io_uring: make io_kiocb_to_cmd() typesafe

We need to make sure (at build time) that struct io_cmd_data is not casted to a structure that's larger. Signed-off-by: Stefan Metzmacher <metze@samba.org> Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
kv2019i · Aug 12, 2022 · f2ccb5a · f2ccb5a
1 parent addebd9
commit f2ccb5a
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Showing 20 changed files with 134 additions and 129 deletions.
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
@@ -491,7 +491,14 @@ struct io_cmd_data {
 	__u8			data[56];
 };
 
-#define io_kiocb_to_cmd(req)	((void *) &(req)->cmd)
+static inline void io_kiocb_cmd_sz_check(size_t cmd_sz)
+{
+	BUILD_BUG_ON(cmd_sz > sizeof(struct io_cmd_data));
+}
+#define io_kiocb_to_cmd(req, cmd_type) ( \
+	io_kiocb_cmd_sz_check(sizeof(cmd_type)) , \
+	((cmd_type *)&(req)->cmd) \
+)
 #define cmd_to_io_kiocb(ptr)	((struct io_kiocb *) ptr)
 
 struct io_kiocb {

diff --git a/io_uring/advise.c b/io_uring/advise.c
@@ -31,7 +31,7 @@ struct io_madvise {
 int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
-	struct io_madvise *ma = io_kiocb_to_cmd(req);
+	struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
 
 	if (sqe->buf_index || sqe->off || sqe->splice_fd_in)
 		return -EINVAL;
@@ -48,7 +48,7 @@ int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
 {
 #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
-	struct io_madvise *ma = io_kiocb_to_cmd(req);
+	struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -64,7 +64,7 @@ int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
 
 int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_fadvise *fa = io_kiocb_to_cmd(req);
+	struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);
 
 	if (sqe->buf_index || sqe->addr || sqe->splice_fd_in)
 		return -EINVAL;
@@ -77,7 +77,7 @@ int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_fadvise(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_fadvise *fa = io_kiocb_to_cmd(req);
+	struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK) {

diff --git a/io_uring/cancel.c b/io_uring/cancel.c
@@ -107,7 +107,7 @@ int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd,
 
 int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_cancel *cancel = io_kiocb_to_cmd(req);
+	struct io_cancel *cancel = io_kiocb_to_cmd(req, struct io_cancel);
 
 	if (unlikely(req->flags & REQ_F_BUFFER_SELECT))
 		return -EINVAL;
@@ -164,7 +164,7 @@ static int __io_async_cancel(struct io_cancel_data *cd,
 
 int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_cancel *cancel = io_kiocb_to_cmd(req);
+	struct io_cancel *cancel = io_kiocb_to_cmd(req, struct io_cancel);
 	struct io_cancel_data cd = {
 		.ctx	= req->ctx,
 		.data	= cancel->addr,

diff --git a/io_uring/epoll.c b/io_uring/epoll.c
@@ -23,7 +23,7 @@ struct io_epoll {
 
 int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_epoll *epoll = io_kiocb_to_cmd(req);
+	struct io_epoll *epoll = io_kiocb_to_cmd(req, struct io_epoll);
 
 	pr_warn_once("%s: epoll_ctl support in io_uring is deprecated and will "
 		     "be removed in a future Linux kernel version.\n",
@@ -49,7 +49,7 @@ int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_epoll *ie = io_kiocb_to_cmd(req);
+	struct io_epoll *ie = io_kiocb_to_cmd(req, struct io_epoll);
 	int ret;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 

diff --git a/io_uring/fs.c b/io_uring/fs.c
@@ -49,7 +49,7 @@ struct io_link {
 
 int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_rename *ren = io_kiocb_to_cmd(req);
+	struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
 	const char __user *oldf, *newf;
 
 	if (sqe->buf_index || sqe->splice_fd_in)
@@ -79,7 +79,7 @@ int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_rename *ren = io_kiocb_to_cmd(req);
+	struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -95,15 +95,15 @@ int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
 
 void io_renameat_cleanup(struct io_kiocb *req)
 {
-	struct io_rename *ren = io_kiocb_to_cmd(req);
+	struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
 
