From af895b219876b293d551e6dec825aba3905c0588 Mon Sep 17 00:00:00 2001
From: "qiwu.chen" <qiwu.chen@transsion.com>
Date: Wed, 24 Jul 2024 01:36:09 +0000
Subject: [PATCH] arm64: fix a potential segfault when unwind frame

The range of frame->fp is checked insufficiently, which may lead to a wrong
next fp. As a result, bt->stackbuf will be accessed out of range, and segfault.

  crash> bt
  [Detaching after fork from child process 11409]
  PID: 7661     TASK: ffffff81858aa500  CPU: 4    COMMAND: "sh"
   #0 [ffffffc008003f50] local_cpu_stop at ffffffdd7669444c

  Thread 1 "crash" received signal SIGSEGV, Segmentation fault.
  0x00005555558266cc in arm64_unwind_frame (bt=0x7fffffffd8f0, frame=0x7fffffffd080) at
  arm64.c:2821
  2821            frame->fp = GET_STACK_ULONG(fp);
  (gdb) bt
  arm64.c:2821
  out>) at main.c:1338
  gdb_interface.c:81
  (gdb) p /x *(struct bt_info*) 0x7fffffffd8f0
  $3 = {task = 0xffffff81858aa500, flags = 0x0, instptr = 0xffffffdd76694450, stkptr =
  0xffffffc008003f40, bptr = 0x0, stackbase = 0xffffffc027288000,
    stacktop = 0xffffffc02728c000, stackbuf = 0x555556115a40, tc = 0x55559d16fdc0, hp = 0x0,
  textlist = 0x0, ref = 0x0, frameptr = 0xffffffc008003f50,
    call_target = 0x0, machdep = 0x0, debug = 0x0, eframe_ip = 0x0, radix = 0x0, cpumask =
  0x0}
  (gdb) p /x *(struct arm64_stackframe*) 0x7fffffffd080
  $4 = {fp = 0xffffffc008003f50, sp = 0xffffffc008003f60, pc = 0xffffffdd76694450}
  crash> bt -S 0xffffffc008003f50
  PID: 7661     TASK: ffffff81858aa500  CPU: 4    COMMAND: "sh"
  bt: non-process stack address for this task: ffffffc008003f50
      (valid range: ffffffc027288000 - ffffffc02728c000)

Check frame->fp value sufficiently before access it. Only frame->fp within
the range of bt->stackbase and bt->stacktop will be regarded as valid.

Signed-off-by: qiwu.chen <qiwu.chen@transsion.com>

Conflict: NA
Reference: https://github.com/crash-utility/crash/commit/af895b219876b293d551e6dec825aba3905c0588

---
 arm64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arm64.c b/arm64.c
index b3040d7..624dba2 100644
--- a/arm64.c
+++ b/arm64.c
@@ -2814,7 +2814,7 @@ arm64_unwind_frame(struct bt_info *bt, struct arm64_stackframe *frame)
 	low  = frame->sp;
 	high = (low + stack_mask) & ~(stack_mask);
 
-	if (fp < low || fp > high || fp & 0xf)
+	if (fp < low || fp > high || fp & 0xf || !INSTACK(fp, bt))
 		return FALSE;
 
 	frame->sp = fp + 0x10;
@@ -3024,7 +3024,7 @@ arm64_unwind_frame_v2(struct bt_info *bt, struct arm64_stackframe *frame,
 	low  = frame->sp;
 	high = (low + stack_mask) & ~(stack_mask);
 
-	if (fp < low || fp > high || fp & 0xf)
+	if (fp < low || fp > high || fp & 0xf || !INSTACK(fp, bt))
 		return FALSE;
 
 	if (CRASHDEBUG(1))
-- 
2.33.0