Merge tag 'io_uring-6.11-20240823' of git://git.kernel.dk/linux

Pull io_uring fix from Jens Axboe:
 "Just a single fix for provided buffer validation"

* tag 'io_uring-6.11-20240823' of git://git.kernel.dk/linux:
  io_uring/kbuf: sanitize peek buffer setup

Author: torvalds

io_uring/kbuf.c

@@ -218,10 +218,13 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg,
 
 	buf = io_ring_head_to_buf(br, head, bl->mask);
 	if (arg->max_len) {
-		int needed;
+		u32 len = READ_ONCE(buf->len);
+		size_t needed;
 
-		needed = (arg->max_len + buf->len - 1) / buf->len;
-		needed = min(needed, PEEK_MAX_IMPORT);
+		if (unlikely(!len))
+			return -ENOBUFS;
+		needed = (arg->max_len + len - 1) / len;
+		needed = min_not_zero(needed, (size_t) PEEK_MAX_IMPORT);
 		if (nr_avail > needed)
 			nr_avail = needed;
 	}