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| author | Ali Ahmet Memis <ali@iusegentoo.com> | 2026-08-21 01:45:27 +0000 |
|---|---|---|
| committer | Stafford Horne <shorne@gmail.com> | 2026-08-29 07:32:26 +0100 |
| commit | 78004e9a87f240df03e2f73120d291763c32e0a7 (patch) | |
| tree | 137c22dd795222931b9d2bf2501d37cd766741aa /Documentation/ABI/testing/sysfs-class-stm | |
| download | linux-stable-78004e9a87f240df03e2f73120d291763c32e0a7.tar.gz linux-stable-78004e9a87f240df03e2f73120d291763c32e0a7.zip | |
openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted
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 <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-stm')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-stm | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-stm b/Documentation/ABI/testing/sysfs-class-stm new file mode 100644 index 000000000..77ed3da0f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-stm @@ -0,0 +1,24 @@ +What: /sys/class/stm/<stm>/masters +Date: June 2015 +KernelVersion: 4.3 +Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com> +Description: + Shows first and last available to software master numbers on + this STM device. + +What: /sys/class/stm/<stm>/channels +Date: June 2015 +KernelVersion: 4.3 +Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com> +Description: + Shows the number of channels per master on this STM device. + +What: /sys/class/stm/<stm>/hw_override +Date: March 2016 +KernelVersion: 4.7 +Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com> +Description: + Reads as 0 if master numbers in the STP stream produced by + this stm device will match the master numbers assigned by + the software or 1 if the stm hardware overrides software + assigned masters. |