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>

1 files changed, 82 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-data.txt b/tools/perf/Documentation/perf-data.txt
new file mode 100644
index 000000000..20f178d61
--- /dev/null
+++ b/tools/perf/Documentation/perf-data.txt
@@ -0,0 +1,82 @@
+perf-data(1)
+============
+
+NAME
+----
+perf-data - Data file related processing
+
+SYNOPSIS
+--------
+[verse]
+'perf data' [<common options>] <command> [<options>]",
+
+DESCRIPTION
+-----------
+Data file related processing.
+
+COMMANDS
+--------
+convert::
+	Converts perf data file into another format.
+	It's possible to set data-convert debug variable to get debug messages from conversion,
+	like:
+	  perf --debug data-convert data convert ...
+
+OPTIONS for 'convert'
+---------------------
+--to-ctf::
+	Triggers the CTF conversion, specify the path of CTF data directory.
+
+--to-json::
+	Triggers JSON conversion. Specify the JSON filename to output.
+
+--tod::
+	Convert time to wall clock time.
+
+-i::
+	Specify input perf data file path.
+
+-f::
+--force::
+	Don't complain, do it.
+
+--time::
+	Only convert samples within given time window: <start>,<stop>. Times
+	have the format seconds.nanoseconds. If start is not given (i.e. time
+	string is ',x.y') then analysis starts at the beginning of the file. If
+	stop time is not given (i.e. time string is 'x.y,') then analysis goes
+	to end of file. Multiple ranges can be separated by spaces, which
+	requires the argument to be quoted e.g. --time "1234.567,1234.789 1235,"
+
+	Also support time percent with multiple time ranges. Time string is
+	'a%/n,b%/m,...' or 'a%-b%,c%-%d,...'.
+
+	For example:
+	Select the second 10% time slice:
+
+	  perf data convert --to-json out.json --time 10%/2
+
+	Select from 0% to 10% time slice:
+
+	  perf data convert --to-json out.json --time 0%-10%
+
+	Select the first and second 10% time slices:
+
+	  perf data convert --to-json out.json --time 10%/1,10%/2
+
+	Select from 0% to 10% and 30% to 40% slices:
+
+	  perf data convert --to-json out.json --time 0%-10%,30%-40%
+
+-v::
+--verbose::
+        Be more verbose (show counter open errors, etc).
+
+--all::
+	Convert all events, including non-sample events (comm, fork, ...), to output.
+	Default is off, only convert samples.
+
+SEE ALSO
+--------
+linkperf:perf[1]
+[1] Common Trace Format - http://www.efficios.com/ctf