From 187df76325af5d9e12ae9daec1510307797e54f0 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Fri, 22 Mar 2019 22:14:19 +0100 Subject: [PATCH 1/2] libceph: fix breakage caused by multipage bvecs A bvec can now consist of multiple physically contiguous pages. This means that bvec_iter_advance() can move to a different page while staying in the same bvec (i.e. ->bi_bvec_done != 0). The messenger works in terms of segments which can now be defined as the smaller of a bvec and a page. The "more bytes to process in this segment" condition holds only if bvec_iter_advance() leaves us in the same bvec _and_ in the same page. On next bvec (possibly in the same page) and on next page (possibly in the same bvec) we may need to set ->last_piece. Signed-off-by: Ilya Dryomov --- net/ceph/messenger.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 7e71b0df1fbc..3083988ce729 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -840,6 +840,7 @@ static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor, size_t bytes) { struct ceph_bio_iter *it = &cursor->bio_iter; + struct page *page = bio_iter_page(it->bio, it->iter); BUG_ON(bytes > cursor->resid); BUG_ON(bytes > bio_iter_len(it->bio, it->iter)); @@ -851,7 +852,8 @@ static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor, return false; /* no more data */ } - if (!bytes || (it->iter.bi_size && it->iter.bi_bvec_done)) + if (!bytes || (it->iter.bi_size && it->iter.bi_bvec_done && + page == bio_iter_page(it->bio, it->iter))) return false; /* more bytes to process in this segment */ if (!it->iter.bi_size) { @@ -899,6 +901,7 @@ static bool ceph_msg_data_bvecs_advance(struct ceph_msg_data_cursor *cursor, size_t bytes) { struct bio_vec *bvecs = cursor->data->bvec_pos.bvecs; + struct page *page = bvec_iter_page(bvecs, cursor->bvec_iter); BUG_ON(bytes > cursor->resid); BUG_ON(bytes > bvec_iter_len(bvecs, cursor->bvec_iter)); @@ -910,7 +913,8 @@ static bool ceph_msg_data_bvecs_advance(struct ceph_msg_data_cursor *cursor, return false; /* no more data */ } - if (!bytes || cursor->bvec_iter.bi_bvec_done) + if (!bytes || (cursor->bvec_iter.bi_bvec_done && + page == bvec_iter_page(bvecs, cursor->bvec_iter))) return false; /* more bytes to process in this segment */ BUG_ON(cursor->last_piece); From daf5cc27eed99afdea8d96e71b89ba41f5406ef6 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 26 Mar 2019 01:38:58 +0000 Subject: [PATCH 2/2] ceph: fix use-after-free on symlink traversal free the symlink body after the same RCU delay we have for freeing the struct inode itself, so that traversal during RCU pathwalk wouldn't step into freed memory. Signed-off-by: Al Viro Reviewed-by: Jeff Layton Signed-off-by: Ilya Dryomov --- fs/ceph/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index e3346628efe2..2d61ddda9bf5 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -524,6 +524,7 @@ static void ceph_i_callback(struct rcu_head *head) struct inode *inode = container_of(head, struct inode, i_rcu); struct ceph_inode_info *ci = ceph_inode(inode); + kfree(ci->i_symlink); kmem_cache_free(ceph_inode_cachep, ci); } @@ -566,7 +567,6 @@ void ceph_destroy_inode(struct inode *inode) } } - kfree(ci->i_symlink); while ((n = rb_first(&ci->i_fragtree)) != NULL) { frag = rb_entry(n, struct ceph_inode_frag, node); rb_erase(n, &ci->i_fragtree);