From 0953fffec9ba022f63bfe01e86427530d8320d5c Mon Sep 17 00:00:00 2001 From: Mark Bloch Date: Tue, 28 Aug 2018 14:18:50 +0300 Subject: RDMA/uverbs: Add UVERBS_ATTR_CONST_IN to the specs language This makes it clear and safe to access constants passed in from user space. We define a consistent ABI of u64 for all constants, and verify that the data passed in can be represented by the type the user supplies. The expectation is this will always be used with an enum declaring the constant values, and the user will use the enum type as input to the accessor. To retrieve the attribute value we introduce two helper calls - one standard which may fail if attribute is not valid and one where caller can provide a default value which will be used in case the attribute is not valid (useful when attribute is optional). Signed-off-by: Jason Gunthorpe Signed-off-by: Ariel Levkovich Signed-off-by: Mark Bloch Signed-off-by: Leon Romanovsky --- drivers/infiniband/core/uverbs_ioctl.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c index 1a6b229e3db3..4bafd4671de2 100644 --- a/drivers/infiniband/core/uverbs_ioctl.c +++ b/drivers/infiniband/core/uverbs_ioctl.c @@ -611,3 +611,26 @@ int uverbs_copy_to(const struct uverbs_attr_bundle *bundle, size_t idx, return 0; } EXPORT_SYMBOL(uverbs_copy_to); + +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) +{ + const struct uverbs_attr *attr; + + attr = uverbs_attr_get(attrs_bundle, idx); + if (IS_ERR(attr)) { + if ((PTR_ERR(attr) != -ENOENT) || !def_val) + return PTR_ERR(attr); + + *to = *def_val; + } else { + *to = attr->ptr_attr.data; + } + + if (*to < lower_bound || (*to > 0 && (u64)*to > upper_bound)) + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL(_uverbs_get_const); -- cgit v1.2.3-59-g8ed1b