#1067 fix use-after-free in deliver pending command

Do not release the json object twice, once from og_send_request() and
again og_cmd_free().

Valgrind reports:

==11885== Invalid read of size 8
==11885==    at 0x117B9A: json_decref (jansson.h:128)
==11885==    by 0x117B9A: og_cmd_free (rest.c:2409)
==11885==    by 0x113465: og_agent_deliver_pending_cmd (core.c:211)
==11885==    by 0x113465: og_agent_read_cb (core.c:256)
==11885==    by 0x4E41D72: ev_invoke_pending (in /usr/lib/x86_64-linux-gnu/libev.so.4.0.0)
==11885==    by 0x4E453DD: ev_run (in /usr/lib/x86_64-linux-gnu/libev.so.4.0.0)
==11885==    by 0x110C2D: ev_loop (ev.h:835)
==11885==    by 0x110C2D: main (main.c:104)
==11885==  Address 0x8e7e988 is 8 bytes inside a block of size 72 free'd
==11885==    at 0x4C32D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==11885==    by 0x117437: json_decref (jansson.h:129)
==11885==    by 0x117437: og_send_request (rest.c:330)
==11885==    by 0x113454: og_agent_deliver_pending_cmd (core.c:208)
==11885==    by 0x113454: og_agent_read_cb (core.c:256)
==11885==    by 0x4E41D72: ev_invoke_pending (in /usr/lib/x86_64-linux-gnu/libev.so.4.0.0)
==11885==    by 0x4E453DD: ev_run (in /usr/lib/x86_64-linux-gnu/libev.so.4.0.0)
==11885==    by 0x110C2D: ev_loop (ev.h:835)
==11885==    by 0x110C2D: main (main.c:104)
==11885==  Block was alloc'd at
==11885==    at 0x4C31B0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==11885==    by 0x526461A: json_object (in /usr/lib/x86_64-linux-gnu/libjansson.so.4.11.0)
==11885==    by 0x116A07: og_cmd_legacy_image_restore (rest.c:2627)
==11885==    by 0x116A07: og_cmd_legacy (rest.c:2757)
==11885==    by 0x116A07: og_queue_task_command (rest.c:2848)
==11885==    by 0x118284: og_dbi_queue_command (rest.c:3109)
==11885==    by 0x118284: og_schedule_run (rest.c:3190)
==11885==    by 0x1147B9: og_agent_timer_cb (schedule.c:445)
==11885==    by 0x4E41D72: ev_invoke_pending (in /usr/lib/x86_64-linux-gnu/libev.so.4.0.0)
==11885==    by 0x4E453DD: ev_run (in /usr/lib/x86_64-linux-gnu/libev.so.4.0.0)
==11885==    by 0x110C2D: ev_loop (ev.h:835)
==11885==    by 0x110C2D: main (main.c:104)

1 files changed, 1 insertions, 0 deletions

diff --git a/src/core.c b/src/core.c
index ad7799b..0f95ad9 100644
--- a/src/core.c
+++ b/src/core.c
@@ -205,6 +205,7 @@ static void og_agent_deliver_pending_cmd(struct og_client *cli)
 		return;
 	}
 
+	json_incref(cmd->json);
 	og_send_request(cmd->method, cmd->type, &cmd->params, cmd->json);
 	cli->last_cmd_id = cmd->id;