methods/gpgv: Rewrite error handling and message

[apt.git] / methods / gpgv.cc

diff --git a/methods/gpgv.cc b/methods/gpgv.cc
index 5800a04f00dae07d6bf441e58b9c68c92057d39d..f355aaac345911ec257287d4131dff9ff131fa77 100644 (file)
--- a/methods/gpgv.cc
+++ b/methods/gpgv.cc
@@ -17,7 +17,10 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include <array>
 #include <algorithm>
+#include <sstream>
+#include <iterator>
 #include <iostream>
 #include <string>
 #include <vector>
@@ -29,7 +32,6 @@ using std::vector;
 
 #define GNUPGPREFIX "[GNUPG:]"
 #define GNUPGBADSIG "[GNUPG:] BADSIG"
-#define GNUPGERRSIG "[GNUPG:] ERRSIG"
 #define GNUPGNOPUBKEY "[GNUPG:] NO_PUBKEY"
 #define GNUPGVALIDSIG "[GNUPG:] VALIDSIG"
 #define GNUPGGOODSIG "[GNUPG:] GOODSIG"
@@ -37,6 +39,45 @@ using std::vector;
 #define GNUPGREVKEYSIG "[GNUPG:] REVKEYSIG"
 #define GNUPGNODATA "[GNUPG:] NODATA"
 
+struct Digest {
+   enum class State {
+      Untrusted,
+      Weak,
+      Trusted,
+   } state;
+   char name[32];
+};
+
+static constexpr Digest Digests[] = {
+   {Digest::State::Untrusted, "Invalid digest"},
+   {Digest::State::Untrusted, "MD5"},
+   {Digest::State::Weak, "SHA1"},
+   {Digest::State::Weak, "RIPE-MD/160"},
+   {Digest::State::Trusted, "Reserved digest"},
+   {Digest::State::Trusted, "Reserved digest"},
+   {Digest::State::Trusted, "Reserved digest"},
+   {Digest::State::Trusted, "Reserved digest"},
+   {Digest::State::Trusted, "SHA256"},
+   {Digest::State::Trusted, "SHA384"},
+   {Digest::State::Trusted, "SHA512"},
+   {Digest::State::Trusted, "SHA224"},
+};
+
+static Digest FindDigest(std::string const & Digest)
+{
+   int id = atoi(Digest.c_str());
+   if (id >= 0 && static_cast<unsigned>(id) < _count(Digests)) {
+      return Digests[id];
+   } else {
+      return Digests[0];
+   }
+}
+
+struct Signer {
+   std::string key;
+   std::string note;
+};
+
 class GPGVMethod : public aptMethod
 {
    private:
@@ -45,8 +86,8 @@ class GPGVMethod : public aptMethod
                                vector<string> &GoodSigners,
                                 vector<string> &BadSigners,
                                 vector<string> &WorthlessSigners,
+                                vector<Signer> &SoonWorthlessSigners,
                                vector<string> &NoPubKeySigners);
-   
    protected:
    virtual bool URIAcquire(std::string const &Message, FetchItem *Itm) APT_OVERRIDE;
    public:
@@ -59,6 +100,7 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
                                         vector<string> &GoodSigners,
                                         vector<string> &BadSigners,
                                         vector<string> &WorthlessSigners,
+                                        vector<Signer> &SoonWorthlessSigners,
                                         vector<string> &NoPubKeySigners)
 {
    bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
@@ -102,12 +144,6 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
             std::clog << "Got BADSIG! " << std::endl;
          BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
       }
-      else if (strncmp(buffer, GNUPGERRSIG, sizeof(GNUPGERRSIG)-1) == 0)
-      {
-         if (Debug == true)
-            std::clog << "Got ERRSIG! " << std::endl;
-         BadSigners.push_back(string(buffer+sizeof(GNUPGPREFIX)));
-      }
       else if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
       {
          if (Debug == true)
@@ -146,12 +182,33 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
       else if (strncmp(buffer, GNUPGVALIDSIG, sizeof(GNUPGVALIDSIG)-1) == 0)
       {
          char *sig = buffer + sizeof(GNUPGVALIDSIG);
+         std::istringstream iss((string(sig)));
+         vector<string> tokens{std::istream_iterator<string>{iss},
+                               std::istream_iterator<string>{}};
          char *p = sig;
          while (*p && isxdigit(*p))
             p++;
          *p = 0;
          if (Debug == true)
             std::clog << "Got VALIDSIG, key ID: " << sig << std::endl;
+         // Reject weak digest algorithms
+         Digest digest = FindDigest(tokens[7]);
+         switch (digest.state) {
+         case Digest::State::Weak:
+            // Treat them like an expired key: For that a message about expiry
+            // is emitted, a VALIDSIG, but no GOODSIG.
+            SoonWorthlessSigners.push_back({string(sig), digest.name});
+            break;
+         case Digest::State::Untrusted:
+            // Treat them like an expired key: For that a message about expiry
+            // is emitted, a VALIDSIG, but no GOODSIG.
+            WorthlessSigners.push_back(string(sig));
+            GoodSigners.erase(std::remove(GoodSigners.begin(), GoodSigners.end(), string(sig)));
+            break;
+         case Digest::State::Trusted:
+            break;
+         }
+
          ValidSigners.push_back(string(sig));
       }
    }
@@ -233,6 +290,7 @@ bool GPGVMethod::URIAcquire(std::string const &Message, FetchItem *Itm)
    vector<string> BadSigners;
    // a worthless signature is a expired or revoked one
    vector<string> WorthlessSigners;
+   vector<Signer> SoonWorthlessSigners;
    vector<string> NoPubKeySigners;
    
    FetchResult Res;
@@ -242,7 +300,20 @@ bool GPGVMethod::URIAcquire(std::string const &Message, FetchItem *Itm)
    // Run apt-key on file, extract contents and get the key ID of the signer
    string msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(), key,
                                  GoodSigners, BadSigners, WorthlessSigners,
-                                 NoPubKeySigners);
+                                 SoonWorthlessSigners, NoPubKeySigners);
+
+
+   // Check if there are any good signers that are not soon worthless
+   std::vector<std::string> NotWarnAboutSigners(GoodSigners);
+   for (auto const & Signer : SoonWorthlessSigners)
+      NotWarnAboutSigners.erase(std::remove(NotWarnAboutSigners.begin(), NotWarnAboutSigners.end(), "GOODSIG " + Signer.key));
+   // If all signers are soon worthless, report them.
+   if (NotWarnAboutSigners.empty()) {
+      for (auto const & Signer : SoonWorthlessSigners)
+         // TRANSLATORS: The second %s is the reason and is untranslated for repository owners.
+         Warning(_("Weak signature from %s (%s)"), Signer.key.c_str(), Signer.note.c_str());
+   }
+
    if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.empty())
    {
       string errmsg;