modules: add modalias file to sysfs for modules.
Commit Message
USB devices support the authorized attribute which can be used by
user-space to implement trust-based systems for enabling USB devices. It
would be helpful when building these systems to be able to know in
advance which kernel drivers (or modules) are reachable from a
particular USB device.
This information is readily available for external modules in
modules.alias. However, builtin kernel modules are not covered. This
patch adds a sys-fs attribute to both builtin and loaded modules
exposing the matching rules in the modalias format for integration
with tools like USBGuard.
Signed-off-by: Allen Webb <allenwebb@google.com>
---
drivers/base/Makefile | 2 +-
drivers/base/base.h | 8 ++
drivers/base/bus.c | 42 ++++++
drivers/base/mod_devicetable.c | 241 +++++++++++++++++++++++++++++++++
drivers/usb/core/driver.c | 2 +
include/linux/device/bus.h | 8 ++
include/linux/module.h | 1 +
kernel/module/internal.h | 2 +
kernel/module/sysfs.c | 100 ++++++++++++++
kernel/params.c | 2 +
10 files changed, 407 insertions(+), 1 deletion(-)
create mode 100644 drivers/base/mod_devicetable.c
Comments
On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> USB devices support the authorized attribute which can be used by
> user-space to implement trust-based systems for enabling USB devices. It
> would be helpful when building these systems to be able to know in
> advance which kernel drivers (or modules) are reachable from a
> particular USB device.
>
> This information is readily available for external modules in
> modules.alias. However, builtin kernel modules are not covered. This
> patch adds a sys-fs attribute to both builtin and loaded modules
> exposing the matching rules in the modalias format for integration
> with tools like USBGuard.
>
> Signed-off-by: Allen Webb <allenwebb@google.com>
> ---
> drivers/base/Makefile | 2 +-
> drivers/base/base.h | 8 ++
> drivers/base/bus.c | 42 ++++++
> drivers/base/mod_devicetable.c | 241 +++++++++++++++++++++++++++++++++
> drivers/usb/core/driver.c | 2 +
> include/linux/device/bus.h | 8 ++
> include/linux/module.h | 1 +
> kernel/module/internal.h | 2 +
> kernel/module/sysfs.c | 100 ++++++++++++++
> kernel/params.c | 2 +
> 10 files changed, 407 insertions(+), 1 deletion(-)
> create mode 100644 drivers/base/mod_devicetable.c
>
Hi,
This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created. Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.
You are receiving this message because of the following common error(s)
as indicated below:
- This looks like a new version of a previously submitted patch, but you
did not list below the --- line any changes from the previous version.
Please read the section entitled "The canonical patch format" in the
kernel file, Documentation/SubmittingPatches for what needs to be done
here to properly describe this.
If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
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thanks,
greg k-h's patch email bot
On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> USB devices support the authorized attribute which can be used by
> user-space to implement trust-based systems for enabling USB devices. It
> would be helpful when building these systems to be able to know in
> advance which kernel drivers (or modules) are reachable from a
> particular USB device.
>
> This information is readily available for external modules in
> modules.alias. However, builtin kernel modules are not covered. This
> patch adds a sys-fs attribute to both builtin and loaded modules
> exposing the matching rules in the modalias format for integration
> with tools like USBGuard.
>
> Signed-off-by: Allen Webb <allenwebb@google.com>
Thanks for the patch Allen!
I'd rather have something generic though, and it would seem kmod [0] already
does this, have you seen the kmod support for builtin.alias.bin
Can't that be used?
[0] git://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git
Luis
Hi Allen,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on driver-core/driver-core-testing]
[also build test ERROR on driver-core/driver-core-next driver-core/driver-core-linus mcgrof/modules-next usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.1-rc4 next-20221111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Allen-Webb/modules-add-modalias-file-to-sysfs-for-modules/20221111-233314
patch link: https://lore.kernel.org/r/20221111152852.2837363-1-allenwebb%40google.com
patch subject: [PATCH] modules: add modalias file to sysfs for modules.
config: um-i386_defconfig
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/6dda398b2e01f44f8fb5f03116ba5e6143360140
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Allen-Webb/modules-add-modalias-file-to-sysfs-for-modules/20221111-233314
git checkout 6dda398b2e01f44f8fb5f03116ba5e6143360140
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
/usr/bin/ld: warning: arch/x86/um/checksum_32.o: missing .note.GNU-stack section implies executable stack
/usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
/usr/bin/ld: warning: .tmp_vmlinux.kallsyms1 has a LOAD segment with RWX permissions
/usr/bin/ld: drivers/base/mod_devicetable.o: in function `usb_drv_to_modalias':
>> drivers/base/mod_devicetable.c:221: undefined reference to `usb_bus_type'
>> collect2: error: ld returned 1 exit status
vim +221 drivers/base/mod_devicetable.c
203
204 /* Print the modaliases for the given driver assumed to be an usb_driver or
205 * usb_device_driver.
206 *
207 * "alias" is prepended and the module name is appended to each modalias to
208 * match the format in modules.aliases.
209 *
210 * The modaliases will be written out to @buf with @count being the maximum
211 * bytes to write. The return value is a negative errno on error or the number
212 * of bytes written to @buf on success.
213 */
214 ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
215 size_t count)
216 {
217 ssize_t len = 0;
218 const struct usb_device_id *id;
219 const char *mod_name;
220
> 221 if (drv->bus != &usb_bus_type)
Hi Allen,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on driver-core/driver-core-testing]
[also build test ERROR on driver-core/driver-core-next driver-core/driver-core-linus mcgrof/modules-next usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.1-rc4 next-20221111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Allen-Webb/modules-add-modalias-file-to-sysfs-for-modules/20221111-233314
patch link: https://lore.kernel.org/r/20221111152852.2837363-1-allenwebb%40google.com
patch subject: [PATCH] modules: add modalias file to sysfs for modules.
config: m68k-m5208evb_defconfig
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/6dda398b2e01f44f8fb5f03116ba5e6143360140
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Allen-Webb/modules-add-modalias-file-to-sysfs-for-modules/20221111-233314
git checkout 6dda398b2e01f44f8fb5f03116ba5e6143360140
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from drivers/base/core.c:35:
drivers/base/base.h: In function 'usb_drv_to_modalias':
>> drivers/base/base.h:180:67: error: 'ENOSUP' undeclared (first use in this function); did you mean 'ENOSYS'?
