io_uring: explicit sqe padding for ioctl commands

32 bit sqe->cmd_op is an union with 64 bit values. It's always a good idea to do padding explicitly. Also zero check it in prep, so it can be used in the future if needed without compatibility concerns. Signed-off-by: Pavel Begunkov <[email protected]> Link: https://lore.kernel.org/r/e6b95a05e970af79000435166185e85b196b2ba2.1657202417.git.asml.silence@gmail.com [axboe: turn bitwise OR into logical variant] Signed-off-by: Jens Axboe <[email protected]>
kawasaki · Jul 7, 2022 · bdb2c48 · bdb2c48
1 parent 09007af
commit bdb2c48
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/fs/io_uring.c b/fs/io_uring.c
@@ -5066,7 +5066,7 @@ static int io_uring_cmd_prep(struct io_kiocb *req,
 {
 	struct io_uring_cmd *ioucmd = &req->uring_cmd;
 
-	if (sqe->rw_flags)
+	if (sqe->rw_flags || sqe->__pad1)
 		return -EINVAL;
 	ioucmd->cmd = sqe->cmd;
 	ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
@@ -22,7 +22,10 @@ struct io_uring_sqe {
 	union {
 		__u64	off;	/* offset into file */
 		__u64	addr2;
-		__u32	cmd_op;
+		struct {
+			__u32	cmd_op;
+			__u32	__pad1;
+		};
 	};
 	union {
 		__u64	addr;	/* pointer to buffer or iovecs */