linux-cve-announce - CVE-2025-68194: media: imon: make send

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <2025121636-CVE-2025-68194-2b2f@gregkh>
Date: Tue, 16 Dec 2025 14:43:55 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68194: media: imon: make send_packet() more robust

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

media: imon: make send_packet() more robust

syzbot is reporting that imon has three problems which result in
hung tasks due to forever holding device lock [1].

First problem is that when usb_rx_callback_intf0() once got -EPROTO error
after ictx->dev_present_intf0 became true, usb_rx_callback_intf0()
resubmits urb after printk(), and resubmitted urb causes
usb_rx_callback_intf0() to again get -EPROTO error. This results in
printk() flooding (RCU stalls).

Alan Stern commented [2] that

  In theory it's okay to resubmit _if_ the driver has a robust
  error-recovery scheme (such as giving up after some fixed limit on the
  number of errors or after some fixed time has elapsed, perhaps with a
  time delay to prevent a flood of errors).  Most drivers don't bother to
  do this; they simply give up right away.  This makes them more
  vulnerable to short-term noise interference during USB transfers, but in
  reality such interference is quite rare.  There's nothing really wrong
  with giving up right away.

but imon has a poor error-recovery scheme which just retries forever;
this behavior should be fixed.

Since I'm not sure whether it is safe for imon users to give up upon any
error code, this patch takes care of only union of error codes chosen from
modules in drivers/media/rc/ directory which handle -EPROTO error (i.e.
ir_toy, mceusb and igorplugusb).

Second problem is that when usb_rx_callback_intf0() once got -EPROTO error
before ictx->dev_present_intf0 becomes true, usb_rx_callback_intf0() always
resubmits urb due to commit 8791d63af0cf ("[media] imon: don't wedge
hardware after early callbacks"). Move the ictx->dev_present_intf0 test
introduced by commit 6f6b90c9231a ("[media] imon: don't parse scancodes
until intf configured") to immediately before imon_incoming_packet(), or
the first problem explained above happens without printk() flooding (i.e.
hung task).

Third problem is that when usb_rx_callback_intf0() is not called for some
reason (e.g. flaky hardware; the reproducer for this problem sometimes
prevents usb_rx_callback_intf0() from being called),
wait_for_completion_interruptible() in send_packet() never returns (i.e.
hung task). As a workaround for such situation, change send_packet() to
wait for completion with timeout of 10 seconds.

The Linux kernel CVE team has assigned CVE-2025-68194 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.4.302 with commit 519737af11c03590819a6eec2ad532cfdb87ea63
	Fixed in 5.10.247 with commit f58ab83b7b7133e6baefe03a46846c4f6ce45e2f
	Fixed in 5.15.197 with commit 26f6a1dd5d81ad61a875a747698da6f27abf389b
	Fixed in 6.1.159 with commit 667afd4681781f60a644cd0d2ee6c59cb1c36208
	Fixed in 6.6.117 with commit 8231e80118463be5598daaf266c1c83650f1948b
	Fixed in 6.12.58 with commit 0213e4175abbb9dfcbf7c197e3817d527f459ad5
	Fixed in 6.17.8 with commit f7f3ecb4934fff782fa9bb1cd16e2290c041b22d
	Fixed in 6.18 with commit eecd203ada43a4693ce6fdd3a58ae10c7819252c

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-68194
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/media/rc/imon.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/519737af11c03590819a6eec2ad532cfdb87ea63
	https://git.kernel.org/stable/c/f58ab83b7b7133e6baefe03a46846c4f6ce45e2f
	https://git.kernel.org/stable/c/26f6a1dd5d81ad61a875a747698da6f27abf389b
	https://git.kernel.org/stable/c/667afd4681781f60a644cd0d2ee6c59cb1c36208
	https://git.kernel.org/stable/c/8231e80118463be5598daaf266c1c83650f1948b
	https://git.kernel.org/stable/c/0213e4175abbb9dfcbf7c197e3817d527f459ad5
	https://git.kernel.org/stable/c/f7f3ecb4934fff782fa9bb1cd16e2290c041b22d
	https://git.kernel.org/stable/c/eecd203ada43a4693ce6fdd3a58ae10c7819252c