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/admin-guide/lcd-panel-cgram.rst | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 Documentation/admin-guide/lcd-panel-cgram.rst (limited to 'Documentation/admin-guide/lcd-panel-cgram.rst') diff --git a/Documentation/admin-guide/lcd-panel-cgram.rst b/Documentation/admin-guide/lcd-panel-cgram.rst new file mode 100644 index 000000000..a3eb00c62 --- /dev/null +++ b/Documentation/admin-guide/lcd-panel-cgram.rst @@ -0,0 +1,27 @@ +====================================== +Parallel port LCD/Keypad Panel support +====================================== + +Some LCDs allow you to define up to 8 characters, mapped to ASCII +characters 0 to 7. The escape code to define a new character is +'\e[LG' followed by one digit from 0 to 7, representing the character +number, and up to 8 couples of hex digits terminated by a semi-colon +(';'). Each couple of digits represents a line, with 1-bits for each +illuminated pixel with LSB on the right. Lines are numbered from the +top of the character to the bottom. On a 5x7 matrix, only the 5 lower +bits of the 7 first bytes are used for each character. If the string +is incomplete, only complete lines will be redefined. Here are some +examples:: + + printf "\e[LG0010101050D1F0C04;" => 0 = [enter] + printf "\e[LG1040E1F0000000000;" => 1 = [up] + printf "\e[LG2000000001F0E0400;" => 2 = [down] + printf "\e[LG3040E1F001F0E0400;" => 3 = [up-down] + printf "\e[LG40002060E1E0E0602;" => 4 = [left] + printf "\e[LG500080C0E0F0E0C08;" => 5 = [right] + printf "\e[LG60016051516141400;" => 6 = "IP" + + printf "\e[LG00103071F1F070301;" => big speaker + printf "\e[LG00002061E1E060200;" => small speaker + +Willy -- cgit v1.3.1