180 | size_t count) { return -ENOSUP; }
| ^~~~~~
| ENOSYS
drivers/base/base.h:180:67: note: each undeclared identifier is reported only once for each function it appears in
vim +180 drivers/base/base.h
174
175 #if defined(CONFIG_SYSFS)
176 ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
177 size_t count);
178 #else
179 static inline ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
> 180 size_t count) { return -ENOSUP; }
181 #endif
182
Hi Allen,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on driver-core/driver-core-testing]
[also build test WARNING on driver-core/driver-core-next driver-core/driver-core-linus mcgrof/modules-next usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.1-rc4 next-20221111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Allen-Webb/modules-add-modalias-file-to-sysfs-for-modules/20221111-233314
patch link: https://lore.kernel.org/r/20221111152852.2837363-1-allenwebb%40google.com
patch subject: [PATCH] modules: add modalias file to sysfs for modules.
config: sparc-allyesconfig
compiler: sparc64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/6dda398b2e01f44f8fb5f03116ba5e6143360140
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Allen-Webb/modules-add-modalias-file-to-sysfs-for-modules/20221111-233314
git checkout 6dda398b2e01f44f8fb5f03116ba5e6143360140
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sparc SHELL=/bin/bash drivers/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> drivers/base/mod_devicetable.c:214:9: warning: no previous prototype for 'usb_drv_to_modalias' [-Wmissing-prototypes]
214 | ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
| ^~~~~~~~~~~~~~~~~~~
vim +/usb_drv_to_modalias +214 drivers/base/mod_devicetable.c
203
204 /* Print the modaliases for the given driver assumed to be an usb_driver or
205 * usb_device_driver.
206 *
207 * "alias" is prepended and the module name is appended to each modalias to
208 * match the format in modules.aliases.
209 *
210 * The modaliases will be written out to @buf with @count being the maximum
211 * bytes to write. The return value is a negative errno on error or the number
212 * of bytes written to @buf on success.
213 */
> 214 ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> > USB devices support the authorized attribute which can be used by
> > user-space to implement trust-based systems for enabling USB devices. It
> > would be helpful when building these systems to be able to know in
> > advance which kernel drivers (or modules) are reachable from a
> > particular USB device.
> >
> > This information is readily available for external modules in
> > modules.alias. However, builtin kernel modules are not covered. This
> > patch adds a sys-fs attribute to both builtin and loaded modules
> > exposing the matching rules in the modalias format for integration
> > with tools like USBGuard.
> >
> > Signed-off-by: Allen Webb <allenwebb@google.com>
>
> Thanks for the patch Allen!
>
> I'd rather have something generic though, and it would seem kmod [0] already
> does this, have you seen the kmod support for builtin.alias.bin
>
> Can't that be used?
Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
>
> [0] git://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git
>
> Luis
On Mon, Nov 14, 2022 at 10:42:50AM -0600, Allen Webb wrote:
>On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>>
>> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
>> > USB devices support the authorized attribute which can be used by
>> > user-space to implement trust-based systems for enabling USB devices. It
>> > would be helpful when building these systems to be able to know in
>> > advance which kernel drivers (or modules) are reachable from a
>> > particular USB device.
>> >
>> > This information is readily available for external modules in
>> > modules.alias. However, builtin kernel modules are not covered. This
>> > patch adds a sys-fs attribute to both builtin and loaded modules
>> > exposing the matching rules in the modalias format for integration
>> > with tools like USBGuard.
>> >
>> > Signed-off-by: Allen Webb <allenwebb@google.com>
>>
>> Thanks for the patch Allen!
>>
>> I'd rather have something generic though, and it would seem kmod [0] already
>> does this, have you seen the kmod support for builtin.alias.bin
>>
>> Can't that be used?
>
>Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
no. That is generated by depmod since v27 using modules.builtin.modinfo
generated by the kernel build system. Highly recommend v30 though
as there were fixes in v28 and v29 and some changes to speed up its
generation/use in v30: See entries mentioning
builtin.alias and bultin.modinfo in
https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/NEWS
libkmod/modprobe/modinfo also have the corresponding changes to lookup that
index when resolving aliases.
Lucas De Marchi
>
>>
>> [0] git://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git
>>
>> Luis
On Mon, Nov 14, 2022 at 11:22 AM Lucas De Marchi
<lucas.demarchi@intel.com> wrote:
>
> On Mon, Nov 14, 2022 at 10:42:50AM -0600, Allen Webb wrote:
> >On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> >>
> >> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> >> > USB devices support the authorized attribute which can be used by
> >> > user-space to implement trust-based systems for enabling USB devices. It
> >> > would be helpful when building these systems to be able to know in
> >> > advance which kernel drivers (or modules) are reachable from a
> >> > particular USB device.
> >> >
> >> > This information is readily available for external modules in
> >> > modules.alias. However, builtin kernel modules are not covered. This
> >> > patch adds a sys-fs attribute to both builtin and loaded modules
> >> > exposing the matching rules in the modalias format for integration
> >> > with tools like USBGuard.
> >> >
> >> > Signed-off-by: Allen Webb <allenwebb@google.com>
> >>
> >> Thanks for the patch Allen!
> >>
> >> I'd rather have something generic though, and it would seem kmod [0] already
> >> does this, have you seen the kmod support for builtin.alias.bin
> >>
> >> Can't that be used?
