From 4c8ecf9e0eb2dac47fdb590351d2330127dd7014 Mon Sep 17 00:00:00 2001 From: Ralph Boehme Date: Wed, 17 Mar 2021 16:22:37 +0100 Subject: [PATCH 1/3] smbd: reset dangling watch_req pointer in poll_open_done We just freed subreq and a pointer to subreq is stored in open_rec->watch_req, so we must invalidate the pointer. Otherwise if the poll open timer fires it will do a TALLOC_FREE(open_rec->watch_req); on the dangling pointer which may crash or do something worse like freeing some other random talloc memory. BUG: https://bugzilla.samba.org/show_bug.cgi?id=14672 CI: https://gitlab.com/samba-team/samba/-/merge_requests/1843 --- source3/smbd/open.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/source3/smbd/open.c b/source3/smbd/open.c index 5b3dc246e8a..fd4536b4914 100644 --- a/source3/smbd/open.c +++ b/source3/smbd/open.c @@ -3040,6 +3040,8 @@ static void poll_open_done(struct tevent_req *subreq) status = share_mode_watch_recv(subreq, NULL, NULL); TALLOC_FREE(subreq); + open_rec->watch_req = NULL; + DBG_DEBUG("dbwrap_watched_watch_recv returned %s\n", nt_errstr(status)); -- 2.30.2 From e22cb2f278af5ff6ca8f93ba9048b983877d5af8 Mon Sep 17 00:00:00 2001 From: Ralph Boehme Date: Wed, 17 Mar 2021 16:24:28 +0100 Subject: [PATCH 2/3] smbd: cancel pending poll open timer in poll_open_done() The retry of the open is scheduled below, avoid rescheduling it a second time in the open retry timeout function. BUG: https://bugzilla.samba.org/show_bug.cgi?id=14672 CI: https://gitlab.com/samba-team/samba/-/merge_requests/1843 --- source3/smbd/open.c | 1 + 1 file changed, 1 insertion(+) diff --git a/source3/smbd/open.c b/source3/smbd/open.c index fd4536b4914..1659df90366 100644 --- a/source3/smbd/open.c +++ b/source3/smbd/open.c @@ -3041,6 +3041,7 @@ static void poll_open_done(struct tevent_req *subreq) status = share_mode_watch_recv(subreq, NULL, NULL); TALLOC_FREE(subreq); open_rec->watch_req = NULL; + TALLOC_FREE(open_rec->te); DBG_DEBUG("dbwrap_watched_watch_recv returned %s\n", nt_errstr(status)); -- 2.30.2 From 86bd2c7d62ec5dcae201d8456a2b23856855b9d9 Mon Sep 17 00:00:00 2001 From: Ralph Boehme Date: Tue, 16 Mar 2021 18:18:46 +0100 Subject: [PATCH 3/3] smbd: free open_rec state in remove_deferred_open_message_smb2_internal() The lifetime of open_rec (struct deferred_open_record) ojects is the time processing the SMB open request every time the request is scheduled, ie once we reschedule we must wipe the slate clean. In case the request gets deferred again, a new open_rec will be created by the schedule functions. This ensures any timer event tied to the open_rec gets cancelled and doesn't fire unexpectedly. BUG: https://bugzilla.samba.org/show_bug.cgi?id=14672 CI: https://gitlab.com/samba-team/samba/-/merge_requests/1843 RN: smbd panic when two clients open same file --- source3/smbd/smb2_create.c | 1 + 1 file changed, 1 insertion(+) diff --git a/source3/smbd/smb2_create.c b/source3/smbd/smb2_create.c index 2dd3745dd32..8ff57c94aa0 100644 --- a/source3/smbd/smb2_create.c +++ b/source3/smbd/smb2_create.c @@ -1714,6 +1714,7 @@ static void remove_deferred_open_message_smb2_internal(struct smbd_smb2_request state->open_was_deferred = false; /* Ensure we don't have any outstanding immediate event. */ TALLOC_FREE(state->im); + TALLOC_FREE(state->open_rec); } void remove_deferred_open_message_smb2( -- 2.30.2