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 --- Documentation/ABI/testing/sysfs-block-dm | 47 ++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-block-dm (limited to 'Documentation/ABI/testing/sysfs-block-dm') diff --git a/Documentation/ABI/testing/sysfs-block-dm b/Documentation/ABI/testing/sysfs-block-dm new file mode 100644 index 000000000..f9f2339b9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-block-dm @@ -0,0 +1,47 @@ +What: /sys/block/dm-/dm/name +Date: January 2009 +KernelVersion: 2.6.29 +Contact: dm-devel@redhat.com +Description: Device-mapper device name. + Read-only string containing mapped device name. +Users: util-linux, device-mapper udev rules + +What: /sys/block/dm-/dm/uuid +Date: January 2009 +KernelVersion: 2.6.29 +Contact: dm-devel@redhat.com +Description: Device-mapper device UUID. + Read-only string containing DM-UUID or empty string + if DM-UUID is not set. +Users: util-linux, device-mapper udev rules + +What: /sys/block/dm-/dm/suspended +Date: June 2009 +KernelVersion: 2.6.31 +Contact: dm-devel@redhat.com +Description: Device-mapper device suspend state. + Contains the value 1 while the device is suspended. + Otherwise it contains 0. Read-only attribute. +Users: util-linux, device-mapper udev rules + +What: /sys/block/dm-/dm/rq_based_seq_io_merge_deadline +Date: March 2015 +KernelVersion: 4.1 +Contact: dm-devel@redhat.com +Description: Allow control over how long a request that is a + reasonable merge candidate can be queued on the request + queue. The resolution of this deadline is in + microseconds (ranging from 1 to 100000 usecs). + Setting this attribute to 0 (the default) will disable + request-based DM's merge heuristic and associated extra + accounting. This attribute is not applicable to + bio-based DM devices so it will only ever report 0 for + them. + +What: /sys/block/dm-/dm/use_blk_mq +Date: March 2015 +KernelVersion: 4.1 +Contact: dm-devel@redhat.com +Description: Request-based Device-mapper blk-mq I/O path mode. + Contains the value 1 if the device is using blk-mq. + Otherwise it contains 0. Read-only attribute. -- cgit v1.3.1