Merge branch 'sg/gpg-sig'
authorJunio C Hamano <gitster@pobox.com>
Fri, 5 Apr 2013 21:15:16 +0000 (14:15 -0700)
committerJunio C Hamano <gitster@pobox.com>
Fri, 5 Apr 2013 21:15:16 +0000 (14:15 -0700)
Teach "merge/pull" to optionally verify and reject commits that are
not signed properly.

* sg/gpg-sig:
pretty printing: extend %G? to include 'N' and 'U'
merge/pull Check for untrusted good GPG signatures
merge/pull: verify GPG signatures of commits being merged
commit.c/GPG signature verification: Also look at the first GPG status line
Move commit GPG signature verification to commit.c

13 files changed:
Documentation/merge-options.txt
Documentation/pretty-formats.txt
builtin/merge.c
commit.c
commit.h
git-pull.sh
gpg-interface.h
pretty.c
t/lib-gpg/pubring.gpg
t/lib-gpg/random_seed
t/lib-gpg/secring.gpg
t/lib-gpg/trustdb.gpg
t/t7612-merge-verify-signatures.sh [new file with mode: 0755]
index 34a844582846ae409e17347a65ac6cbeb28202a5..2adccf8fec71c10f8223490f1be4b2a215ace5ea 100644 (file)
@@ -84,6 +84,11 @@ option can be used to override --squash.
        Pass merge strategy specific option through to the merge
        strategy.
 
+--verify-signatures::
+--no-verify-signatures::
+       Verify that the commits being merged have good and trusted GPG signatures
+       and abort the merge in case they do not.
+
 --summary::
 --no-summary::
        Synonyms to --stat and --no-stat; these are deprecated and will be
index 293965524e81b240996a795498ba127f723d18eb..afac703f21245b6fa34af90b1da4b3194372a81d 100644 (file)
@@ -131,7 +131,8 @@ The placeholders are:
 - '%B': raw body (unwrapped subject and body)
 - '%N': commit notes
 - '%GG': raw verification message from GPG for a signed commit
-- '%G?': show either "G" for Good or "B" for Bad for a signed commit
+- '%G?': show "G" for a Good signature, "B" for a Bad signature, "U" for a good,
+  untrusted signature and "N" for no signature
 - '%GS': show the name of the signer for a signed commit
 - '%GK': show the key used to sign a signed commit
 - '%gD': reflog selector, e.g., `refs/stash@{1}`
index 0d94d89e7409c625fd2a15f65205a45d4a6d2b89..3e2daa37c367560450217cfae5cbb717bfb508af 100644 (file)
@@ -49,7 +49,7 @@ static const char * const builtin_merge_usage[] = {
 static int show_diffstat = 1, shortlog_len = -1, squash;
 static int option_commit = 1, allow_fast_forward = 1;
 static int fast_forward_only, option_edit = -1;
-static int allow_trivial = 1, have_message;
+static int allow_trivial = 1, have_message, verify_signatures;
 static int overwrite_ignore = 1;
 static struct strbuf merge_msg = STRBUF_INIT;
 static struct strategy **use_strategies;
@@ -199,6 +199,8 @@ static struct option builtin_merge_options[] = {
        OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
                N_("abort if fast-forward is not possible")),
        OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
+       OPT_BOOL(0, "verify-signatures", &verify_signatures,
+               N_("Verify that the named commit has a valid GPG signature")),
        OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
                N_("merge strategy to use"), option_parse_strategy),
        OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
@@ -1246,6 +1248,39 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                usage_with_options(builtin_merge_usage,
                        builtin_merge_options);
 
+       if (verify_signatures) {
+               for (p = remoteheads; p; p = p->next) {
+                       struct commit *commit = p->item;
+                       char hex[41];
+                       struct signature_check signature_check;
+                       memset(&signature_check, 0, sizeof(signature_check));
+
+                       check_commit_signature(commit, &signature_check);
+
+                       strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+                       switch (signature_check.result) {
+                       case 'G':
+                               break;
+                       case 'U':
+                               die(_("Commit %s has an untrusted GPG signature, "
+                                     "allegedly by %s."), hex, signature_check.signer);
+                       case 'B':
+                               die(_("Commit %s has a bad GPG signature "
+                                     "allegedly by %s."), hex, signature_check.signer);
+                       default: /* 'N' */
+                               die(_("Commit %s does not have a GPG signature."), hex);
+                       }
+                       if (verbosity >= 0 && signature_check.result == 'G')
+                               printf(_("Commit %s has a good GPG signature by %s\n"),
+                                      hex, signature_check.signer);
+
+                       free(signature_check.gpg_output);
+                       free(signature_check.gpg_status);
+                       free(signature_check.signer);
+                       free(signature_check.key);
+               }
+       }
+
        strbuf_addstr(&buf, "merge");
        for (p = remoteheads; p; p = p->next)
                strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
index b4512ab0b2ebd008aa90e0dfe00fbc1aa42a5c64..516a4ff7d21d5ebcfabda7b1b886eb10b05cebfc 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -1041,6 +1041,76 @@ static void handle_signed_tag(struct commit *parent, struct commit_extra_header
        free(buf);
 }
 