 	putname(ren->oldpath);
 	putname(ren->newpath);
 }
 
 int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_unlink *un = io_kiocb_to_cmd(req);
+	struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
 	const char __user *fname;
 
 	if (sqe->off || sqe->len || sqe->buf_index || sqe->splice_fd_in)
@@ -128,7 +128,7 @@ int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_unlink *un = io_kiocb_to_cmd(req);
+	struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -146,14 +146,14 @@ int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
 
 void io_unlinkat_cleanup(struct io_kiocb *req)
 {
-	struct io_unlink *ul = io_kiocb_to_cmd(req);
+	struct io_unlink *ul = io_kiocb_to_cmd(req, struct io_unlink);
 
 	putname(ul->filename);
 }
 
 int io_mkdirat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_mkdir *mkd = io_kiocb_to_cmd(req);
+	struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
 	const char __user *fname;
 
 	if (sqe->off || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
@@ -175,7 +175,7 @@ int io_mkdirat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_mkdir *mkd = io_kiocb_to_cmd(req);
+	struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -190,14 +190,14 @@ int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags)
 
 void io_mkdirat_cleanup(struct io_kiocb *req)
 {
-	struct io_mkdir *md = io_kiocb_to_cmd(req);
+	struct io_mkdir *md = io_kiocb_to_cmd(req, struct io_mkdir);
 
 	putname(md->filename);
 }
 
 int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_link *sl = io_kiocb_to_cmd(req);
+	struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
 	const char __user *oldpath, *newpath;
 
 	if (sqe->len || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
@@ -225,7 +225,7 @@ int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_link *sl = io_kiocb_to_cmd(req);
+	struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -240,7 +240,7 @@ int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
 
 int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_link *lnk = io_kiocb_to_cmd(req);
+	struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
 	const char __user *oldf, *newf;
 
 	if (sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
@@ -270,7 +270,7 @@ int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_link *lnk = io_kiocb_to_cmd(req);
+	struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
 	int ret;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -286,7 +286,7 @@ int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
 
 void io_link_cleanup(struct io_kiocb *req)
 {
-	struct io_link *sl = io_kiocb_to_cmd(req);
+	struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
 
 	putname(sl->oldpath);
 	putname(sl->newpath);

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
@@ -272,7 +272,7 @@ void io_destroy_buffers(struct io_ring_ctx *ctx)
 
 int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_provide_buf *p = io_kiocb_to_cmd(req);
+	struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
 	u64 tmp;
 
 	if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off ||
@@ -291,7 +291,7 @@ int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_provide_buf *p = io_kiocb_to_cmd(req);
+	struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_buffer_list *bl;
 	int ret = 0;
@@ -319,7 +319,7 @@ int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
 int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	unsigned long size, tmp_check;
-	struct io_provide_buf *p = io_kiocb_to_cmd(req);
+	struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
 	u64 tmp;
 
 	if (sqe->rw_flags || sqe->splice_fd_in)
@@ -421,7 +421,7 @@ static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf,
 
 int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_provide_buf *p = io_kiocb_to_cmd(req);
+	struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_buffer_list *bl;
 	int ret = 0;

diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c
@@ -26,7 +26,7 @@ struct io_msg {
 static int io_msg_ring_data(struct io_kiocb *req)
 {
 	struct io_ring_ctx *target_ctx = req->file->private_data;
-	struct io_msg *msg = io_kiocb_to_cmd(req);
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
 
 	if (msg->src_fd || msg->dst_fd || msg->flags)
 		return -EINVAL;
@@ -76,7 +76,7 @@ static int io_double_lock_ctx(struct io_ring_ctx *ctx,
 static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_ring_ctx *target_ctx = req->file->private_data;
-	struct io_msg *msg = io_kiocb_to_cmd(req);
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
 	struct io_ring_ctx *ctx = req->ctx;
 	unsigned long file_ptr;
 	struct file *src_file;
@@ -122,7 +122,7 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
 
 int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	struct io_msg *msg = io_kiocb_to_cmd(req);
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
 
 	if (unlikely(sqe->buf_index || sqe->personality))
 		return -EINVAL;
@@ -141,7 +141,7 @@ int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_msg *msg = io_kiocb_to_cmd(req);
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
 	int ret;
 
 	ret = -EBADFD;