IB/uverbs: Always use the attribute size provided by the user
This fixes several bugs around the copy_to/from user path:
- copy_to used the user provided size of the attribute
and could copy data beyond the end of the kernel buffer into
userspace.
- copy_from didn't know the size of the kernel buffer and
could have left kernel memory unexpectedly un-initialized.
- copy_from did not use the user length to determine if the
attribute data is inlined or not.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
index 6da4407..32cb147 100644
--- a/include/rdma/uverbs_ioctl.h
+++ b/include/rdma/uverbs_ioctl.h
@@ -351,29 +351,50 @@
}
static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
- size_t idx, const void *from)
+ size_t idx, const void *from, size_t size)
{
const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
u16 flags;
+ size_t min_size;
if (IS_ERR(attr))
return PTR_ERR(attr);
+ min_size = min_t(size_t, attr->ptr_attr.len, size);
+ if (copy_to_user(attr->ptr_attr.ptr, from, min_size))
+ return -EFAULT;
+
flags = attr->ptr_attr.flags | UVERBS_ATTR_F_VALID_OUTPUT;
- return (!copy_to_user(attr->ptr_attr.ptr, from, attr->ptr_attr.len) &&
- !put_user(flags, &attr->uattr->flags)) ? 0 : -EFAULT;
+ if (put_user(flags, &attr->uattr->flags))
+ return -EFAULT;
+
+ return 0;
}
-static inline int _uverbs_copy_from(void *to, size_t to_size,
+static inline bool uverbs_attr_ptr_is_inline(const struct uverbs_attr *attr)
+{
+ return attr->ptr_attr.len <= sizeof(attr->ptr_attr.data);
+}
+
+static inline int _uverbs_copy_from(void *to,
const struct uverbs_attr_bundle *attrs_bundle,
- size_t idx)
+ size_t idx,
+ size_t size)
{
const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
if (IS_ERR(attr))
return PTR_ERR(attr);
- if (to_size <= sizeof(((struct ib_uverbs_attr *)0)->data))
+ /*
+ * Validation ensures attr->ptr_attr.len >= size. If the caller is
+ * using UVERBS_ATTR_SPEC_F_MIN_SZ then it must call copy_from with
+ * the right size.
+ */
+ if (unlikely(size < attr->ptr_attr.len))
+ return -EINVAL;
+
+ if (uverbs_attr_ptr_is_inline(attr))
memcpy(to, &attr->ptr_attr.data, attr->ptr_attr.len);
else if (copy_from_user(to, attr->ptr_attr.ptr, attr->ptr_attr.len))
return -EFAULT;
@@ -382,7 +403,7 @@
}
#define uverbs_copy_from(to, attrs_bundle, idx) \
- _uverbs_copy_from(to, sizeof(*(to)), attrs_bundle, idx)
+ _uverbs_copy_from(to, attrs_bundle, idx, sizeof(*to))
/* =================================================
* Definitions -> Specs infrastructure