linux-stable.git/drivers/base/firmware_loader/main.c, branch linux-4.19.y Linux kernel stable tree firmware_loader: Block path traversal 2024-11-08T15:19:09+00:00 Jann Horn jannh@google.com 2024-08-27T23:45:48+00:00 d1768e5535d3ded59f888637016e6f821f4e069f commit f0e5311aa8022107d63c54e2f03684ec097d1394 upstream. Most firmware names are hardcoded strings, or are constructed from fairly constrained format strings where the dynamic parts are just some hex numbers or such. However, there are a couple codepaths in the kernel where firmware file names contain string components that are passed through from a device or semi-privileged userspace; the ones I could find (not counting interfaces that require root privileges) are: - lpfc_sli4_request_firmware_update() seems to construct the firmware filename from "ModelName", a string that was previously parsed out of some descriptor ("Vital Product Data") in lpfc_fill_vpd() - nfp_net_fw_find() seems to construct a firmware filename from a model name coming from nfp_hwinfo_lookup(pf->hwinfo, "nffw.partno"), which I think parses some descriptor that was read from the device. (But this case likely isn't exploitable because the format string looks like "netronome/nic_%s", and there shouldn't be any *folders* starting with "netronome/nic_". The previous case was different because there, the "%s" is *at the start* of the format string.) - module_flash_fw_schedule() is reachable from the ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command, which is marked as GENL_UNS_ADMIN_PERM (meaning CAP_NET_ADMIN inside a user namespace is enough to pass the privilege check), and takes a userspace-provided firmware name. (But I think to reach this case, you need to have CAP_NET_ADMIN over a network namespace that a special kind of ethernet device is mapped into, so I think this is not a viable attack path in practice.) Fix it by rejecting any firmware names containing ".." path components. For what it's worth, I went looking and haven't found any USB device drivers that use the firmware loader dangerously. Cc: stable@vger.kernel.org Reviewed-by: Danilo Krummrich <dakr@kernel.org> Fixes: abb139e75c2c ("firmware: teach the kernel to load firmware files directly from the filesystem") Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20240828-firmware-traversal-v3-1-c76529c63b5f@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f0e5311aa8022107d63c54e2f03684ec097d1394 upstream.

Most firmware names are hardcoded strings, or are constructed from fairly
constrained format strings where the dynamic parts are just some hex
numbers or such.

However, there are a couple codepaths in the kernel where firmware file
names contain string components that are passed through from a device or
semi-privileged userspace; the ones I could find (not counting interfaces
that require root privileges) are:

 - lpfc_sli4_request_firmware_update() seems to construct the firmware
   filename from "ModelName", a string that was previously parsed out of
   some descriptor ("Vital Product Data") in lpfc_fill_vpd()
 - nfp_net_fw_find() seems to construct a firmware filename from a model
   name coming from nfp_hwinfo_lookup(pf->hwinfo, "nffw.partno"), which I
   think parses some descriptor that was read from the device.
   (But this case likely isn't exploitable because the format string looks
   like "netronome/nic_%s", and there shouldn't be any *folders* starting
   with "netronome/nic_". The previous case was different because there,
   the "%s" is *at the start* of the format string.)
 - module_flash_fw_schedule() is reachable from the
   ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command, which is marked as
   GENL_UNS_ADMIN_PERM (meaning CAP_NET_ADMIN inside a user namespace is
   enough to pass the privilege check), and takes a userspace-provided
   firmware name.
   (But I think to reach this case, you need to have CAP_NET_ADMIN over a
   network namespace that a special kind of ethernet device is mapped into,
   so I think this is not a viable attack path in practice.)

Fix it by rejecting any firmware names containing ".." path components.

For what it's worth, I went looking and haven't found any USB device
drivers that use the firmware loader dangerously.