> >
> >Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
>
> no. That is generated by depmod since v27 using modules.builtin.modinfo
> generated by the kernel build system. Highly recommend v30 though
> as there were fixes in v28 and v29 and some changes to speed up its
> generation/use in v30: See entries mentioning
> builtin.alias and bultin.modinfo in
> https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/NEWS
>
> libkmod/modprobe/modinfo also have the corresponding changes to lookup that
> index when resolving aliases.
I see the file but it is largely missing the aliases I am interested
in, so it looks like I might need to modify my patch that creates
buildin.alias to add the missing alias defines in the header along
with the other module metadata for builtin modules. Does this sound
right to you?
>
> Lucas De Marchi
>
>
> >
> >>
> >> [0] git://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git
> >>
> >> Luis
On Tue, Nov 15, 2022 at 10:05:35AM -0600, Allen Webb wrote:
> On Mon, Nov 14, 2022 at 11:22 AM Lucas De Marchi
> <lucas.demarchi@intel.com> wrote:
> >
> > On Mon, Nov 14, 2022 at 10:42:50AM -0600, Allen Webb wrote:
> > >On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> > >>
> > >> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> > >> > USB devices support the authorized attribute which can be used by
> > >> > user-space to implement trust-based systems for enabling USB devices. It
> > >> > would be helpful when building these systems to be able to know in
> > >> > advance which kernel drivers (or modules) are reachable from a
> > >> > particular USB device.
> > >> >
> > >> > This information is readily available for external modules in
> > >> > modules.alias. However, builtin kernel modules are not covered. This
> > >> > patch adds a sys-fs attribute to both builtin and loaded modules
> > >> > exposing the matching rules in the modalias format for integration
> > >> > with tools like USBGuard.
> > >> >
> > >> > Signed-off-by: Allen Webb <allenwebb@google.com>
> > >>
> > >> Thanks for the patch Allen!
> > >>
> > >> I'd rather have something generic though, and it would seem kmod [0] already
> > >> does this, have you seen the kmod support for builtin.alias.bin
> > >>
> > >> Can't that be used?
> > >
> > >Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
> >
> > no. That is generated by depmod since v27 using modules.builtin.modinfo
> > generated by the kernel build system. Highly recommend v30 though
> > as there were fixes in v28 and v29 and some changes to speed up its
> > generation/use in v30: See entries mentioning
> > builtin.alias and bultin.modinfo in
> > https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/NEWS
> >
> > libkmod/modprobe/modinfo also have the corresponding changes to lookup that
> > index when resolving aliases.
>
> I see the file but it is largely missing the aliases I am interested
> in, so it looks like I might need to modify my patch that creates
> buildin.alias to add the missing alias defines in the header along
> with the other module metadata for builtin modules. Does this sound
> right to you?
Can you clarify what is missing and why? And an RFC is welcomed if it
helps demonstrates what you mean.
Luis
When i get the modinfo for usbhid, there are no aliases listed:
```
localhost ~ # modinfo usbhid
name: usbhid
filename: (builtin)
author: Andreas Gal
author: Vojtech Pavlik
author: Jiri Kosina
description: USB HID core driver
file: drivers/hid/usbhid/usbhid
license: GPL
parm: quirks:Add/modify USB HID quirks by specifying
quirks=vendorID:productID:quirks where vendorID, productID, and quirks
are all in 0x-prefixed hex (array of charp)
parm: ignoreled:Autosuspend with active leds (uint)
parm: kbpoll:Polling interval of keyboards (uint)
parm: jspoll:Polling interval of joysticks (uint)
parm: mousepoll:Polling interval of mice (uint)
```
bluetooth however has an alias listed:
```
localhost ~ # modinfo bluetooth
filename:
/lib/modules/5.10.154-20424-gea7532c123d8/kernel/net/bluetooth/bluetooth.ko.gz
author: Marcel Holtmann <marcel@holtmann.org>
description: Bluetooth Core ver 2.22
version: 2.22
license: GPL
alias: net-pf-31
vermagic: 5.10.154-20424-gea7532c123d8 SMP preempt mod_unload
name: bluetooth
intree: Y
retpoline: Y
depends: ecdh_generic
srcversion: F8E46CD048C50B0AA1CD471
parm: disable_esco:Disable eSCO connection creation (bool)
parm: enable_ecred:Enable enhanced credit flow control mode (bool)
parm: disable_ertm:Disable enhanced retransmission mode (bool)
```
I believe the reason for this is many modules use `#define
MODULE_DEVICE_TABLE(type, name)` which is a noop for buildin modules.
I have a local patch that resolves that issue here:
See: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3840672/1/include/linux/module.h#b246
However, I probably ought to rework that patch to create the
MODULE_ALIAS defines instead of the buildin.alias file.
On Tue, Nov 15, 2022 at 11:35 AM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Tue, Nov 15, 2022 at 10:05:35AM -0600, Allen Webb wrote:
> > On Mon, Nov 14, 2022 at 11:22 AM Lucas De Marchi
> > <lucas.demarchi@intel.com> wrote:
> > >
> > > On Mon, Nov 14, 2022 at 10:42:50AM -0600, Allen Webb wrote:
> > > >On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> > > >>
> > > >> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> > > >> > USB devices support the authorized attribute which can be used by
> > > >> > user-space to implement trust-based systems for enabling USB devices. It
> > > >> > would be helpful when building these systems to be able to know in
> > > >> > advance which kernel drivers (or modules) are reachable from a
> > > >> > particular USB device.
> > > >> >
> > > >> > This information is readily available for external modules in
> > > >> > modules.alias. However, builtin kernel modules are not covered. This
> > > >> > patch adds a sys-fs attribute to both builtin and loaded modules
> > > >> > exposing the matching rules in the modalias format for integration
> > > >> > with tools like USBGuard.
