| Message ID | 20161222091538.28702-5-jack@suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Dec 22, 2016 at 4:15 AM, Jan Kara <jack@suse.cz> wrote: > There are only two calls sites of fsnotify_duplicate_mark(). Those are > in kernel/audit_tree.c and both are bogus. Vfsmount pointer is unused > for audit tree, inode pointer and group gets set in > fsnotify_add_mark_locked() later anyway, mask and free_mark are already > set in alloc_chunk(). In fact, calling fsnotify_duplicate_mark() is > actively harmful because following fsnotify_add_mark_locked() will leak > group reference by overwriting the group pointer. So just remove the two > calls to fsnotify_duplicate_mark() and the function. > > Signed-off-by: Jan Kara <jack@suse.cz> > --- > fs/notify/mark.c | 12 ------------ > include/linux/fsnotify_backend.h | 2 -- > kernel/audit_tree.c | 6 ++---- > 3 files changed, 2 insertions(+), 18 deletions(-) At first glance this looks reasonable, although you keep mentioning "fsnotify_add_mark_locked" above when untag_chunk() is calling "fsnotify_add_mark"; I just wanted to make sure you hadn't intended to take the mutex in the audit code instead of relying on the locking in fsnotify_add_mark(). > diff --git a/fs/notify/mark.c b/fs/notify/mark.c > index d3fea0bd89e2..6043306e8e21 100644 > --- a/fs/notify/mark.c > +++ b/fs/notify/mark.c > @@ -510,18 +510,6 @@ void fsnotify_detach_group_marks(struct fsnotify_group *group) > } > } > > -void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) > -{ > - assert_spin_locked(&old->lock); > - new->inode = old->inode; > - new->mnt = old->mnt; > - if (old->group) > - fsnotify_get_group(old->group); > - new->group = old->group; > - new->mask = old->mask; > - new->free_mark = old->free_mark; > -} > - > /* > * Nothing fancy, just initialize lists and locks and counters. > */ > diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h > index 0cf34d6cc253..487246546ebe 100644 > --- a/include/linux/fsnotify_backend.h > +++ b/include/linux/fsnotify_backend.h > @@ -323,8 +323,6 @@ extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(str > extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode); > /* find (and take a reference) to a mark associated with group and vfsmount */ > extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt); > -/* copy the values from old into new */ > -extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old); > /* set the ignored_mask of a mark */ > extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask); > /* set the mask of a mark (might pin the object into memory */ > diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c > index 8b1dde96a0fa..f3130eb0a4bd 100644 > --- a/kernel/audit_tree.c > +++ b/kernel/audit_tree.c > @@ -258,8 +258,7 @@ static void untag_chunk(struct node *p) > if (!new) > goto Fallback; > > - fsnotify_duplicate_mark(&new->mark, entry); > - if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, NULL, 1)) { > + if (fsnotify_add_mark(&new->mark, entry->group, entry->inode, NULL, 1)) { > fsnotify_put_mark(&new->mark); > goto Fallback; > } > @@ -395,8 +394,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) > return -ENOENT; > } > > - fsnotify_duplicate_mark(chunk_entry, old_entry); > - if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, NULL, 1)) { > + if (fsnotify_add_mark(chunk_entry, old_entry->group, old_entry->inode, NULL, 1)) { > spin_unlock(&old_entry->lock); > fsnotify_put_mark(chunk_entry); > fsnotify_put_mark(old_entry); > -- > 2.10.2 >
On Thu 22-12-16 18:13:11, Paul Moore wrote: > On Thu, Dec 22, 2016 at 4:15 AM, Jan Kara <jack@suse.cz> wrote: > > There are only two calls sites of fsnotify_duplicate_mark(). Those are > > in kernel/audit_tree.c and both are bogus. Vfsmount pointer is unused > > for audit tree, inode pointer and group gets set in > > fsnotify_add_mark_locked() later anyway, mask and free_mark are already > > set in alloc_chunk(). In fact, calling fsnotify_duplicate_mark() is > > actively harmful because following fsnotify_add_mark_locked() will leak > > group reference by overwriting the group pointer. So just remove the two > > calls to fsnotify_duplicate_mark() and the function. > > > > Signed-off-by: Jan Kara <jack@suse.cz> > > --- > > fs/notify/mark.c | 12 ------------ > > include/linux/fsnotify_backend.h | 2 -- > > kernel/audit_tree.c | 6 ++---- > > 3 files changed, 2 insertions(+), 18 deletions(-) > > At first glance this looks reasonable, although you keep mentioning > "fsnotify_add_mark_locked" above when untag_chunk() is calling > "fsnotify_add_mark"; I just wanted to make sure you hadn't intended to > take the mutex in the audit code instead of relying on the locking in > fsnotify_add_mark(). No, I didn't want to take mutex in the audit code. It is just that fsnotify_add_mark() is a thin wrapper around