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-rw-r--r--methods/gpgv.cc525
1 files changed, 525 insertions, 0 deletions
diff --git a/methods/gpgv.cc b/methods/gpgv.cc
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index 0000000..a9da456
--- /dev/null
+++ b/methods/gpgv.cc
@@ -0,0 +1,525 @@
+#include <config.h>
+
+#include "aptmethod.h"
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/strutl.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <array>
+#include <iostream>
+#include <iterator>
+#include <map>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include <apti18n.h>
+
+using std::string;
+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"
+#define GNUPGEXPKEYSIG "[GNUPG:] EXPKEYSIG"
+#define GNUPGEXPSIG "[GNUPG:] EXPSIG"
+#define GNUPGREVKEYSIG "[GNUPG:] REVKEYSIG"
+#define GNUPGNODATA "[GNUPG:] NODATA"
+#define APTKEYWARNING "[APTKEY:] WARNING"
+#define APTKEYERROR "[APTKEY:] ERROR"
+
+struct Digest {
+ enum class State {
+ Untrusted,
+ Weak,
+ Trusted,
+ } state;
+ char name[32];
+
+ State getState() const {
+ std::string optionUntrusted;
+ std::string optionWeak;
+ strprintf(optionUntrusted, "APT::Hashes::%s::Untrusted", name);
+ strprintf(optionWeak, "APT::Hashes::%s::Weak", name);
+ if (_config->FindB(optionUntrusted, false) == true)
+ return State::Untrusted;
+ if (_config->FindB(optionWeak, false) == true)
+ return State::Weak;
+
+ return state;
+ }
+};
+
+static constexpr Digest Digests[] = {
+ {Digest::State::Untrusted, "Invalid digest"},
+ {Digest::State::Untrusted, "MD5"},
+ {Digest::State::Untrusted, "SHA1"},
+ {Digest::State::Untrusted, "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) < APT_ARRAY_SIZE(Digests))
+ {
+ return Digests[id];
+ } else {
+ return Digests[0];
+ }
+}
+
+struct Signer {
+ std::string key;
+ std::string note;
+};
+static bool IsTheSameKey(std::string const &validsig, std::string const &goodsig) {
+ // VALIDSIG reports a fingerprint (40 = 24 + 16), GOODSIG can be longid (16) or
+ // fingerprint according to documentation in DETAILS.gz
+ if (goodsig.length() == 40 + strlen("GOODSIG "))
+ return validsig.compare(0, 40, goodsig, strlen("GOODSIG "), 40) == 0;
+ return validsig.compare(24, 16, goodsig, strlen("GOODSIG "), 16) == 0;
+}
+
+struct APT_HIDDEN SignersStorage {
+ std::vector<std::string> Good;
+ std::vector<std::string> Bad;
+ std::vector<std::string> Worthless;
+ // a worthless signature is a expired or revoked one
+ std::vector<Signer> SoonWorthless;
+ std::vector<std::string> NoPubKey;
+ std::vector<std::string> Valid;
+ std::vector<std::string> SignedBy;
+};
+class GPGVMethod : public aptMethod
+{
+ private:
+ string VerifyGetSigners(const char *file, const char *outfile,
+ vector<string> const &keyFpts,
+ vector<string> const &keyFiles,
+ SignersStorage &Signers);
+ protected:
+ virtual bool URIAcquire(std::string const &Message, FetchItem *Itm) APT_OVERRIDE;
+ public:
+ GPGVMethod() : aptMethod("gpgv", "1.1", SingleInstance | SendConfig | SendURIEncoded){};
+};
+static void PushEntryWithKeyID(std::vector<std::string> &Signers, char * const buffer, bool const Debug)
+{
+ char * const msg = buffer + sizeof(GNUPGPREFIX);
+ char *p = msg;
+ // skip the message
+ while (*p && !isspace(*p))
+ ++p;
+ // skip the separator whitespace
+ ++p;
+ // skip the hexdigit fingerprint
+ while (*p && isxdigit(*p))
+ ++p;
+ // cut the rest from the message
+ *p = '\0';
+ if (Debug == true)
+ std::clog << "Got " << msg << " !" << std::endl;
+ Signers.push_back(msg);
+}
