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| author | Wang Hai <wanghai38@huawei.com> | 2021-10-15 16:57:41 +0800 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2021-11-19 15:17:57 +0000 |
| commit | ab599eb11882f834951c436cc080c3455ba32b9b (patch) | |
| tree | 4efef4c3db5b67e4a3d8cb6958f5d2b65f47a428 | |
| parent | ea8587d9de22aa08e1449779c59687407f7de21e (diff) | |
| download | lwn-ab599eb11882f834951c436cc080c3455ba32b9b.tar.gz lwn-ab599eb11882f834951c436cc080c3455ba32b9b.zip | |
media: dmxdev: fix UAF when dvb_register_device() fails
I got a use-after-free report:
dvbdev: dvb_register_device: failed to create device dvb1.dvr0 (-12)
...
==================================================================
BUG: KASAN: use-after-free in dvb_dmxdev_release+0xce/0x2f0
...
Call Trace:
dump_stack_lvl+0x6c/0x8b
print_address_description.constprop.0+0x48/0x70
kasan_report.cold+0x82/0xdb
__asan_load4+0x6b/0x90
dvb_dmxdev_release+0xce/0x2f0
...
Allocated by task 7666:
kasan_save_stack+0x23/0x50
__kasan_kmalloc+0x83/0xa0
kmem_cache_alloc_trace+0x22e/0x470
dvb_register_device+0x12f/0x980
dvb_dmxdev_init+0x1f3/0x230
...
Freed by task 7666:
kasan_save_stack+0x23/0x50
kasan_set_track+0x20/0x30
kasan_set_free_info+0x24/0x40
__kasan_slab_free+0xf2/0x130
kfree+0xd1/0x5c0
dvb_register_device.cold+0x1ac/0x1fa
dvb_dmxdev_init+0x1f3/0x230
...
When dvb_register_device() in dvb_dmxdev_init() fails, dvb_dmxdev_init()
does not return a failure, and the memory pointed to by dvbdev or
dvr_dvbdev is invalid at this point. If they are used subsequently, it
will result in UFA or null-ptr-deref.
If dvb_register_device() in dvb_dmxdev_init() fails, fix the bug by making
dvb_dmxdev_init() return an error as well.
Link: https://lore.kernel.org/linux-media/20211015085741.1203283-1-wanghai38@huawei.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
| -rw-r--r-- | drivers/media/dvb-core/dmxdev.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c index 5d5a48475a54..01f288fa37e0 100644 --- a/drivers/media/dvb-core/dmxdev.c +++ b/drivers/media/dvb-core/dmxdev.c @@ -1413,7 +1413,7 @@ static const struct dvb_device dvbdev_dvr = { }; int dvb_dmxdev_init(struct dmxdev *dmxdev, struct dvb_adapter *dvb_adapter) { - int i; + int i, ret; if (dmxdev->demux->open(dmxdev->demux) < 0) return -EUSERS; @@ -1432,14 +1432,26 @@ int dvb_dmxdev_init(struct dmxdev *dmxdev, struct dvb_adapter *dvb_adapter) DMXDEV_STATE_FREE); } - dvb_register_device(dvb_adapter, &dmxdev->dvbdev, &dvbdev_demux, dmxdev, + ret = dvb_register_device(dvb_adapter, &dmxdev->dvbdev, &dvbdev_demux, dmxdev, DVB_DEVICE_DEMUX, dmxdev->filternum); - dvb_register_device(dvb_adapter, &dmxdev->dvr_dvbdev, &dvbdev_dvr, + if (ret < 0) + goto err_register_dvbdev; + + ret = dvb_register_device(dvb_adapter, &dmxdev->dvr_dvbdev, &dvbdev_dvr, dmxdev, DVB_DEVICE_DVR, dmxdev->filternum); + if (ret < 0) + goto err_register_dvr_dvbdev; dvb_ringbuffer_init(&dmxdev->dvr_buffer, NULL, 8192); return 0; + +err_register_dvr_dvbdev: + dvb_unregister_device(dmxdev->dvbdev); +err_register_dvbdev: + vfree(dmxdev->filter); + dmxdev->filter = NULL; + return ret; } EXPORT_SYMBOL(dvb_dmxdev_init); |