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/coccinelle/misc/boolconv.cocci | 91 ++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 scripts/coccinelle/misc/boolconv.cocci (limited to 'scripts/coccinelle/misc/boolconv.cocci') diff --git a/scripts/coccinelle/misc/boolconv.cocci b/scripts/coccinelle/misc/boolconv.cocci new file mode 100644 index 000000000..392994e93 --- /dev/null +++ b/scripts/coccinelle/misc/boolconv.cocci @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: GPL-2.0-only +/// Remove unneeded conversion to bool +/// +//# Relational and logical operators evaluate to bool, +//# explicit conversion is overly verbose and unneeded. +// +// Copyright: (C) 2016 Andrew F. Davis + +virtual patch +virtual context +virtual org +virtual report + +//---------------------------------------------------------- +// For patch mode +//---------------------------------------------------------- + +@depends on patch@ +expression A, B; +symbol true, false; +@@ + +( + A == B +| + A != B +| + A > B +| + A < B +| + A >= B +| + A <= B +| + A && B +| + A || B +) +- ? true : false + +//---------------------------------------------------------- +// For context mode +//---------------------------------------------------------- + +@r depends on !patch@ +expression A, B; +symbol true, false; +position p; +@@ + +( + A == B +| + A != B +| + A > B +| + A < B +| + A >= B +| + A <= B +| + A && B +| + A || B +) +* ? true : false@p + +//---------------------------------------------------------- +// For org mode +//---------------------------------------------------------- + +@script:python depends on r&&org@ +p << r.p; +@@ + +msg = "WARNING: conversion to bool not needed here" +coccilib.org.print_todo(p[0], msg) + +//---------------------------------------------------------- +// For report mode +//---------------------------------------------------------- + +@script:python depends on r&&report@ +p << r.p; +@@ + +msg = "WARNING: conversion to bool not needed here" +coccilib.report.print_report(p[0], msg) -- cgit v1.3.1