From 619f5c794620b6541a41cedd6d22e469a2b3df54 Mon Sep 17 00:00:00 2001
From: Matt Mueller <mattm@chromium.org>
Date: Thu, 21 May 2026 19:52:09 -0700
Subject: [PATCH] client_cert_matcher: fix break from nested loop

Bug: 513465245
Change-Id: I9eab79863695c44b46515574080b4f543b057165
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7862009
Reviewed-by: Nick Harper <nharper@chromium.org>
Commit-Queue: Matt Mueller <mattm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1634691}
---

diff --git a/net/ssl/client_cert_matcher.cc b/net/ssl/client_cert_matcher.cc
index 6aa0cc3d..cdfd5e39 100644
--- a/net/ssl/client_cert_matcher.cc
+++ b/net/ssl/client_cert_matcher.cc
@@ -17,6 +17,31 @@
 
 namespace {
 
+// Searches in `sources` for a certificate with subject matching
+// `current_issuer`. If found, the certificate is added to `intermediates`,
+// `current_issuer` and `current_subject` are updated to the values from the
+// certificate, and true is returned.
+bool FindIssuerCert(const ClientCertIssuerSourceCollection& sources,
+                    std::vector<bssl::UniquePtr<CRYPTO_BUFFER>>* intermediates,
+                    base::span<const uint8_t>* current_issuer,
+                    base::span<const uint8_t>* current_subject) {
+  for (const auto& source : sources) {
+    std::vector<bssl::UniquePtr<CRYPTO_BUFFER>> issuers =
+        source->GetCertsByName(*current_issuer);
+    for (auto& issuer : issuers) {
+      if (asn1::ExtractIssuerAndSubjectFromDERCert(
+              x509_util::CryptoBufferAsSpan(issuer.get()), current_issuer,
+              current_subject)) {
+        // The first matching issuer found at each step is used. This algorithm
+        // doesn't do a full graph exploration.
+        intermediates->push_back(std::move(issuer));
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 bool MatchClientCertificateIssuers(
     X509Certificate* cert,
     const std::vector<std::string>& cert_authorities,
@@ -54,24 +79,8 @@
     }
 
     // Look for an issuer of the current cert.
-    bool found_issuer = false;
-    for (const auto& source : sources) {
-      std::vector<bssl::UniquePtr<CRYPTO_BUFFER>> issuers =
-          source->GetCertsByName(current_issuer);
-      for (auto& issuer : issuers) {
-        if (asn1::ExtractIssuerAndSubjectFromDERCert(
-                x509_util::CryptoBufferAsSpan(issuer.get()), &current_issuer,
-                &current_subject)) {
-          // The first issuer found at each step is used. This algorithm doesn't
-          // do a full graph exploration.
-          found_issuer = true;
-          intermediates->push_back(std::move(issuer));
-          break;
-        }
-      }
-    }
-
-    if (!found_issuer) {
+    if (!FindIssuerCert(sources, intermediates, &current_issuer,
+                        &current_subject)) {
       // No issuers were found, give up.
       return false;
     }