IB/core: Split uverbs_get_const/default to consider target type

Change uverbs_get_const/uverbs_get_const_default to work properly with
both signed/unsigned parameters.

Current APIs mix s64 and u64 which leads to incorrect check when u64
value was supplied and its upper bit was set. In that case
uverbs_get_const() / uverbs_get_const_default() lower bound check may
fail unexpectedly, target is unsigned (lower bound is 0) but value
became negative as of the s64 usage.

Split to have two different APIs, no change to callers as the required
API will be called internally according to the target type.

Link: https://lore.kernel.org/r/20210304130501.1102577-3-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 28 insertions, 4 deletions

diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c
index ff047eb024ab..990f0724acc6 100644
--- a/drivers/infiniband/core/uverbs_ioctl.c
+++ b/drivers/infiniband/core/uverbs_ioctl.c
@@ -752,9 +752,10 @@ int uverbs_output_written(const struct uverbs_attr_bundle *bundle, size_t idx)
 	return uverbs_set_output(bundle, attr);
 }
 
-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_get_const_signed(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;
 
@@ -773,7 +774,30 @@ int _uverbs_get_const(s64 *to, const struct uverbs_attr_bundle *attrs_bundle,
 
 	return 0;
 }
-EXPORT_SYMBOL(_uverbs_get_const);
+EXPORT_SYMBOL(_uverbs_get_const_signed);
+
+int _uverbs_get_const_unsigned(u64 *to,
+			       const struct uverbs_attr_bundle *attrs_bundle,
+			       size_t idx, u64 upper_bound, u64 *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 > upper_bound)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL(_uverbs_get_const_unsigned);
 
 int uverbs_copy_to_struct_or_zero(const struct uverbs_attr_bundle *bundle,
 				  size_t idx, const void *from, size_t size)