| 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-2021-47241: ethtool: strset: fix message length calculation |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ethtool: strset: fix message length calculation |
| |
| Outer nest for ETHTOOL_A_STRSET_STRINGSETS is not accounted for. |
| This may result in ETHTOOL_MSG_STRSET_GET producing a warning like: |
| |
| calculated message payload length (684) not sufficient |
| WARNING: CPU: 0 PID: 30967 at net/ethtool/netlink.c:369 ethnl_default_doit+0x87a/0xa20 |
| |
| and a splat. |
| |
| As usually with such warnings three conditions must be met for the warning |
| to trigger: |
| - there must be no skb size rounding up (e.g. reply_size of 684); |
| - string set must be per-device (so that the header gets populated); |
| - the device name must be at least 12 characters long. |
| |
| all in all with current user space it looks like reading priv flags |
| is the only place this could potentially happen. Or with syzbot :) |
| |
| The Linux kernel CVE team has assigned CVE-2021-47241 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.6 with commit 71921690f9745fef60a2bad425f30adf8cdc9da0 and fixed in 5.10.46 with commit fb3a948143688e14e2cfd2a2812877923d0e5e92 |
| Issue introduced in 5.6 with commit 71921690f9745fef60a2bad425f30adf8cdc9da0 and fixed in 5.12.13 with commit cfc7f0e70d649e6d2233fba0d9390b525677d971 |
| Issue introduced in 5.6 with commit 71921690f9745fef60a2bad425f30adf8cdc9da0 and fixed in 5.13 with commit e175aef902697826d344ce3a12189329848fe898 |
| |
| 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-2021-47241 |
| 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/ethtool/strset.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/fb3a948143688e14e2cfd2a2812877923d0e5e92 |
| https://git.kernel.org/stable/c/cfc7f0e70d649e6d2233fba0d9390b525677d971 |
| https://git.kernel.org/stable/c/e175aef902697826d344ce3a12189329848fe898 |
