Re: [PATCH] spmi: trace: fix stack-out-of-bound access in SPMI tracing functions

[Greg Kroah-Hartman]

On Sat, Jul 23, 2022 at 11:50:50PM -0700, Stephen Boyd wrote:
> Quoting David Collins (2022-06-27 16:55:12)
> > trace_spmi_write_begin() and trace_spmi_read_end() both call
> > memcpy() with a length of "len + 1".  This leads to one extra
> > byte being read beyond the end of the specified buffer.  Fix
> > this out-of-bound memory access by using a length of "len"
> > instead.
> > 
> > Here is a KASAN log showing the issue:
> > 
> > BUG: KASAN: stack-out-of-bounds in trace_event_raw_event_spmi_read_end+0x1d0/0x234
> > Read of size 2 at addr ffffffc0265b7540 by task thermal@2.0-ser/1314
> > ...
> > Call trace:
> >  dump_backtrace+0x0/0x3e8
> >  show_stack+0x2c/0x3c
> >  dump_stack_lvl+0xdc/0x11c
> >  print_address_description+0x74/0x384
> >  kasan_report+0x188/0x268
> >  kasan_check_range+0x270/0x2b0
> >  memcpy+0x90/0xe8
> >  trace_event_raw_event_spmi_read_end+0x1d0/0x234
> >  spmi_read_cmd+0x294/0x3ac
> >  spmi_ext_register_readl+0x84/0x9c
> >  regmap_spmi_ext_read+0x144/0x1b0 [regmap_spmi]
> >  _regmap_raw_read+0x40c/0x754
> >  regmap_raw_read+0x3a0/0x514
> >  regmap_bulk_read+0x418/0x494
> >  adc5_gen3_poll_wait_hs+0xe8/0x1e0 [qcom_spmi_adc5_gen3]
> >  ...
> >  __arm64_sys_read+0x4c/0x60
> >  invoke_syscall+0x80/0x218
> >  el0_svc_common+0xec/0x1c8
> >  ...
> > 
> > addr ffffffc0265b7540 is located in stack of task thermal@2.0-ser/1314 at offset 32 in frame:
> >  adc5_gen3_poll_wait_hs+0x0/0x1e0 [qcom_spmi_adc5_gen3]
> > 
> > this frame has 1 object:
> >  [32, 33) 'status'
> > 
> > Memory state around the buggy address:
> >  ffffffc0265b7400: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
> >  ffffffc0265b7480: 04 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
> > >ffffffc0265b7500: 00 00 00 00 f1 f1 f1 f1 01 f3 f3 f3 00 00 00 00
> >                                            ^
> >  ffffffc0265b7580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >  ffffffc0265b7600: f1 f1 f1 f1 01 f2 07 f2 f2 f2 01 f3 00 00 00 00
> > ==================================================================
> > 
> > Fixes: a9fce374815d ("spmi: add command tracepoints for SPMI")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: David Collins <quic_collinsd@xxxxxxxxxxx>
> > ---
> 
> Reviewed-by: Stephen Boyd <sboyd@xxxxxxxxxx>
> 
> Greg, can you pick this up directly? I don't have anything else for this
> cycle.

Now queued up, thanks.

greg k-h