[Spice-devel] [PATCH spice-gtk 1/5] gio-pipe: fix NULL pointer dereferencing

[Jakub Janků]

In pipe_output_stream_is_writable, if the peer is already gone,
peer_closed is set to TRUE and in this case, peer->read should not be accessed
as peer is NULL.

Otherwise, the following sequence of calls (simplified) would trigger a segfault:

    spice_make_pipe(p1, p2);
    g_output_stream_write_all_async(p1_out);
    g_clear_object(p2);
    g_pollable_output_stream_is_writable(p1_out);

Signed-off-by: Jakub Janků <jjanku at redhat.com>
---
 src/giopipe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/giopipe.c b/src/giopipe.c
index de1adae..fcec844 100644
--- a/src/giopipe.c
+++ b/src/giopipe.c
@@ -420,7 +420,7 @@ pipe_output_stream_is_writable (GPollableOutputStream *stream)
     PipeOutputStream *self = PIPE_OUTPUT_STREAM(stream);
     gboolean writable;
 
-    writable = self->buffer == NULL || self->peer->read >= 0 || self->peer_closed;
+    writable = self->buffer == NULL || self->peer_closed || self->peer->read >= 0;
     //g_debug("writable %p %d", self, writable);
 
     return writable;
-- 
2.21.0