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-rc | 137 +++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-rc (limited to 'Documentation/ABI/testing/sysfs-class-rc') diff --git a/Documentation/ABI/testing/sysfs-class-rc b/Documentation/ABI/testing/sysfs-class-rc new file mode 100644 index 000000000..84e46d70d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-rc @@ -0,0 +1,137 @@ +What: /sys/class/rc/ +Date: Apr 2010 +KernelVersion: 2.6.35 +Contact: Mauro Carvalho Chehab +Description: + The rc/ class sub-directory belongs to the Remote Controller + core and provides a sysfs interface for configuring infrared + remote controller receivers. + +What: /sys/class/rc/rc/ +Date: Apr 2010 +KernelVersion: 2.6.35 +Contact: Mauro Carvalho Chehab +Description: + A /sys/class/rc/rcN directory is created for each remote + control receiver device where N is the number of the receiver. + +What: /sys/class/rc/rc/protocols +Date: Jun 2010 +KernelVersion: 2.6.36 +Contact: Mauro Carvalho Chehab +Description: + Reading this file returns a list of available protocols, + something like:: + + "rc5 [rc6] nec jvc [sony]" + + Enabled protocols are shown in [] brackets. + + Writing "+proto" will add a protocol to the list of enabled + protocols. + + Writing "-proto" will remove a protocol from the list of enabled + protocols. + + Writing "proto" will enable only "proto". + + Writing "none" will disable all protocols. + + Write fails with EINVAL if an invalid protocol combination or + unknown protocol name is used. + +What: /sys/class/rc/rc/filter +Date: Jan 2014 +KernelVersion: 3.15 +Contact: Mauro Carvalho Chehab +Description: + Sets the scancode filter expected value. + + Use in combination with /sys/class/rc/rcN/filter_mask to set the + expected value of the bits set in the filter mask. + If the hardware supports it then scancodes which do not match + the filter will be ignored. Otherwise the write will fail with + an error. + + This value may be reset to 0 if the current protocol is altered. + +What: /sys/class/rc/rc/filter_mask +Date: Jan 2014 +KernelVersion: 3.15 +Contact: Mauro Carvalho Chehab +Description: + Sets the scancode filter mask of bits to compare. + Use in combination with /sys/class/rc/rcN/filter to set the bits + of the scancode which should be compared against the expected + value. A value of 0 disables the filter to allow all valid + scancodes to be processed. + + If the hardware supports it then scancodes which do not match + the filter will be ignored. Otherwise the write will fail with + an error. + + This value may be reset to 0 if the current protocol is altered. + +What: /sys/class/rc/rc/wakeup_protocols +Date: Feb 2017 +KernelVersion: 4.11 +Contact: Mauro Carvalho Chehab +Description: + Reading this file returns a list of available protocols to use + for the wakeup filter, something like:: + + "rc-5 nec nec-x rc-6-0 rc-6-6a-24 [rc-6-6a-32] rc-6-mce" + + Note that protocol variants are listed, so "nec", "sony", + "rc-5", "rc-6" have their different bit length encodings + listed if available. + + The enabled wakeup protocol is shown in [] brackets. + + Only one protocol can be selected at a time. + + Writing "proto" will use "proto" for wakeup events. + + Writing "none" will disable wakeup. + + Write fails with EINVAL if an invalid protocol combination or + unknown protocol name is used, or if wakeup is not supported by + the hardware. + +What: /sys/class/rc/rc/wakeup_filter +Date: Jan 2014 +KernelVersion: 3.15 +Contact: Mauro Carvalho Chehab +Description: + Sets the scancode wakeup filter expected value. + + Use in combination with /sys/class/rc/rcN/wakeup_filter_mask to + set the expected value of the bits set in the wakeup filter mask + to trigger a system wake event. + + If the hardware supports it and wakeup_filter_mask is not 0 then + scancodes which match the filter will wake the system from e.g. + suspend to RAM or power off. + + Otherwise the write will fail with an error. + + This value may be reset to 0 if the wakeup protocol is altered. + +What: /sys/class/rc/rc/wakeup_filter_mask +Date: Jan 2014 +KernelVersion: 3.15 +Contact: Mauro Carvalho Chehab +Description: + Sets the scancode wakeup filter mask of bits to compare. + + Use in combination with /sys/class/rc/rcN/wakeup_filter to set + the bits of the scancode which should be compared against the + expected value to trigger a system wake event. + + If the hardware supports it and wakeup_filter_mask is not 0 then + scancodes which match the filter will wake the system from e.g. + suspend to RAM or power off. + + Otherwise the write will fail with an error. + + This value may be reset to 0 if the wakeup protocol is altered. -- cgit v1.3.1