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/as-version.sh | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100755 scripts/as-version.sh (limited to 'scripts/as-version.sh') diff --git a/scripts/as-version.sh b/scripts/as-version.sh new file mode 100755 index 000000000..af7174761 --- /dev/null +++ b/scripts/as-version.sh @@ -0,0 +1,82 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only +# +# Print the assembler name and its version in a 5 or 6-digit form. +# Also, perform the minimum version check. +# (If it is the integrated assembler, return 0 as the version, and +# skip the version check.) + +set -e + +# Convert the version string x.y.z to a canonical 5 or 6-digit form. +get_canonical_version() +{ + IFS=. + set -- $1 + + # If the 2nd or 3rd field is missing, fill it with a zero. + # + # The 4th field, if present, is ignored. + # This occurs in development snapshots as in 2.35.1.20201116 + echo $((10000 * $1 + 100 * ${2:-0} + ${3:-0})) +} + +# Clang fails to handle -Wa,--version unless -fno-integrated-as is given. +# We check -fintegrated-as, expecting it is explicitly passed in for the +# integrated assembler case. +check_integrated_as() +{ + while [ $# -gt 0 ]; do + if [ "$1" = -fintegrated-as ]; then + # For the integrated assembler, we do not check the + # version here. It is the same as the clang version, and + # it has been already checked by scripts/cc-version.sh. + echo LLVM 0 + exit 0 + fi + shift + done +} + +check_integrated_as "$@" + +orig_args="$@" + +# Get the first line of the --version output. +IFS=' +' +set -- $(LC_ALL=C "$@" -Wa,--version -c -x assembler-with-cpp /dev/null -o /dev/null 2>/dev/null) + +# Split the line on spaces. +IFS=' ' +set -- $1 + +min_tool_version=$(dirname $0)/min-tool-version.sh + +if [ "$1" = GNU -a "$2" = assembler ]; then + shift $(($# - 1)) + version=$1 + min_version=$($min_tool_version binutils) + name=GNU +else + echo "$orig_args: unknown assembler invoked" >&2 + exit 1 +fi + +# Some distributions append a package release number, as in 2.34-4.fc32 +# Trim the hyphen and any characters that follow. +version=${version%-*} + +cversion=$(get_canonical_version $version) +min_cversion=$(get_canonical_version $min_version) + +if [ "$cversion" -lt "$min_cversion" ]; then + echo >&2 "***" + echo >&2 "*** Assembler is too old." + echo >&2 "*** Your $name assembler version: $version" + echo >&2 "*** Minimum $name assembler version: $min_version" + echo >&2 "***" + exit 1 +fi + +echo $name $cversion -- cgit v1.3.1