| 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-2024-46695: selinux,smack: don't bypass permissions check in inode_setsecctx hook |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| selinux,smack: don't bypass permissions check in inode_setsecctx hook |
| |
| Marek Gresko reports that the root user on an NFS client is able to |
| change the security labels on files on an NFS filesystem that is |
| exported with root squashing enabled. |
| |
| The end of the kerneldoc comment for __vfs_setxattr_noperm() states: |
| |
| * This function requires the caller to lock the inode's i_mutex before it |
| * is executed. It also assumes that the caller will make the appropriate |
| * permission checks. |
| |
| nfsd_setattr() does do permissions checking via fh_verify() and |
| nfsd_permission(), but those don't do all the same permissions checks |
| that are done by security_inode_setxattr() and its related LSM hooks do. |
| |
| Since nfsd_setattr() is the only consumer of security_inode_setsecctx(), |
| simplest solution appears to be to replace the call to |
| __vfs_setxattr_noperm() with a call to __vfs_setxattr_locked(). This |
| fixes the above issue and has the added benefit of causing nfsd to |
| recall conflicting delegations on a file when a client tries to change |
| its security label. |
| |
| The Linux kernel CVE team has assigned CVE-2024-46695 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.10.227 with commit 2dbc4b7bac60b02cc6e70d05bf6a7dfd551f9dda |
| Fixed in 5.15.168 with commit fe0cd53791119f6287b6532af8ce41576d664930 |
| Fixed in 6.1.113 with commit eebec98791d0137e455cc006411bb92a54250924 |
| Fixed in 6.6.49 with commit 459584258d47ec3cc6245a82e8a49c9d08eb8b57 |
| Fixed in 6.10.8 with commit f71ec019257ba4f7ab198bd948c5902a207bad96 |
| Fixed in 6.11 with commit 76a0e79bc84f466999fa501fce5bf7a07641b8a7 |
| |
| 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-2024-46695 |
| 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: |
| security/selinux/hooks.c |
| security/smack/smack_lsm.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/2dbc4b7bac60b02cc6e70d05bf6a7dfd551f9dda |
| https://git.kernel.org/stable/c/fe0cd53791119f6287b6532af8ce41576d664930 |
| https://git.kernel.org/stable/c/eebec98791d0137e455cc006411bb92a54250924 |
| https://git.kernel.org/stable/c/459584258d47ec3cc6245a82e8a49c9d08eb8b57 |
| https://git.kernel.org/stable/c/f71ec019257ba4f7ab198bd948c5902a207bad96 |
| https://git.kernel.org/stable/c/76a0e79bc84f466999fa501fce5bf7a07641b8a7 |
