From 89d9e8d3f14d807bbd7725f8f6f5eeb7f6f5c42f Mon Sep 17 00:00:00 2001 From: Matan Barak Date: Tue, 13 Feb 2018 12:18:29 +0200 Subject: [PATCH] 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 Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/uverbs_std_types.c | 5 ++-- include/rdma/uverbs_ioctl.h | 35 +++++++++++++++++----- 2 files changed, 31 insertions(+), 9 deletions(-) diff --git a/drivers/infiniband/core/uverbs_std_types.c b/drivers/infiniband/core/uverbs_std_types.c index cab0ac3556eb..c6502c7b7c46 100644 --- a/drivers/infiniband/core/uverbs_std_types.c +++ b/drivers/infiniband/core/uverbs_std_types.c @@ -323,7 +323,8 @@ static int uverbs_create_cq_handler(struct ib_device *ib_dev, cq->res.type = RDMA_RESTRACK_CQ; rdma_restrack_add(&cq->res); - ret = uverbs_copy_to(attrs, CREATE_CQ_RESP_CQE, &cq->cqe); + ret = uverbs_copy_to(attrs, CREATE_CQ_RESP_CQE, &cq->cqe, + sizeof(cq->cqe)); if (ret) goto err_cq; @@ -375,7 +376,7 @@ static int uverbs_destroy_cq_handler(struct ib_device *ib_dev, resp.comp_events_reported = obj->comp_events_reported; resp.async_events_reported = obj->async_events_reported; - return uverbs_copy_to(attrs, DESTROY_CQ_RESP, &resp); + return uverbs_copy_to(attrs, DESTROY_CQ_RESP, &resp, sizeof(resp)); } static DECLARE_UVERBS_METHOD( diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h index 6da44079aa58..32cb14703914 100644 --- a/include/rdma/uverbs_ioctl.h +++ b/include/rdma/uverbs_ioctl.h @@ -351,29 +351,50 @@ static inline const struct uverbs_attr *uverbs_attr_get(const struct uverbs_attr } 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 @@ static inline int _uverbs_copy_from(void *to, size_t to_size, } #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