[PATCH 6.12 212/567] media: vidtv: initialize local pointers upon transfer of memory ownership

Greg Kroah-Hartman
2026-01-06T17:27:43Z

From: Jeongjun Park <aha310510@gmail.com>

commit 98aabfe2d79f74613abc2b0b1cef08f97eaf5322 upstream.

vidtv_channel_si_init() creates a temporary list (program, service, event)
and ownership of the memory itself is transferred to the PAT/SDT/EIT
tables through vidtv_psi_pat_program_assign(),
vidtv_psi_sdt_service_assign(), vidtv_psi_eit_event_assign().

The problem here is that the local pointer where the memory ownership
transfer was completed is not initialized to NULL. This causes the
vidtv_psi_pmt_create_sec_for_each_pat_entry() function to fail, and
in the flow that jumps to free_eit, the memory that was freed by
vidtv_psi_*_table_destroy() can be accessed again by
vidtv_psi_*_event_destroy() due to the uninitialized local pointer, so it
is freed once again.

Therefore, to prevent use-after-free and double-free vulnerability,
local pointers must be initialized to NULL when transferring memory
ownership.

Cc: <stable@vger.kernel.org>
Reported-by: syzbot+1d9c0edea5907af239e0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1d9c0edea5907af239e0
Fixes: 3be8037960bc ("media: vidtv: add error checks")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/media/test-drivers/vidtv/vidtv_channel.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/media/test-drivers/vidtv/vidtv_channel.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_channel.c
@@ -461,12 +461,15 @@ int vidtv_channel_si_init(struct vidtv_m

/* assemble all programs and assign to PAT */
vidtv_psi_pat_program_assign(m->si.pat, programs);
+ programs = NULL;

/* assemble all services and assign to SDT */
vidtv_psi_sdt_service_assign(m->si.sdt, services);
+ services = NULL;

/* assemble all events and assign to EIT */
vidtv_psi_eit_event_assign(m->si.eit, events);
+ events = NULL;

m->si.pmt_secs = vidtv_psi_pmt_create_sec_for_each_pat_entry(m->si.pat,
m->pcr_pid);