mdssvc: Do an early talloc_free() in _mdssvc_open()

Environment setup:
When macOS Finder connect to a samba server with 'spotlight = yes',
macOS would issue mdssvc open (mdssvc.opnum == 0) to samba and it goes
through api _mdssvc_open().

After applied 578e434a94147dc2d7dbfc006d2ab84807859c1d,
(this is reported by jaywei@qnap.com)
this line 'talloc_free(path);' is deleted if _mdssvc_open() normal exit,
so memory is lazy de-allocate: delayed to
smbd_tevent_trace_callback() @ smb2_process.c. [1]

Supposed to explicitly free 'path' in _mdssvc_open() @ srv_mdssvc_nt.c[2]
just like abnormal exit, do not wait for main loop to free 'path' which is
no longer used, this is more consistent while reading source code.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15449

[1] gdb tracing 'path' address 0x56204ccc67e0 to know how it is freed.
Breakpoint 2, _tc_free_children_internal (tc=0x56204ccc6780, ptr=0x56204ccc67e0, location=0x7ff430d96410 "../../lib/talloc/talloc.c:1714") at ../../lib/talloc/talloc.c:1656
1656            while (tc->child) {
(gdb) bt
0  _tc_free_children_internal (tc=0x56204ccc6780, ptr=0x56204ccc67e0, location=0x7ff430d96410 "../../lib/talloc/talloc.c:1714") at ../../lib/talloc/talloc.c:1656
1  0x00007ff430d92b14 in _tc_free_internal (tc=0x56204ccc6780, location=0x7ff430d96410 "../../lib/talloc/talloc.c:1714") at ../../lib/talloc/talloc.c:1183
2  0x00007ff430d93b71 in _tc_free_children_internal (tc=0x56204ccc6720, ptr=0x56204ccc6780, location=0x7ff430d96410 "../../lib/talloc/talloc.c:1714") at ../../lib/talloc/talloc.c:1668
3  0x00007ff430d93d66 in talloc_free_children (ptr=0x56204ccc6780) at ../../lib/talloc/talloc.c:1714
4  0x00007ff432235aca in talloc_pop (frame=0x56204ccc6780) at ../../lib/util/talloc_stack.c:125
5  0x00007ff430d92959 in _tc_free_internal (tc=0x56204ccc6720, location=0x7ff431f358d0 "../../source3/smbd/process.c:3726") at ../../lib/talloc/talloc.c:1157
6  0x00007ff430d92cd5 in _talloc_free_internal (ptr=0x56204ccc6780, location=0x7ff431f358d0 "../../source3/smbd/process.c:3726") at ../../lib/talloc/talloc.c:1247
7  0x00007ff430d93f96 in _talloc_free (ptr=0x56204ccc6780, location=0x7ff431f358d0 "../../source3/smbd/process.c:3726") at ../../lib/talloc/talloc.c:1791
8  0x00007ff431d81292 in smbd_tevent_trace_callback (point=TEVENT_TRACE_AFTER_LOOP_ONCE, private_data=0x7ffe46591e30) at ../../source3/smbd/process.c:3726
<...cut...>

[2] gdb tracing 'path' address 0x55a6d66deed0 to know how it is freed.
Breakpoint 2, _tc_free_children_internal (tc=0x55a6d66deed0, ptr=0x55a6d66def30, location=0x7fc4cca84040 "../../source3/rpc_server/mdssvc/srv_mdssvc_nt.c:189") at ../../lib/talloc/talloc.c:1656
1656            while (tc->child) {
(gdb) bt
0  _tc_free_children_internal (tc=0x55a6d66deed0, ptr=0x55a6d66def30, location=0x7fc4cca84040 "../../source3/rpc_server/mdssvc/srv_mdssvc_nt.c:189") at ../../lib/talloc/talloc.c:1656
1  0x00007fc4cb892b14 in _tc_free_internal (tc=0x55a6d66deed0, location=0x7fc4cca84040 "../../source3/rpc_server/mdssvc/srv_mdssvc_nt.c:189") at ../../lib/talloc/talloc.c:1183
2  0x00007fc4cb892cd5 in _talloc_free_internal (ptr=0x55a6d66def30, location=0x7fc4cca84040 "../../source3/rpc_server/mdssvc/srv_mdssvc_nt.c:189") at ../../lib/talloc/talloc.c:1247
3  0x00007fc4cb893f96 in _talloc_free (ptr=0x55a6d66def30, location=0x7fc4cca84040 "../../source3/rpc_server/mdssvc/srv_mdssvc_nt.c:189") at ../../lib/talloc/talloc.c:1791
4  0x00007fc4cc9396e4 in _mdssvc_open (p=0x55a6d66d5600, r=0x55a6d66edc60) at ../../source3/rpc_server/mdssvc/srv_mdssvc_nt.c:189
<...cut...>

Signed-off-by: Jones Syue <jonessyue@qnap.com>
Reviewed-by: Noel Power <npower@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Noel Power <npower@samba.org>
Autobuild-Date(master): Mon Aug 14 18:11:37 UTC 2023 on atb-devel-224

(cherry picked from commit 044cb8f9d558bfcd7658cae0f05ff36330538748)

diff --git a/source3/rpc_server/mdssvc/srv_mdssvc_nt.c b/source3/rpc_server/mdssvc/srv_mdssvc_nt.c
index c77e71855211766f4b848f26aed7d86c70de5eb1..9a166244df5ea83c8af312e773b8db850aa8e8d6 100644 (file)
--- a/source3/rpc_server/mdssvc/srv_mdssvc_nt.c
+++ b/source3/rpc_server/mdssvc/srv_mdssvc_nt.c
@@ -135,6 +135,7 @@ void _mdssvc_open(struct pipes_struct *p, struct mdssvc_open *r)
        }
 
        strlcpy(outpath, fake_path, 1024);
+       talloc_free(path);
        talloc_free(fake_path);
        return;
 }