media: vidtv: Terminating the subsequent process of initialization failure

syzbot reported a slab-use-after-free Read in vidtv_mux_init. [1]

After PSI initialization fails, the si member is accessed again, resulting
in this uaf.

After si initialization fails, the subsequent process needs to be exited.

[1]
BUG: KASAN: slab-use-after-free in vidtv_mux_pid_ctx_init drivers/media/test-drivers/vidtv/vidtv_mux.c:78 [inline]
BUG: KASAN: slab-use-after-free in vidtv_mux_init+0xac2/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:524
Read of size 8 at addr ffff88802fa42acc by task syz.2.37/6059

CPU: 0 UID: 0 PID: 6059 Comm: syz.2.37 Not tainted 6.14.0-rc5-syzkaller #0
Hardware name: Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xc3/0x670 mm/kasan/report.c:521
kasan_report+0xd9/0x110 mm/kasan/report.c:634
vidtv_mux_pid_ctx_init drivers/media/test-drivers/vidtv/vidtv_mux.c:78
vidtv_mux_init+0xac2/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:524
vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194
vidtv_start_feed drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
dmx_section_feed_start_filtering drivers/media/dvb-core/dvb_demux.c:973
dvb_dmxdev_feed_start drivers/media/dvb-core/dmxdev.c:508 [inline]
dvb_dmxdev_feed_restart.isra.0 drivers/media/dvb-core/dmxdev.c:537
dvb_dmxdev_filter_stop+0x2b4/0x3a0 drivers/media/dvb-core/dmxdev.c:564
dvb_dmxdev_filter_free drivers/media/dvb-core/dmxdev.c:840 [inline]
dvb_demux_release+0x92/0x550 drivers/media/dvb-core/dmxdev.c:1246
__fput+0x3ff/0xb70 fs/file_table.c:464
task_work_run+0x14e/0x250 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0xad8/0x2d70 kernel/exit.c:938
do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
__do_sys_exit_group kernel/exit.c:1098 [inline]
__se_sys_exit_group kernel/exit.c:1096 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1096
x64_sys_call+0x151f/0x1720 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f871d58d169
Code: Unable to access opcode bytes at 0x7f871d58d13f.
RSP: 002b:00007fff4b19a788 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f871d58d169
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fff4b19a7ec R08: 0000000b4b19a87f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000000927c0 R14: 000000000001d553 R15: 00007fff4b19a840
 </TASK>

Allocated by task 6059:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 vidtv_psi_pat_table_init drivers/media/test-drivers/vidtv/vidtv_psi.c:970
 vidtv_channel_si_init drivers/media/test-drivers/vidtv/vidtv_channel.c:423
 vidtv_mux_init drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194
 vidtv_start_feed drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering drivers/media/dvb-core/dvb_demux.c:973
 dvb_dmxdev_feed_start drivers/media/dvb-core/dmxdev.c:508 [inline]
 dvb_dmxdev_feed_restart.isra.0 drivers/media/dvb-core/dmxdev.c:537
 dvb_dmxdev_filter_stop+0x2b4/0x3a0 drivers/media/dvb-core/dmxdev.c:564
 dvb_dmxdev_filter_free drivers/media/dvb-core/dmxdev.c:840 [inline]
 dvb_demux_release+0x92/0x550 drivers/media/dvb-core/dmxdev.c:1246
 __fput+0x3ff/0xb70 fs/file_table.c:464
 task_work_run+0x14e/0x250 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1096
 x64_sys_call arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6059:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kfree+0x2c4/0x4d0 mm/slub.c:4757
 vidtv_channel_si_init drivers/media/test-drivers/vidtv/vidtv_channel.c:499
 vidtv_mux_init drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194
 vidtv_start_feed drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering drivers/media/dvb-core/dvb_demux.c:973
 dvb_dmxdev_feed_start drivers/media/dvb-core/dmxdev.c:508 [inline]
 dvb_dmxdev_feed_restart.isra.0 drivers/media/dvb-core/dmxdev.c:537
 dvb_dmxdev_filter_stop+0x2b4/0x3a0 drivers/media/dvb-core/dmxdev.c:564
 dvb_dmxdev_filter_free drivers/media/dvb-core/dmxdev.c:840 [inline]
 dvb_demux_release+0x92/0x550 drivers/media/dvb-core/dmxdev.c:1246
 __fput+0x3ff/0xb70 fs/file_table.c:464
 task_work_run+0x14e/0x250 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1096
 x64_sys_call arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 3be8037960bc ("media: vidtv: add error checks")
Cc: stable@vger.kernel.org
Reported-by: syzbot+0d33ab192bd50b6c91e6@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=0d33ab192bd50b6c91e6
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/drivers/media/test-drivers/vidtv/vidtv_channel.c b/drivers/media/test-drivers/vidtv/vidtv_channel.c
index 7838e62727128fca89e07cfa691b7671f3cf0e58..f3023e91b3ebc8003fda4cd0049c1f0accd8727b 100644 (file)
--- a/drivers/media/test-drivers/vidtv/vidtv_channel.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_channel.c
@@ -497,7 +497,7 @@ free_sdt:
        vidtv_psi_sdt_table_destroy(m->si.sdt);
 free_pat:
        vidtv_psi_pat_table_destroy(m->si.pat);
-       return 0;
+       return -EINVAL;
 }
 
 void vidtv_channel_si_destroy(struct vidtv_mux *m)