+static struct {
+       char result;
+       const char *check;
+} sigcheck_gpg_status[] = {
+       { 'G', "\n[GNUPG:] GOODSIG " },
+       { 'B', "\n[GNUPG:] BADSIG " },
+       { 'U', "\n[GNUPG:] TRUST_NEVER" },
+       { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
+};
+
+static void parse_gpg_output(struct signature_check *sigc)
+{
+       const char *buf = sigc->gpg_status;
+       int i;
+
+       /* Iterate over all search strings */
+       for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
+               const char *found, *next;
+
+               if (!prefixcmp(buf, sigcheck_gpg_status[i].check + 1)) {
+                       /* At the very beginning of the buffer */
+                       found = buf + strlen(sigcheck_gpg_status[i].check + 1);
+               } else {
+                       found = strstr(buf, sigcheck_gpg_status[i].check);
+                       if (!found)
+                               continue;
+                       found += strlen(sigcheck_gpg_status[i].check);
+               }
+               sigc->result = sigcheck_gpg_status[i].result;
+               /* The trust messages are not followed by key/signer information */
+               if (sigc->result != 'U') {
+                       sigc->key = xmemdupz(found, 16);
+                       found += 17;
+                       next = strchrnul(found, '\n');
+                       sigc->signer = xmemdupz(found, next - found);
+               }
+       }
+}
+
+void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
+{
+       struct strbuf payload = STRBUF_INIT;
+       struct strbuf signature = STRBUF_INIT;
+       struct strbuf gpg_output = STRBUF_INIT;
+       struct strbuf gpg_status = STRBUF_INIT;
+       int status;
+
+       sigc->result = 'N';
+
+       if (parse_signed_commit(commit->object.sha1,
+                               &payload, &signature) <= 0)
+               goto out;
+       status = verify_signed_buffer(payload.buf, payload.len,
+                                     signature.buf, signature.len,
+                                     &gpg_output, &gpg_status);
+       if (status && !gpg_output.len)
+               goto out;
+       sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
+       sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
+       parse_gpg_output(sigc);
+
+ out:
+       strbuf_release(&gpg_status);
+       strbuf_release(&gpg_output);
+       strbuf_release(&payload);
+       strbuf_release(&signature);
+}
+
+
+
 void append_merge_tag_headers(struct commit_list *parents,
                              struct commit_extra_header ***tail)
 {
index 2d90d9c27c8fb947e30a368cb5fb266f643b8bae..87b4b6cc0c036d4b7d2ff67cf9d6e98c58f13793 100644 (file)
--- a/commit.h
+++ b/commit.h
@@ -5,6 +5,7 @@
 #include "tree.h"
 #include "strbuf.h"
 #include "decorate.h"
+#include "gpg-interface.h"
 
 struct commit_list {
        struct commit *item;
@@ -232,4 +233,13 @@ extern void print_commit_list(struct commit_list *list,
                              const char *format_cur,
                              const char *format_last);
 
+/*
+ * Check the signature of the given commit. The result of the check is stored
+ * in sig->check_result, 'G' for a good signature, 'U' for a good signature
+ * from an untrusted signer, 'B' for a bad signature and 'N' for no signature
+ * at all.  This may allocate memory for sig->gpg_output, sig->gpg_status,
+ * sig->signer and sig->key.
+ */
+extern void check_commit_signature(const struct commit* commit, struct signature_check *sigc);
+
 #endif /* COMMIT_H */
index 5d97e97bd95fe25d158058af025c48e47f6d241f..638aabb7b347e2afeb9bf327902de9e3702cd9d4 100755 (executable)
@@ -39,7 +39,7 @@ test -z "$(git ls-files -u)" || die_conflict
 test -f "$GIT_DIR/MERGE_HEAD" && die_merge
 
 strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
-log_arg= verbosity= progress= recurse_submodules=
+log_arg= verbosity= progress= recurse_submodules= verify_signatures=
 merge_args= edit=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short="${curr_branch#refs/heads/}"
@@ -125,6 +125,12 @@ do
        --no-recurse-submodules)
                recurse_submodules=--no-recurse-submodules
                ;;
+       --verify-signatures)
+               verify_signatures=--verify-signatures
+               ;;
+       --no-verify-signatures)
+               verify_signatures=--no-verify-signatures
+               ;;
        --d|--dr|--dry|--dry-|--dry-r|--dry-ru|--dry-run)
                dry_run=--dry-run
                ;;
@@ -283,7 +289,7 @@ true)
        eval="$eval --onto $merge_head ${oldremoteref:-$merge_head}"
        ;;
 *)
-       eval="git-merge $diffstat $no_commit $edit $squash $no_ff $ff_only"
+       eval="git-merge $diffstat $no_commit $verify_signatures $edit $squash $no_ff $ff_only"
        eval="$eval  $log_arg $strategy_args $merge_args $verbosity $progress"
        eval="$eval \"\$merge_name\" HEAD $merge_head"
        ;;
index cf9902184272d20c6d5826cf9f10dcaebeb3e6e8..a85cb5bc97cdd61000b4c48c54faa656aa3cfaca 100644 (file)
@@ -1,6 +1,18 @@
 #ifndef GPG_INTERFACE_H
 #define GPG_INTERFACE_H
 
