tracing: disable regular expression matching in log filters

Cargo.lock

@@ -2632,9 +2632,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-subscriber"
-version = "0.3.9"
+version = "0.3.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e0ab7bdc962035a87fba73f3acca9b8a8d0034c2e6f60b84aeaaddddc155dce"
+checksum = "b9df98b037d039d03400d9dd06b0f8ce05486b5f25e9a2d7d36196e142ebbc52"
 dependencies = [
  "ansi_term",
  "lazy_static",

linkerd/tracing/Cargo.toml

@@ -17,6 +17,6 @@ tracing = "0.1"
 tracing-log = "0.1"
 
 [dependencies.tracing-subscriber]
-version = "0.3"
+version = "0.3.10"
 default-features = false
 features = ["env-filter", "fmt", "smallvec", "tracing-log", "json", "parking_lot", "registry"]

linkerd/tracing/src/level.rs

@@ -1,10 +1,23 @@
 use linkerd_error::Error;
 use tracing::trace;
-use tracing_subscriber::{reload, EnvFilter, Registry};
+use tracing_subscriber::{
+    filter::{self, EnvFilter, LevelFilter},
+    reload, Registry,
+};
 
 #[derive(Clone)]
 pub struct Handle(reload::Handle<EnvFilter, Registry>);
 
+/// Returns an `EnvFilter` builder with the configuration used for parsing new
+/// filter strings.
+pub(crate) fn filter_builder() -> filter::Builder {
+    EnvFilter::builder()
+        .with_default_directive(LevelFilter::WARN.into())
+        // Disable regular expression matching for `fmt::Debug` fields, use
+        // exact string matching instead.
+        .with_regex(false)
+}
+
 impl Handle {
     pub(crate) fn new(handle: reload::Handle<EnvFilter, Registry>) -> Self {
         Self(handle)
@@ -18,7 +31,7 @@ impl Handle {
 
     pub fn set_level(&self, level: impl AsRef<str>) -> Result<(), Error> {
         let level = level.as_ref();
-        let filter = level.parse::<EnvFilter>()?;
+        let filter = filter_builder().parse(level)?;
         self.0.reload(filter)?;
         tracing::info!(%level, "set new log level");
         Ok(())

linkerd/tracing/src/lib.rs

@@ -16,7 +16,7 @@ use linkerd_error::Error;
 use std::str;
 use tracing::{Dispatch, Subscriber};
 use tracing_subscriber::{
-    filter::{EnvFilter, FilterFn},
+    filter::{FilterFn, LevelFilter},
     fmt::format,
     prelude::*,
     registry::LookupSpan,
@@ -60,7 +60,6 @@ pub fn init() -> Result<Handle, Error> {
 
 #[inline]
 pub(crate) fn update_max_level() {
-    use tracing::level_filters::LevelFilter;
     use tracing_log::{log, AsLog};
     log::set_max_level(LevelFilter::current().as_log());
 }
@@ -167,7 +166,11 @@ impl Settings {
     pub fn build(self) -> (Dispatch, Handle) {
         let log_level = self.filter.as_deref().unwrap_or(DEFAULT_LOG_LEVEL);
 
-        let mut filter = EnvFilter::new(log_level);
+        let mut filter = level::filter_builder()
+            // When parsing the initial filter configuration from the
+            // environment variable, use `parse_lossy` to skip any invalid
+            // filter directives and print an error.
+            .parse_lossy(log_level);
 
         // If access logging is enabled, build the access log layer.
         let access_log = if let Some(format) = self.access_log {