sanitize iov_iter_fault_in_readable()

[linux-block.git] / lib / iov_iter.c

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index cd23c79acb9439bdaf605551f017b81313745379..2b543bea1e0d4906b42449e2ca84e6263ae21769 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -466,19 +466,25 @@ out:
  * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
  * because it is an invalid address).
  */
-int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
+int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes)
 {
-       size_t skip = i->iov_offset;
-       const struct iovec *iov;
-       int err;
-       struct iovec v;
-
        if (iter_is_iovec(i)) {
-               iterate_iovec(i, bytes, v, iov, skip, ({
-                       err = fault_in_pages_readable(v.iov_base, v.iov_len);
+               const struct iovec *p;
+               size_t skip;
+
+               if (bytes > i->count)
+                       bytes = i->count;
+               for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) {
+                       size_t len = min(bytes, p->iov_len - skip);
+                       int err;
+
+                       if (unlikely(!len))
+                               continue;
+                       err = fault_in_pages_readable(p->iov_base + skip, len);
                        if (unlikely(err))
-                       return err;
-               0;}))
+                               return err;
+                       bytes -= len;
+               }
        }
        return 0;
 }