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/basic/Makefile | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 scripts/basic/Makefile (limited to 'scripts/basic/Makefile') diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile new file mode 100644 index 000000000..fb8e2c38f --- /dev/null +++ b/scripts/basic/Makefile @@ -0,0 +1,21 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# fixdep: used to generate dependency information during build process + +hostprogs-always-y += fixdep + +# randstruct: the seed is needed before building the gcc-plugin or +# before running a Clang kernel build. +gen-randstruct-seed := $(srctree)/scripts/gen-randstruct-seed.sh +quiet_cmd_create_randstruct_seed = GENSEED $@ +cmd_create_randstruct_seed = \ + $(CONFIG_SHELL) $(gen-randstruct-seed) \ + $@ $(objtree)/include/generated/randstruct_hash.h +$(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE + $(call if_changed,create_randstruct_seed) +always-$(CONFIG_RANDSTRUCT) += randstruct.seed + +# integer-wrap: if the .scl file changes, we need to do a full rebuild. +$(obj)/../../include/generated/integer-wrap.h: $(srctree)/scripts/integer-wrap-ignore.scl FORCE + $(call if_changed,touch) +always-$(CONFIG_UBSAN_INTEGER_WRAP) += ../../include/generated/integer-wrap.h -- cgit v1.3.1