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/alpha/lib/Makefile | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 arch/alpha/lib/Makefile (limited to 'arch/alpha/lib/Makefile') diff --git a/arch/alpha/lib/Makefile b/arch/alpha/lib/Makefile new file mode 100644 index 000000000..84046e730 --- /dev/null +++ b/arch/alpha/lib/Makefile @@ -0,0 +1,46 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for alpha-specific library files.. +# + +asflags-y := $(KBUILD_CFLAGS) + +# Many of these routines have implementations tuned for ev6. +# Choose them iff we're targeting ev6 specifically. +ev6-$(CONFIG_ALPHA_EV6) := ev6- + +# Several make use of the cttz instruction introduced in ev67. +ev67-$(CONFIG_ALPHA_EV67) := ev67- + +lib-y = __divqu.o __remqu.o __divlu.o __remlu.o \ + udiv-qrnnd.o \ + udelay.o \ + $(ev6-y)memset.o \ + $(ev6-y)memcpy.o \ + memmove.o \ + checksum.o \ + csum_partial_copy.o \ + $(ev67-y)strlen.o \ + stycpy.o \ + styncpy.o \ + $(ev67-y)strchr.o \ + $(ev67-y)strrchr.o \ + $(ev6-y)memchr.o \ + $(ev6-y)copy_user.o \ + $(ev6-y)clear_user.o \ + $(ev6-y)csum_ipv6_magic.o \ + $(ev6-y)clear_page.o \ + $(ev6-y)copy_page.o \ + fpreg.o \ + callback_srm.o srm_puts.o srm_printk.o \ + fls.o + +# The division routines are built from single source, with different defines. +AFLAGS___divqu.o = -DDIV +AFLAGS___remqu.o = -DREM +AFLAGS___divlu.o = -DDIV -DINTSIZE +AFLAGS___remlu.o = -DREM -DINTSIZE + +$(addprefix $(obj)/,__divqu.o __remqu.o __divlu.o __remlu.o): \ + $(src)/$(ev6-y)divide.S FORCE + $(call if_changed_rule,as_o_S) -- cgit v1.3.1