> > > >> >
> > > >> > Signed-off-by: Allen Webb <allenwebb@google.com>
> > > >>
> > > >> Thanks for the patch Allen!
> > > >>
> > > >> I'd rather have something generic though, and it would seem kmod [0] already
> > > >> does this, have you seen the kmod support for builtin.alias.bin
> > > >>
> > > >> Can't that be used?
> > > >
> > > >Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
> > >
> > > no. That is generated by depmod since v27 using modules.builtin.modinfo
> > > generated by the kernel build system. Highly recommend v30 though
> > > as there were fixes in v28 and v29 and some changes to speed up its
> > > generation/use in v30: See entries mentioning
> > > builtin.alias and bultin.modinfo in
> > > https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/NEWS
> > >
> > > libkmod/modprobe/modinfo also have the corresponding changes to lookup that
> > > index when resolving aliases.
> >
> > I see the file but it is largely missing the aliases I am interested
> > in, so it looks like I might need to modify my patch that creates
> > buildin.alias to add the missing alias defines in the header along
> > with the other module metadata for builtin modules. Does this sound
> > right to you?
>
> Can you clarify what is missing and why? And an RFC is welcomed if it
> helps demonstrates what you mean.
>
> Luis
I think I am misunderstanding something because the aliases visible
through kmod_config_get_aliases don't look anything like the
modaliases used by udev to match devices to modules.
I have some concern that making the changes necessary to use kmod
would result in the files/indexes being much larger to include all the
extra values that are being left out, so I think the sysfs approach
might be the better way to go.
On Tue, Nov 15, 2022 at 12:40 PM Allen Webb <allenwebb@google.com> wrote:
>
> When i get the modinfo for usbhid, there are no aliases listed:
> ```
> localhost ~ # modinfo usbhid
> name: usbhid
> filename: (builtin)
> author: Andreas Gal
> author: Vojtech Pavlik
> author: Jiri Kosina
> description: USB HID core driver
> file: drivers/hid/usbhid/usbhid
> license: GPL
> parm: quirks:Add/modify USB HID quirks by specifying
> quirks=vendorID:productID:quirks where vendorID, productID, and quirks
> are all in 0x-prefixed hex (array of charp)
> parm: ignoreled:Autosuspend with active leds (uint)
> parm: kbpoll:Polling interval of keyboards (uint)
> parm: jspoll:Polling interval of joysticks (uint)
> parm: mousepoll:Polling interval of mice (uint)
> ```
>
> bluetooth however has an alias listed:
> ```
> localhost ~ # modinfo bluetooth
> filename:
> /lib/modules/5.10.154-20424-gea7532c123d8/kernel/net/bluetooth/bluetooth.ko.gz
> author: Marcel Holtmann <marcel@holtmann.org>
> description: Bluetooth Core ver 2.22
> version: 2.22
> license: GPL
> alias: net-pf-31
> vermagic: 5.10.154-20424-gea7532c123d8 SMP preempt mod_unload
> name: bluetooth
> intree: Y
> retpoline: Y
> depends: ecdh_generic
> srcversion: F8E46CD048C50B0AA1CD471
> parm: disable_esco:Disable eSCO connection creation (bool)
> parm: enable_ecred:Enable enhanced credit flow control mode (bool)
> parm: disable_ertm:Disable enhanced retransmission mode (bool)
> ```
>
> I believe the reason for this is many modules use `#define
> MODULE_DEVICE_TABLE(type, name)` which is a noop for buildin modules.
> I have a local patch that resolves that issue here:
> See: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3840672/1/include/linux/module.h#b246
>
> However, I probably ought to rework that patch to create the
> MODULE_ALIAS defines instead of the buildin.alias file.
>
> On Tue, Nov 15, 2022 at 11:35 AM Luis Chamberlain <mcgrof@kernel.org> wrote:
> >
> > On Tue, Nov 15, 2022 at 10:05:35AM -0600, Allen Webb wrote:
> > > On Mon, Nov 14, 2022 at 11:22 AM Lucas De Marchi
> > > <lucas.demarchi@intel.com> wrote:
> > > >
> > > > On Mon, Nov 14, 2022 at 10:42:50AM -0600, Allen Webb wrote:
> > > > >On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> > > > >>
> > > > >> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> > > > >> > USB devices support the authorized attribute which can be used by
> > > > >> > user-space to implement trust-based systems for enabling USB devices. It
> > > > >> > would be helpful when building these systems to be able to know in
> > > > >> > advance which kernel drivers (or modules) are reachable from a
> > > > >> > particular USB device.
> > > > >> >
> > > > >> > This information is readily available for external modules in
> > > > >> > modules.alias. However, builtin kernel modules are not covered. This
> > > > >> > patch adds a sys-fs attribute to both builtin and loaded modules
> > > > >> > exposing the matching rules in the modalias format for integration
> > > > >> > with tools like USBGuard.
> > > > >> >
> > > > >> > Signed-off-by: Allen Webb <allenwebb@google.com>
> > > > >>
> > > > >> Thanks for the patch Allen!
> > > > >>
> > > > >> I'd rather have something generic though, and it would seem kmod [0] already
> > > > >> does this, have you seen the kmod support for builtin.alias.bin
> > > > >>
> > > > >> Can't that be used?
> > > > >
> > > > >Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
> > > >
> > > > no. That is generated by depmod since v27 using modules.builtin.modinfo
> > > > generated by the kernel build system. Highly recommend v30 though
> > > > as there were fixes in v28 and v29 and some changes to speed up its
> > > > generation/use in v30: See entries mentioning
> > > > builtin.alias and bultin.modinfo in
> > > > https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/NEWS
> > > >
> > > > libkmod/modprobe/modinfo also have the corresponding changes to lookup that
> > > > index when resolving aliases.
> > >
> > > I see the file but it is largely missing the aliases I am interested
> > > in, so it looks like I might need to modify my patch that creates
> > > buildin.alias to add the missing alias defines in the header along
> > > with the other module metadata for builtin modules. Does this sound
> > > right to you?
