CVE-2021-47413 usb: chipidea: ci_hdrc_imx: Also search for 'phys' phandle
A NULL pointer dereference in the Linux kernel i.MX USB driver causes a system crash when specific device tree configurations are used.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-47413?
CVE-2021-47413 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
usb: chipidea: ci_hdrc_imx: Also search for 'phys' phandle
When passing 'phys' in the devicetree to describe the USB PHY phandle (which is the recommended way according to Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt) the following NULL pointer dereference is observed on i.MX7 and i.MX8MM:
[ 1.489344] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098 [ 1.498170] Mem abort info: [ 1.500966] ESR = 0x96000044 [ 1.504030] EC = 0x25: DABT (current EL), IL = 32 bits [ 1.509356] SET = 0, FnV = 0 [ 1.512416] EA = 0, S1PTW = 0 [ 1.515569] FSC = 0x04: level 0 translation fault [ 1.520458] Data abort info: [ 1.523349] ISV = 0, ISS = 0x00000044 [ 1.527196] CM = 0, WnR = 1 [ 1.530176] [0000000000000098] user address but active_mm is swapper [ 1.536544] Internal error: Oops: 96000044 [#1] PREEMPT SMP [ 1.542125] Modules linked in: [ 1.545190] CPU: 3 PID: 7 Comm: kworker/u8:0 Not tainted 5.14.0-dirty #3 [ 1.551901] Hardware name: Kontron i.MX8MM N801X S (DT) [ 1.557133] Workqueue: events_unbound deferred_probe_work_func [ 1.562984] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) [ 1.568998] pc : imx7d_charger_detection+0x3f0/0x510 [ 1.573973] lr : imx7d_charger_detection+0x22c/0x510
This happens because the charger functions check for the phy presence inside the imx_usbmisc_data structure (data->usb_phy), but the chipidea core populates the usb_phy passed via 'phys' inside 'struct ci_hdrc' (ci->usb_phy) instead.
This causes the NULL pointer dereference inside imx7d_charger_detection().
Fix it by also searching for 'phys' in case 'fsl,usbphy' is not found.
Tested on a imx7s-warp board.
Weakness: CWE-476
Which versions are affected by CVE-2021-47413?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47413?
Apply the vendor's patch.
Is CVE-2021-47413 being exploited?
There is no known exploitation of CVE-2021-47413 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47413, GHSA-qj4q-cgq8-w2m4, UBUNTU-CVE-2021-47413.