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-rw-r--r--methods/gpgv.cc452
1 files changed, 452 insertions, 0 deletions
diff --git a/methods/gpgv.cc b/methods/gpgv.cc
new file mode 100644
index 000000000..51c268d02
--- /dev/null
+++ b/methods/gpgv.cc
@@ -0,0 +1,452 @@
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/fileutl.h>
+#include "aptmethod.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 <array>
+#include <algorithm>
+#include <sstream>
+#include <iterator>
+#include <iostream>
+#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) < _count(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 keyid (40 = 24 + 16), GOODSIG is a longid (16) only
+ return validsig.compare(24, 16, goodsig, strlen("GOODSIG "), 16) == 0;
+}
+
+class GPGVMethod : public aptMethod
+{
+ private:
+ string VerifyGetSigners(const char *file, const char *outfile,
+ std::string const &key,
+ 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:
+ GPGVMethod() : aptMethod("gpgv","1.0",SingleInstance | SendConfig) {};
+};
+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);
+}
+string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
+ std::string const &key,
+ vector<string> &GoodSigners,
+ vector<string> &BadSigners,
+ vector<string> &WorthlessSigners,
+ vector<Signer> &SoonWorthlessSigners,
+ vector<string> &NoPubKeySigners)
+{
+ bool const Debug = DebugEnabled();
+
+ if (Debug == true)
+ std::clog << "inside VerifyGetSigners" << std::endl;
+
+ int fd[2];
+ bool const keyIsID = (key.empty() == false && key[0] != '/');
+
+ 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)
+ ExecGPGV(outfile, file, 3, fd, (keyIsID ? "" : key));
+ 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> ValidSigners;
+ std::vector<std::string> ErrSigners;
+ 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(BadSigners, 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(NoPubKeySigners, 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(WorthlessSigners, buffer, Debug);
+ else if (strncmp(buffer, GNUPGEXPSIG, sizeof(GNUPGEXPSIG)-1) == 0)
+ PushEntryWithUID(WorthlessSigners, buffer, Debug);
+ else if (strncmp(buffer, GNUPGREVKEYSIG, sizeof(GNUPGREVKEYSIG)-1) == 0)
+ PushEntryWithUID(WorthlessSigners, buffer, Debug);
+ else if (strncmp(buffer, GNUPGGOODSIG, sizeof(GNUPGGOODSIG)-1) == 0)
+ PushEntryWithKeyID(GoodSigners, 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.
+ SoonWorthlessSigners.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.
+ WorthlessSigners.push_back(sig);
+ GoodSigners.erase(std::remove_if(GoodSigners.begin(), GoodSigners.end(), [&](std::string const &goodsig) {
+ return IsTheSameKey(sig, goodsig); }), GoodSigners.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;
+ }
+
+ ValidSigners.push_back(sig);
+ }
+ else if (strncmp(buffer, APTKEYWARNING, sizeof(APTKEYWARNING)-1) == 0)
+ Warning("%s", 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(WorthlessSigners));
+
+ // 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 (keyIsID == true)
+ {
+ if (Debug == true)
+ std::clog << "GoodSigs needs to be limited to keyid " << key << std::endl;
+ bool foundGood = false;
+ for (auto const &k: VectorizeString(key, ','))
+ {
+ if (std::find(ValidSigners.begin(), ValidSigners.end(), k) == ValidSigners.end())
+ continue;
+ // we look for GOODSIG here as well as an expired sig is a valid sig as well (but not a good one)
+ std::string const goodfingerprint = "GOODSIG " + k;
+ std::string const goodlongkeyid = "GOODSIG " + k.substr(24, 16);
+ foundGood = std::find(GoodSigners.begin(), GoodSigners.end(), goodfingerprint) != GoodSigners.end();
+ if (Debug == true)
+ std::clog << "Key " << k << " is valid sig, is " << goodfingerprint << " also a good one? " << (foundGood ? "yes" : "no") << std::endl;
+ std::string goodsig;
+ if (foundGood == false)
+ {
+ foundGood = std::find(GoodSigners.begin(), GoodSigners.end(), goodlongkeyid) != GoodSigners.end();
+ if (Debug == true)
+ std::clog << "Key " << k << " is valid sig, is " << goodlongkeyid << " also a good one? " << (foundGood ? "yes" : "no") << std::endl;
+ goodsig = goodlongkeyid;
+ }
+ else
+ goodsig = goodfingerprint;
+ if (foundGood == false)
+ continue;
+ std::copy(GoodSigners.begin(), GoodSigners.end(), std::back_insert_iterator<std::vector<std::string> >(NoPubKeySigners));
