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/extract-fwblobs | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100755 scripts/extract-fwblobs (limited to 'scripts/extract-fwblobs') diff --git a/scripts/extract-fwblobs b/scripts/extract-fwblobs new file mode 100755 index 000000000..53729124e --- /dev/null +++ b/scripts/extract-fwblobs @@ -0,0 +1,30 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# ----------------------------------------------------------------------------- +# Extracts the vmlinux built-in firmware blobs - requires a non-stripped image +# ----------------------------------------------------------------------------- + +if [ -z "$1" ]; then + echo "Must provide a non-stripped vmlinux as argument" + exit 1 +fi + +read -r RD_ADDR_HEX RD_OFF_HEX <<< "$( readelf -SW "$1" |\ +grep -w rodata | awk '{print "0x"$5" 0x"$6}' )" + +FW_SYMS="$(readelf -sW "$1" |\ +awk -n '/fw_end/ { end=$2 ; print name " 0x" start " 0x" end; } { start=$2; name=$8; }')" + +while IFS= read -r entry; do + read -r FW_NAME FW_ADDR_ST_HEX FW_ADDR_END_HEX <<< "$entry" + + # Notice kernel prepends _fw_ and appends _bin to the FW name + # in rodata; hence we hereby filter that out. + FW_NAME=${FW_NAME:4:-4} + + FW_OFFSET="$(printf "%d" $((FW_ADDR_ST_HEX - RD_ADDR_HEX + RD_OFF_HEX)))" + FW_SIZE="$(printf "%d" $((FW_ADDR_END_HEX - FW_ADDR_ST_HEX)))" + + dd if="$1" of="./${FW_NAME}" bs="${FW_SIZE}" count=1 iflag=skip_bytes skip="${FW_OFFSET}" +done <<< "${FW_SYMS}" -- cgit v1.3.1