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.vdsoinst | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 scripts/Makefile.vdsoinst (limited to 'scripts/Makefile.vdsoinst') diff --git a/scripts/Makefile.vdsoinst b/scripts/Makefile.vdsoinst new file mode 100644 index 000000000..d9f724321 --- /dev/null +++ b/scripts/Makefile.vdsoinst @@ -0,0 +1,45 @@ +# SPDX-License-Identifier: GPL-2.0-only +# ========================================================================== +# Install unstripped copies of vDSO +# ========================================================================== + +PHONY := __default +__default: + @: + +include $(srctree)/scripts/Kbuild.include + +install-dir := $(MODLIB)/vdso + +define gen_install_rules + +dest := $(install-dir)/$$(patsubst %.dbg,%,$$(notdir $(1))) + +__default: $$(dest) +$$(dest): $(1) FORCE + $$(call cmd,install) + +build-id-file := $$(shell $(READELF) -n $(1) 2>/dev/null | sed -n 's@^.*Build ID: \(..\)\(.*\)@\1/\2@p') + +ifneq ($$(build-id-file),) +link := $(install-dir)/.build-id/$$(build-id-file).debug + +__default: $$(link) +$$(link): $$(dest) FORCE + $$(call cmd,symlink) +endif + +endef + +$(foreach x, $(sort $(INSTALL_FILES)), $(eval $(call gen_install_rules,$(x)))) + +quiet_cmd_install = INSTALL $@ + cmd_install = mkdir -p $(dir $@); cp $< $@ + +quiet_cmd_symlink = SYMLINK $@ + cmd_symlink = mkdir -p $(dir $@); ln -sf --relative $< $@ + +PHONY += FORCE +FORCE: + +.PHONY: $(PHONY) -- cgit v1.3.1