Message ID | 20221114051901.15371-2-xiubli@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | ceph: fix the use-after-free bug for file_lock | expand |
On Mon, 2022-11-14 at 13:19 +0800, 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 > URL: https://tracker.ceph.com/issues/57986 > Signed-off-by: Xiubo Li <xiubli@redhat.com> > --- > fs/ceph/locks.c | 18 +++++++++++++++--- > include/linux/ceph/ceph_fs_fl.h | 26 ++++++++++++++++++++++++++ > include/linux/fs.h | 2 ++ > 3 files changed, 43 insertions(+), 3 deletions(-) > create mode 100644 include/linux/ceph/ceph_fs_fl.h > > diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c > index 3e2843e86e27..d8385dd0076e 100644 > --- a/fs/ceph/locks.c > +++ b/fs/ceph/locks.c > @@ -34,22 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) > { > struct ceph_file_info *fi = dst->fl_file->private_data; > struct inode *inode = file_inode(dst->fl_file); > + > atomic_inc(&ceph_inode(inode)->i_filelock_ref); > atomic_inc(&fi->num_locks); > + dst->fl_u.ceph_fl.fl_inode = igrab(inode); > } > > static void ceph_fl_release_lock(struct file_lock *fl) > { > struct ceph_file_info *fi = fl->fl_file->private_data; > - struct inode *inode = file_inode(fl->fl_file); > - struct ceph_inode_info *ci = ceph_inode(inode); > - atomic_dec(&fi->num_locks); > + struct inode *inode = fl->fl_u.ceph_fl.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); > } > + iput(inode); > + atomic_dec(&fi->num_locks); It doesn't look like this fixes the original issue. "fi" may be pointing to freed memory at this point, right? I think you may need to get rid of the "num_locks" field in ceph_file_info, and do that in a different way? > } > > static const struct file_lock_operations ceph_fl_lock_ops = { > diff --git a/include/linux/ceph/ceph_fs_fl.h b/include/linux/ceph/ceph_fs_fl.h > new file mode 100644 > index 000000000000..02a412b26095 > --- /dev/null > +++ b/include/linux/ceph/ceph_fs_fl.h > @@ -0,0 +1,26 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * ceph_fs.h - Ceph constants and data types to share between kernel and > + * user space. > + * > + * Most types in this file are defined as little-endian, and are > + * primarily intended to describe data structures that pass over the > + * wire or that are stored on disk. > + * > + * LGPL2 > + */ > + > +#ifndef CEPH_FS_FL_H > +#define CEPH_FS_FL_H > + > +#include <linux/fs.h> > + > +/* > + * Ceph lock info > + */ > + > +struct ceph_lock_info { > + struct inode *fl_inode; > +}; > + > +#endif > diff --git a/include/linux/fs.h b/include/linux/fs.h > index e654435f1651..db4810d19e26 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1066,6 +1066,7 @@ bool opens_in_grace(struct net *); > > /* that will die - we need it for nfs_lock_info */ > #include <linux/nfs_fs_i.h> > +#include <linux/ceph/ceph_fs_fl.h> > > /* > * struct file_lock represents a generic "file lock". It's used to represent > @@ -1119,6 +1120,7 @@ struct file_lock { > int state; /* state of grant or error if -ve */ > unsigned int debug_id; > } afs; > + struct ceph_lock_info ceph_fl; > } fl_u; > } __randomize_layout; >
On 14/11/2022 19:24, Jeff Layton wrote: > On Mon, 2022-11-14 at 13:19 +0800, 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 >> URL: https://tracker.ceph.com/issues/57986 >> Signed-off-by: Xiubo Li <xiubli@redhat.com> >> --- >> fs/ceph/locks.c | 18 +++++++++++++++--- >> include/linux/ceph/ceph_fs_fl.h | 26 ++++++++++++++++++++++++++ >> include/linux/fs.h | 2 ++ >> 3 files changed, 43 insertions(+), 3 deletions(-) >> create mode 100644 include/linux/ceph/ceph_fs_fl.h >> >> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c >> index 3e2843e86e27..d8385dd0076e 100644 >> --- a/fs/ceph/locks.c >> +++ b/fs/ceph/locks.c >> @@ -34,22 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) >> { >> struct ceph_file_info *fi = dst->fl_file->private_data; >> struct inode *inode = file_inode(dst->fl_file); >> + >> atomic_inc(&ceph_inode(inode)->i_filelock_ref); >> atomic_inc(&fi->num_locks); >> + dst->fl_u.ceph_fl.fl_inode = igrab(inode); >> } >> >> static void ceph_fl_release_lock(struct file_lock *fl) >> { >> struct ceph_file_info *fi = fl->fl_file->private_data; >> - struct inode *inode = file_inode(fl->fl_file); >> - struct ceph_inode_info *ci = ceph_inode(inode); >> - atomic_dec(&fi->num_locks); >> + struct inode *inode = fl->fl_u.ceph_fl.