+static void PushEntryWithUID(std::vector<std::string> &Signers, char * const buffer, bool const Debug)
+{
+ std::string msg = buffer + sizeof(GNUPGPREFIX);
+ auto const nuke = msg.find_last_not_of("\n\t\r");
+ if (nuke != std::string::npos)
+ msg.erase(nuke + 1);
+ if (Debug == true)
+ std::clog << "Got " << msg << " !" << std::endl;
+ Signers.push_back(msg);
+}
+static void implodeVector(std::vector<std::string> const &vec, std::ostream &out, char const * const sep)
+{
+ if (vec.empty())
+ return;
+ std::copy(vec.begin(), std::prev(vec.end()), std::ostream_iterator<std::string>(out, sep));
+ out << *vec.rbegin();
+ return;
+}
+string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
+ vector<string> const &keyFpts,
+ vector<string> const &keyFiles,
+ SignersStorage &Signers)
+{
+ bool const Debug = DebugEnabled();
+
+ if (Debug == true)
+ std::clog << "inside VerifyGetSigners" << std::endl;
+
+ int fd[2];
+
+ if (pipe(fd) < 0)
+ return "Couldn't create pipe";
+
+ pid_t pid = fork();
+ if (pid < 0)
+ return string("Couldn't spawn new process") + strerror(errno);
+ else if (pid == 0)
+ {
+ std::ostringstream keys;
+ implodeVector(keyFiles, keys, ",");
+ ExecGPGV(outfile, file, 3, fd, keys.str());
+ }
+ close(fd[1]);
+
+ FILE *pipein = fdopen(fd[0], "r");
+
+ // Loop over the output of apt-key (which really is gnupg), and check the signatures.
+ std::vector<std::string> ErrSigners;
+ std::map<std::string, std::vector<std::string>> SubKeyMapping;
+ size_t buffersize = 0;
+ char *buffer = NULL;
+ bool gotNODATA = false;
+ while (1)
+ {
+ if (getline(&buffer, &buffersize, pipein) == -1)
+ break;
+ if (Debug == true)
+ std::clog << "Read: " << buffer << std::endl;
+
+ // Push the data into three separate vectors, which
+ // we later concatenate. They're kept separate so
+ // if we improve the apt method communication stuff later
+ // it will be better.
+ if (strncmp(buffer, GNUPGBADSIG, sizeof(GNUPGBADSIG)-1) == 0)
+ PushEntryWithUID(Signers.Bad, buffer, Debug);
+ else if (strncmp(buffer, GNUPGERRSIG, sizeof(GNUPGERRSIG)-1) == 0)
+ PushEntryWithKeyID(ErrSigners, buffer, Debug);
+ else if (strncmp(buffer, GNUPGNOPUBKEY, sizeof(GNUPGNOPUBKEY)-1) == 0)
+ {
+ PushEntryWithKeyID(Signers.NoPubKey, buffer, Debug);
+ ErrSigners.erase(std::remove_if(ErrSigners.begin(), ErrSigners.end(), [&](std::string const &errsig) {
+ return errsig.compare(strlen("ERRSIG "), 16, buffer, sizeof(GNUPGNOPUBKEY), 16) == 0; }), ErrSigners.end());
+ }
+ else if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGNODATA)-1) == 0)
+ gotNODATA = true;
+ else if (strncmp(buffer, GNUPGEXPKEYSIG, sizeof(GNUPGEXPKEYSIG)-1) == 0)
+ PushEntryWithUID(Signers.Worthless, buffer, Debug);
+ else if (strncmp(buffer, GNUPGEXPSIG, sizeof(GNUPGEXPSIG)-1) == 0)
+ PushEntryWithUID(Signers.Worthless, buffer, Debug);
+ else if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
+ PushEntryWithUID(Signers.Worthless, buffer, Debug);
+ else if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
+ PushEntryWithKeyID(Signers.Good, buffer, Debug);
+ else if (strncmp(buffer, GNUPGVALIDSIG, sizeof(GNUPGVALIDSIG)-1) == 0)
+ {
+ std::istringstream iss(buffer + sizeof(GNUPGVALIDSIG));
+ vector<string> tokens{std::istream_iterator<string>{iss},
+ std::istream_iterator<string>{}};
+ auto const sig = tokens[0];
+ // Reject weak digest algorithms
+ Digest digest = FindDigest(tokens[7]);
+ switch (digest.getState()) {
+ case Digest::State::Weak:
+ // Treat them like an expired key: For that a message about expiry
+ // is emitted, a VALIDSIG, but no GOODSIG.
