| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-46941: usb: dwc3: core: Do core softreset when switch mode |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| usb: dwc3: core: Do core softreset when switch mode |
| |
| |
| According to the programming guide, to switch mode for DRD controller, |
| the driver needs to do the following. |
| |
| To switch from device to host: |
| 1. Reset controller with GCTL.CoreSoftReset |
| 2. Set GCTL.PrtCapDir(host mode) |
| 3. Reset the host with USBCMD.HCRESET |
| 4. Then follow up with the initializing host registers sequence |
| |
| To switch from host to device: |
| 1. Reset controller with GCTL.CoreSoftReset |
| 2. Set GCTL.PrtCapDir(device mode) |
| 3. Reset the device with DCTL.CSftRst |
| 4. Then follow up with the initializing registers sequence |
| |
| Currently we're missing step 1) to do GCTL.CoreSoftReset and step 3) of |
| switching from host to device. John Stult reported a lockup issue seen |
| with HiKey960 platform without these steps[1]. Similar issue is observed |
| with Ferry's testing platform[2]. |
| |
| So, apply the required steps along with some fixes to Yu Chen's and John |
| Stultz's version. The main fixes to their versions are the missing wait |
| for clocks synchronization before clearing GCTL.CoreSoftReset and only |
| apply DCTL.CSftRst when switching from host to device. |
| |
| [1] https://lore.kernel.org/linux-usb/20210108015115.27920-1-john.stultz@linaro.org/ |
| [2] https://lore.kernel.org/linux-usb/0ba7a6ba-e6a7-9cd4-0695-64fc927e01f1@gmail.com/ |
| |
| The Linux kernel CVE team has assigned CVE-2021-46941 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.12 with commit 41ce1456e1dbbc7355d0fcc10cf7c337c13def24 and fixed in 5.10.36 with commit fce7bbcd07d59ac30dba8ce225316b3b4c1c7b50 |
| Issue introduced in 4.12 with commit 41ce1456e1dbbc7355d0fcc10cf7c337c13def24 and fixed in 5.11.20 with commit 800f58217626c8b147aa40660e572ed8a0d56e3b |
| Issue introduced in 4.12 with commit 41ce1456e1dbbc7355d0fcc10cf7c337c13def24 and fixed in 5.12.3 with commit 1c10fd60c8595ea7ff7e29d3cf1fa88069941da3 |
| Issue introduced in 4.12 with commit 41ce1456e1dbbc7355d0fcc10cf7c337c13def24 and fixed in 5.13 with commit f88359e1588b85cf0e8209ab7d6620085f3441d9 |
| |
| 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-2021-46941 |
| 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/usb/dwc3/core.c |
| drivers/usb/dwc3/core.h |
| |
| |
| 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/fce7bbcd07d59ac30dba8ce225316b3b4c1c7b50 |
| https://git.kernel.org/stable/c/800f58217626c8b147aa40660e572ed8a0d56e3b |
| https://git.kernel.org/stable/c/1c10fd60c8595ea7ff7e29d3cf1fa88069941da3 |
| https://git.kernel.org/stable/c/f88359e1588b85cf0e8209ab7d6620085f3441d9 |
