-stable review patch. If anyone has any objections, please let us know. ------------------ From: Miklos Szeredi Fix bug in certain error paths of lookup routines. The request object was reused for sending FORGET, which is illegal. This bug could cause an Oops in 2.6.18. In earlier versions it might silently corrupt memory, but this is very unlikely. These error paths are never triggered by libfuse, so this wasn't noticed even with the 2.6.18 kernel, only with a filesystem using the raw kernel interface. Thanks to Russ Cox for the bug report and test filesystem. Signed-off-by: Miklos Szeredi Cc: Signed-off-by: Andrew Morton [chrisw: backport to 2.6.18 -stable] Signed-off-by: Chris Wright --- fs/fuse/dir.c | 52 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 38 insertions(+), 14 deletions(-) --- linux-2.6.18.4.orig/fs/fuse/dir.c +++ linux-2.6.18.4/fs/fuse/dir.c @@ -138,6 +138,7 @@ static int fuse_dentry_revalidate(struct struct fuse_entry_out outarg; struct fuse_conn *fc; struct fuse_req *req; + struct fuse_req *forget_req; /* Doesn't hurt to "reset" the validity timeout */ fuse_invalidate_entry_cache(entry); @@ -151,21 +152,29 @@ static int fuse_dentry_revalidate(struct if (IS_ERR(req)) return 0; + forget_req = fuse_get_req(fc); + if (IS_ERR(forget_req)) { + fuse_put_request(fc, req); + return 0; + } + fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg); request_send(fc, req); err = req->out.h.error; + fuse_put_request(fc, req); /* Zero nodeid is same as -ENOENT */ if (!err && !outarg.nodeid) err = -ENOENT; if (!err) { struct fuse_inode *fi = get_fuse_inode(inode); if (outarg.nodeid != get_node_id(inode)) { - fuse_send_forget(fc, req, outarg.nodeid, 1); + fuse_send_forget(fc, forget_req, + outarg.nodeid, 1); return 0; } fi->nlookup ++; } - fuse_put_request(fc, req); + fuse_put_request(fc, forget_req); if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT) return 0; @@ -214,6 +223,7 @@ static struct dentry *fuse_lookup(struct struct inode *inode = NULL; struct fuse_conn *fc = get_fuse_conn(dir); struct fuse_req *req; + struct fuse_req *forget_req; if (entry->d_name.len > FUSE_NAME_MAX) return ERR_PTR(-ENAMETOOLONG); @@ -222,9 +232,16 @@ static struct dentry *fuse_lookup(struct if (IS_ERR(req)) return ERR_PTR(PTR_ERR(req)); + forget_req = fuse_get_req(fc); + if (IS_ERR(forget_req)) { + fuse_put_request(fc, req); + return ERR_PTR(PTR_ERR(forget_req)); + } + fuse_lookup_init(req, dir, entry, &outarg); request_send(fc, req); err = req->out.h.error; + fuse_put_request(fc, req); /* Zero nodeid is same as -ENOENT, but with valid timeout */ if (!err && outarg.nodeid && (invalid_nodeid(outarg.nodeid) || !valid_mode(outarg.attr.mode))) @@ -233,11 +250,11 @@ static struct dentry *fuse_lookup(struct inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation, &outarg.attr); if (!inode) { - fuse_send_forget(fc, req, outarg.nodeid, 1); + fuse_send_forget(fc, forget_req, outarg.nodeid, 1); return ERR_PTR(-ENOMEM); } } - fuse_put_request(fc, req); + fuse_put_request(fc, forget_req); if (err && err != -ENOENT) return ERR_PTR(err); @@ -375,6 +392,13 @@ static int create_new_entry(struct fuse_ struct fuse_entry_out outarg; struct inode *inode; int err; + struct fuse_req *forget_req; + + forget_req = fuse_get_req(fc); + if (IS_ERR(forget_req)) { + fuse_put_request(fc, req); + return PTR_ERR(forget_req); + } req->in.h.nodeid = get_node_id(dir); req->out.numargs = 1; @@ -382,24 +406,24 @@ static int create_new_entry(struct fuse_ req->out.args[0].value = &outarg; request_send(fc, req); err = req->out.h.error; - if (err) { - fuse_put_request(fc, req); - return err; - } + fuse_put_request(fc, req); + if (err) + goto out_put_forget_req; + err = -EIO; if (invalid_nodeid(outarg.nodeid)) - goto out_put_request; + goto out_put_forget_req; if ((outarg.attr.mode ^ mode) & S_IFMT) - goto out_put_request; + goto out_put_forget_req; inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation, &outarg.attr); if (!inode) { - fuse_send_forget(fc, req, outarg.nodeid, 1); + fuse_send_forget(fc, forget_req, outarg.nodeid, 1); return -ENOMEM; } - fuse_put_request(fc, req); + fuse_put_request(fc, forget_req); if (dir_alias(inode)) { iput(inode); @@ -411,8 +435,8 @@ static int create_new_entry(struct fuse_ fuse_invalidate_attr(dir); return 0; - out_put_request: - fuse_put_request(fc, req); + out_put_forget_req: + fuse_put_request(fc, forget_req); return err; } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/