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/riscv/lib/Makefile | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 arch/riscv/lib/Makefile (limited to 'arch/riscv/lib/Makefile') diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile new file mode 100644 index 000000000..f668b9897 --- /dev/null +++ b/arch/riscv/lib/Makefile @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0-only +lib-y += delay.o +lib-y += memcpy.o +lib-y += memset.o +lib-y += memmove.o +ifeq ($(CONFIG_KASAN_GENERIC)$(CONFIG_KASAN_SW_TAGS),) +lib-y += strcmp.o +lib-y += strlen.o +lib-y += strncmp.o +lib-y += strnlen.o +lib-y += strchr.o +lib-y += strrchr.o +endif +lib-y += csum.o +ifeq ($(CONFIG_MMU), y) +lib-$(CONFIG_RISCV_ISA_V) += uaccess_vector.o +endif +lib-$(CONFIG_MMU) += uaccess.o +lib-$(CONFIG_32BIT) += ashldi3.o ashrdi3.o lshrdi3.o +lib-$(CONFIG_64BIT) += tishift.o +lib-$(CONFIG_RISCV_ISA_ZICBOZ) += clear_page.o +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o +lib-$(CONFIG_RISCV_ISA_V) += riscv_v_helpers.o -- cgit v1.3.1