Cc: stable@vger.kernel.org
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Fixes: abb139e75c2c ("firmware: teach the kernel to load firmware files directly from the filesystem")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20240828-firmware-traversal-v3-1-c76529c63b5f@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware_loader: fix pre-allocated buf built-in firmware use 2021-11-26T10:36:20+00:00 Luis Chamberlain mcgrof@kernel.org 2021-09-17T18:22:13+00:00 f2d22b13baa6d61d28788a5754a12e0c08ff213d [ Upstream commit f7a07f7b96033df7709042ff38e998720a3f7119 ] The firmware_loader can be used with a pre-allocated buffer through the use of the API calls: o request_firmware_into_buf() o request_partial_firmware_into_buf() If the firmware was built-in and present, our current check for if the built-in firmware fits into the pre-allocated buffer does not return any errors, and we proceed to tell the caller that everything worked fine. It's a lie and no firmware would end up being copied into the pre-allocated buffer. So if the caller trust the result it may end up writing a bunch of 0's to a device! Fix this by making the function that checks for the pre-allocated buffer return non-void. Since the typical use case is when no pre-allocated buffer is provided make this return successfully for that case. If the built-in firmware does *not* fit into the pre-allocated buffer size return a failure as we should have been doing before. I'm not aware of users of the built-in firmware using the API calls with a pre-allocated buffer, as such I doubt this fixes any real life issue. But you never know... perhaps some oddball private tree might use it. In so far as upstream is concerned this just fixes our code for correctness. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20210917182226.3532898-2-mcgrof@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f7a07f7b96033df7709042ff38e998720a3f7119 ]

The firmware_loader can be used with a pre-allocated buffer
through the use of the API calls:

  o request_firmware_into_buf()
  o request_partial_firmware_into_buf()

If the firmware was built-in and present, our current check
for if the built-in firmware fits into the pre-allocated buffer
does not return any errors, and we proceed to tell the caller
that everything worked fine. It's a lie and no firmware would
end up being copied into the pre-allocated buffer. So if the
caller trust the result it may end up writing a bunch of 0's
to a device!

Fix this by making the function that checks for the pre-allocated
buffer return non-void. Since the typical use case is when no
pre-allocated buffer is provided make this return successfully
for that case. If the built-in firmware does *not* fit into the
pre-allocated buffer size return a failure as we should have
been doing before.

I'm not aware of users of the built-in firmware using the API
calls with a pre-allocated buffer, as such I doubt this fixes
any real life issue. But you never know... perhaps some oddball
private tree might use it.

In so far as upstream is concerned this just fixes our code for
correctness.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20210917182226.3532898-2-mcgrof@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
firmware_loader: fix use-after-free in firmware_fallback_sysfs 2021-08-12T11:19:41+00:00 Anirudh Rayabharam mail@anirudhrb.com 2021-07-28T08:51:07+00:00 67cf0fbcac0d42d4d4686cddc1e39f465bbfec37 commit 75d95e2e39b27f733f21e6668af1c9893a97de5e upstream. This use-after-free happens when a fw_priv object has been freed but hasn't been removed from the pending list (pending_fw_head). The next time fw_load_sysfs_fallback tries to insert into the list, it ends up accessing the pending_list member of the previously freed fw_priv. The root cause here is that all code paths that abort the fw load don't delete it from the pending list. For example: _request_firmware() -> fw_abort_batch_reqs() -> fw_state_aborted() To fix this, delete the fw_priv from the list in __fw_set_state() if the new state is DONE or ABORTED. This way, all aborts will remove the fw_priv from the list. Accordingly, remove calls to list_del_init that were being made before calling fw_state_(aborted|done). Also, in fw_load_sysfs_fallback, don't add the fw_priv to the pending list if it is already aborted. Instead, just jump out and return early. Fixes: bcfbd3523f3c ("firmware: fix a double abort case with fw_load_sysfs_fallback") Cc: stable <stable@vger.kernel.org> Reported-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com Tested-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com Reviewed-by: Shuah Khan <skhan@linuxfoundation.org> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com> Link: https://lore.kernel.org/r/20210728085107.4141-3-mail@anirudhrb.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 75d95e2e39b27f733f21e6668af1c9893a97de5e upstream.

This use-after-free happens when a fw_priv object has been freed but
hasn't been removed from the pending list (pending_fw_head). The next
time fw_load_sysfs_fallback tries to insert into the list, it ends up
accessing the pending_list member of the previously freed fw_priv.

