| Message ID | 20221213121103.213631-3-xiubli@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ceph: fix the use-after-free bug for file_lock | expand |
On Tue, Dec 13, 2022 at 1:11 PM <xiubli@redhat.com> wrote: > > From: Xiubo Li <xiubli@redhat.com> > > When ceph releasing the file_lock it will try to get the inode pointer > from the fl->fl_file, which the memory could already be released by > another thread in filp_close(). Because in VFS layer the fl->fl_file > doesn't increase the file's reference counter. > > Will switch to use ceph dedicate lock info to track the inode. > > And in ceph_fl_release_lock() we should skip all the operations if > the fl->fl_u.ceph_fl.fl_inode is not set, which should come from > the request file_lock. And we will set fl->fl_u.ceph_fl.fl_inode when > inserting it to the inode lock list, which is when copying the lock. > > Cc: stable@vger.kernel.org > Cc: Jeff Layton <jlayton@kernel.org> > URL: https://tracker.ceph.com/issues/57986 > Signed-off-by: Xiubo Li <xiubli@redhat.com> > --- > fs/ceph/locks.c | 20 ++++++++++++++++++-- > include/linux/fs.h | 3 +++ > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c > index b191426bf880..cf78608a3f9a 100644 > --- a/fs/ceph/locks.c > +++ b/fs/ceph/locks.c > @@ -34,18 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) > { > struct inode *inode = file_inode(dst->fl_file); > atomic_inc(&ceph_inode(inode)->i_filelock_ref); > + dst->fl_u.ceph.fl_inode = igrab(inode); > } > > +/* > + * Do not use the 'fl->fl_file' in release function, which > + * is possibly already released by another thread. > + */ > static void ceph_fl_release_lock(struct file_lock *fl) > { > - struct inode *inode = file_inode(fl->fl_file); > - struct ceph_inode_info *ci = ceph_inode(inode); > + struct inode *inode = fl->fl_u.ceph.fl_inode; > + struct ceph_inode_info *ci; > + > + /* > + * If inode is NULL it should be a request file_lock, > + * nothing we can do. > + */ > + if (!inode) > + return; > + > + ci = ceph_inode(inode); > if (atomic_dec_and_test(&ci->i_filelock_ref)) { > /* clear error when all locks are released */ > spin_lock(&ci->i_ceph_lock); > ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK; > spin_unlock(&ci->i_ceph_lock); > } > + fl->fl_u.ceph.fl_inode = NULL; > + iput(inode); > } > > static const struct file_lock_operations ceph_fl_lock_ops = { > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 7b52fdfb6da0..6106374f5257 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1119,6 +1119,9 @@ struct file_lock { > int state; /* state of grant or error if -ve */ > unsigned int debug_id; > } afs; > + struct { > + struct inode *fl_inode; Hi Xiubo, Nit: I think it could be just "inode", without the prefix which is already present in the union field name. Thanks, Ilya
On 14/12/2022 02:05, Ilya Dryomov wrote: > On Tue, Dec 13, 2022 at 1:11 PM <xiubli@redhat.com> wrote: >> From: Xiubo Li <xiubli@redhat.com> >> >> When ceph releasing the file_lock it will try to get the inode pointer >> from the fl->fl_file, which the memory could already be released by >> another thread in filp_close(). Because in VFS layer the fl->fl_file >> doesn't increase the file's reference counter. >> >> Will switch to use ceph dedicate lock info to track the inode. >> >> And in ceph_fl_release_lock() we should skip all the operations if >> the fl->fl_u.ceph_fl.fl_inode is not set, which should come from >> the request file_lock. And we will set fl->fl_u.ceph_fl.fl_inode when >> inserting it to the inode lock list, which is when copying the lock. >> >> Cc: stable@vger.kernel.org >> Cc: Jeff Layton <jlayton@kernel.org> >> URL: https://tracker.ceph.com/issues/57986 >> Signed-off-by: Xiubo Li <xiubli@redhat.com> >> --- >> fs/ceph/locks.c | 20 ++++++++++++++++++-- >> include/linux/fs.h | 3 +++ >> 2 files changed, 21 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c >> index b191426bf880..cf78608a3f9a 100644 >> --- a/fs/ceph/locks.c >> +++ b/fs/ceph/locks.c >> @@ -34,18 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) >> { >> struct inode *inode = file_inode(dst->fl_file); >> atomic_inc(&ceph_inode(inode)->i_filelock_ref); >> + dst->fl_u.ceph.fl_inode = igrab(inode); >> } >> >> +/* >> + * Do not use the 'fl->fl_file' in release function, which >> + * is possibly already released by another thread. >> + */ >> static void ceph_fl_release_lock(struct file_lock *fl) >> { >> - struct inode *inode = file_inode(fl->fl_file); >> - struct ceph_inode_info *ci = ceph_inode(inode); >> + struct inode *inode = fl->fl_u.ceph.fl_inode; >> + struct ceph_inode_info *ci; >> + >> + /* >> + * If inode is NULL it should be a request file_lock, >> + * nothing we can do. >> + */ >> + if (!inode) >> + return; >> + >> + ci = ceph_inode(inode); >> if (atomic_dec_and_test(&ci->i_filelock_ref)) { >> /* clear error when all locks are released */ >> spin_lock(&ci->i_ceph_lock); >> ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK; >> spin_unlock(&ci->i_ceph_lock); >> } >> + fl->fl_u.ceph.fl_inode = NULL; >> + iput(inode); >> } >> >> static const struct file_lock_operations ceph_fl_lock_ops = { >> diff --git a/include/linux/fs.h b/include/linux/fs.h >> index 7b52fdfb6da0..6106374f5257 100644 >> --- a/include/linux/fs.h >> +++ b/include/linux/fs.h >> @@ -1119,6 +1119,9 @@ struct file_lock { >> int state; /* state of grant or error if -ve */ >> unsigned int debug_id; >> } afs; >> + struct { >> + struct inode *fl_inode; > Hi Xiubo, > > Nit: I think it could be just "inode", without the prefix which is > already present in the union field name. Okay, I can fix this in the next version. Thanks. - Xiubo > Thanks, > > Ilya >
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c index b191426bf880..cf78608a3f9a 100644 --- a/fs/ceph/locks.c +++ b/fs/ceph/locks.c @@ -34,18 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) { struct inode *inode = file_inode(dst->fl_file); atomic_inc(&ceph_inode(inode)->i_filelock_ref); + dst->fl_u.ceph.fl_inode = igrab(inode); } +/* + * Do not use the 'fl->fl_file' in release function, which + * is possibly already released by another thread. + */ static void ceph_fl_release_lock(struct file_lock *fl) { - struct inode *inode = file_inode(fl->fl_file); - struct ceph_inode_info *ci = ceph_inode(inode); + struct inode *inode = fl->fl_u.ceph.fl_inode; + struct ceph_inode_info *ci; + + /* + * If inode is NULL it should be a request file_lock, + * nothing we can do. + */ + if (!inode) + return; + + ci = ceph_inode(inode); if (atomic_dec_and_test(&ci->i_filelock_ref)) { /* clear error when all locks are released */ spin_lock(&ci->i_ceph_lock); ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK; spin_unlock(&ci->i_ceph_lock); } + fl->fl_u.ceph.fl_inode = NULL; + iput(inode); } static const struct file_lock_operations ceph_fl_lock_ops = { diff --git a/include/linux/fs.h b/include/linux/fs.h index 7b52fdfb6da0..6106374f5257 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1119,6 +1119,9 @@ struct file_lock { int state; /* state of grant or error if -ve */ unsigned int debug_id; } afs; + struct { + struct inode *fl_inode; + } ceph; } fl_u; } __randomize_layout;