Messages in this thread Patch in this message | | | From | Tuo Li <> | Subject | [PATCH v2] ceph: fix possible null-pointer dereference in ceph_mdsmap_decode() | Date | Thu, 5 Aug 2021 08:14:34 -0700 |
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kcalloc() is called to allocate memory for m->m_info, and if it fails, ceph_mdsmap_destroy() behind the label out_err will be called: ceph_mdsmap_destroy(m);
In ceph_mdsmap_destroy(), m->m_info is dereferenced through: kfree(m->m_info[i].export_targets);
To fix this possible null-pointer dereference, check m->m_info before the for loop to free m->m_info[i].export_targets.
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Signed-off-by: Tuo Li <islituo@gmail.com> --- v2: * Put an "if (m->m_info)" around the for loop in ceph_mdsmap_destroy() instead of freeing m and returning -ENOMEM in ceph_mdsmap_decode(). Thank Jeff Layton for helpful advice. --- fs/ceph/mdsmap.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c index abd9af7727ad..26d6fa049b44 100644 --- a/fs/ceph/mdsmap.c +++ b/fs/ceph/mdsmap.c @@ -393,9 +393,11 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end, bool msgr2) void ceph_mdsmap_destroy(struct ceph_mdsmap *m) { int i; - - for (i = 0; i < m->possible_max_rank; i++) - kfree(m->m_info[i].export_targets); + + if (m->m_info) { + for (i = 0; i < m->possible_max_rank; i++) + kfree(m->m_info[i].export_targets); + } kfree(m->m_info); kfree(m->m_data_pg_pools); kfree(m); -- 2.25.1
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