| 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-2024-35982: batman-adv: Avoid infinite loop trying to resize local TT |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| batman-adv: Avoid infinite loop trying to resize local TT |
| |
| If the MTU of one of an attached interface becomes too small to transmit |
| the local translation table then it must be resized to fit inside all |
| fragments (when enabled) or a single packet. |
| |
| But if the MTU becomes too low to transmit even the header + the VLAN |
| specific part then the resizing of the local TT will never succeed. This |
| can for example happen when the usable space is 110 bytes and 11 VLANs are |
| on top of batman-adv. In this case, at least 116 byte would be needed. |
| There will just be an endless spam of |
| |
| batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (110) |
| |
| in the log but the function will never finish. Problem here is that the |
| timeout will be halved all the time and will then stagnate at 0 and |
| therefore never be able to reduce the table even more. |
| |
| There are other scenarios possible with a similar result. The number of |
| BATADV_TT_CLIENT_NOPURGE entries in the local TT can for example be too |
| high to fit inside a packet. Such a scenario can therefore happen also with |
| only a single VLAN + 7 non-purgable addresses - requiring at least 120 |
| bytes. |
| |
| While this should be handled proactively when: |
| |
| * interface with too low MTU is added |
| * VLAN is added |
| * non-purgeable local mac is added |
| * MTU of an attached interface is reduced |
| * fragmentation setting gets disabled (which most likely requires dropping |
| attached interfaces) |
| |
| not all of these scenarios can be prevented because batman-adv is only |
| consuming events without the the possibility to prevent these actions |
| (non-purgable MAC address added, MTU of an attached interface is reduced). |
| It is therefore necessary to also make sure that the code is able to handle |
| also the situations when there were already incompatible system |
| configuration are present. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35982 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 4.19.313 with commit 04720ea2e6c64459a90ca28570ea78335eccd924 |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 5.4.275 with commit b3ddf6904073990492454b1dd1c10a24be8c74c6 |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 5.10.216 with commit 70a8be9dc2fb65d67f8c1e0c88c587e08e2e575d |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 5.15.156 with commit 87b6af1a7683e021710c08fc0551fc078346032f |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 6.1.87 with commit 3fe79b2c83461edbbf86ed8a6f3924820ff89259 |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 6.6.28 with commit 4ca2a5fb54ea2cc43edea614207fcede562d91c2 |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 6.8.7 with commit ca54e2671548616ad34885f90d4f26f7adb088f0 |
| Issue introduced in 3.13 with commit a19d3d85e1b854e4a483a55d740a42458085560d and fixed in 6.9 with commit b1f532a3b1e6d2e5559c7ace49322922637a28aa |
| |
| 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-2024-35982 |
| 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/batman-adv/translation-table.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/04720ea2e6c64459a90ca28570ea78335eccd924 |
| https://git.kernel.org/stable/c/b3ddf6904073990492454b1dd1c10a24be8c74c6 |
| https://git.kernel.org/stable/c/70a8be9dc2fb65d67f8c1e0c88c587e08e2e575d |
| https://git.kernel.org/stable/c/87b6af1a7683e021710c08fc0551fc078346032f |
| https://git.kernel.org/stable/c/3fe79b2c83461edbbf86ed8a6f3924820ff89259 |
| https://git.kernel.org/stable/c/4ca2a5fb54ea2cc43edea614207fcede562d91c2 |
| https://git.kernel.org/stable/c/ca54e2671548616ad34885f90d4f26f7adb088f0 |
| https://git.kernel.org/stable/c/b1f532a3b1e6d2e5559c7ace49322922637a28aa |
