In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix buffer head management in ocfs2_read_blocks()
In ocfs2_read_blocks(), caller should’t assume that buffer head returned
by ‘sb_getblk()’ is exclusively owned and so ‘put_bh()’ always drops
b_count from 1 to 0. If it is not so, buffer head remains on hold and
likely to be returned by the next call to ‘sb_getblk()’ unchanged – that
is, with BH_Uptodate bit set even if it has failed validation previously,
thus allowing to insert that buffer head into OCFS2 metadata cache and
submit it to upper layers. To avoid such a scenario, BH_Uptodate should
be cleared immediately after ‘validate()’ callback has detected some data
inconsistency.