fsnotify_add_mark_locked() so I was speaking about that function. Honza > > > diff --git a/fs/notify/mark.c b/fs/notify/mark.c > > index d3fea0bd89e2..6043306e8e21 100644 > > --- a/fs/notify/mark.c > > +++ b/fs/notify/mark.c > > @@ -510,18 +510,6 @@ void fsnotify_detach_group_marks(struct fsnotify_group *group) > > } > > } > > > > -void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) > > -{ > > - assert_spin_locked(&old->lock); > > - new->inode = old->inode; > > - new->mnt = old->mnt; > > - if (old->group) > > - fsnotify_get_group(old->group); > > - new->group = old->group; > > - new->mask = old->mask; > > - new->free_mark = old->free_mark; > > -} > > - > > /* > > * Nothing fancy, just initialize lists and locks and counters. > > */ > > diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h > > index 0cf34d6cc253..487246546ebe 100644 > > --- a/include/linux/fsnotify_backend.h > > +++ b/include/linux/fsnotify_backend.h > > @@ -323,8 +323,6 @@ extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(str > > extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode); > > /* find (and take a reference) to a mark associated with group and vfsmount */ > > extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt); > > -/* copy the values from old into new */ > > -extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old); > > /* set the ignored_mask of a mark */ > > extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask); > > /* set the mask of a mark (might pin the object into memory */ > > diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c > > index 8b1dde96a0fa..f3130eb0a4bd 100644 > > --- a/kernel/audit_tree.c > > +++ b/kernel/audit_tree.c > > @@ -258,8 +258,7 @@ static void untag_chunk(struct node *p) > > if (!new) > > goto Fallback; > > > > - fsnotify_duplicate_mark(&new->mark, entry); > > - if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, NULL, 1)) { > > + if (fsnotify_add_mark(&new->mark, entry->group, entry->inode, NULL, 1)) { > > fsnotify_put_mark(&new->mark); > > goto Fallback; > > } > > @@ -395,8 +394,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) > > return -ENOENT; > > } > > > > - fsnotify_duplicate_mark(chunk_entry, old_entry); > > - if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, NULL, 1)) { > > + if (fsnotify_add_mark(chunk_entry, old_entry->group, old_entry->inode, NULL, 1)) { > > spin_unlock(&old_entry->lock); > > fsnotify_put_mark(chunk_entry); > > fsnotify_put_mark(old_entry); > > -- > > 2.10.2 > > > > -- > paul moore > www.paul-moore.com
On Fri, Dec 23, 2016 at 8:22 AM, Jan Kara <jack@suse.cz> wrote: > On Thu 22-12-16 18:13:11, Paul Moore wrote: >> On Thu, Dec 22, 2016 at 4:15 AM, Jan Kara <jack@suse.cz> wrote: >> > There are only two calls sites of fsnotify_duplicate_mark(). Those are >> > in kernel/audit_tree.c and both are bogus. Vfsmount pointer is unused >> > for audit tree, inode pointer and group gets set in >> > fsnotify_add_mark_locked() later anyway, mask and free_mark are already >> > set in alloc_chunk(). In fact, calling fsnotify_duplicate_mark() is >> > actively harmful because following fsnotify_add_mark_locked() will leak >> > group reference by overwriting the group pointer. So just remove the two >> > calls to fsnotify_duplicate_mark() and the function. >> > >> > Signed-off-by: Jan Kara <jack@suse.cz> >> > --- >> > fs/notify/mark.c | 12 ------------ >> > include/linux/fsnotify_backend.h | 2 -- >> > kernel/audit_tree.c | 6 ++---- >> > 3 files changed, 2 insertions(+), 18 deletions(-) >> >> At first glance this looks reasonable, although you keep mentioning >> "fsnotify_add_mark_locked" above when untag_chunk() is calling >> "fsnotify_add_mark"; I just wanted to make sure you hadn't intended to >> take the mutex in the audit code instead of relying on the locking in >> fsnotify_add_mark(). > > No, I didn't want to take mutex in the audit code. It is just that > fsnotify_add_mark() is a thin wrapper around fsnotify_add_mark_locked() so > I was speaking about that function. Understood. I just wanted to make sure this is what you intended since the commit description and patch did not match. If you end up respinning the patchset for any reason I might suggest changing the function name in the description above. >> >> > diff --git a/fs/notify/mark.c b/fs/notify/mark.c >> > index d3fea0bd89e2..6043306e8e21 100644 >> > --- a/fs/notify/mark.c >> > +++ b/fs/notify/mark.c >> > @@ -510,18 +510,6 @@ void fsnotify_detach_group_marks(struct fsnotify_group *group) >> > } >> > } >> > >> > -void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) >> > -{ >> > - assert_spin_locked(&old->lock); >> > - new->inode = old->inode; >> > - new->mnt = old->mnt; >> > - if (old->group) >> > - fsnotify_get_group(old->group); >> > - new->group = old->group; >> > - new->mask = old->mask; >> > - new->free_mark = old->free_mark; >> > -} >> > - >> > /* >> > * Nothing fancy, just initialize lists and locks and counters. >> > */ >> > diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h >> > index 0cf34d6cc253..487246546ebe 100644 >> > --- a/include/linux/fsnotify_backend.h >> > +++ b/include/linux/fsnotify_backend.h >> > @@ -323,8 +323,6 @@ extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(str >> > extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode); >> > /* find (and take a reference) to a mark associated with group and vfsmount */ >> > extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt); >> > -/* copy the values from old into new */ >> > -extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old); >> > /* set the ignored_mask of a mark */ >> > extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask); >> > /* set the mask of a mark (might pin the object into memory */ >> > diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c >> > index 8b1dde96a0fa..f3130eb0a4bd 100644 >> > --- a/kernel/audit_tree.c >> > +++ b/kernel/audit_tree.c >> > @@ -258,8 +258,7 @@ static void untag_chunk(struct node *p) >> > if (!new) >> > goto Fallback; >> > >> > - fsnotify_duplicate_mark(&new->mark, entry); >> > - if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, NULL, 1)) { >> > + if (fsnotify_add_mark(&new->mark, entry->group, entry->inode, NULL, 1)) { >> > fsnotify_put_mark(&new->mark); >> > goto Fallback; >> > } >> > @@ -395,8 +394,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) >> > return -ENOENT; >> > } >> > >> > - fsnotify_duplicate_mark(chunk_entry, old_entry); >> > - if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, NULL, 1)) { >> > + if (fsnotify_add_mark(chunk_entry, old_entry->group, old_entry->inode, NULL, 1)) { >> > spin_unlock(&old_entry->lock); >> > fsnotify_put_mark(chunk_entry); >> > fsnotify_put_mark(old_entry); >> > -- >> > 2.10.2 >> > >> >> -- >> paul moore >> www.paul-moore.com > -- > Jan Kara <jack@suse.com> > SUSE Labs, CR
diff --git a/fs/notify/mark.c b/fs/notify/mark.c index d3fea0bd89e2..6043306e8e21 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -510,18 +510,6 @@ void fsnotify_detach_group_marks(struct fsnotify_group *group) } } -void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) -{ - assert_spin_locked(&old->lock); - new->inode = old->inode; - new->mnt = old->mnt; - if (old->group) - fsnotify_get_group(old->group); - new->group = old->group; - new->mask = old->mask; - new->free_mark = old->free_mark; -} - /* * Nothing fancy, just initialize lists and locks and counters. */ diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 0cf34d6cc253..487246546ebe 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -323,8 +323,6 @@ extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(str extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode); /* find (and take a reference) to a mark associated with group and vfsmount */ extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt); -/* copy the values from old into new */ -extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old); /* set the ignored_mask of a mark */ extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask); /* set the mask of a mark (might pin the object into memory */ diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 8b1dde96a0fa..f3130eb0a4bd 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -258,8 +258,7 @@ static void untag_chunk(struct node *p) if (!new) goto Fallback; - fsnotify_duplicate_mark(&new->mark, entry); - if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, NULL, 1)) { + if (fsnotify_add_mark(&new->mark, entry->group, entry->inode, NULL, 1)) { fsnotify_put_mark(&new->mark); goto Fallback; } @@ -395,8 +394,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) return -ENOENT; } - fsnotify_duplicate_mark(chunk_entry, old_entry); - if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, NULL, 1)) { + if (fsnotify_add_mark(chunk_entry, old_entry->group, old_entry->inode, NULL, 1)) { spin_unlock(&old_entry->lock); fsnotify_put_mark(chunk_entry); fsnotify_put_mark(old_entry);
There are only two calls sites of fsnotify_duplicate_mark(). Those are in kernel/audit_tree.c and both are bogus. Vfsmount pointer is unused for audit tree, inode pointer and group gets set in fsnotify_add_mark_locked() later anyway, mask and free_mark are already set in alloc_chunk(). In fact, calling fsnotify_duplicate_mark() is actively harmful because following fsnotify_add_mark_locked() will leak group reference by overwriting the group pointer. So just remove the two calls to fsnotify_duplicate_mark() and the function. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/notify/mark.c | 12 ------------ include/linux/fsnotify_backend.h | 2 -- kernel/audit_tree.c | 6 ++---- 3 files changed, 2 insertions(+), 18 deletions(-)