The root cause here is that all code paths that abort the fw load
don't delete it from the pending list. For example:

        _request_firmware()
          -> fw_abort_batch_reqs()
              -> fw_state_aborted()

To fix this, delete the fw_priv from the list in __fw_set_state() if
the new state is DONE or ABORTED. This way, all aborts will remove
the fw_priv from the list. Accordingly, remove calls to list_del_init
that were being made before calling fw_state_(aborted|done).

Also, in fw_load_sysfs_fallback, don't add the fw_priv to the pending
list if it is already aborted. Instead, just jump out and return early.

Fixes: bcfbd3523f3c ("firmware: fix a double abort case with fw_load_sysfs_fallback")
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com
Tested-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
Link: https://lore.kernel.org/r/20210728085107.4141-3-mail@anirudhrb.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: Always initialize the fw_priv list object 2018-09-30T15:49:55+00:00 Bjorn Andersson bjorn.andersson@linaro.org 2018-09-20T01:09:38+00:00 7012040576c6ae25a47035659ee48673612c2c27 When freeing the fw_priv the item is taken off the list. This causes an oops in the FW_OPT_NOCACHE case as the list object is not initialized. Make sure to initialize the list object regardless of this flag. Fixes: 422b3db2a503 ("firmware: Fix security issue with request_firmware_into_buf()") Cc: stable@vger.kernel.org Cc: Rishabh Bhatnagar <rishabhb@codeaurora.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
When freeing the fw_priv the item is taken off the list. This causes an
oops in the FW_OPT_NOCACHE case as the list object is not initialized.

Make sure to initialize the list object regardless of this flag.

Fixes: 422b3db2a503 ("firmware: Fix security issue with request_firmware_into_buf()")
Cc: stable@vger.kernel.org
Cc: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: Fix security issue with request_firmware_into_buf() 2018-09-12T07:31:00+00:00 Rishabh Bhatnagar rishabhb@codeaurora.org 2018-08-31T15:43:31+00:00 422b3db2a5036add39a82425b1dd9fb6c96481e8 When calling request_firmware_into_buf() with the FW_OPT_NOCACHE flag it is expected that firmware is loaded into buffer from memory. But inside alloc_lookup_fw_priv every new firmware that is loaded is added to the firmware cache (fwc) list head. So if any driver requests a firmware that is already loaded the code iterates over the above mentioned list and it can end up giving a pointer to other device driver's firmware buffer. Also the existing copy may either be modified by drivers, remote processors or even freed. This causes a potential security issue with batched requests when using request_firmware_into_buf. Fix alloc_lookup_fw_priv to not add to the fwc head list if FW_OPT_NOCACHE is set, and also don't do the lookup in the list. Fixes: 0e742e9275 ("firmware: provide infrastructure to make fw caching optional") [mcgrof: broken since feature introduction on v4.8] Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org> Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
When calling request_firmware_into_buf() with the FW_OPT_NOCACHE flag
it is expected that firmware is loaded into buffer from memory.
But inside alloc_lookup_fw_priv every new firmware that is loaded is
added to the firmware cache (fwc) list head. So if any driver requests
a firmware that is already loaded the code iterates over the above
mentioned list and it can end up giving a pointer to other device driver's
firmware buffer.
Also the existing copy may either be modified by drivers, remote processors
or even freed. This causes a potential security issue with batched requests
when using request_firmware_into_buf.

Fix alloc_lookup_fw_priv to not add to the fwc head list if FW_OPT_NOCACHE
is set, and also don't do the lookup in the list.

