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Fix invalid DNS SAN entries (#795) #802

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merged 4 commits into from
Feb 4, 2019
Merged

Fix invalid DNS SAN entries (#795) #802

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a8148cc
Fix invalid DNS SAN entries (#795)
mrohera Feb 4, 2019
fc4a0c6
Revert "Fix invalid DNS SAN entries (#795)"
myagley Feb 4, 2019
d1c1521
prepare_dns_san_entries was allowing characters that are not A-Za-z0-…
darobs Jan 24, 2019
d134081
Fix invalid DNS SAN entries (#795)
mrohera Feb 4, 2019
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21 changes: 13 additions & 8 deletions edgelet/edgelet-http-workload/src/server/cert/server.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,9 @@ use edgelet_core::{
};
use edgelet_http::route::{Handler, Parameters};
use edgelet_http::Error as HttpError;
use edgelet_utils::{ensure_not_empty_with_context, prepare_dns_san_entries};
use edgelet_utils::{
append_dns_san_entries, ensure_not_empty_with_context, prepare_dns_san_entries,
};
use workload::models::ServerCertificateRequest;

use error::{CertOperation, Error, ErrorKind};
Expand Down Expand Up @@ -87,7 +89,10 @@ where
// an alternative DNS name; we also need to add the common_name that we are using
// as a DNS name since the presence of a DNS name SAN will take precedence over
// the common name
let sans = vec![prepare_dns_san_entries(&[&module_id, common_name])];
let sans = vec![append_dns_san_entries(
&prepare_dns_san_entries(&[&module_id]),
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Feels like this should be made prepare_dns_san_entry again..

&[common_name],
)];

#[cfg_attr(feature = "cargo-clippy", allow(cast_sign_loss))]
let props = CertificateProperties::new(
Expand Down Expand Up @@ -546,12 +551,12 @@ mod tests {
fn succeeds_key() {
let handler = ServerCertHandler::new(
TestHsm::default().with_on_create(|props| {
assert_eq!("marvin", props.common_name());
assert_eq!("beeblebroxIserver", props.alias());
assert_eq!("2020marvin", props.common_name());
assert_eq!("$beeblebroxIserver", props.alias());
assert_eq!(CertificateType::Server, *props.certificate_type());
let san_entries = props.san_entries().unwrap();
assert_eq!(1, san_entries.len());
assert_eq!("DNS:beeblebrox, DNS:marvin", san_entries[0]);
assert_eq!("DNS:2020marvin, DNS:beeblebrox", san_entries[0]);
assert!(MAX_DURATION_SEC >= *props.validity_in_secs());
Ok(TestCert::default()
.with_private_key(PrivateKey::Key(KeyBytes::Pem("Betelgeuse".to_string()))))
Expand All @@ -560,17 +565,17 @@ mod tests {
);

let cert_req = ServerCertificateRequest::new(
"marvin".to_string(),
"2020marvin".to_string(),
(Utc::now() + Duration::hours(1)).to_rfc3339(),
);

let request =
Request::get("http://localhost/modules/beeblebrox/genid/I/certificate/server")
Request::get("http://localhost/modules/$beeblebrox/genid/I/certificate/server")
.body(serde_json::to_string(&cert_req).unwrap().into())
.unwrap();

let params = Parameters::with_captures(vec![
(Some("name".to_string()), "beeblebrox".to_string()),
(Some("name".to_string()), "$beeblebrox".to_string()),
(Some("genid".to_string()), "I".to_string()),
]);
let response = handler.handle(request, params).wait().unwrap();
Expand Down
100 changes: 86 additions & 14 deletions edgelet/edgelet-utils/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,6 @@ mod logging;
pub mod macros;
mod ser_de;

use std::cmp;
use std::collections::HashMap;

pub use error::{Error, ErrorKind};
Expand Down Expand Up @@ -70,27 +69,56 @@ pub fn prepare_cert_uri_module(hub_name: &str, device_id: &str, module_id: &str)
)
}

const ALLOWED_CHAR_DNS: char = '-';
const DNS_MAX_SIZE: usize = 63;

