From 07d6056ef070de8bccf856540da1125db656625a Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Sat, 7 Dec 2024 10:54:25 +0100
Subject: [PATCH] stat: handle error better. should make
 tests/stat/stat-printf.pl pass

---
 src/uu/stat/src/stat.rs    |  9 +++++++++
 tests/by-util/test_stat.rs | 17 +++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/src/uu/stat/src/stat.rs b/src/uu/stat/src/stat.rs
index 0a6a4a6c4ef..2a61f9b7b34 100644
--- a/src/uu/stat/src/stat.rs
+++ b/src/uu/stat/src/stat.rs
@@ -563,6 +563,15 @@ impl Stater {
         if let Some((field_width, offset)) = format_str[j..].scan_num::<usize>() {
             width = field_width;
             j += offset;
+
+            // Reject directives like `%<NUMBER>` by checking if width has been parsed.
+            if j >= bound || chars[j] == '%' {
+                let invalid_directive: String = chars[old..=j.min(bound - 1)].iter().collect();
+                return Err(USimpleError::new(
+                    1,
+                    format!("{}: invalid directive", invalid_directive.quote()),
+                ));
+            }
         }
         check_bound(format_str, bound, old, j)?;
 
diff --git a/tests/by-util/test_stat.rs b/tests/by-util/test_stat.rs
index cb52f19e055..161efd061f9 100644
--- a/tests/by-util/test_stat.rs
+++ b/tests/by-util/test_stat.rs
@@ -412,3 +412,20 @@ fn test_printf_bel_etc() {
         .succeeds()
         .stdout_is_bytes(expected_stdout);
 }
+
+#[test]
+fn test_printf_invalid_directive() {
+    let ts = TestScenario::new(util_name!());
+
+    ts.ucmd()
+        .args(&["--printf=%9", "."])
+        .fails()
+        .code_is(1)
+        .stderr_contains("'%9': invalid directive");
+
+    ts.ucmd()
+        .args(&["--printf=%9%", "."])
+        .fails()
+        .code_is(1)
+        .stderr_contains("'%9%': invalid directive");
+}