| 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-2025-38000: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() |
| |
| When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the |
| child qdisc's peek() operation before incrementing sch->q.qlen and |
| sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may |
| trigger an immediate dequeue and potential packet drop. In such cases, |
| qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog |
| have not yet been updated, leading to inconsistent queue accounting. This |
| can leave an empty HFSC class in the active list, causing further |
| consequences like use-after-free. |
| |
| This patch fixes the bug by moving the increment of sch->q.qlen and |
| sch->qstats.backlog before the call to the child qdisc's peek() operation. |
| This ensures that queue length and backlog are always accurate when packet |
| drops or dequeues are triggered during the peek. |
| |
| The Linux kernel CVE team has assigned CVE-2025-38000 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 5.4.294 with commit 1034e3310752e8675e313f7271b348914008719a |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 5.10.238 with commit f9f593e34d2fb67644372c8f7b033bdc622ad228 |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 5.15.185 with commit 89c301e929a0db14ebd94b4d97764ce1d6981653 |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 6.1.141 with commit f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4 |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 6.6.93 with commit 93c276942e75de0e5bc91576300d292e968f5a02 |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 6.12.31 with commit 49b21795b8e5654a7df3d910a12e1060da4c04cf |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 6.14.9 with commit 3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335 |
| Issue introduced in 4.8 with commit 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and fixed in 6.15 with commit 3f981138109f63232a5fb7165938d4c945cc1b9d |
| |
| 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-2025-38000 |
| 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: |
| net/sched/sch_hfsc.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/1034e3310752e8675e313f7271b348914008719a |
| https://git.kernel.org/stable/c/f9f593e34d2fb67644372c8f7b033bdc622ad228 |
| https://git.kernel.org/stable/c/89c301e929a0db14ebd94b4d97764ce1d6981653 |
| https://git.kernel.org/stable/c/f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4 |
| https://git.kernel.org/stable/c/93c276942e75de0e5bc91576300d292e968f5a02 |
| https://git.kernel.org/stable/c/49b21795b8e5654a7df3d910a12e1060da4c04cf |
| https://git.kernel.org/stable/c/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335 |
| https://git.kernel.org/stable/c/3f981138109f63232a5fb7165938d4c945cc1b9d |
