36 ` [PATCH v3 08/19] fs/kernel_read_file: Remove redundant size argument Kees Cook
2020-07-27 16:29   ` Mimi Zohar
2020-07-24 21:36 ` [PATCH v3 09/19] fs/kernel_read_file: Switch buffer size arg to size_t Kees Cook
2020-07-27 16:29   ` Mimi Zohar
2020-07-24 21:36 ` [PATCH v3 10/19] fs/kernel_read_file: Add file_size output argument Kees Cook
2020-07-27 16:29   ` Mimi Zohar
2020-07-24 21:36 ` [PATCH v3 11/19] LSM: Introduce kernel_post_load_data() hook Kees Cook
2020-07-27 10:49   ` Mimi Zohar
2020-07-28 19:41     ` Kees Cook
2020-07-24 21:36 ` [PATCH v3 12/19] firmware_loader: Use security_post_load_data() Kees Cook
2020-07-27 10:57   ` Mimi Zohar
2020-07-28 19:43     ` Kees Cook
2020-07-29 16:29       ` Mimi Zohar
2020-07-29 18:10         ` Mimi Zohar
2020-07-29 19:13           ` Kees Cook
2020-07-24 21:36 ` [PATCH v3 13/19] module: Call security_kernel_post_load_data() Kees Cook
2020-07-24 21:36 ` [PATCH v3 14/19] LSM: Add "contents" flag to kernel_read_file hook Kees Cook
2020-07-24 21:36 ` [PATCH v3 15/19] IMA: Add support for file reads without contents Kees Cook
2020-07-27 13:23   ` Mimi Zohar
2020-07-28 19:44     ` Kees Cook
2020-07-28 19:56       ` Greg Kroah-Hartman
2020-07-28 20:12         ` Kees Cook
2020-07-24 21:36 ` [PATCH v3 16/19] fs/kernel_file_read: Add "offset" arg for partial reads Kees Cook
2020-07-24 21:36 ` [PATCH v3 17/19] firmware: Store opt_flags in fw_priv Kees Cook
2020-07-24 21:36 ` [PATCH v3 18/19] firmware: Add request_partial_firmware_into_buf() Kees Cook
2020-07-29  1:17   ` Luis Chamberlain
2020-07-29  6:22     ` Takashi Iwai
2020-07-29 17:43       ` Kees Cook [this message]
2020-07-24 21:36 ` [PATCH v3 19/19] test_firmware: Test partial read support Kees Cook
2020-07-25  5:14 ` [PATCH v3 00/19] Introduce partial kernel_read_file() support Scott Branden
2020-07-25 10:05 ` Greg Kroah-Hartman
2020-07-25 15:48   ` Kees Cook
2020-07-27 11:16 ` Mimi Zohar
2020-07-27 19:18   ` Scott Branden
2020-07-28 18:48     ` Mimi Zohar
2020-07-28 19:56       ` Scott Branden
2020-07-29  1:19 ` Luis Chamberlain

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