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.userprogs | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 scripts/Makefile.userprogs (limited to 'scripts/Makefile.userprogs') diff --git a/scripts/Makefile.userprogs b/scripts/Makefile.userprogs new file mode 100644 index 000000000..f3a7e1ef3 --- /dev/null +++ b/scripts/Makefile.userprogs @@ -0,0 +1,45 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Build userspace programs for the target system +# + +# Executables compiled from a single .c file +user-csingle := $(foreach m, $(userprogs), $(if $($(m)-objs),,$(m))) + +# Executables linked based on several .o files +user-cmulti := $(foreach m, $(userprogs), $(if $($(m)-objs),$(m))) + +# Objects compiled from .c files +user-cobjs := $(sort $(foreach m, $(userprogs), $($(m)-objs))) + +user-csingle := $(addprefix $(obj)/, $(user-csingle)) +user-cmulti := $(addprefix $(obj)/, $(user-cmulti)) +user-cobjs := $(addprefix $(obj)/, $(user-cobjs)) + +user_ccflags = -Wp,-MMD,$(depfile) $(KBUILD_USERCFLAGS) $(userccflags) \ + $($(target-stem)-userccflags) +user_ldflags = $(KBUILD_USERLDFLAGS) $(userldflags) $($(target-stem)-userldflags) +user_ldlibs = $(userldlibs) $($(target-stem)-userldlibs) + +# Create an executable from a single .c file +quiet_cmd_user_cc_c = CC [U] $@ + cmd_user_cc_c = $(CC) $(user_ccflags) $(user_ldflags) -o $@ $< \ + $(user_ldlibs) +$(user-csingle): $(obj)/%: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_c) + +# Link an executable based on list of .o files +quiet_cmd_user_ld = LD [U] $@ + cmd_user_ld = $(CC) $(user_ldflags) -o $@ \ + $(addprefix $(obj)/, $($(target-stem)-objs)) $(user_ldlibs) +$(user-cmulti): FORCE + $(call if_changed,user_ld) +$(call multi_depend, $(user-cmulti), , -objs) + +# Create .o file from a .c file +quiet_cmd_user_cc_o_c = CC [U] $@ + cmd_user_cc_o_c = $(CC) $(user_ccflags) -c -o $@ $< +$(user-cobjs): $(obj)/%.o: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_o_c) + +targets += $(user-csingle) $(user-cmulti) $(user-cobjs) -- cgit v1.3.1