From: Wang Hai <wanghai38@huawei.com>
To: <mchehab@kernel.org>
Cc: <linux-media@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH] media: dmxdev: fix UAF when dvb_register_device() fails
Date: Fri, 15 Oct 2021 16:57:41 +0800 [thread overview]
Message-ID: <20211015085741.1203283-1-wanghai38@huawei.com> (raw)
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.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
---
drivers/media/dvb-core/dmxdev.c | 18 +++++++++++++++---
1 file 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);
--
2.25.1
reply other threads:[~2021-10-15 8:58 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211015085741.1203283-1-wanghai38@huawei.com \
--to=wanghai38@huawei.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=mchehab@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).