From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- Documentation/ABI/testing/sysfs-class-led-flash | 89 +++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-led-flash (limited to 'Documentation/ABI/testing/sysfs-class-led-flash') diff --git a/Documentation/ABI/testing/sysfs-class-led-flash b/Documentation/ABI/testing/sysfs-class-led-flash new file mode 100644 index 000000000..11e5677c3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led-flash @@ -0,0 +1,89 @@ +What: /sys/class/leds//flash_brightness +Date: March 2015 +KernelVersion: 4.0 +Contact: Jacek Anaszewski +Description: read/write + Set the brightness of this LED in the flash strobe mode, in + microamperes. The file is created only for the flash LED devices + that support setting flash brightness. + + The value is between 0 and + /sys/class/leds//max_flash_brightness. + +What: /sys/class/leds//max_flash_brightness +Date: March 2015 +KernelVersion: 4.0 +Contact: Jacek Anaszewski +Description: read only + Maximum brightness level for this LED in the flash strobe mode, + in microamperes. + +What: /sys/class/leds//flash_timeout +Date: March 2015 +KernelVersion: 4.0 +Contact: Jacek Anaszewski +Description: read/write + Hardware timeout for flash, in microseconds. The flash strobe + is stopped after this period of time has passed from the start + of the strobe. The file is created only for the flash LED + devices that support setting flash timeout. + +What: /sys/class/leds//max_flash_timeout +Date: March 2015 +KernelVersion: 4.0 +Contact: Jacek Anaszewski +Description: read only + Maximum flash timeout for this LED, in microseconds. + +What: /sys/class/leds//flash_strobe +Date: March 2015 +KernelVersion: 4.0 +Contact: Jacek Anaszewski +Description: read/write + Flash strobe state. When written with 1 it triggers flash strobe + and when written with 0 it turns the flash off. + + On read 1 means that flash is currently strobing and 0 means + that flash is off. + +What: /sys/class/leds//flash_fault +Date: March 2015 +KernelVersion: 4.0 +Contact: Jacek Anaszewski +Description: read only + Space separated list of flash faults that may have occurred. + Flash faults are re-read after strobing the flash. Possible + flash faults: + + * led-over-voltage + flash controller voltage to the flash LED + has exceeded the limit specific to the flash controller + * flash-timeout-exceeded + the flash strobe was still on when + the timeout set by the user has expired; not all flash + controllers may set this in all such conditions + * controller-over-temperature + the flash controller has + overheated + * controller-short-circuit + the short circuit protection + of the flash controller has been triggered + * led-power-supply-over-current + current in the LED power + supply has exceeded the limit specific to the flash + controller + * indicator-led-fault + the flash controller has detected + a short or open circuit condition on the indicator LED + * led-under-voltage + flash controller voltage to the flash + LED has been below the minimum limit specific to + the flash + * controller-under-voltage + the input voltage of the flash + controller is below the limit under which strobing the + flash at full current will not be possible; + the condition persists until this flag is no longer set + * led-over-temperature + the temperature of the LED has exceeded + its allowed upper limit -- cgit v1.3.1