On Mon, 27 Jun 2022 16:55:12 -0700 David Collins quic_collinsd@quicinc.com wrote:

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@vger.kernel.org Signed-off-by: David Collins quic_collinsd@quicinc.com

---

include/trace/events/spmi.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/trace/events/spmi.h b/include/trace/events/spmi.h index 8b60efe18ba6..a6819fd85cdf 100644 --- a/include/trace/events/spmi.h +++ b/include/trace/events/spmi.h @@ -21,15 +21,15 @@ TRACE_EVENT(spmi_write_begin, __field ( u8, sid ) __field ( u16, addr ) __field ( u8, len )

• __dynamic_array	( u8,   buf,  len + 1   )
  

• __dynamic_array	( u8,   buf,  len       )
  

  ),

TP_fast_assign( __entry->opcode = opcode; __entry->sid = sid; __entry->addr = addr;

• __entry->len    = len + 1;
  

• memcpy(__get_dynamic_array(buf), buf, len + 1);
  

• __entry->len    = len;
  

• memcpy(__get_dynamic_array(buf), buf, len);
  

  ),

TP_printk("opc=%d sid=%02d addr=0x%04x len=%d buf=0x[%*phD]", @@ -92,7 +92,7 @@ TRACE_EVENT(spmi_read_end, __field ( u16, addr ) __field ( int, ret ) __field ( u8, len )

• __dynamic_array	( u8,   buf,  len + 1   )
  

• __dynamic_array	( u8,   buf,  len       )
  

  ),

TP_fast_assign( @@ -100,8 +100,8 @@ TRACE_EVENT(spmi_read_end, __entry->sid = sid; __entry->addr = addr; __entry->ret = ret;

• __entry->len    = len + 1;
  

• memcpy(__get_dynamic_array(buf), buf, len + 1);
  

• __entry->len    = len;
  

• memcpy(__get_dynamic_array(buf), buf, len);
  

  ),

Looks legit,

Acked-by: Steven Rostedt (Google) rostedt@goodmis.org

-- Steve

TP_printk("opc=%d sid=%02d addr=0x%04x ret=%d len=%02d buf=0x[%*phD]",