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From: Edward Adam Davis <eadavis@qq.com>
To: syzbot+0d33ab192bd50b6c91e6@syzkaller.appspotmail.com
Cc: dwlsalmeida@gmail.com, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, mchehab@kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: [PATCH] media/vidtv: Terminating the subsequent process of initialization failure
Date: Tue, 11 Mar 2025 09:00:03 +0800	[thread overview]
Message-ID: <tencent_97C074C976B367CE3D9D36A0968E361A4B09@qq.com> (raw)
In-Reply-To: <67cee9e2.050a0220.1939a6.0004.GAE@google.com>

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-00039-g848e07631744 #0
Hardware name: Google Google Compute Engine/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 [inline]
 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 [inline]
 vidtv_start_feed+0x334/0x4c0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering+0x3a5/0x660 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+0x457/0x530 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+0x46/0x2c0 drivers/media/test-drivers/vidtv/vidtv_psi.c:970
 vidtv_channel_si_init+0x67/0x1a90 drivers/media/test-drivers/vidtv/vidtv_channel.c:423
 vidtv_mux_init+0x526/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]
 vidtv_start_feed+0x334/0x4c0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering+0x3a5/0x660 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+0x457/0x530 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

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+0x34a/0x1a90 drivers/media/test-drivers/vidtv/vidtv_channel.c:499
 vidtv_mux_init+0x526/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]
 vidtv_start_feed+0x334/0x4c0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering+0x3a5/0x660 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+0x457/0x530 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

Reported-by: syzbot+0d33ab192bd50b6c91e6@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=0d33ab192bd50b6c91e6
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 drivers/media/test-drivers/vidtv/vidtv_channel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/test-drivers/vidtv/vidtv_channel.c b/drivers/media/test-drivers/vidtv/vidtv_channel.c
index 7838e6272712..f3023e91b3eb 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_channel.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_channel.c
@@ -497,7 +497,7 @@ int vidtv_channel_si_init(struct vidtv_mux *m)
 	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)
-- 
2.43.0


  reply	other threads:[~2025-03-11  1:01 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-10 13:32 [syzbot] [media?] KASAN: slab-use-after-free Read in vidtv_mux_init syzbot
2025-03-11  1:00 ` Edward Adam Davis [this message]
2025-03-11  3:34 ` [PATCH V2] media: vidtv: Terminating the subsequent process of initialization failure Edward Adam Davis
2025-03-11  7:20 ` [PATCH V3] " Edward Adam Davis

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