| 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-2024-57843: virtio-net: fix overflow inside virtnet_rq_alloc |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| virtio-net: fix overflow inside virtnet_rq_alloc |
| |
| When the frag just got a page, then may lead to regression on VM. |
| Specially if the sysctl net.core.high_order_alloc_disable value is 1, |
| then the frag always get a page when do refill. |
| |
| Which could see reliable crashes or scp failure (scp a file 100M in size |
| to VM). |
| |
| The issue is that the virtnet_rq_dma takes up 16 bytes at the beginning |
| of a new frag. When the frag size is larger than PAGE_SIZE, |
| everything is fine. However, if the frag is only one page and the |
| total size of the buffer and virtnet_rq_dma is larger than one page, an |
| overflow may occur. |
| |
| The commit f9dac92ba908 ("virtio_ring: enable premapped mode whatever |
| use_dma_api") introduced this problem. And we reverted some commits to |
| fix this in last linux version. Now we try to enable it and fix this |
| bug directly. |
| |
| Here, when the frag size is not enough, we reduce the buffer len to fix |
| this problem. |
| |
| The Linux kernel CVE team has assigned CVE-2024-57843 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.6.66 with commit a8f7d6963768b114ec9644ff0148dde4c104e84b |
| Fixed in 6.12.5 with commit 67a11de8965c2ab19e215fb6651d44847e068614 |
| Fixed in 6.13 with commit 6aacd1484468361d1d04badfe75f264fa5314864 |
| |
| 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-2024-57843 |
| 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/net/virtio_net.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/a8f7d6963768b114ec9644ff0148dde4c104e84b |
| https://git.kernel.org/stable/c/67a11de8965c2ab19e215fb6651d44847e068614 |
| https://git.kernel.org/stable/c/6aacd1484468361d1d04badfe75f264fa5314864 |