> >
> > Can you clarify what is missing and why? And an RFC is welcomed if it
> > helps demonstrates what you mean.
> >
> > Luis
On Tue, Nov 15, 2022 at 12:40:57PM -0600, Allen Webb wrote:
> When i get the modinfo for usbhid, there are no aliases listed:
> ```
> localhost ~ # modinfo usbhid
> name: usbhid
> filename: (builtin)
> author: Andreas Gal
> author: Vojtech Pavlik
> author: Jiri Kosina
> description: USB HID core driver
> file: drivers/hid/usbhid/usbhid
> license: GPL
> parm: quirks:Add/modify USB HID quirks by specifying
> quirks=vendorID:productID:quirks where vendorID, productID, and quirks
> are all in 0x-prefixed hex (array of charp)
> parm: ignoreled:Autosuspend with active leds (uint)
> parm: kbpoll:Polling interval of keyboards (uint)
> parm: jspoll:Polling interval of joysticks (uint)
> parm: mousepoll:Polling interval of mice (uint)
> ```
Hm. Interesting. Actually, alias gets into modules.builtin.modinfo:
$ tr '\0' '\n' < /lib/modules/`uname -r`/modules.builtin.modinfo |grep ^crc32c_generic.alias=
crc32c_generic.alias=crypto-crc32c-generic
crc32c_generic.alias=crc32c-generic
crc32c_generic.alias=crypto-crc32c
crc32c_generic.alias=crc32c
> bluetooth however has an alias listed:
> ```
> localhost ~ # modinfo bluetooth
> filename:
> /lib/modules/5.10.154-20424-gea7532c123d8/kernel/net/bluetooth/bluetooth.ko.gz
> author: Marcel Holtmann <marcel@holtmann.org>
> description: Bluetooth Core ver 2.22
> version: 2.22
> license: GPL
> alias: net-pf-31
> vermagic: 5.10.154-20424-gea7532c123d8 SMP preempt mod_unload
> name: bluetooth
> intree: Y
> retpoline: Y
> depends: ecdh_generic
> srcversion: F8E46CD048C50B0AA1CD471
> parm: disable_esco:Disable eSCO connection creation (bool)
> parm: enable_ecred:Enable enhanced credit flow control mode (bool)
> parm: disable_ertm:Disable enhanced retransmission mode (bool)
> ```
>
> I believe the reason for this is many modules use `#define
> MODULE_DEVICE_TABLE(type, name)` which is a noop for buildin modules.
> I have a local patch that resolves that issue here:
> See: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3840672/1/include/linux/module.h#b246
>
> However, I probably ought to rework that patch to create the
> MODULE_ALIAS defines instead of the buildin.alias file.
>
> On Tue, Nov 15, 2022 at 11:35 AM Luis Chamberlain <mcgrof@kernel.org> wrote:
> >
> > On Tue, Nov 15, 2022 at 10:05:35AM -0600, Allen Webb wrote:
> > > On Mon, Nov 14, 2022 at 11:22 AM Lucas De Marchi
> > > <lucas.demarchi@intel.com> wrote:
> > > >
> > > > On Mon, Nov 14, 2022 at 10:42:50AM -0600, Allen Webb wrote:
> > > > >On Fri, Nov 11, 2022 at 12:29 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> > > > >>
> > > > >> On Fri, Nov 11, 2022 at 09:28:52AM -0600, Allen Webb wrote:
> > > > >> > USB devices support the authorized attribute which can be used by
> > > > >> > user-space to implement trust-based systems for enabling USB devices. It
> > > > >> > would be helpful when building these systems to be able to know in
> > > > >> > advance which kernel drivers (or modules) are reachable from a
> > > > >> > particular USB device.
> > > > >> >
> > > > >> > This information is readily available for external modules in
> > > > >> > modules.alias. However, builtin kernel modules are not covered. This
> > > > >> > patch adds a sys-fs attribute to both builtin and loaded modules
> > > > >> > exposing the matching rules in the modalias format for integration
> > > > >> > with tools like USBGuard.
> > > > >> >
> > > > >> > Signed-off-by: Allen Webb <allenwebb@google.com>
> > > > >>
> > > > >> Thanks for the patch Allen!
> > > > >>
> > > > >> I'd rather have something generic though, and it would seem kmod [0] already
> > > > >> does this, have you seen the kmod support for builtin.alias.bin
> > > > >>
> > > > >> Can't that be used?
> > > > >
> > > > >Probably, but I don't see the builtin.alias.bin in my build. Is it experimental?
> > > >
> > > > no. That is generated by depmod since v27 using modules.builtin.modinfo
> > > > generated by the kernel build system. Highly recommend v30 though
> > > > as there were fixes in v28 and v29 and some changes to speed up its
> > > > generation/use in v30: See entries mentioning
> > > > builtin.alias and bultin.modinfo in
> > > > https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/NEWS
> > > >
> > > > libkmod/modprobe/modinfo also have the corresponding changes to lookup that
> > > > index when resolving aliases.
> > >
> > > I see the file but it is largely missing the aliases I am interested
> > > in, so it looks like I might need to modify my patch that creates
> > > buildin.alias to add the missing alias defines in the header along
> > > with the other module metadata for builtin modules. Does this sound
> > > right to you?
> >
> > Can you clarify what is missing and why? And an RFC is welcomed if it
> > helps demonstrates what you mean.