+ Signers.SoonWorthless.push_back({sig, digest.name});
+ if (Debug == true)
+ std::clog << "Got weak VALIDSIG, key ID: " << sig << std::endl;
+ break;
+ case Digest::State::Untrusted:
+ // Treat them like an expired key: For that a message about expiry
+ // is emitted, a VALIDSIG, but no GOODSIG.
+ Signers.Worthless.push_back(sig);
+ Signers.Good.erase(std::remove_if(Signers.Good.begin(), Signers.Good.end(), [&](std::string const &goodsig) {
+ return IsTheSameKey(sig, goodsig); }), Signers.Good.end());
+ if (Debug == true)
+ std::clog << "Got untrusted VALIDSIG, key ID: " << sig << std::endl;
+ break;
+
+ case Digest::State::Trusted:
+ if (Debug == true)
+ std::clog << "Got trusted VALIDSIG, key ID: " << sig << std::endl;
+ break;
+ }
+
+ Signers.Valid.push_back(sig);
+
+ if (tokens.size() > 9 && sig != tokens[9])
+ SubKeyMapping[tokens[9]].emplace_back(sig);
+ }
+ else if (strncmp(buffer, APTKEYWARNING, sizeof(APTKEYWARNING)-1) == 0)
+ Warning(buffer + sizeof(APTKEYWARNING));
+ else if (strncmp(buffer, APTKEYERROR, sizeof(APTKEYERROR)-1) == 0)
+ _error->Error("%s", buffer + sizeof(APTKEYERROR));
+ }
+ fclose(pipein);
+ free(buffer);
+ std::move(ErrSigners.begin(), ErrSigners.end(), std::back_inserter(Signers.Worthless));
+
+ // apt-key has a --keyid parameter, but this requires gpg, so we call it without it
+ // and instead check after the fact which keyids where used for verification
+ if (keyFpts.empty() == false)
+ {
+ if (Debug == true)
+ {
+ std::clog << "GoodSigs needs to be limited to keyid(s): ";
+ implodeVector(keyFpts, std::clog, ", ");
+ std::clog << "\n";
+ }
+ std::vector<std::string> filteredGood;
+ for (auto &&good: Signers.Good)
+ {
+ if (Debug == true)
+ std::clog << "Key " << good << " is good sig, is it also a valid and allowed one? ";
+ bool found = false;
+ for (auto l : keyFpts)
+ {
+ bool exactKey = false;
+ if (APT::String::Endswith(l, "!"))
