| 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-2021-46968: s390/zcrypt: fix zcard and zqueue hot-unplug memleak |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| s390/zcrypt: fix zcard and zqueue hot-unplug memleak |
| |
| Tests with kvm and a kmemdebug kernel showed, that on hot unplug the |
| zcard and zqueue structs for the unplugged card or queue are not |
| properly freed because of a mismatch with get/put for the embedded |
| kref counter. |
| |
| This fix now adjusts the handling of the kref counters. With init the |
| kref counter starts with 1. This initial value needs to drop to zero |
| with the unregister of the card or queue to trigger the release and |
| free the object. |
| |
| The Linux kernel CVE team has assigned CVE-2021-46968 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.10 with commit 29c2680fd2bf3862ff5cf2957f198512493156f9 and fixed in 5.10.36 with commit 026499a9c2e002e621ad568d1378324ae97e5524 |
| Issue introduced in 5.10 with commit 29c2680fd2bf3862ff5cf2957f198512493156f9 and fixed in 5.11.20 with commit 055a063a18bcd19b93709e3eac8078d6b2f04599 |
| Issue introduced in 5.10 with commit 29c2680fd2bf3862ff5cf2957f198512493156f9 and fixed in 5.12.3 with commit 971dc8706cee47393d393905d294ea47e39503d3 |
| Issue introduced in 5.10 with commit 29c2680fd2bf3862ff5cf2957f198512493156f9 and fixed in 5.13 with commit 70fac8088cfad9f3b379c9082832b4d7532c16c2 |
| |
| 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-2021-46968 |
| 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/s390/crypto/zcrypt_card.c |
| drivers/s390/crypto/zcrypt_queue.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/026499a9c2e002e621ad568d1378324ae97e5524 |
| https://git.kernel.org/stable/c/055a063a18bcd19b93709e3eac8078d6b2f04599 |
| https://git.kernel.org/stable/c/971dc8706cee47393d393905d294ea47e39503d3 |
| https://git.kernel.org/stable/c/70fac8088cfad9f3b379c9082832b4d7532c16c2 |