> >
> > Luis
>
@@ -15,7 +15,7 @@ obj-y += firmware_loader/
obj-$(CONFIG_NUMA) += node.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory.o
ifeq ($(CONFIG_SYSFS),y)
-obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_MODULES) += mod_devicetable.o module.o
endif
obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
obj-$(CONFIG_REGMAP) += regmap/
@@ -175,6 +175,14 @@ static inline void module_add_driver(struct module *mod,
static inline void module_remove_driver(struct device_driver *drv) { }
#endif
+#if defined(CONFIG_SYSFS)
+ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
+ size_t count);
+#else
+static inline ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
+ size_t count) { return -ENOSUP; }
+#endif
+
#ifdef CONFIG_DEVTMPFS
extern int devtmpfs_init(void);
#else
@@ -178,6 +178,48 @@ static const struct kset_uevent_ops bus_uevent_ops = {
static struct kset *bus_kset;
+/**
+ * bus_for_each - bus iterator.
+ * @start: bus to start iterating from.
+ * @data: data for the callback.
+ * @fn: function to be called for each device.
+ *
+ * Iterate over list of buses, and call @fn for each,
+ * passing it @data. If @start is not NULL, we use that bus to
+ * begin iterating from.
+ *
+ * We check the return of @fn each time. If it returns anything
+ * other than 0, we break out and return that value.
+ *
+ * NOTE: The bus that returns a non-zero value is not retained
+ * in any way, nor is its refcount incremented. If the caller needs
+ * to retain this data, it should do so, and increment the reference
+ * count in the supplied callback.
+ */
+int bus_for_each(void *data, int (*fn)(struct bus_type *, void *))
+{
+ int error = 0;
+ struct bus_type *bus;
+ struct subsys_private *bus_prv;
+ struct kset *subsys;
+ struct kobject *k;
+
+ spin_lock(&bus_kset->list_lock);
+
+ list_for_each_entry(k, &bus_kset->list, entry) {
+ subsys = container_of(k, struct kset, kobj);
+ bus_prv = container_of(subsys, struct subsys_private, subsys);
+ bus = bus_prv->bus;
+ error = fn(bus, data);
+ if (error)
+ break;
+ }
+
+ spin_unlock(&bus_kset->list_lock);
+ return error;
+}
+EXPORT_SYMBOL_GPL(bus_for_each);
+
/* Manually detach a device from its associated driver. */
static ssize_t unbind_store(struct device_driver *drv, const char *buf,
size_t count)
new file mode 100644
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * mod_devicetable.c - helpers for displaying modaliases through sysfs.
+ *
+ * This borrows a lot from file2alias.c
+ */
+
+#include <linux/device/bus.h>
+#include <linux/device.h>
+#include <linux/usb.h>
+
+#include "../usb/core/usb.h"
+
+#define ADD(buf, count, len, sep, cond, field) \
+do { \
+ if (cond) \
+ (len) += scnprintf(&(buf)[len], \
+ (count) - (len), \
+ sizeof(field) == 1 ? (sep "%02X") : \
+ sizeof(field) == 2 ? (sep "%04X") : \
+ sizeof(field) == 4 ? (sep "%08X") : "", \
+ (field)); \
+ else \
+ (len) += scnprintf(&(buf)[len], (count) - (len), (sep "*")); \
+} while (0)
+
+/* USB related modaliases can be split because of device number matching, so
+ * this function handles individual modaliases for one segment of the range.
+ *
+ *
+ */
+static ssize_t usb_id_to_modalias(const struct usb_device_id *id,
+ unsigned int bcdDevice_initial,
+ int bcdDevice_initial_digits,
+ unsigned char range_lo,
+ unsigned char range_hi,
+ unsigned char max, const char *mod_name,
+ char *buf, size_t count)
+{
+ ssize_t len = 0;
+
+ ADD(buf, count, len, "alias usb:v",
+ id->match_flags & USB_DEVICE_ID_MATCH_VENDOR, id->idVendor);
+ ADD(buf, count, len, "p", id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT,
+ id->idProduct);
+
+ len += scnprintf(&buf[len], count - len, "d");
+ if (bcdDevice_initial_digits)
+ len += scnprintf(&buf[len], count - len, "%0*X",
+ bcdDevice_initial_digits, bcdDevice_initial);
+ if (range_lo == range_hi) {
+ len += scnprintf(&buf[len], count - len, "%X", range_lo);
+ } else if (range_lo > 0 || range_hi < max) {
+ if (range_lo > 0x9 || range_hi < 0xA) {
+ len += scnprintf(&buf[len], count - len, "[%X-%X]",
+ range_lo, range_hi);
+ } else {
+ len += scnprintf(&buf[len], count - len,
+ range_lo < 0x9 ? "[%X-9" : "[%X",
+ range_lo);
+ len += scnprintf(&buf[len], count - len,
+ range_hi > 0xA ? "A-%X]" : "%X]",
+ range_hi);
+ }
+ }
+ if (bcdDevice_initial_digits < (sizeof(id->bcdDevice_lo) * 2 - 1))
+ len += scnprintf(&buf[len], count - len, "*");
+
+ ADD(buf, count, len, "dc",
+ id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS, id->bDeviceClass);
+ ADD(buf, count, len, "dsc",
+ id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS,
+ id->bDeviceSubClass);
+ ADD(buf, count, len, "dp",
+ id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL,
+ id->bDeviceProtocol);
+ ADD(buf, count, len, "ic",
+ id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS,
+ id->bInterfaceClass);
+ ADD(buf, count, len, "isc",
+ id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS,
+ id->bInterfaceSubClass);
+ ADD(buf, count, len, "ip",
+ id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL,
+ id->bInterfaceProtocol);
+ ADD(buf, count, len, "in",
+ id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER,
+ id->bInterfaceNumber);
+
+ len += scnprintf(&buf[len], count - len, " %s\n", mod_name);
+ return len;
+}
+
+/* Handles increment/decrement of BCD formatted integers */
+/* Returns the previous value, so it works like i++ or i-- */
+static unsigned int incbcd(unsigned int *bcd,
+ int inc,
+ unsigned char max,
+ size_t chars)
+{
+ unsigned int init = *bcd, i, j;
+ unsigned long long c, dec = 0;
+
+ /* If bcd is not in BCD format, just increment */
+ if (max > 0x9) {
+ *bcd += inc;
+ return init;
+ }
+
+ /* Convert BCD to Decimal */
+ for (i = 0 ; i < chars ; i++) {
+ c = (*bcd >> (i << 2)) & 0xf;
+ c = c > 9 ? 9 : c; /* force to bcd just in case */
+ for (j = 0 ; j < i ; j++)
+ c = c * 10;
+ dec += c;
+ }
+
+ /* Do our increment/decrement */
+ dec += inc;
+ *bcd = 0;
+
+ /* Convert back to BCD */
+ for (i = 0 ; i < chars ; i++) {
+ for (c = 1, j = 0 ; j < i ; j++)
+ c = c * 10;
+ c = (dec / c) % 10;
+ *bcd += c << (i << 2);
+ }
+ return init;
+}
+
+/* Print the modaliases for the specified struct usb_device_id.
