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Date: Mon, 18 Jun 2018 14:48:54 -0600
From: Jason Gunthorpe <jgg@...pe.ca>
To: Leon Romanovsky <leon@...nel.org>
Cc: Doug Ledford <dledford@...hat.com>,
Leon Romanovsky <leonro@...lanox.com>,
RDMA mailing list <linux-rdma@...r.kernel.org>,
Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
Yishai Hadas <yishaih@...lanox.com>,
Saeed Mahameed <saeedm@...lanox.com>,
linux-netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH rdma-next v2 06/20] IB/uverbs: Add PTR_IN attributes that
are allocated/copied automatically
On Sun, Jun 17, 2018 at 12:59:52PM +0300, Leon Romanovsky wrote:
> From: Matan Barak <matanb@...lanox.com>
>
> Adding UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY flag to PTR_IN attributes.
> By using this flag, the parse automatically allocates and copies the
> user-space data. This data is accessible by using uverbs_attr_get_len
> and uverbs_attr_get_alloced_ptr inline accessor functions from the
> handler.
>
> Signed-off-by: Matan Barak <matanb@...lanox.com>
> Signed-off-by: Yishai Hadas <yishaih@...lanox.com>
> Signed-off-by: Leon Romanovsky <leonro@...lanox.com>
> drivers/infiniband/core/uverbs_ioctl.c | 25 ++++++++++++++++++++++++-
> include/rdma/uverbs_ioctl.h | 25 +++++++++++++++++++++++++
> 2 files changed, 49 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c
> index 8cc3e8dad9b5..ee15c9ca788b 100644
> +++ b/drivers/infiniband/core/uverbs_ioctl.c
> @@ -114,7 +114,26 @@ static int uverbs_process_attr(struct ib_device *ibdev,
> uattr->attr_data.reserved)
> return -EINVAL;
>
> - e->ptr_attr.data = uattr->data;
> + if (val_spec->flags & UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY &&
> + uattr->len > sizeof(((struct ib_uverbs_attr *)0)->data)) {
Why open-code uverbs_attr_ptr_is_inline() ?
> diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
> index bd6bba3a6e04..0e6f782727bd 100644
> +++ b/include/rdma/uverbs_ioctl.h
> @@ -65,6 +65,8 @@ enum {
> UVERBS_ATTR_SPEC_F_MANDATORY = 1U << 0,
> /* Support extending attributes by length, validate all unknown size == zero */
> UVERBS_ATTR_SPEC_F_MIN_SZ_OR_ZERO = 1U << 1,
> + /* Valid only for PTR_IN. Allocate and copy the data inside the parser */
> + UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY = 1U << 2,
> };
>
> /* Specification of a single attribute inside the ioctl message */
> @@ -431,6 +433,17 @@ static inline struct ib_uobject *uverbs_attr_get_uobject(const struct uverbs_att
> return attr->obj_attr.uobject;
> }
>
> +static inline int uverbs_attr_get_len(const struct uverbs_attr_bundle *attrs_bundle,
> + u16 idx)
> +{
> + const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
> +
> + if (IS_ERR(attr))
> + return PTR_ERR(attr);
> +
> + return attr->ptr_attr.len;
> +}
> +
> static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
> size_t idx, const void *from, size_t size)
> {
> @@ -457,6 +470,18 @@ 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 void *uverbs_attr_get_alloced_ptr(const struct uverbs_attr_bundle *attrs_bundle,
> + u16 idx)
> +{
> + const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
> +
> + if (IS_ERR(attr))
> + return (void *)attr;
> +
> + return uverbs_attr_ptr_is_inline(attr) ? u64_to_ptr(void *, attr->ptr_attr.data) :
> + u64_to_ptr(void, attr->ptr_attr.data);
WTF is this:
u64_to_ptr(void *, attr->ptr_attr.data)
That returns attr->ptr_attr.data casted to a void **, then casts it to
a void * - which is identical to u64_to_ptr(void, attr->ptr_attr.data)
It should be &attr->ptr_attr.data. And the return should be const, the
caller shouldn't be mutating the copy.
