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path: root/drivers/acpi/device_sysfs.c
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2021-07-20ACPI: sysfs: Fix a buffer overrun problem with description_show()Krzysztof Wilczyński
[ Upstream commit 888be6067b97132c3992866bbcf647572253ab3f ] Currently, a device description can be obtained using ACPI, if the _STR method exists for a particular device, and then exposed to the userspace via a sysfs object as a string value. If the _STR method is available for a given device then the data (usually a Unicode string) is read and stored in a buffer (of the ACPI_TYPE_BUFFER type) with a pointer to said buffer cached in the struct acpi_device_pnp for later access. The description_show() function is responsible for exposing the device description to the userspace via a corresponding sysfs object and internally calls the utf16s_to_utf8s() function with a pointer to the buffer that contains the Unicode string so that it can be converted from UTF16 encoding to UTF8 and thus allowing for the value to be safely stored and later displayed. When invoking the utf16s_to_utf8s() function, the description_show() function also sets a limit of the data that can be saved into a provided buffer as a result of the character conversion to be a total of PAGE_SIZE, and upon completion, the utf16s_to_utf8s() function returns an integer value denoting the number of bytes that have been written into the provided buffer. Following the execution of the utf16s_to_utf8s() a newline character will be added at the end of the resulting buffer so that when the value is read in the userspace through the sysfs object then it would include newline making it more accessible when working with the sysfs file system in the shell, etc. Normally, this wouldn't be a problem, but if the function utf16s_to_utf8s() happens to return the number of bytes written to be precisely PAGE_SIZE, then we would overrun the buffer and write the newline character outside the allotted space which can have undefined consequences or result in a failure. To fix this buffer overrun, ensure that there always is enough space left for the newline character to be safely appended. Fixes: d1efe3c324ea ("ACPI: Add new sysfs interface to export device description") Signed-off-by: Krzysztof Wilczyński <kw@linux.com> Reviewed-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-02-03ACPI: sysfs: Prefer "compatible" modaliasKai-Heng Feng
commit 36af2d5c4433fb40ee2af912c4ac0a30991aecfc upstream. Commit 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present") may create two "MODALIAS=" in one uevent file if specific conditions are met. This breaks systemd-udevd, which assumes each "key" in one uevent file to be unique. The internal implementation of systemd-udevd overwrites the first MODALIAS with the second one, so its kmod rule doesn't load the driver for the first MODALIAS. So if both the ACPI modalias and the OF modalias are present, use the latter to ensure that there will be only one MODALIAS. Link: https://github.com/systemd/systemd/pull/18163 Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present") Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: 4.1+ <stable@vger.kernel.org> # 4.1+ [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-23ACPI / device_sysfs: Avoid OF modalias creation for removed deviceAndy Shevchenko
commit f16eb8a4b096514ac06fb25bf599dcc792899b3d upstream. If SSDT overlay is loaded via ConfigFS and then unloaded the device, we would like to have OF modalias for, already gone. Thus, acpi_get_name() returns no allocated buffer for such case and kernel crashes afterwards: ACPI: Host-directed Dynamic ACPI Table Unload ads7950 spi-PRP0001:00: Dropping the link to regulator.0 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] PGD 80000000070d6067 P4D 80000000070d6067 PUD 70d0067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 40 Comm: kworker/u4:2 Not tainted 5.0.0+ #96 Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48 Workqueue: kacpi_hotplug acpi_device_del_work_fn RIP: 0010:create_of_modalias.isra.1+0x4c/0x150 Code: 00 00 48 89 44 24 18 31 c0 48 8d 54 24 08 48 c7 44 24 10 00 00 00 00 48 c7 44 24 08 ff ff ff ff e8 7a b0 03 00 48 8b 4c 24 10 <0f> b6 01 84 c0 74 27 48 c7 c7 00 09 f4 a5 0f b6 f0 8d 50 20 f6 04 RSP: 0000:ffffa51040297c10 EFLAGS: 00010246 RAX: 0000000000001001 RBX: 0000000000000785 RCX: 0000000000000000 RDX: 0000000000001001 RSI: 0000000000000286 RDI: ffffa2163dc042e0 RBP: ffffa216062b1196 R08: 0000000000001001 R09: ffffa21639873000 R10: ffffffffa606761d R11: 0000000000000001 R12: ffffa21639873218 R13: ffffa2163deb5060 R14: ffffa216063d1010 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffffa2163e000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000007114000 CR4: 00000000001006f0 Call Trace: __acpi_device_uevent_modalias+0xb0/0x100 spi_uevent+0xd/0x40 ... In order to fix above let create_of_modalias() check the status returned by acpi_get_name() and bail out in case of failure. Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present") Link: https://bugzilla.kernel.org/show_bug.cgi?id=201381 Reported-by: Ferry Toth <fntoth@gmail.com> Tested-by: Ferry Toth<fntoth@gmail.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: 4.1+ <stable@vger.kernel.org> # 4.1+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03ACPI / bus: Leave modalias empty for devices which are not presentHans de Goede
[ Upstream commit 10809bb976648ac58194a629e3d7af99e7400297 ] Most Bay and Cherry Trail devices use a generic DSDT with all possible peripheral devices present in the DSDT, with their _STA returning 0x00 or 0x0f based on AML variables which describe what is actually present on the board. Since ACPI device objects with a 0x00 status (not present) still get an entry under /sys/bus/acpi/devices, and those entry had an acpi:PNPID modalias, userspace would end up loading modules for non present hardware. This commit fixes this by leaving the modalias empty for non present devices. This results in 10 modules less being loaded with a generic distro kernel config on my Cherry Trail test-device (a GPD pocket). Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-24ACPI / property: Hierarchical properties support updateRafael J. Wysocki
The definition document of the Hierarchical Properties Extension UUID for _DSD has been changed recently to allow local references to be used as sub-node link targets (previously, it only allowed strings to be used for that purpose). Update the code in drivers/acpi/property.c to reflect that change. Link: http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-05-04ACPI / device_sysfs: Clean up checkpatch errorsBetty Dall
Cleaning up two existing checkpatch errors (and 2 warnings) in device_sysfs.c since the file is being changed. The change in acpi_device_setup_files() is changing spaces to a tab. Signed-off-by: Betty Dall <betty.dall@hpe.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-05-04ACPI / device_sysfs: Change _SUN and _STA show functions error return to EIOBetty Dall
The error return from a sysfs show function is passed up through the call chain and visible as the return from the read system call. The show functions for the _STA and _SUN object currently return -ENODEV. This patch changes the return to -EIO. ENODEV makes less sense since the "device' exists or there wouldn't be a sysfs file. Signed-off-by: Betty Dall <betty.dall@hpe.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-05-04ACPI / device_sysfs: Add sysfs support for _HRV hardware revisionBetty Dall
The ACPI _HRV object on the device is used to supply Linux with the device's hardware revision. This is an optional object. Add sysfs support for the _HRV object if it exists on the device. This change allows users to easily find the hardware version of non-PCI hardware by looking at the sysfs 'hrv' file. It is most useful for non-PCI devices because lspci can list the hardware version for PCI devices. Signed-off-by: Betty Dall <betty.dall@hpe.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-01-08ACPI / property: avoid leaking format string into kobject nameKees Cook
The dn->name is expected to be used as a literal, so add the missing "%s". Fixes: 263b4c1a64bc (ACPI / property: Expose data-only subnodes via sysfs) Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-09-15ACPI / property: Expose data-only subnodes via sysfsRafael J. Wysocki
Add infrastructure needed to expose data-only subnodes of ACPI device objects introduced previously via sysfs. Each data-only subnode is represented as a sysfs directory under the directory corresponding to its parent object (a device or a data-only subnode). Each of them has a "path" attribute (containing the full ACPI namespace path to the object the subnode data come from) at this time. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2015-07-17ACPI / scan: Move sysfs-related device code to a separate fileRafael J. Wysocki
To reduce the size of scan.c and improve the readability of it, move all code related to device sysfs, modalias creation etc. to a new file called device_sysfs.c. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>