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.defconf | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 scripts/Makefile.defconf (limited to 'scripts/Makefile.defconf') diff --git a/scripts/Makefile.defconf b/scripts/Makefile.defconf new file mode 100644 index 000000000..a44307f08 --- /dev/null +++ b/scripts/Makefile.defconf @@ -0,0 +1,30 @@ +# SPDX-License-Identifier: GPL-2.0 +# Configuration heplers + +cmd_merge_fragments = \ + $(srctree)/scripts/kconfig/merge_config.sh \ + $4 -m -O $(objtree) $(srctree)/arch/$(SRCARCH)/configs/$2 \ + $(foreach config,$3,$(srctree)/arch/$(SRCARCH)/configs/$(config).config) + +# Creates 'merged defconfigs' +# --------------------------------------------------------------------------- +# Usage: +# $(call merge_into_defconfig,base_config,config_fragment1 config_fragment2 ...) +# +# Input config fragments without '.config' suffix +define merge_into_defconfig + $(call cmd,merge_fragments,$1,$2) + +$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig +endef + + +# Creates 'merged defconfigs without warning about overrides' +# --------------------------------------------------------------------------- +# Usage: +# $(call merge_into_defconfig_override,base_config,config_fragment1 config_fragment2 ...) +# +# Input config fragments without '.config' suffix +define merge_into_defconfig_override + $(call cmd,merge_fragments,$1,$2,-Q) + +$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig +endef -- cgit v1.3.1