diff --git a/flake.lock b/flake.lock
index c9b0f69..bca20aa 100644
--- a/flake.lock
+++ b/flake.lock
@@ -92,10 +92,49 @@
         "type": "github"
       }
     },
+    "flake-parts_2": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1712014858,
+        "narHash": "sha256-sB4SWl2lX95bExY2gMFG5HIzvva5AVMJd4Igm+GpZNw=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "9126214d0a59633752a136528f5f3b9aa8565b7d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
       },
+      "locked": {
+        "lastModified": 1710146030,
+        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
       "locked": {
         "lastModified": 1701680307,
         "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
@@ -166,23 +205,24 @@
     "nix": {
       "inputs": {
         "flake-compat": "flake-compat",
+        "flake-parts": "flake-parts_2",
         "libgit2": "libgit2",
         "nixpkgs": [
           "nixpkgs"
         ],
-        "nixpkgs-regression": "nixpkgs-regression"
+        "nixpkgs-regression": "nixpkgs-regression",
+        "pre-commit-hooks": "pre-commit-hooks"
       },
       "locked": {
-        "lastModified": 1711717219,
-        "narHash": "sha256-8nzsGORuUIkM91yKYz9f8/+eRMrLRHrqs+ExwLT01+8=",
-        "owner": "tweag",
+        "lastModified": 1713862243,
+        "narHash": "sha256-mfJSQyO7je+/WSBmnl/LTGvqrzv3k1F0kEd7Wg+VXw4=",
+        "owner": "nixos",
         "repo": "nix",
-        "rev": "926fbadcc30a4614b5f5a3d18a6f4096914f97da",
+        "rev": "1cfc9da472f8dcfa7f521e544531d5e4daf2076c",
         "type": "github"
       },
       "original": {
-        "owner": "tweag",
-        "ref": "nix-c-bindings",
+        "owner": "nixos",
         "repo": "nix",
         "type": "github"
       }
@@ -282,10 +322,42 @@
         "type": "github"
       }
     },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": [
+          "nix"
+        ],
+        "flake-utils": "flake-utils",
+        "gitignore": [
+          "nix"
+        ],
+        "nixpkgs": [
+          "nix",
+          "nixpkgs"
+        ],
+        "nixpkgs-stable": [
+          "nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1713775815,
+        "narHash": "sha256-Wu9cdYTnGQQwtT20QQMg7jzkANKQjwBD9iccfGKkfls=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "2ac4dcbf55ed43f3be0bae15e181f08a57af24a4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
     "pre-commit-hooks-nix": {
       "inputs": {
         "flake-compat": "flake-compat_2",
-        "flake-utils": "flake-utils",
+        "flake-utils": "flake-utils_2",
         "gitignore": "gitignore",
         "nixpkgs": [
           "nixpkgs"
@@ -409,6 +481,21 @@
         "type": "github"
       }
     },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
     "treefmt": {
       "inputs": {
         "nixpkgs": [
diff --git a/flake.nix b/flake.nix
index ed97fa8..af50710 100644
--- a/flake.nix
+++ b/flake.nix
@@ -4,7 +4,7 @@
   inputs = {
     flake-parts.url = "github:hercules-ci/flake-parts";
     flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
-    nix.url = "github:tweag/nix/nix-c-bindings";
+    nix.url = "github:nixos/nix";
     nix.inputs.nixpkgs.follows = "nixpkgs";
     nix-cargo-integration.url = "github:yusdacra/nix-cargo-integration";
     nix-cargo-integration.inputs.nixpkgs.follows = "nixpkgs";
diff --git a/rust/nix-expr/src/eval_state.rs b/rust/nix-expr/src/eval_state.rs
index a5ed53a..37458b1 100644
--- a/rust/nix-expr/src/eval_state.rs
+++ b/rust/nix-expr/src/eval_state.rs
@@ -5,6 +5,7 @@ use lazy_static::lazy_static;
 use nix_c_raw as raw;
 use nix_store::store::Store;
 use nix_util::context::Context;
+use nix_util::string_return::callback_get_vec_u8;
 use std::ffi::CString;
 use std::ptr::null_mut;
 use std::ptr::NonNull;
@@ -108,13 +109,18 @@ impl EvalState {
     }
     /// Not exposed, because the caller must always explicitly handle the context or not accept one at all.
     fn get_string(&self, value: &Value) -> Result<String> {
-        let c_str_raw = unsafe { raw::nix_get_string(self.context.ptr(), value.raw_ptr()) };
+        let mut raw_buffer: Vec<u8> = Vec::new();
+        unsafe {
+            raw::nix_get_string(
+                self.context.ptr(),
+                value.raw_ptr(),
+                Some(callback_get_vec_u8),
+                &mut raw_buffer as *mut Vec<u8> as *mut std::ffi::c_void,
+            )
+        };
         self.context.check_err()?;
-        let cstring = unsafe { std::ffi::CStr::from_ptr(c_str_raw) };
-        let str = cstring
-            .to_str()
-            .map_err(|e| anyhow::format_err!("Nix string is not valid UTF-8: {}", e))?;
-        Ok(str.to_owned())
+        String::from_utf8(raw_buffer)
+            .map_err(|e| anyhow::format_err!("Nix string is not valid UTF-8: {}", e))
     }
     /// NOTE: this will be replaced by two methods, one that also returns the context, and one that checks that the context is empty
     pub fn require_string(&self, value: &Value) -> Result<String> {
diff --git a/rust/nix-store/src/store.rs b/rust/nix-store/src/store.rs
index 9304a6f..6b568dd 100644
--- a/rust/nix-store/src/store.rs
+++ b/rust/nix-store/src/store.rs
@@ -83,7 +83,7 @@ impl Store {
             raw::nix_store_get_uri(
                 self.context.ptr(),
                 self.inner.ptr(),
-                callback_get_vec_u8 as *mut std::ffi::c_void,
+                Some(callback_get_vec_u8),
                 &mut raw_buffer as *mut Vec<u8> as *mut std::ffi::c_void,
             )
         };