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 --- block/Kconfig.iosched | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 block/Kconfig.iosched (limited to 'block/Kconfig.iosched') diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched new file mode 100644 index 000000000..27f11320b --- /dev/null +++ b/block/Kconfig.iosched @@ -0,0 +1,47 @@ +# SPDX-License-Identifier: GPL-2.0 +menu "IO Schedulers" + +config MQ_IOSCHED_DEADLINE + tristate "MQ deadline I/O scheduler" + default y + help + MQ version of the deadline IO scheduler. + +config MQ_IOSCHED_KYBER + tristate "Kyber I/O scheduler" + default y + help + The Kyber I/O scheduler is a low-overhead scheduler suitable for + multiqueue and other fast devices. Given target latencies for reads and + synchronous writes, it will self-tune queue depths to achieve that + goal. + +config IOSCHED_BFQ + tristate "BFQ I/O scheduler" + select BLK_ICQ + help + BFQ I/O scheduler for BLK-MQ. BFQ distributes the bandwidth of + of the device among all processes according to their weights, + regardless of the device parameters and with any workload. It + also guarantees a low latency to interactive and soft + real-time applications. Details in + Documentation/block/bfq-iosched.rst + +config BFQ_GROUP_IOSCHED + bool "BFQ hierarchical scheduling support" + depends on IOSCHED_BFQ && BLK_CGROUP + default y + select BLK_CGROUP_RWSTAT + help + + Enable hierarchical scheduling in BFQ, using the blkio + (cgroups-v1) or io (cgroups-v2) controller. + +config BFQ_CGROUP_DEBUG + bool "BFQ IO controller debugging" + depends on BFQ_GROUP_IOSCHED + help + Enable some debugging help. Currently it exports additional stat + files in a cgroup which can be useful for debugging. + +endmenu -- cgit v1.3.1