| 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-2021-47316: nfsd: fix NULL dereference in nfs3svc_encode_getaclres |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| nfsd: fix NULL dereference in nfs3svc_encode_getaclres |
| |
| In error cases the dentry may be NULL. |
| |
| Before 20798dfe249a, the encoder also checked dentry and |
| d_really_is_positive(dentry), but that looks like overkill to me--zero |
| status should be enough to guarantee a positive dentry. |
| |
| This isn't the first time we've seen an error-case NULL dereference |
| hidden in the initialization of a local variable in an xdr encoder. But |
| I went back through the other recent rewrites and didn't spot any |
| similar bugs. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47316 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.13 with commit 20798dfe249a01ad1b12eec7dbc572db5003244a and fixed in 5.13.4 with commit 650e6f383a6eb40f7c0a010982a74ab4b6893870 |
| Issue introduced in 5.13 with commit 20798dfe249a01ad1b12eec7dbc572db5003244a and fixed in 5.14 with commit ab1016d39cc052064e32f25ad18ef8767a0ee3b8 |
| |
| 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-2021-47316 |
| 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: |
| fs/nfsd/nfs3acl.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/e79057d15d96ef19de4de6d7e479bae3d58a2a8d |
| https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 |
| https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 |
