diff --git a/src/bio.rs b/src/bio.rs
index 6a72552..0324218 100644
--- a/src/bio.rs
+++ b/src/bio.rs
@@ -4,7 +4,7 @@ use std::marker::PhantomData;
 use std::ptr;
 use std::slice;
 
-use crate::cvt_p;
+use crate::{cvt_p, SignedLenType};
 use crate::error::ErrorStack;
 
 pub struct MemBioSlice<'a>(*mut ffi::BIO, PhantomData<&'a [u8]>);
@@ -25,7 +25,7 @@ impl<'a> MemBioSlice<'a> {
         let bio = unsafe {
             cvt_p(BIO_new_mem_buf(
                 buf.as_ptr() as *const _,
-                buf.len() as c_int,
+                buf.len() as SignedLenType,
             ))?
         };
 
@@ -78,7 +78,7 @@ cfg_if! {
         use ffi::BIO_new_mem_buf;
     } else {
         #[allow(bad_style)]
-        unsafe fn BIO_new_mem_buf(buf: *const ::libc::c_void, len: ::libc::c_int) -> *mut ffi::BIO {
+        unsafe fn BIO_new_mem_buf(buf: *const ::libc::c_void, len: SignedLenType) -> *mut ffi::BIO {
             ffi::BIO_new_mem_buf(buf as *mut _, len)
         }
     }
diff --git a/src/dh.rs b/src/dh.rs
index 12170b9..e781543 100644
--- a/src/dh.rs
+++ b/src/dh.rs
@@ -239,7 +239,7 @@ where
 }
 
 cfg_if! {
-    if #[cfg(any(ossl110, libressl270))] {
+    if #[cfg(any(ossl110, libressl270, boringssl))] {
         use ffi::{DH_set0_pqg, DH_get0_pqg, DH_get0_key, DH_set0_key};
     } else {
         #[allow(bad_style)]
diff --git a/src/lib.rs b/src/lib.rs
index f149bfd..e8d07d8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -196,6 +196,11 @@ type LenType = libc::size_t;
 #[cfg(not(boringssl))]
 type LenType = libc::c_int;
 
+#[cfg(boringssl)]
+type SignedLenType = libc::ssize_t;
+#[cfg(not(boringssl))]
+type SignedLenType = libc::c_int;
+
 #[inline]
 fn cvt_p<T>(r: *mut T) -> Result<*mut T, ErrorStack> {
     if r.is_null() {