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/driver-api/tty/console.rst | 45 ++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 Documentation/driver-api/tty/console.rst (limited to 'Documentation/driver-api/tty/console.rst') diff --git a/Documentation/driver-api/tty/console.rst b/Documentation/driver-api/tty/console.rst new file mode 100644 index 000000000..4348e36cd --- /dev/null +++ b/Documentation/driver-api/tty/console.rst @@ -0,0 +1,45 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======= +Console +======= + +.. contents:: :local: + +Struct Console +============== + +.. kernel-doc:: include/linux/console.h + :identifiers: console cons_flags + +Internals +--------- + +.. kernel-doc:: include/linux/console.h + :identifiers: nbcon_state nbcon_prio nbcon_context nbcon_write_context + +Struct Consw +============ + +.. kernel-doc:: include/linux/console.h + :identifiers: consw + +Console functions +================= + +.. kernel-doc:: include/linux/console.h + :identifiers: console_srcu_read_flags console_srcu_write_flags + console_is_registered for_each_console_srcu for_each_console + +.. kernel-doc:: drivers/tty/vt/selection.c + :export: +.. kernel-doc:: drivers/tty/vt/vt.c + :export: + +Internals +--------- + +.. kernel-doc:: drivers/tty/vt/selection.c + :internal: +.. kernel-doc:: drivers/tty/vt/vt.c + :internal: -- cgit v1.3.1