From: Michael Guralnik <michaelgur@xxxxxxxxxxxx>
Add a helper to zero fill fields before copying data to UVERBS_ATTR_STRUCT.
As UVERBS_ATTR_STRUCT can be used as an extensible struct, we want to make
sure that if the user supplies us with a struct that has new fields that
we are not aware of, we return them zeroed to the user.
This helper should be used when using UVERBS_ATTR_STRUCT for an extendable
data structure and there is a need to make sure that extended members of
the struct, that the kernel doesn't handle, are returned zeroed to the
user. This is needed due to the fact that UVERBS_ATTR_STRUCT allows
non-zero values for members after 'last' member.
Signed-off-by: Michael Guralnik <michaelgur@xxxxxxxxxxxx>
Reviewed-by: Majd Dibbiny <majd@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
---
drivers/infiniband/core/uverbs_ioctl.c | 11 +++++++++++
include/rdma/uverbs_ioctl.h | 7 +++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c
index 3cc46447240e..8c81ff698052 100644
--- a/drivers/infiniband/core/uverbs_ioctl.c
+++ b/drivers/infiniband/core/uverbs_ioctl.c
@@ -751,3 +751,14 @@ int _uverbs_get_const(s64 *to, const struct uverbs_attr_bundle *attrs_bundle,
return 0;
}
EXPORT_SYMBOL(_uverbs_get_const);
+
+int uverbs_copy_to_struct_or_zero(const struct uverbs_attr_bundle *bundle,
+ size_t idx, const void *from, size_t size)
+{
+ const struct uverbs_attr *attr = uverbs_attr_get(bundle, idx);
+
+ if (clear_user(u64_to_user_ptr(attr->ptr_attr.data),
+ attr->ptr_attr.len))
+ return -EFAULT;
+ return uverbs_copy_to(bundle, idx, from, size);
+}
diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
index bdff3fbf8b68..c61d23f325a5 100644
--- a/include/rdma/uverbs_ioctl.h
+++ b/include/rdma/uverbs_ioctl.h
@@ -871,6 +871,8 @@ static inline __malloc void *uverbs_zalloc(struct uverbs_attr_bundle *bundle,
int _uverbs_get_const(s64 *to, const struct uverbs_attr_bundle *attrs_bundle,
size_t idx, s64 lower_bound, u64 upper_bound,
s64 *def_val);
+int uverbs_copy_to_struct_or_zero(const struct uverbs_attr_bundle *bundle,
+ size_t idx, const void *from, size_t size);
#else
static inline int
uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
@@ -906,6 +908,11 @@ _uverbs_get_const(s64 *to, const struct uverbs_attr_bundle *attrs_bundle,
{
return -EINVAL;
}
+static inline int uverbs_copy_to_struct_or_zero(const struct uverbs_attr_bundle *bundle,
+ size_t idx, const void *from, size_t size)
+{
+ return -EINVAL;
+}
#endif
#define uverbs_get_const(_to, _attrs_bundle, _idx) \
--
2.19.1
