| 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-2021-47223: net: bridge: fix vlan tunnel dst null pointer dereference |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: bridge: fix vlan tunnel dst null pointer dereference |
| |
| This patch fixes a tunnel_dst null pointer dereference due to lockless |
| access in the tunnel egress path. When deleting a vlan tunnel the |
| tunnel_dst pointer is set to NULL without waiting a grace period (i.e. |
| while it's still usable) and packets egressing are dereferencing it |
| without checking. Use READ/WRITE_ONCE to annotate the lockless use of |
| tunnel_id, use RCU for accessing tunnel_dst and make sure it is read |
| only once and checked in the egress path. The dst is already properly RCU |
| protected so we don't need to do anything fancy than to make sure |
| tunnel_id and tunnel_dst are read only once and checked in the egress path. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47223 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.11 with commit 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd and fixed in 4.14.238 with commit ad7feefe7164892db424c45687472db803d87f79 |
| Issue introduced in 4.11 with commit 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd and fixed in 4.19.196 with commit 24a6e55f17aa123bc1fc54b7d3c410b41bc16530 |
| Issue introduced in 4.11 with commit 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd and fixed in 5.4.128 with commit a2241e62f6b4a774d8a92048fdf59c45f6c2fe5c |
| Issue introduced in 4.11 with commit 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd and fixed in 5.10.46 with commit fe0448a3fad365a747283a00a1d1ad5e8d6675b7 |
| Issue introduced in 4.11 with commit 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd and fixed in 5.12.13 with commit abb02e05cb1c0a30dd873a29f33bc092067dc35d |
| Issue introduced in 4.11 with commit 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd and fixed in 5.13 with commit 58e2071742e38f29f051b709a5cca014ba51166f |
| |
| 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-2021-47223 |
| 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/bridge/br_private.h |
| net/bridge/br_vlan_tunnel.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/ad7feefe7164892db424c45687472db803d87f79 |
| https://git.kernel.org/stable/c/24a6e55f17aa123bc1fc54b7d3c410b41bc16530 |
| https://git.kernel.org/stable/c/a2241e62f6b4a774d8a92048fdf59c45f6c2fe5c |
| https://git.kernel.org/stable/c/fe0448a3fad365a747283a00a1d1ad5e8d6675b7 |
| https://git.kernel.org/stable/c/abb02e05cb1c0a30dd873a29f33bc092067dc35d |
| https://git.kernel.org/stable/c/58e2071742e38f29f051b709a5cca014ba51166f |
