find: -printf: reject an over-large field width instead of panicking

src/find/matchers/printf.rs

@@ -207,7 +207,7 @@ impl FormatStringParser<'_> {
         }
     }
 
-    fn parse_format_width(&mut self) -> Option<usize> {
+    fn parse_format_width(&mut self) -> Result<Option<usize>, Box<dyn Error>> {
         let start = self.string;
         let mut digits = 0;
 
@@ -218,11 +218,16 @@ impl FormatStringParser<'_> {
         }
 
         if digits > 0 {
-            // safe to unwrap: we already know all the digits are valid due to
-            // the above checks.
-            Some((start[0..digits]).parse().unwrap())
+            let digits = &start[0..digits];
+            let width: usize = digits
+                .parse()
+                .map_err(|_| format!("Invalid format width: {digits}"))?;
+            if width > u16::MAX as usize {
+                return Err(format!("Format width too large: {digits}").into());
+            }
+            Ok(Some(width))
         } else {
-            None
+            Ok(None)
         }
     }
 
@@ -258,7 +263,7 @@ impl FormatStringParser<'_> {
             self.advance_one().unwrap();
         }
 
-        let width = self.parse_format_width();
+        let width = self.parse_format_width()?;
 
         let first = self.advance_one()?;
         if first == '%' {

tests/test_find.rs

@@ -519,6 +519,30 @@ fn find_printf_octal_escape_before_multibyte_char() {
         .stdout_only("\0€\n");
 }
 
+#[test]
+fn find_printf_width_too_large() {
+    ucmd()
+        .args(&[
+            "./test_data/simple",
+            "-maxdepth",
+            "0",
+            "-printf",
+            "%70000s\\n",
+        ])
+        .fails()
+        .stderr_contains("find: Format width too large");
+    ucmd()
+        .args(&[
+            "./test_data/simple",
+            "-maxdepth",
+            "0",
+            "-printf",
+            "%99999999999999999999s\\n",
+        ])
+        .fails()
+        .stderr_contains("find: Invalid format width");
+}
+
 #[cfg(unix)]
 #[test]
 fn find_perm() {