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[PATCH] Fix use-after-free in record_btrace_start_replaying
- From: Tom Tromey <tom at tromey dot com>
- To: gdb-patches at sourceware dot org
- Cc: Tom Tromey <tom at tromey dot com>
- Date: Fri, 19 Oct 2018 12:58:40 -0600
- Subject: [PATCH] Fix use-after-free in record_btrace_start_replaying
-fsanitize=address showed a use-after-free in
record_btrace_start_replaying. The bug occurred because
get_thread_current_frame returned a frame_info, but this object was
then invalidated before the return by ~scoped_restore_current_thread.
This patch fixes the problem by renaming get_thread_current_frame and
having it return a frame id.
gdb/ChangeLog
2018-10-19 Tom Tromey <tom@tromey.com>
* record-btrace.c (get_thread_current_frame_id): Rename from
get_thread_current_frame. Return a frame_id.
(record_btrace_start_replaying): Update.
---
gdb/ChangeLog | 6 ++++++
gdb/record-btrace.c | 19 ++++++++-----------
2 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 483b00e32a1..c9662d7ae4b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2018-10-19 Tom Tromey <tom@tromey.com>
+
+ * record-btrace.c (get_thread_current_frame_id): Rename from
+ get_thread_current_frame. Return a frame_id.
+ (record_btrace_start_replaying): Update.
+
2018-10-19 Tom Tromey <tom@tromey.com>
* symfile.c (reread_symbols): Clear "static_links".
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index aabe9f5e27e..c0e3341a1f6 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1967,10 +1967,10 @@ record_btrace_resume_thread (struct thread_info *tp,
/* Get the current frame for TP. */
-static struct frame_info *
-get_thread_current_frame (struct thread_info *tp)
+static struct frame_id
+get_thread_current_frame_id (struct thread_info *tp)
{
- struct frame_info *frame;
+ struct frame_id id;
int executing;
/* Set current thread, which is implicitly used by
@@ -1989,10 +1989,10 @@ get_thread_current_frame (struct thread_info *tp)
executing = tp->executing;
set_executing (inferior_ptid, false);
- frame = NULL;
+ id = null_frame_id;
TRY
{
- frame = get_current_frame ();
+ id = get_frame_id (get_current_frame ());
}
CATCH (except, RETURN_MASK_ALL)
{
@@ -2006,7 +2006,7 @@ get_thread_current_frame (struct thread_info *tp)
/* Restore the previous execution state. */
set_executing (inferior_ptid, executing);
- return frame;
+ return id;
}
/* Start replaying a thread. */
@@ -2031,13 +2031,11 @@ record_btrace_start_replaying (struct thread_info *tp)
subroutines after we started replaying. */
TRY
{
- struct frame_info *frame;
struct frame_id frame_id;
int upd_step_frame_id, upd_step_stack_frame_id;
/* The current frame without replaying - computed via normal unwind. */
- frame = get_thread_current_frame (tp);
- frame_id = get_frame_id (frame);
+ frame_id = get_thread_current_frame_id (tp);
/* Check if we need to update any stepping-related frame id's. */
upd_step_frame_id = frame_id_eq (frame_id,
@@ -2068,8 +2066,7 @@ record_btrace_start_replaying (struct thread_info *tp)
registers_changed_thread (tp);
/* The current frame with replaying - computed via btrace unwind. */
- frame = get_thread_current_frame (tp);
- frame_id = get_frame_id (frame);
+ frame_id = get_thread_current_frame_id (tp);
/* Replace stepping related frames where necessary. */
if (upd_step_frame_id)
--
2.17.2