/// The name returned from here must conform to following rules (as per RFC 1035):
/// - length must be <= 63 characters
/// - must be all lower case alphanumeric characters or '-'
/// - must start with an alphabet
/// - must end with an alphanumeric character
pub fn sanitize_dns_label(name: &str) -> String {
name.trim_start_matches(|c: char| !c.is_ascii_alphabetic())
.trim_end_matches(|c: char| !c.is_ascii_alphanumeric())
.to_lowercase()
.chars()
.filter(|c| c.is_ascii_alphanumeric() || c == &ALLOWED_CHAR_DNS)
.take(DNS_MAX_SIZE)
.collect::<String>()
}

pub fn prepare_dns_san_entries(names: &[&str]) -> String {
names
.iter()
.map(|name| {
// The name returned from here must conform to following rules (as per RFC 1035):
// - length must be <= 63 characters
// - must be all lower case alphanumeric characters or '-'
// - must start with an alphabet
// - must end with an alphanumeric character
let name = name
.to_lowercase()
.trim_start_matches(|c| !char::is_ascii_lowercase(&c))
.trim_end_matches(|c| !char::is_alphanumeric(c))
.replace(|c| !(char::is_alphanumeric(c) || c == '-'), "");

format!("DNS:{}", &name[0..cmp::min(name.len(), 63)])
.filter_map(|name| {
let dns = sanitize_dns_label(name);
if dns.is_empty() {
None
} else {
Some(format!("DNS:{}", dns))
}
})
.collect::<Vec<String>>()
.join(", ")
}

pub fn append_dns_san_entries(sans: &str, names: &[&str]) -> String {
let mut dns_sans = names
.iter()
.filter_map(|name| {
if name.trim().is_empty() {
None
} else {
Some(format!("DNS:{}", name.to_lowercase()))
}
})
.collect::<Vec<String>>()
.join(", ");
dns_sans.push_str(", ");
dns_sans.push_str(sans);
dns_sans
}

#[cfg(test)]
mod tests {
use super::*;
Expand Down Expand Up @@ -151,11 +179,43 @@ mod tests {
);
}

#[test]
fn dns_label() {
assert_eq!(
"abcdefg-hijklmnop-qrs-tuv-wxyz",
sanitize_dns_label(" -abcdefg-hijklmnop-qrs-tuv-wxyz- ")
);
assert!('\u{4eac}'.is_alphanumeric());
assert_eq!(
"abcdefg-hijklmnop-qrs-tuv-wxyz",
sanitize_dns_label("\u{4eac}ABCDEFG-\u{4eac}HIJKLMNOP-QRS-TUV-WXYZ\u{4eac}")
);
assert_eq!(String::default(), sanitize_dns_label("--------------"));
assert_eq!("a", sanitize_dns_label("a"));
assert_eq!("a-1", sanitize_dns_label("a - 1"));
assert_eq!("edgehub", sanitize_dns_label("$edgeHub"));
let expected_name = "a23456789-123456789-123456789-123456789-123456789-123456789-123";
assert_eq!(expected_name.len(), DNS_MAX_SIZE);
assert_eq!(
expected_name,
sanitize_dns_label("a23456789-123456789-123456789-123456789-123456789-123456789-1234")
);

assert_eq!(
expected_name,
sanitize_dns_label("$a23456789-123456789-123456789-123456789-123456789-123456789-1234")
);
}

#[test]
fn dns_san() {
assert_eq!("DNS:edgehub", prepare_dns_san_entries(&["edgehub"]));
assert_eq!("DNS:edgehub", prepare_dns_san_entries(&["EDGEhub"]));
assert_eq!("DNS:edgehub", prepare_dns_san_entries(&["$$$Edgehub"]));
assert_eq!(
"DNS:edgehub",
prepare_dns_san_entries(&["\u{4eac}Edge\u{4eac}hub\u{4eac}"])
);
assert_eq!(
"DNS:edgehub",
prepare_dns_san_entries(&["$$$Edgehub###$$$"])
Expand Down Expand Up @@ -187,5 +247,17 @@ mod tests {
"DNS:edgehub, DNS:edgy, DNS:moo",
prepare_dns_san_entries(&["edgehub", "edgy", "moo"])
);
// test skipping invalid entries
assert_eq!(
"DNS:edgehub, DNS:moo",
prepare_dns_san_entries(&[" -edgehub -", "-----", "- moo- "])
);

// test appending host name to sanitized label
let sanitized_labels = prepare_dns_san_entries(&["1edgehub", "2edgy"]);
assert_eq!(
"DNS:2019host, DNS:2020host, DNS:edgehub, DNS:edgy",
append_dns_san_entries(&sanitized_labels, &["2019host", " ", "2020host"])
);
}
}