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/headers_install.sh | 74 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100755 scripts/headers_install.sh (limited to 'scripts/headers_install.sh') diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh new file mode 100755 index 000000000..9c15e7487 --- /dev/null +++ b/scripts/headers_install.sh @@ -0,0 +1,74 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +if [ $# -ne 2 ] +then + echo "Usage: headers_install.sh INFILE OUTFILE" + echo + echo "Prepares kernel header files for use by user space, by removing" + echo "all compiler.h definitions and #includes, removing any" + echo "#ifdef __KERNEL__ sections, and putting __underscores__ around" + echo "asm/inline/volatile keywords." + echo + echo "INFILE: header file to operate on" + echo "OUTFILE: output file which the processed header is written to" + + exit 1 +fi + +# Grab arguments +INFILE=$1 +OUTFILE=$2 +TMPFILE=$OUTFILE.tmp + +trap 'rm -f $OUTFILE $TMPFILE' EXIT + +# SPDX-License-Identifier with GPL variants must have "WITH Linux-syscall-note" +if [ -n "$(sed -n -e "/SPDX-License-Identifier:.*GPL-/{/WITH Linux-syscall-note/!p}" $INFILE)" ]; then + echo "error: $INFILE: missing \"WITH Linux-syscall-note\" for SPDX-License-Identifier" >&2 + exit 1 +fi + +sed -E -e ' + s/([[:space:](])(__user|__force|__iomem)[[:space:]]/\1/g + s/__attribute_const__([[:space:]]|$)/\1/g + s@^#include @@ + s/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g + s/(^|[[:space:](])(inline|asm|volatile)([[:space:](]|$)/\1__\2__\3/g + s@#(ifndef|define|endif[[:space:]]*/[*])[[:space:]]*_UAPI@#\1 @ +' $INFILE > $TMPFILE || exit 1 + +scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ $TMPFILE > $OUTFILE +[ $? -gt 1 ] && exit 1 + +# Remove /* ... */ style comments, and find CONFIG_ references in code +configs=$(sed -e ' +:comment + s:/\*[^*][^*]*:/*: + s:/\*\*\**\([^/]\):/*\1: + t comment + s:/\*\*/: : + t comment + /\/\*/! b check + N + b comment +:print + P + D +:check + s:^\(CONFIG_[[:alnum:]_]*\):\1\n: + t print + s:^[[:alnum:]_][[:alnum:]_]*:: + s:^[^[:alnum:]_][^[:alnum:]_]*:: + t check + d +' $OUTFILE) + +for c in $configs +do + echo "error: $INFILE: leak $c to user-space" >&2 + exit 1 +done + +rm -f $TMPFILE +trap - EXIT -- cgit v1.3.1