| Message ID | 20210805151434.142619-1-islituo@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] ceph: fix possible null-pointer dereference in ceph_mdsmap_decode() | expand |
On Thu, 2021-08-05 at 08:14 -0700, Tuo Li wrote: > 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); > + This patch added some whitespace damage above. I went ahead and fixed it up before merging. > + if (m->m_info) { > + for (i = 0; i < m->possible_max_rank; i++) > + kfree(m->m_info[i].export_targets); > + } > kfree(m->m_info); I also moved the above kfree into the if statement since we have to check it anyway (no need to do it twice). > kfree(m->m_data_pg_pools); > kfree(m); Merged! Thanks for the patch.
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);
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(-)