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/procfs-diskstats | 43 ++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 Documentation/ABI/testing/procfs-diskstats (limited to 'Documentation/ABI/testing/procfs-diskstats') diff --git a/Documentation/ABI/testing/procfs-diskstats b/Documentation/ABI/testing/procfs-diskstats new file mode 100644 index 000000000..6a719cf20 --- /dev/null +++ b/Documentation/ABI/testing/procfs-diskstats @@ -0,0 +1,43 @@ +What: /proc/diskstats +Date: February 2008 +Contact: Jerome Marchand +Description: + The /proc/diskstats file displays the I/O statistics + of block devices. Each line contains the following 14 + fields: + + == =================================== + 1 major number + 2 minor number + 3 device name + 4 reads completed successfully + 5 reads merged + 6 sectors read + 7 time spent reading (ms) + 8 writes completed + 9 writes merged + 10 sectors written + 11 time spent writing (ms) + 12 I/Os currently in progress + 13 time spent doing I/Os (ms) + 14 weighted time spent doing I/Os (ms) + == =================================== + + Kernel 4.18+ appends four more fields for discard + tracking putting the total at 18: + + == =================================== + 15 discards completed successfully + 16 discards merged + 17 sectors discarded + 18 time spent discarding + == =================================== + + Kernel 5.5+ appends two more fields for flush requests: + + == ===================================== + 19 flush requests completed successfully + 20 time spent flushing + == ===================================== + + For more details refer to Documentation/admin-guide/iostats.rst -- cgit v1.3.1