Fixes: 0e742e9275 ("firmware: provide infrastructure to make fw caching optional")
[mcgrof: broken since feature introduction on v4.8]

Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: add firmware_request_nowarn() - load firmware without warnings 2018-05-14T14:44:41+00:00 Andres Rodriguez andresx7@gmail.com 2018-05-10T20:08:45+00:00 7dcc01343e483efda0882456f8361f061a5f416d Currently the firmware loader only exposes one silent path for querying optional firmware, and that is firmware_request_direct(). This function also disables the sysfs fallback mechanism, which might not always be the desired behaviour [0]. This patch introduces a variations of request_firmware() that enable the caller to disable the undesired warning messages but enables the sysfs fallback mechanism. This is equivalent to adding FW_OPT_NO_WARN to the old behaviour. [0]: https://git.kernel.org/linus/c0cc00f250e1 Signed-off-by: Andres Rodriguez <andresx7@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Luis R. Rodriguez <mcgrof@kernel.org> [mcgrof: used the old API calls as the full rename is not done yet, and add the caller for when FW_LOADER is disabled, enhance documentation ] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Currently the firmware loader only exposes one silent path for querying
optional firmware, and that is firmware_request_direct(). This function
also disables the sysfs fallback mechanism, which might not always be the
desired behaviour [0].

This patch introduces a variations of request_firmware() that enable the
caller to disable the undesired warning messages but enables the sysfs
fallback mechanism. This is equivalent to adding FW_OPT_NO_WARN to the
old behaviour.

[0]: https://git.kernel.org/linus/c0cc00f250e1

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
[mcgrof: used the old API calls as the full rename is not done yet, and
 add the caller for when FW_LOADER is disabled, enhance documentation ]
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: rename fw_sysfs_fallback to firmware_fallback_sysfs() 2018-05-14T14:43:09+00:00 Andres Rodriguez andresx7@gmail.com 2018-05-10T20:08:39+00:00 cf1cde7cd6e42aa65aa7a80e4980afe6d1a1330e This is done since this call is now exposed through kernel-doc, and since this also paves the way for different future types of fallback mechanims. Signed-off-by: Andres Rodriguez <andresx7@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Luis R. Rodriguez <mcgrof@kernel.org> [mcgrof: small coding style changes] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This is done since this call is now exposed through kernel-doc,
and since this also paves the way for different future types of
fallback mechanims.

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
[mcgrof: small coding style changes]
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: use () to terminate kernel-doc function names 2018-05-14T14:43:09+00:00 Andres Rodriguez andresx7@gmail.com 2018-05-10T20:08:38+00:00 c35f9cbb1df8f17d398112173024a76964b5154d The kernel-doc spec dictates a function name ends in (). Signed-off-by: Andres Rodriguez <andresx7@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Luis R. Rodriguez <mcgrof@kernel.org> [mcgrof: adjust since the wide API rename is not yet merged] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The kernel-doc spec dictates a function name ends in ().

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
[mcgrof: adjust since the wide API rename is not yet merged]
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: wrap FW_OPT_* into an enum 2018-05-14T14:43:09+00:00 Andres Rodriguez andresx7@gmail.com 2018-05-10T20:08:37+00:00 eb33eb04926e40331750f538a58d93cde87afaa4 This should let us associate enum kdoc to these values. While at it, kdocify the fw_opt. Signed-off-by: Andres Rodriguez <andresx7@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Luis R. Rodriguez <mcgrof@kernel.org> [mcgrof: coding style fixes, merge kdoc with enum move] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This should let us associate enum kdoc to these values.
While at it, kdocify the fw_opt.

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
[mcgrof: coding style fixes, merge kdoc with enum move]
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: add firmware_request_cache() to help with cache on reboot 2018-03-22T17:33:26+00:00 Luis R. Rodriguez mcgrof@kernel.org 2018-03-21T22:34:29+00:00 5d42c96e1cf98bdfea18e7d32e5f6cf75aac93b9 Some devices have an optimization in place to enable the firmware to be retaineed during a system reboot, so after reboot the device can skip requesting and loading the firmware. This can save up to 1s in load time. The mt7601u 802.11 device happens to be such a device. When these devices retain the firmware on a reboot and then suspend they can miss looking for the firmware on resume. To help with this we need a way to cache the firmware when such an optimization has taken place. Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Some devices have an optimization in place to enable the firmware to
be retaineed during a system reboot, so after reboot the device can skip
requesting and loading the firmware. This can save up to 1s in load
time. The mt7601u 802.11 device happens to be such a device.

When these devices retain the firmware on a reboot and then suspend
they can miss looking for the firmware on resume. To help with this we
need a way to cache the firmware when such an optimization has taken
place.

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>