1.4 KiB
CVE-2024-26689
Description
In the Linux kernel, the following vulnerability has been resolved:ceph: prevent use-after-free in encode_cap_msg()In fs/ceph/caps.c, in encode_cap_msg(), "use after free" error wascaught by KASAN at this line - 'ceph_buffer_get(arg->xattr_buf);'. Thisimplies before the refcount could be increment here, it was freed.In same file, in "handle_cap_grant()" refcount is decremented by thisline - 'ceph_buffer_put(ci->i_xattrs.blob);'. It appears that a raceoccurred and resource was freed by the latter line before the formerline could increment it.encode_cap_msg() is called by __send_cap() and __send_cap() is called byceph_check_caps() after calling __prep_cap(). __prep_cap() is wherearg->xattr_buf is assigned to ci->i_xattrs.blob. This is the spot wherethe refcount must be increased to prevent "use after free" error.
POC
Reference
No PoCs from references.