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Commit 2e8039c6 authored by Michael Guralnik's avatar Michael Guralnik Committed by Jason Gunthorpe
Browse files

IB/core: uverbs copy to struct or zero helper 



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: default avatarMichael Guralnik <michaelgur@mellanox.com>
Reviewed-by: default avatarMajd Dibbiny <majd@mellanox.com>
Signed-off-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent f55c3ec4

drivers/infiniband/core/uverbs_ioctl.c

+11 −0
Original line number Diff line number Diff line
@@ -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);

}

include/rdma/uverbs_ioctl.h

+8 −0
Original line number Diff line number Diff line
@@ -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 +908,12 @@ _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)                             \