+ */
+static ssize_t usb_id_to_modalias_multi(const struct usb_device_id *id,
+ const char *mod_name, char *buf,
+ size_t count)
+{
+ ssize_t len = 0;
+ unsigned int devlo, devhi;
+ unsigned char chi, clo, max;
+ int ndigits;
+
+ devlo = id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO ?
+ id->bcdDevice_lo : 0x0U;
+ devhi = id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI ?
+ id->bcdDevice_hi : ~0x0U;
+
+ /* Figure out if this entry is in bcd or hex format */
+ max = 0x9; /* Default to decimal format */
+ for (ndigits = 0 ; ndigits < sizeof(id->bcdDevice_lo) * 2 ; ndigits++) {
+ clo = (devlo >> (ndigits << 2)) & 0xf;
+ chi = ((devhi > 0x9999 ? 0x9999 : devhi) >>
+ (ndigits << 2)) & 0xf;
+ if (clo > max || chi > max) {
+ max = 0xf;
+ break;
+ }
+ }
+
+ /*
+ * Some modules (visor) have empty slots as placeholder for
+ * run-time specification that results in catch-all alias
+ */
+ if (!(id->idVendor || id->idProduct || id->bDeviceClass ||
+ id->bInterfaceClass))
+ return len;
+
+ /* Convert numeric bcdDevice range into fnmatch-able pattern(s) */
+ for (ndigits = sizeof(id->bcdDevice_lo) * 2 - 1; devlo <= devhi;
+ ndigits--) {
+ clo = devlo & 0xf;
+ chi = devhi & 0xf;
+ /* If we are in bcd mode, truncate if necessary */
+ if (chi > max)
+ chi = max;
+ devlo >>= 4;
+ devhi >>= 4;
+
+ if (devlo == devhi || !ndigits) {
+ len += usb_id_to_modalias(id, devlo, ndigits, clo, chi,
+ max, mod_name, buf + len,
+ count - len);
+ break;
+ }
+
+ if (clo > 0x0)
+ len += usb_id_to_modalias(id,
+ incbcd(&devlo, 1, max,
+ sizeof(id->bcdDevice_lo) * 2),
+ ndigits, clo, max, max, mod_name, buf + len,
+ count - len);
+
+ if (chi < max)
+ len += usb_id_to_modalias(id,
+ incbcd(&devhi, -1, max,
+ sizeof(id->bcdDevice_lo) * 2),
+ ndigits, 0x0, chi, max, mod_name, buf + len,
+ count - len);
+ }
+ return len;
+}
+
+/* Print the modaliases for the given driver assumed to be an usb_driver or
+ * usb_device_driver.
+ *
+ * "alias" is prepended and the module name is appended to each modalias to
+ * match the format in modules.aliases.
+ *
+ * The modaliases will be written out to @buf with @count being the maximum
+ * bytes to write. The return value is a negative errno on error or the number
+ * of bytes written to @buf on success.
+ */
+ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf,
+ size_t count)
+{
+ ssize_t len = 0;
+ const struct usb_device_id *id;
+ const char *mod_name;
+
+ if (drv->bus != &usb_bus_type)
+ return -EINVAL;
+
+ if (drv->owner)
+ mod_name = drv->owner->name;
+ else
+ mod_name = drv->mod_name;
+
+ if (is_usb_device_driver(drv))
+ id = to_usb_device_driver(drv)->id_table;
+ else
+ id = to_usb_driver(drv)->id_table;
+ if (!id)
+ return len;
+
+ for (; id->match_flags; id++) {
+ len += usb_id_to_modalias_multi(id, mod_name, buf + len,
+ count - len);
+ }
+ return len;
+}
@@ -32,6 +32,7 @@
#include <linux/usb/quirks.h>
#include <linux/usb/hcd.h>
+#include "../../base/base.h"
#include "usb.h"
@@ -2030,4 +2031,5 @@ struct bus_type usb_bus_type = {
.match = usb_device_match,
.uevent = usb_uevent,
.need_parent_lock = true,
+ .drv_to_modalias = usb_drv_to_modalias,
};
@@ -61,6 +61,10 @@ struct fwnode_handle;
* this bus.
* @dma_cleanup: Called to cleanup DMA configuration on a device on
* this bus.
+ * @drv_to_modalias: Called to convert the matching IDs in a
+ * struct device_driver to their corresponding modaliases.
+ * Note that the struct device_driver is expected to belong
+ * to this bus.
* @pm: Power management operations of this bus, callback the specific
* device driver's pm-ops.
