CVE-2026-23189

Description

In the Linux kernel, the following vulnerability has been resolved:ceph: fix null pointer dereference in ceph_mds_auth_match()The CephFS kernel client has regression starting from 6.18-rc1.We have issue in ceph_mds_auth_match() if fs_name == null: const char fs_name = mdsc->fsc->mount_options->mds_namespace; ... if (auth->match.fs_name && strcmp(auth->match.fs_name, fs_name)) { / fsname mismatch, try next one */ return 0; }Patrick Donnelly suggested that: In summary, we should definitely startdecoding fs_name from the MDSMap and do strict authorizations checksagainst it. Note that the -o mds_namespace=foo should only be used forselecting the file system to mount and nothing else. Its possibleno mds_namespace is specified but the kernel will mount the onlyfile system that exists which may have name foo.This patch reworks ceph_mdsmap_decode() and namespace_equals() withthe goal of supporting the suggested concept. Now struct ceph_mdsmapcontains m_fs_name field that receives copy of extracted FS nameby ceph_extract_encoded_string(). For the case of old CephFS filesystems, it is used cephfs name.[ idryomov: replace redundant %*pE with %s in ceph_mdsmap_decode(), get rid of a series of strlen() calls in ceph_namespace_match(), drop changes to namespace_equals() body to avoid treating empty mds_namespace as equal, drop changes to ceph_mdsc_handle_fsmap() as namespace_equals() isnt an equivalent substitution there ]

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234