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 --- arch/mips/math-emu/Makefile | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 arch/mips/math-emu/Makefile (limited to 'arch/mips/math-emu/Makefile') diff --git a/arch/mips/math-emu/Makefile b/arch/mips/math-emu/Makefile new file mode 100644 index 000000000..81d25ff32 --- /dev/null +++ b/arch/mips/math-emu/Makefile @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the Linux/MIPS kernel FPU emulation. +# + +obj-y += cp1emu.o ieee754dp.o ieee754sp.o ieee754.o \ + dp_div.o dp_mul.o dp_sub.o dp_add.o dp_fsp.o dp_cmp.o dp_simple.o \ + dp_tint.o dp_fint.o dp_rint.o dp_maddf.o dp_2008class.o dp_fmin.o \ + dp_fmax.o \ + sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_simple.o \ + sp_tint.o sp_fint.o sp_rint.o sp_maddf.o sp_2008class.o sp_fmin.o \ + sp_fmax.o \ + dsemul.o + +lib-y += ieee754d.o \ + dp_tlong.o dp_flong.o dp_sqrt.o \ + sp_tlong.o sp_flong.o sp_sqrt.o + +obj-$(CONFIG_DEBUG_FS) += me-debugfs.o -- cgit v1.3.1