+ {
+ exactKey = true;
+ l.erase(l.length() - 1);
+ }
+ if (IsTheSameKey(l, good))
+ {
+ // GOODSIG might be "just" a longid, so we check VALIDSIG which is always a fingerprint
+ if (std::find(Signers.Valid.cbegin(), Signers.Valid.cend(), l) == Signers.Valid.cend())
+ continue;
+ found = true;
+ Signers.SignedBy.push_back(l + "!");
+ break;
+ }
+ else if (exactKey == false)
+ {
+ auto const primary = SubKeyMapping.find(l);
+ if (primary == SubKeyMapping.end())
+ continue;
+ auto const validsubkeysig = std::find_if(primary->second.cbegin(), primary->second.cend(), [&](auto const subkey) {
+ return IsTheSameKey(subkey, good) && std::find(Signers.Valid.cbegin(), Signers.Valid.cend(), subkey) != Signers.Valid.cend();
+ });
+ if (validsubkeysig != primary->second.cend())
+ {
+ found = true;
+ Signers.SignedBy.push_back(l);
+ Signers.SignedBy.push_back(*validsubkeysig + "!");
+ break;
+ }
+ }
+ }
+ if (Debug)
+ std::clog << (found ? "yes" : "no") << "\n";
+ if (found)
+ filteredGood.emplace_back(std::move(good));
+ else
+ Signers.NoPubKey.emplace_back(std::move(good));
+ }
+ Signers.Good= std::move(filteredGood);
+ }
+ else
+ {
+ // for gpg an expired key is valid, too, but we want only the valid & good ones
+ for (auto const &v : Signers.Valid)
+ if (std::any_of(Signers.Good.begin(), Signers.Good.end(),
+ [&v](std::string const &g) { return IsTheSameKey(v, g); }))
+ Signers.SignedBy.push_back(v + "!");
+ for (auto sub : SubKeyMapping)
+ if (std::any_of(sub.second.begin(), sub.second.end(),
+ [&](std::string const &s) {
+ if (std::find(Signers.Valid.begin(), Signers.Valid.end(), s) == Signers.Valid.end())
+ return false;
+ return std::any_of(Signers.Good.begin(), Signers.Good.end(),
+ [&s](std::string const &g) { return IsTheSameKey(s, g); });
+ }))
+ Signers.SignedBy.push_back(sub.first);
+ }
+ std::sort(Signers.SignedBy.begin(), Signers.SignedBy.end());
+
+ int status;
+ waitpid(pid, &status, 0);
+ if (Debug == true)
+ {
+ ioprintf(std::clog, "gpgv exited with status %i\n", WEXITSTATUS(status));
+ }
+
+ if (Debug)
+ {
+ std::cerr << "Summary:\n Good: ";
+ implodeVector(Signers.Good, std::cerr, ", ");
+ std::cerr << "\n Valid: ";
+ implodeVector(Signers.Valid, std::cerr, ", ");
+ std::cerr << "\n Bad: ";
+ implodeVector(Signers.Bad, std::cerr, ", ");
+ std::cerr << "\n Worthless: ";
+ implodeVector(Signers.Worthless, std::cerr, ", ");
+ std::cerr << "\n SoonWorthless: ";
+ std::for_each(Signers.SoonWorthless.begin(), Signers.SoonWorthless.end(), [](Signer const &sig) { std::cerr << sig.key << ", "; });
+ std::cerr << "\n NoPubKey: ";
+ implodeVector(Signers.NoPubKey, std::cerr, ", ");
+ std::cerr << "\n Signed-By: ";
+ implodeVector(Signers.SignedBy, std::cerr, ", ");
+ std::cerr << std::endl << " NODATA: " << (gotNODATA ? "yes" : "no") << std::endl;
+ }
+
+ if (WEXITSTATUS(status) == 112)
+ {
+ // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
+ std::string errmsg;
+ //TRANSLATORS: %s is a single techy word like 'NODATA'
+ strprintf(errmsg, _("Clearsigned file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
+ return errmsg;
+ }
+ else if (gotNODATA)
+ {
+ // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
+ std::string errmsg;
+ //TRANSLATORS: %s is a single techy word like 'NODATA'
+ strprintf(errmsg, _("Signed file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
+ return errmsg;
+ }
+ else if (WEXITSTATUS(status) == 0)
+ {
+ if (keyFpts.empty() == false)
+ {
+ // gpgv will report success, but we want to enforce a certain keyring
+ // so if we haven't found the key the valid we found is in fact invalid
+ if (Signers.Good.empty())
+ return _("At least one invalid signature was encountered.");
+ }
+ else
+ {
+ if (Signers.Good.empty())
+ return _("Internal error: Good signature, but could not determine key fingerprint?!");
+ }
+ return "";
+ }
+ else if (WEXITSTATUS(status) == 1)
+ return _("At least one invalid signature was encountered.");
+ else if (WEXITSTATUS(status) == 111)
+ return _("Could not execute 'apt-key' to verify signature (is gnupg installed?)");
+ else
+ return _("Unknown error executing apt-key");
+}
+
+bool GPGVMethod::URIAcquire(std::string const &Message, FetchItem *Itm)
+{
+ URI const Get(Itm->Uri);
+ std::string const Path = DecodeSendURI(Get.Host + Get.Path); // To account for relative paths
+ SignersStorage Signers;
+
+ std::vector<std::string> keyFpts, keyFiles;
+ for (auto &&key : VectorizeString(LookupTag(Message, "Signed-By"), ','))
+ if (key.empty() == false && key[0] == '/')
+ keyFiles.emplace_back(std::move(key));
+ else
+ keyFpts.emplace_back(std::move(key));
+
+ // Run apt-key on file, extract contents and get the key ID of the signer
+ string const msg = VerifyGetSigners(Path.c_str(), Itm->DestFile.c_str(), keyFpts, keyFiles, Signers);
+ if (_error->PendingError())
+ return false;
+
+ // Check if all good signers are soon worthless and warn in that case
+ if (std::all_of(Signers.Good.begin(), Signers.Good.end(), [&](std::string const &good) {
+ return std::any_of(Signers.SoonWorthless.begin(), Signers.SoonWorthless.end(), [&](Signer const &weak) {
+ return IsTheSameKey(weak.key, good);
+ });
+ }))
+ {
+ for (auto const & Signer : Signers.SoonWorthless)
+ {
+ std::string msg;
+ // TRANSLATORS: The second %s is the reason and is untranslated for repository owners.
