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/powerpc/Makefile.postlink | 53 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 arch/powerpc/Makefile.postlink (limited to 'arch/powerpc/Makefile.postlink') diff --git a/arch/powerpc/Makefile.postlink b/arch/powerpc/Makefile.postlink new file mode 100644 index 000000000..bb601be36 --- /dev/null +++ b/arch/powerpc/Makefile.postlink @@ -0,0 +1,53 @@ +# SPDX-License-Identifier: GPL-2.0 +# =========================================================================== +# Post-link powerpc pass +# =========================================================================== +# +# 1. Check that vmlinux relocations look sane + +PHONY := __archpost +__archpost: + +-include include/config/auto.conf +include $(srctree)/scripts/Kbuild.include + +quiet_cmd_head_check = CHKHEAD $@ + cmd_head_check = $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/head_check.sh "$(NM)" "$@" + +quiet_cmd_relocs_check = CHKREL $@ +ifdef CONFIG_PPC_BOOK3S_64 + cmd_relocs_check = \ + $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@" ; \ + $(BASH) $(srctree)/arch/powerpc/tools/unrel_branch_check.sh "$(OBJDUMP)" "$(NM)" "$@" +else + cmd_relocs_check = \ + $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@" +endif + +quiet_cmd_ftrace_check = CHKFTRC $@ + cmd_ftrace_check = $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/ftrace_check.sh "$(NM)" "$@" + +# `@true` prevents complaint when there is nothing to be done + +vmlinux: FORCE + @true +ifdef CONFIG_PPC64 + $(call cmd,head_check) +endif +ifdef CONFIG_RELOCATABLE + $(call if_changed,relocs_check) +endif +ifdef CONFIG_FUNCTION_TRACER +ifndef CONFIG_PPC64_ELF_ABI_V1 + $(call cmd,ftrace_check) +endif +endif + +clean: + rm -f .tmp_symbols.txt + +PHONY += FORCE clean + +FORCE: + +.PHONY: $(PHONY) -- cgit v1.3.1