| 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-2021-47026: RDMA/rtrs-clt: destroy sysfs after removing session from active list |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| RDMA/rtrs-clt: destroy sysfs after removing session from active list |
| |
| A session can be removed dynamically by sysfs interface "remove_path" that |
| eventually calls rtrs_clt_remove_path_from_sysfs function. The current |
| rtrs_clt_remove_path_from_sysfs first removes the sysfs interfaces and |
| frees sess->stats object. Second it removes the session from the active |
| list. |
| |
| Therefore some functions could access non-connected session and access the |
| freed sess->stats object even-if they check the session status before |
| accessing the session. |
| |
| For instance rtrs_clt_request and get_next_path_min_inflight check the |
| session status and try to send IO to the session. The session status |
| could be changed when they are trying to send IO but they could not catch |
| the change and update the statistics information in sess->stats object, |
| and generate use-after-free problem. |
| (see: "RDMA/rtrs-clt: Check state of the rtrs_clt_sess before reading its |
| stats") |
| |
| This patch changes the rtrs_clt_remove_path_from_sysfs to remove the |
| session from the active session list and then destroy the sysfs |
| interfaces. |
| |
| Each function still should check the session status because closing or |
| error recovery paths can change the status. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47026 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.8 with commit 6a98d71daea186247005099758af549e6afdd244 and fixed in 5.10.37 with commit b64415c6b3476cf9fa4d0aea3807065b8403a937 |
| Issue introduced in 5.8 with commit 6a98d71daea186247005099758af549e6afdd244 and fixed in 5.11.21 with commit 676171f9405dcaa45a33d18241c32f387dbaae39 |
| Issue introduced in 5.8 with commit 6a98d71daea186247005099758af549e6afdd244 and fixed in 5.12.4 with commit d3cca8067d43dfee4a3535c645b55f618708dccb |
| Issue introduced in 5.8 with commit 6a98d71daea186247005099758af549e6afdd244 and fixed in 5.13 with commit 7f4a8592ff29f19c5a2ca549d0973821319afaad |
| |
| 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-2021-47026 |
| 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/infiniband/ulp/rtrs/rtrs-clt.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/b64415c6b3476cf9fa4d0aea3807065b8403a937 |
| https://git.kernel.org/stable/c/676171f9405dcaa45a33d18241c32f387dbaae39 |
| https://git.kernel.org/stable/c/d3cca8067d43dfee4a3535c645b55f618708dccb |
| https://git.kernel.org/stable/c/7f4a8592ff29f19c5a2ca549d0973821319afaad |
