| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-37882: usb: xhci: Fix isochronous Ring Underrun/Overrun event handling |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| usb: xhci: Fix isochronous Ring Underrun/Overrun event handling |
| |
| The TRB pointer of these events points at enqueue at the time of error |
| occurrence on xHCI 1.1+ HCs or it's NULL on older ones. By the time we |
| are handling the event, a new TD may be queued at this ring position. |
| |
| I can trigger this race by rising interrupt moderation to increase IRQ |
| handling delay. Similar delay may occur naturally due to system load. |
| |
| If this ever happens after a Missed Service Error, missed TDs will be |
| skipped and the new TD processed as if it matched the event. It could |
| be given back prematurely, risking data loss or buffer UAF by the xHC. |
| |
| Don't complete TDs on xrun events and don't warn if queued TDs don't |
| match the event's TRB pointer, which can be NULL or a link/no-op TRB. |
| Don't warn if there are no queued TDs at all. |
| |
| Now that it's safe, also handle xrun events if the skip flag is clear. |
| This ensures completion of any TD stuck in 'error mid TD' state right |
| before the xrun event, which could happen if a driver submits a finite |
| number of URBs to a buggy HC and then an error occurs on the last TD. |
| |
| The Linux kernel CVE team has assigned CVE-2025-37882 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.12.26 with commit 16a7a8e6c47fea5c847beb696c8c21a7a44c1915 |
| Fixed in 6.14.5 with commit 39a080a2925c81b0f1da0add44722ef2b78e5454 |
| Fixed in 6.15 with commit 906dec15b9b321b546fd31a3c99ffc13724c7af4 |
| |
| 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-2025-37882 |
| 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/16a7a8e6c47fea5c847beb696c8c21a7a44c1915 |
| https://git.kernel.org/stable/c/39a080a2925c81b0f1da0add44722ef2b78e5454 |
| https://git.kernel.org/stable/c/906dec15b9b321b546fd31a3c99ffc13724c7af4 |