All this use of u64_to_ptr is ugly needless obfuscation here, and
look, it causes bugs. Use a union.
Like this:
diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c
index 8cc3e8dad9b506..82c5d33195dfc7 100644
--- a/drivers/infiniband/core/uverbs_ioctl.c
+++ b/drivers/infiniband/core/uverbs_ioctl.c
@@ -114,9 +114,27 @@ static int uverbs_process_attr(struct ib_device *ibdev,
uattr->attr_data.reserved)
return -EINVAL;
- e->ptr_attr.data = uattr->data;
e->ptr_attr.len = uattr->len;
e->ptr_attr.flags = uattr->flags;
+
+ if (val_spec->flags & UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY &&
+ !uverbs_attr_ptr_is_inline(e)) {
+ void *p;
+
+ p = kvmalloc(uattr->len, GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ e->ptr_attr.ptr = p;
+
+ if (copy_from_user(p, u64_to_user_ptr(uattr->data),
+ uattr->len)) {
+ kvfree(p);
+ return -EFAULT;
+ }
+ } else {
+ e->ptr_attr.data = uattr->data;
+ }
break;
case UVERBS_ATTR_TYPE_IDR:
@@ -201,6 +219,10 @@ static int uverbs_finalize_attrs(struct uverbs_attr_bundle *attrs_bundle,
commit);
if (!ret)
ret = current_ret;
+ } else if (spec->type == UVERBS_ATTR_TYPE_PTR_IN &&
+ spec->flags & UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY &&
+ !uverbs_attr_ptr_is_inline(attr)) {
+ kvfree(attr->ptr_attr.ptr);
}
}
}
diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
index bd6bba3a6e04a1..6e1c322ff5c015 100644
--- a/include/rdma/uverbs_ioctl.h
+++ b/include/rdma/uverbs_ioctl.h
@@ -65,6 +65,8 @@ enum {
UVERBS_ATTR_SPEC_F_MANDATORY = 1U << 0,
/* Support extending attributes by length, validate all unknown size == zero */
UVERBS_ATTR_SPEC_F_MIN_SZ_OR_ZERO = 1U << 1,
+ /* Valid only for PTR_IN. Allocate and copy the data inside the parser */
+ UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY = 1U << 2,
};
/* Specification of a single attribute inside the ioctl message */
@@ -323,7 +325,15 @@ struct uverbs_object_tree_def {
*/
struct uverbs_ptr_attr {
- u64 data;
+ /*
+ * If UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY is set then the 'ptr' is
+ * used.
+ */
+ union
+ {
+ void *ptr;
+ u64 data;
+ };
u16 len;
/* Combination of bits from enum UVERBS_ATTR_F_XXXX */
u16 flags;
@@ -431,6 +441,17 @@ static inline struct ib_uobject *uverbs_attr_get_uobject(const struct uverbs_att
return attr->obj_attr.uobject;
}
+static inline int uverbs_attr_get_len(const struct uverbs_attr_bundle *attrs_bundle,
+ u16 idx)
+{
+ const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
+
+ if (IS_ERR(attr))
+ return PTR_ERR(attr);
+
+ return attr->ptr_attr.len;
+}
+
static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
size_t idx, const void *from, size_t size)
{
@@ -457,6 +478,18 @@ 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 const void *uverbs_attr_get_alloced_ptr(
+ const struct uverbs_attr_bundle *attrs_bundle, u16 idx)
+{
+ const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
+
+ if (IS_ERR(attr))
+ return (void *)attr;
+
+ return uverbs_attr_ptr_is_inline(attr) ? &attr->ptr_attr.data :
+ attr->ptr_attr.ptr;
+}
+
static inline int _uverbs_copy_from(void *to,
const struct uverbs_attr_bundle *attrs_bundle,
size_t idx,
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