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); >> } >> + iput(inode); >> + atomic_dec(&fi->num_locks); > It doesn't look like this fixes the original issue. "fi" may be pointing > to freed memory at this point, right? Yeah, I didn't fix this in the this patch. I fixed it in a dedicated 2/2 patch. > I think you may need to get rid of > the "num_locks" field in ceph_file_info, and do that in a different way? > This is a dedicated field for each 'file' struct. I have no idea how to fix this in a different way yet. Thanks! - Xiubo >> } >> >> static const struct file_lock_operations ceph_fl_lock_ops = { >> diff --git a/include/linux/ceph/ceph_fs_fl.h b/include/linux/ceph/ceph_fs_fl.h >> new file mode 100644 >> index 000000000000..02a412b26095 >> --- /dev/null >> +++ b/include/linux/ceph/ceph_fs_fl.h >> @@ -0,0 +1,26 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * ceph_fs.h - Ceph constants and data types to share between kernel and >> + * user space. >> + * >> + * Most types in this file are defined as little-endian, and are >> + * primarily intended to describe data structures that pass over the >> + * wire or that are stored on disk. >> + * >> + * LGPL2 >> + */ >> + >> +#ifndef CEPH_FS_FL_H >> +#define CEPH_FS_FL_H >> + >> +#include <linux/fs.h> >> + >> +/* >> + * Ceph lock info >> + */ >> + >> +struct ceph_lock_info { >> + struct inode *fl_inode; >> +}; >> + >> +#endif >> diff --git a/include/linux/fs.h b/include/linux/fs.h >> index e654435f1651..db4810d19e26 100644 >> --- a/include/linux/fs.h >> +++ b/include/linux/fs.h >> @@ -1066,6 +1066,7 @@ bool opens_in_grace(struct net *); >> >> /* that will die - we need it for nfs_lock_info */ >> #include <linux/nfs_fs_i.h> >> +#include <linux/ceph/ceph_fs_fl.h> >> >> /* >> * struct file_lock represents a generic "file lock". It's used to represent >> @@ -1119,6 +1120,7 @@ struct file_lock { >> int state; /* state of grant or error if -ve */ >> unsigned int debug_id; >> } afs; >> + struct ceph_lock_info ceph_fl; >> } fl_u; >> } __randomize_layout; >>
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c index 3e2843e86e27..d8385dd0076e 100644 --- a/fs/ceph/locks.c +++ b/fs/ceph/locks.c @@ -34,22 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) { struct ceph_file_info *fi = dst->fl_file->private_data; struct inode *inode = file_inode(dst->fl_file); + atomic_inc(&ceph_inode(inode)->i_filelock_ref); atomic_inc(&fi->num_locks); + dst->fl_u.ceph_fl.fl_inode = igrab(inode); } static void ceph_fl_release_lock(struct file_lock *fl) { struct ceph_file_info *fi = fl->fl_file->private_data; - struct inode *inode = file_inode(fl->fl_file); - struct ceph_inode_info *ci = ceph_inode(inode); - atomic_dec(&fi->num_locks); + struct inode *inode = fl->fl_u.ceph_fl.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); } + iput(inode); + atomic_dec(&fi->num_locks); } static const struct file_lock_operations ceph_fl_lock_ops = { diff --git a/include/linux/ceph/ceph_fs_fl.h b/include/linux/ceph/ceph_fs_fl.h new file mode 100644 index 000000000000..02a412b26095 --- /dev/null +++ b/include/linux/ceph/ceph_fs_fl.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * ceph_fs.h - Ceph constants and data types to share between kernel and + * user space. + * + * Most types in this file are defined as little-endian, and are + * primarily intended to describe data structures that pass over the + * wire or that are stored on disk. + * + * LGPL2 + */ + +#ifndef CEPH_FS_FL_H +#define CEPH_FS_FL_H + +#include <linux/fs.h> + +/* + * Ceph lock info + */ + +struct ceph_lock_info { + struct inode *fl_inode; +}; + +#endif diff --git a/include/linux/fs.h b/include/linux/fs.h index e654435f1651..db4810d19e26 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1066,6 +1066,7 @@ bool opens_in_grace(struct net *); /* that will die - we need it for nfs_lock_info */ #include <linux/nfs_fs_i.h> +#include <linux/ceph/ceph_fs_fl.h> /* * struct file_lock represents a generic "file lock". It's used to represent @@ -1119,6 +1120,7 @@ struct file_lock { int state; /* state of grant or error if -ve */ unsigned int debug_id; } afs; + struct ceph_lock_info ceph_fl; } fl_u; } __randomize_layout;