CVE-2024-26689

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 was caught by KASAN at this line - 'ceph_buffer_get(arg->xattr_buf);'. This implies before the refcount could be increment here, it was freed. In same file, in "handle_cap_grant()" refcount is decremented by this line - 'ceph_buffer_put(ci->i_xattrs.blob);'. It appears that a race occurred and resource was freed by the latter line before the former line could increment it. encode_cap_msg() is called by __send_cap() and __send_cap() is called by ceph_check_caps() after calling __prep_cap(). __prep_cap() is where arg->xattr_buf is assigned to ci->i_xattrs.blob. This is the spot where the refcount must be increased to prevent "use after free" error.

• linux linux kernel (< 5.10.210) • linux linux kernel (>= 5.11 < 5.15.149) • linux linux kernel (>= 5.16 < 6.1.79) • linux linux kernel (>= 6.2 < 6.6.18) • linux linux kernel (>= 6.7 < 6.7.6) • linux linux kernel 6.8 • debian debian linux 10.0