+ GoodSigners.clear();
+ GoodSigners.push_back(goodsig);
+ NoPubKeySigners.erase(
+ std::remove(NoPubKeySigners.begin(),
+ std::remove(NoPubKeySigners.begin(), NoPubKeySigners.end(), goodfingerprint),
+ goodlongkeyid),
+ NoPubKeySigners.end()
+ );
+ break;
+ }
+ if (foundGood == false)
+ {
+ std::copy(GoodSigners.begin(), GoodSigners.end(), std::back_insert_iterator<std::vector<std::string> >(NoPubKeySigners));
+ GoodSigners.clear();
+ }
+ }
+
+ 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:" << std::endl << " Good: ";
+ std::copy(GoodSigners.begin(), GoodSigners.end(), std::ostream_iterator<std::string>(std::cerr, ", "));
+ std::cerr << std::endl << " Bad: ";
+ std::copy(BadSigners.begin(), BadSigners.end(), std::ostream_iterator<std::string>(std::cerr, ", "));
+ std::cerr << std::endl << " Worthless: ";
+ std::copy(WorthlessSigners.begin(), WorthlessSigners.end(), std::ostream_iterator<std::string>(std::cerr, ", "));
+ std::cerr << std::endl << " SoonWorthless: ";
+ std::for_each(SoonWorthlessSigners.begin(), SoonWorthlessSigners.end(), [](Signer const &sig) { std::cerr << sig.key << ", "; });
+ std::cerr << std::endl << " NoPubKey: ";
+ std::copy(NoPubKeySigners.begin(), NoPubKeySigners.end(), std::ostream_iterator<std::string>(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 (keyIsID)
+ {
+ // 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 (GoodSigners.empty())
+ return _("At least one invalid signature was encountered.");
+ }
+ else
+ {
+ if (GoodSigners.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;
+ string const Path = Get.Host + Get.Path; // To account for relative paths
+ std::string const key = LookupTag(Message, "Signed-By");
+ vector<string> GoodSigners;
+ vector<string> BadSigners;
+ // a worthless signature is a expired or revoked one
+ vector<string> WorthlessSigners;
+ vector<Signer> SoonWorthlessSigners;
+ vector<string> NoPubKeySigners;
+
+ FetchResult Res;
+ Res.Filename = Itm->DestFile;
+ URIStart(Res);
+
+ // 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(), key,
+ GoodSigners, BadSigners, WorthlessSigners,
+ SoonWorthlessSigners, NoPubKeySigners);
+ if (_error->PendingError())
+ return false;
+
+ // Check if all good signers are soon worthless and warn in that case
+ if (std::all_of(GoodSigners.begin(), GoodSigners.end(), [&](std::string const &good) {
+ return std::any_of(SoonWorthlessSigners.begin(), SoonWorthlessSigners.end(), [&](Signer const &weak) {
+ return IsTheSameKey(weak.key, good);
+ });
+ }))
+ {
+ for (auto const & Signer : SoonWorthlessSigners)
+ // TRANSLATORS: The second %s is the reason and is untranslated for repository owners.
+ Warning(_("Signature by key %s uses weak digest algorithm (%s)"), Signer.key.c_str(), Signer.note.c_str());
+ }
+
+ if (GoodSigners.empty() || !BadSigners.empty() || !NoPubKeySigners.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 (BadSigners.empty() && WorthlessSigners.empty() && NoPubKeySigners.empty())
+ errmsg = msg;
+ else
+ {
+ if (!BadSigners.empty())
+ {
+ errmsg += _("The following signatures were invalid:\n");
+ for (vector<string>::iterator I = BadSigners.begin();
+ I != BadSigners.end(); ++I)
+ errmsg += (*I + "\n");
+ }
+ if (!WorthlessSigners.empty())
+ {
+ errmsg += _("The following signatures were invalid:\n");
+ for (vector<string>::iterator I = WorthlessSigners.begin();
+ I != WorthlessSigners.end(); ++I)
+ errmsg += (*I + "\n");
+ }
+ if (!NoPubKeySigners.empty())
+ {
+ errmsg += _("The following signatures couldn't be verified because the public key is not available:\n");
+ for (vector<string>::iterator I = NoPubKeySigners.begin();
+ I != NoPubKeySigners.end(); ++I)
+ errmsg += (*I + "\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(GoodSigners.empty() or !BadSigners.empty())
+ return _error->Error("%s", errmsg.c_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.
+ Res.GPGVOutput = GoodSigners;
+ std::move(BadSigners.begin(), BadSigners.end(), std::back_inserter(Res.GPGVOutput));
+ std::move(NoPubKeySigners.begin(), NoPubKeySigners.end(), std::back_inserter(Res.GPGVOutput));
+ URIDone(Res);
+
+ if (DebugEnabled())
+ std::clog << "apt-key succeeded\n";
+
+ return true;
+}
+
+
+int main()
+{
+ return GPGVMethod().Run();
+}
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