Detect SHA-1 when it appears in certificate chains

net/cert/cert_verify_proc_android.cc

Index: net/cert/cert_verify_proc_android.cc
diff --git a/net/cert/cert_verify_proc_android.cc b/net/cert/cert_verify_proc_android.cc
index bd747267a2e0c293465020e2ff35497d806f8c74..8bd7e54f2f417cd12c9cb69f7bbdca20fb6c109f 100644
--- a/net/cert/cert_verify_proc_android.cc
+++ b/net/cert/cert_verify_proc_android.cc
@@ -4,6 +4,8 @@
 
 #include "net/cert/cert_verify_proc_android.h"
 
+#include <openssl/x509v3.h>
+
 #include <string>
 #include <vector>
 
@@ -71,6 +73,38 @@ bool VerifyFromAndroidTrustManager(const std::vector<std::string>& cert_bytes,
       verify_result->verified_cert = verified_cert;
   }
 
+  // Extract the algorithm information from the certs
+  X509Certificate::OSCertHandles chain;
+  const X509Certificate::OSCertHandles& intermediates =
+      verify_result->verified_cert->GetIntermediateCertificates();
+  chain.push_back(verify_result->verified_cert->os_cert_handle());
+  chain.insert(chain.end(), intermediates.begin(), intermediates.end());
+
+  // If a root certificate is present, ignore its signature algorithm. If it
+  // is unclear whether or not a root is present, assume the chain is a full,
+  // but unverified, chain.

[davidben, 2014/08/28 19:42:08]

Is this comment accurate? If we were unable to build a chain,
correction_for_root will be 0 and we would check that everything not have SHA-1.
So we're assuming that it's a partial chain with the root missing.

+  size_t correction_for_root =
+      (verify_result->cert_status &
+       (CERT_STATUS_AUTHORITY_INVALID | CERT_STATUS_INVALID))
+          ? 0
+          : 1;
+  for (size_t i = 0; i < chain.size() - correction_for_root; ++i) {
+    int sig_alg = OBJ_obj2nid(chain[i]->sig_alg->algorithm);
+    if (sig_alg == NID_md2WithRSAEncryption) {
+      verify_result->has_md2 = true;
+    } else if (sig_alg == NID_md4WithRSAEncryption) {
+      verify_result->has_md4 = true;
+    } else if (sig_alg == NID_md5WithRSAEncryption ||
+               sig_alg == NID_md5WithRSA) {
+      verify_result->has_md5 = true;
+    } else if (sig_alg == NID_sha1WithRSAEncryption ||
+               sig_alg == NID_dsaWithSHA || sig_alg == NID_dsaWithSHA1 ||
+               sig_alg == NID_dsaWithSHA1_2 || sig_alg == NID_sha1WithRSA ||
+               sig_alg == NID_ecdsa_with_SHA1) {
+      verify_result->has_sha1 = true;
+    }
+  }
+
   // Extract the public key hashes.
   for (size_t i = 0; i < verified_chain.size(); i++) {
     base::StringPiece spki_bytes;