| 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-2021-47434: xhci: Fix command ring pointer corruption while aborting a command |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| xhci: Fix command ring pointer corruption while aborting a command |
| |
| The command ring pointer is located at [6:63] bits of the command |
| ring control register (CRCR). All the control bits like command stop, |
| abort are located at [0:3] bits. While aborting a command, we read the |
| CRCR and set the abort bit and write to the CRCR. The read will always |
| give command ring pointer as all zeros. So we essentially write only |
| the control bits. Since we split the 64 bit write into two 32 bit writes, |
| there is a possibility of xHC command ring stopped before the upper |
| dword (all zeros) is written. If that happens, xHC updates the upper |
| dword of its internal command ring pointer with all zeros. Next time, |
| when the command ring is restarted, we see xHC memory access failures. |
| Fix this issue by only writing to the lower dword of CRCR where all |
| control bits are located. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47434 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.14.252 with commit 22bcb65ea41072ab5d03c0c6290e04e0df6d09a0 |
| Fixed in 4.19.213 with commit 62c182b5e763e5f4062e72678e72ce3e02dd4d1b |
| Fixed in 5.4.155 with commit 01c2dcb67e71c351006dd17cbba86c26b7f61eaf |
| Fixed in 5.10.75 with commit dec944bb7079b37968cf69c8a438f91f15c4cc61 |
| Fixed in 5.14.14 with commit e54abefe703ab7c4e5983e889babd1447738ca42 |
| Fixed in 5.15 with commit ff0e50d3564f33b7f4b35cadeabd951d66cfc570 |
| |
| 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-2021-47434 |
| 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/host/xhci-ring.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/22bcb65ea41072ab5d03c0c6290e04e0df6d09a0 |
| https://git.kernel.org/stable/c/62c182b5e763e5f4062e72678e72ce3e02dd4d1b |
| https://git.kernel.org/stable/c/01c2dcb67e71c351006dd17cbba86c26b7f61eaf |
| https://git.kernel.org/stable/c/dec944bb7079b37968cf69c8a438f91f15c4cc61 |
| https://git.kernel.org/stable/c/e54abefe703ab7c4e5983e889babd1447738ca42 |
| https://git.kernel.org/stable/c/ff0e50d3564f33b7f4b35cadeabd951d66cfc570 |