* @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU
@@ -107,6 +111,9 @@ struct bus_type {
int (*dma_configure)(struct device *dev);
void (*dma_cleanup)(struct device *dev);
+ ssize_t (*drv_to_modalias)(struct device_driver *drv, char *buf,
+ size_t count);
+
const struct dev_pm_ops *pm;
const struct iommu_ops *iommu_ops;
@@ -161,6 +168,7 @@ void subsys_dev_iter_init(struct subsys_dev_iter *iter,
struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter);
void subsys_dev_iter_exit(struct subsys_dev_iter *iter);
+int bus_for_each(void *data, int (*fn)(struct bus_type *, void *));
int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
int (*fn)(struct device *dev, void *data));
struct device *bus_find_device(struct bus_type *bus, struct device *start,
@@ -48,6 +48,7 @@ struct module_kobject {
struct kobject *drivers_dir;
struct module_param_attrs *mp;
struct completion *kobj_completion;
+ struct bin_attribute modalias_attr;
} __randomize_layout;
struct module_attribute {
@@ -259,11 +259,13 @@ static inline void add_kallsyms(struct module *mod, const struct load_info *info
#endif /* CONFIG_KALLSYMS */
#ifdef CONFIG_SYSFS
+void add_modalias_attr(struct module_kobject *mk);
int mod_sysfs_setup(struct module *mod, const struct load_info *info,
struct kernel_param *kparam, unsigned int num_params);
void mod_sysfs_teardown(struct module *mod);
void init_param_lock(struct module *mod);
#else /* !CONFIG_SYSFS */
+static inline void add_modalias_attr(struct module_kobject *mk) {}
static inline int mod_sysfs_setup(struct module *mod,
const struct load_info *info,
struct kernel_param *kparam,
@@ -5,6 +5,8 @@
* Copyright (C) 2008 Rusty Russell
*/
+#include <linux/device/bus.h>
+#include <linux/device/driver.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
@@ -240,6 +242,102 @@ static inline void add_notes_attrs(struct module *mod, const struct load_info *i
static inline void remove_notes_attrs(struct module *mod) { }
#endif /* CONFIG_KALLSYMS */
+/* Track of the buffer and module identity in callbacks when walking the list of
+ * drivers for each bus.
+ */
+struct modalias_bus_print_state {
+ struct module_kobject *mk;
+ char *buf;
+ size_t count;
+ ssize_t len;
+};
+
+static int print_modalias_for_drv(struct device_driver *drv, void *p)
+{
+ struct modalias_bus_print_state *s = p;
+ struct module_kobject *mk = s->mk;
+ ssize_t len;
+ /* Skip drivers that do not match this module. */
+ if (mk->mod) {
+ if (mk->mod != drv->owner)
+ return 0;
+ } else if (!mk->kobj.name || !drv->mod_name ||
+ strcmp(mk->kobj.name, drv->mod_name))
+ return 0;
+
+ if (drv->bus && drv->bus->drv_to_modalias) {
+ len = drv->bus->drv_to_modalias(drv, s->buf + s->len,
+ s->count - s->len);
+ if (len < 0)
+ return len;
+ s->len += len;
+ }
+
+ s->len += scnprintf(&s->buf[s->len], s->count - s->len, "driver %s\n",
+ drv->name);
+ return 0;
+}
+
+static int print_modalias_for_bus(struct bus_type *type, void *p)
+{
+ return bus_for_each_drv(type, NULL, p, print_modalias_for_drv);
+}
+
+static ssize_t module_modalias_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t pos, size_t count)
+{
+ struct module_kobject *mk = container_of(kobj, struct module_kobject,
+ kobj);
+ struct modalias_bus_print_state state = {mk, buf, count, 0};
+ int error = 0;
+
+ if (pos != 0)
+ return -EINVAL;
+
+ error = bus_for_each(&state, print_modalias_for_bus);
+ if (error)
+ return error;
+
+ if (mk->mod)
+ state.len += scnprintf(&buf[state.len], count - state.len,
+ "modalias %s %s\n", kobject_name(kobj),
+ mk->mod->name);
+ else
+ state.len += scnprintf(&buf[state.len], count - state.len,
+ "modalias %s NULL\n",
+ kobject_name(kobj));
+
+ /*
+ * The caller checked the pos and count against our size.
+ */
+ return state.len;
+}
+
+/* Used in kernel/params.c for builtin modules.
+ *
+ * `struct module_kobject` is used instead of `struct module` because for
+ * builtin modules, the `struct module` is not available when this is called.
+ */
+void add_modalias_attr(struct module_kobject *mk)
+{
+ sysfs_bin_attr_init(&mk->modalias_attr);
+ mk->modalias_attr.attr.name = "modalias";
+ mk->modalias_attr.attr.mode = 0444;
+ mk->modalias_attr.read = module_modalias_read;
+ if (sysfs_create_bin_file(&mk->kobj, &mk->modalias_attr)) {
+ /* We shouldn't ignore the return type, but there is nothing to
+ * do.
+ */
+ return;
+ }
+}
+
+static void remove_modalias_attr(struct module_kobject *mk)
+{
+ sysfs_remove_bin_file(&mk->kobj, &mk->modalias_attr);
+}
+
static void del_usage_links(struct module *mod)
{
#ifdef CONFIG_MODULE_UNLOAD
@@ -398,6 +496,7 @@ int mod_sysfs_setup(struct module *mod,
add_sect_attrs(mod, info);
add_notes_attrs(mod, info);
+ add_modalias_attr(&mod->mkobj);
return 0;
@@ -415,6 +514,7 @@ int mod_sysfs_setup(struct module *mod,
static void mod_sysfs_fini(struct module *mod)
{
+ remove_modalias_attr(&mod->mkobj);
remove_notes_attrs(mod);
remove_sect_attrs(mod);
mod_kobject_put(mod);
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/security.h>
+#include "module/internal.h"
#ifdef CONFIG_SYSFS
/* Protects all built-in parameters, modules use their own param_lock */
@@ -815,6 +816,7 @@ static void __init kernel_add_sysfs_param(const char *name,
BUG_ON(err);
kobject_uevent(&mk->kobj, KOBJ_ADD);
kobject_put(&mk->kobj);
+ add_modalias_attr(mk);
}
/*