+ strprintf(msg, _("Signature by key %s uses weak digest algorithm (%s)"), Signer.key.c_str(), Signer.note.c_str());
+ Warning(std::move(msg));
+ }
+ }
+
+ if (Signers.Good.empty() || !Signers.Bad.empty() || !Signers.NoPubKey.empty())
+ {
+ string errmsg;
+ // In this case, something bad probably happened, so we just go
+ // with what the other method gave us for an error message.
+ if (Signers.Bad.empty() && Signers.Worthless.empty() && Signers.NoPubKey.empty())
+ errmsg = msg;
+ else
+ {
+ if (!Signers.Bad.empty())
+ {
+ errmsg += _("The following signatures were invalid:\n");
+ for (auto const &I : Signers.Bad)
+ errmsg.append(I).append("\n");
+ }
+ if (!Signers.Worthless.empty())
+ {
+ errmsg += _("The following signatures were invalid:\n");
+ for (auto const &I : Signers.Worthless)
+ errmsg.append(I).append("\n");
+ }
+ if (!Signers.NoPubKey.empty())
+ {
+ errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
+ for (auto const &I : Signers.NoPubKey)
+ errmsg.append(I).append("\n");
+ }
+ }
+ // this is only fatal if we have no good sigs or if we have at
+ // least one bad signature. good signatures and NoPubKey signatures
+ // happen easily when a file is signed with multiple signatures
+ if (Signers.Good.empty() or !Signers.Bad.empty())
+ return _error->Error("%s", errmsg.c_str());
+ }
+
+ std::unordered_map<std::string, std::string> fields;
+ fields.emplace("URI", Itm->Uri);
+ fields.emplace("Filename", Itm->DestFile);
+ if (Signers.SignedBy.empty() == false)
+ {
+ std::ostringstream out;
+ implodeVector(Signers.SignedBy, out, "\n");
+ fields.emplace("Signed-By", out.str());
+ }
+ {
+ // Just pass the raw output up, because passing it as a real data
+ // structure is too difficult with the method stuff. We keep it
+ // as three separate vectors for future extensibility.
+ std::vector<std::string> gpgvoutput;
+ std::move(Signers.Good.begin(), Signers.Good.end(), std::back_inserter(gpgvoutput));
+ std::move(Signers.Bad.begin(), Signers.Bad.end(), std::back_inserter(gpgvoutput));
+ std::move(Signers.NoPubKey.begin(), Signers.NoPubKey.end(), std::back_inserter(gpgvoutput));
+ if (gpgvoutput.empty() == false)
+ {
+ std::ostringstream out;
+ implodeVector(gpgvoutput, out, "\n");
+ fields.emplace("GPGVOutput", out.str());
+ }
+ }
+ SendMessage("201 URI Done", std::move(fields));
+ Dequeue();
+
+ if (DebugEnabled())
+ std::clog << "apt-key succeeded\n";
+
+ return true;
+}
+
+
+int main()
+{
+ return GPGVMethod().Run();
+}
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