From d2f662685e678a07c242bba2aaa9736fd7a652c5 Mon Sep 17 00:00:00 2001
From: "Victor M. Alvarez" <vmalvarez@virustotal.com>
Date: Wed, 28 Feb 2024 09:27:32 +0100
Subject: [PATCH] feat(capi): improve error handling when strings are not valid
 UTF-8.

---
 capi/include/yara-x.h |  1 +
 capi/src/lib.rs       |  1 +
 capi/src/scanner.rs   | 24 +++++++++++++++---------
 3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/capi/include/yara-x.h b/capi/include/yara-x.h
index a4b07befb..09dd4fa03 100644
--- a/capi/include/yara-x.h
+++ b/capi/include/yara-x.h
@@ -23,6 +23,7 @@ typedef enum YRX_RESULT {
   SCAN_TIMEOUT,
   INVALID_IDENTIFIER,
   INVALID_ARGUMENT,
+  INVALID_UTF8,
   SERIALIZATION_ERROR,
 } YRX_RESULT;
 
diff --git a/capi/src/lib.rs b/capi/src/lib.rs
index ade9e2ada..80c4b5380 100644
--- a/capi/src/lib.rs
+++ b/capi/src/lib.rs
@@ -43,6 +43,7 @@ pub enum YRX_RESULT {
     SCAN_TIMEOUT,
     INVALID_IDENTIFIER,
     INVALID_ARGUMENT,
+    INVALID_UTF8,
     SERIALIZATION_ERROR,
 }
 
diff --git a/capi/src/scanner.rs b/capi/src/scanner.rs
index e1d3edc89..32a319fb5 100644
--- a/capi/src/scanner.rs
+++ b/capi/src/scanner.rs
@@ -193,7 +193,10 @@ pub unsafe extern "C" fn yrx_scanner_set_module_output(
 
     let module_name = match CStr::from_ptr(name).to_str() {
         Ok(name) => name,
-        Err(_) => return YRX_RESULT::INVALID_ARGUMENT,
+        Err(err) => {
+            LAST_ERROR.set(Some(CString::new(err.to_string()).unwrap()));
+            return YRX_RESULT::INVALID_UTF8;
+        }
     };
 
     let data = match slice_from_ptr_and_len(data, len) {
@@ -228,7 +231,10 @@ unsafe extern "C" fn yrx_scanner_set_global<
 
     let ident = match CStr::from_ptr(ident).to_str() {
         Ok(ident) => ident,
-        Err(_) => return YRX_RESULT::INVALID_ARGUMENT,
+        Err(err) => {
+            LAST_ERROR.set(Some(CString::new(err.to_string()).unwrap()));
+            return YRX_RESULT::INVALID_UTF8;
+        }
     };
 
     let scanner = scanner.as_mut().unwrap();
@@ -252,13 +258,13 @@ pub unsafe extern "C" fn yrx_scanner_set_global_str(
     ident: *const c_char,
     value: *const c_char,
 ) -> YRX_RESULT {
-    let value = if let Ok(value) = CStr::from_ptr(value).to_str() {
-        value
-    } else {
-        return YRX_RESULT::INVALID_ARGUMENT;
-    };
-
-    yrx_scanner_set_global(scanner, ident, value)
+    match CStr::from_ptr(value).to_str() {
+        Ok(value) => yrx_scanner_set_global(scanner, ident, value),
+        Err(err) => {
+            LAST_ERROR.set(Some(CString::new(err.to_string()).unwrap()));
+            YRX_RESULT::INVALID_UTF8
+        }
+    }
 }
 
 /// Sets the value of a global variable of type bool.