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.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
Debian | 12 | all | linux | < 6.1.82-1 | linux_6.1.82-1_all.deb |
Debian | 11 | all | linux | < 5.10.216-1 | linux_5.10.216-1_all.deb |
Debian | 999 | all | linux | < 6.7.7-1 | linux_6.7.7-1_all.deb |
Debian | 13 | all | linux | < 6.7.7-1 | linux_6.7.7-1_all.deb |