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 --- scripts/Makefile.ubsan | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 scripts/Makefile.ubsan (limited to 'scripts/Makefile.ubsan') diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan new file mode 100644 index 000000000..734a102e6 --- /dev/null +++ b/scripts/Makefile.ubsan @@ -0,0 +1,28 @@ +# SPDX-License-Identifier: GPL-2.0 + +# Shared with KVM/arm64. +export CFLAGS_UBSAN_TRAP := $(call cc-option,-fsanitize-trap=undefined,-fsanitize-undefined-trap-on-error) + +# Enable available and selected UBSAN features. +ubsan-cflags-$(CONFIG_UBSAN_ALIGNMENT) += -fsanitize=alignment +ubsan-cflags-$(CONFIG_UBSAN_BOUNDS_STRICT) += -fsanitize=bounds-strict +ubsan-cflags-$(CONFIG_UBSAN_ARRAY_BOUNDS) += -fsanitize=array-bounds +ubsan-cflags-$(CONFIG_UBSAN_LOCAL_BOUNDS) += -fsanitize=local-bounds +ubsan-cflags-$(CONFIG_UBSAN_SHIFT) += -fsanitize=shift +ubsan-cflags-$(CONFIG_UBSAN_DIV_ZERO) += -fsanitize=integer-divide-by-zero +ubsan-cflags-$(CONFIG_UBSAN_UNREACHABLE) += -fsanitize=unreachable +ubsan-cflags-$(CONFIG_UBSAN_BOOL) += -fsanitize=bool +ubsan-cflags-$(CONFIG_UBSAN_ENUM) += -fsanitize=enum +ubsan-cflags-$(CONFIG_UBSAN_TRAP) += $(CFLAGS_UBSAN_TRAP) + +export CFLAGS_UBSAN := $(ubsan-cflags-y) + +ubsan-integer-wrap-cflags-$(CONFIG_UBSAN_INTEGER_WRAP) += \ + -DINTEGER_WRAP \ + -fsanitize-undefined-ignore-overflow-pattern=all \ + -fsanitize=signed-integer-overflow \ + -fsanitize=unsigned-integer-overflow \ + -fsanitize=implicit-signed-integer-truncation \ + -fsanitize=implicit-unsigned-integer-truncation \ + -fsanitize-ignorelist=$(srctree)/scripts/integer-wrap-ignore.scl +export CFLAGS_UBSAN_INTEGER_WRAP := $(ubsan-integer-wrap-cflags-y) -- cgit v1.3.1