max / makenotwork

validation: reject control characters in bio and sync device name (ultra-fuzz NOTE tail) Closes the Run 2 NOTE that validate_bio and validate_sync_device_name accepted control characters, while display-name and sync-app-name already rejected them. Bio allows newlines/tabs (multi-line) but not other control chars; device name rejects all control chars, mirroring validate_sync_app_name. Tests cover NUL and escape. (Bidi/format chars are a separate Trojan-source concern, out of scope for this NOTE; is_control() matches the existing validators' policy.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Max Johnson <me@maxj.phd> · 2026-06-23 20:43 UTC

Signed with PGP, not checked

Commit: ccf8532a5b4ff192b7a3a631fa1a94d45b7ffbb6

Parent: bf7d7c6

2 files changed, +21 insertions, -0 deletions

M server/src/validation/mod.rs +9

			@@ -133,6 +133,12 @@
133	133		limits::SYNC_DEVICE_NAME_MAX
134	134		)));
135	135		}
	136	+	// Reject control characters, mirroring `validate_sync_app_name`.
	137	+	if name.chars().any(\|c\| c.is_control()) {
	138	+	return Err(AppError::validation(
	139	+	"Device name must not contain control characters".to_string(),
	140	+	));
	141	+	}
136	142		Ok(())
137	143		}
138	144
			@@ -234,6 +240,9 @@
234	240		assert!(validate_sync_device_name("Max's MacBook").is_ok());
235	241		assert!(validate_sync_device_name("").is_err());
236	242		assert!(validate_sync_device_name(&"a".repeat(101)).is_err());
	243	+	// Control characters (NUL, escape) are rejected.
	244	+	assert!(validate_sync_device_name("laptop\u{0}").is_err());
	245	+	assert!(validate_sync_device_name("laptop\u{1b}evil").is_err());
237	246		}
238	247
239	248		#[test]

M server/src/validation/users.rs +12

			@@ -29,6 +29,14 @@
29	29		limits::BIO_MAX
30	30		)));
31	31		}
	32	+	// Reject control characters (NUL, escape, etc.) while allowing normal
	33	+	// whitespace (newlines/tabs) so multi-line bios still work. Mirrors the
	34	+	// display-name and sync-app-name validators.
	35	+	if bio.chars().any(\|c\| c.is_control() && !matches!(c, '\n' \| '\r' \| '\t')) {
	36	+	return Err(AppError::validation(
	37	+	"Bio must not contain control characters".to_string(),
	38	+	));
	39	+	}
32	40		Ok(())
33	41		}
34	42
			@@ -233,6 +241,10 @@
233	241		assert!(validate_bio("I make music").is_ok());
234	242		assert!(validate_bio("").is_ok());
235	243		assert!(validate_bio(&"a".repeat(2001)).is_err());
	244	+	// Newlines/tabs are fine (multi-line bios); other control chars aren't.
	245	+	assert!(validate_bio("line one\nline two\ttabbed").is_ok());
	246	+	assert!(validate_bio("evil\u{0}nul").is_err());
	247	+	assert!(validate_bio("esc\u{1b}ape").is_err());
236	248		}
237	249
238	250		#[test]