+struct signature_check {
+       char *gpg_output;
+       char *gpg_status;
+       char result; /* 0 (not checked),
+                     * N (checked but no further result),
+                     * U (untrusted good),
+                     * G (good)
+                     * B (bad) */
+       char *signer;
+       char *key;
+};
+
 extern int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key);
 extern int verify_signed_buffer(const char *payload, size_t payload_size, const char *signature, size_t signature_size, struct strbuf *gpg_output, struct strbuf *gpg_status);
 extern int git_gpg_config(const char *, const char *, void *);
index 41f04e669d3b9c38f49e0853053a6ba27b97357a..d3a82d22d398ae7234f8917f4d8b0770ba4d0c47 100644 (file)
--- a/pretty.c
+++ b/pretty.c
@@ -766,14 +766,7 @@ struct format_commit_context {
        const struct pretty_print_context *pretty_ctx;
        unsigned commit_header_parsed:1;
        unsigned commit_message_parsed:1;
-       unsigned commit_signature_parsed:1;
-       struct {
-               char *gpg_output;
-               char *gpg_status;
-               char good_bad;
-               char *signer;
-               char *key;
-       } signature;
+       struct signature_check signature_check;
        char *message;
        size_t width, indent1, indent2;
 
@@ -956,64 +949,6 @@ static void rewrap_message_tail(struct strbuf *sb,
        c->indent2 = new_indent2;
 }
 
-static struct {
-       char result;
-       const char *check;
-} signature_check[] = {
-       { 'G', "\n[GNUPG:] GOODSIG " },
-       { 'B', "\n[GNUPG:] BADSIG " },
-};
-
-static void parse_signature_lines(struct format_commit_context *ctx)
-{
-       const char *buf = ctx->signature.gpg_status;
-       int i;
-
-       for (i = 0; i < ARRAY_SIZE(signature_check); i++) {
-               const char *found = strstr(buf, signature_check[i].check);
-               const char *next;
-               if (!found)
-                       continue;
-               ctx->signature.good_bad = signature_check[i].result;
-               found += strlen(signature_check[i].check);
-               ctx->signature.key = xmemdupz(found, 16);
-               found += 17;
-               next = strchrnul(found, '\n');
-               ctx->signature.signer = xmemdupz(found, next - found);
-               break;
-       }
-}
-
-static void parse_commit_signature(struct format_commit_context *ctx)
-{
-       struct strbuf payload = STRBUF_INIT;
-       struct strbuf signature = STRBUF_INIT;
-       struct strbuf gpg_output = STRBUF_INIT;
-       struct strbuf gpg_status = STRBUF_INIT;
-       int status;
-
-       ctx->commit_signature_parsed = 1;
-
-       if (parse_signed_commit(ctx->commit->object.sha1,
-                               &payload, &signature) <= 0)
-               goto out;
-       status = verify_signed_buffer(payload.buf, payload.len,
-                                     signature.buf, signature.len,
-                                     &gpg_output, &gpg_status);
-       if (status && !gpg_output.len)
-               goto out;
-       ctx->signature.gpg_output = strbuf_detach(&gpg_output, NULL);
-       ctx->signature.gpg_status = strbuf_detach(&gpg_status, NULL);
-       parse_signature_lines(ctx);
-
- out:
-       strbuf_release(&gpg_status);
-       strbuf_release(&gpg_output);
-       strbuf_release(&payload);
-       strbuf_release(&signature);
-}
-
-
 static int format_reflog_person(struct strbuf *sb,
                                char part,
                                struct reflog_walk_info *log,
@@ -1199,27 +1134,29 @@ static size_t format_commit_one(struct strbuf *sb, const char *placeholder,
        }
 
        if (placeholder[0] == 'G') {
-               if (!c->commit_signature_parsed)
-                       parse_commit_signature(c);
+               if (!c->signature_check.result)
+                       check_commit_signature(c->commit, &(c->signature_check));
                switch (placeholder[1]) {
                case 'G':
-                       if (c->signature.gpg_output)
-                               strbuf_addstr(sb, c->signature.gpg_output);
+                       if (c->signature_check.gpg_output)
+                               strbuf_addstr(sb, c->signature_check.gpg_output);
                        break;
                case '?':
-                       switch (c->signature.good_bad) {
+                       switch (c->signature_check.result) {
                        case 'G':
                        case 'B':
-                               strbuf_addch(sb, c->signature.good_bad);
+                       case 'U':
+                       case 'N':
+                               strbuf_addch(sb, c->signature_check.result);
                        }
                        break;
                case 'S':
-                       if (c->signature.signer)
-                               strbuf_addstr(sb, c->signature.signer);
+                       if (c->signature_check.signer)
+                               strbuf_addstr(sb, c->signature_check.signer);
                        break;
                case 'K':
-                       if (c->signature.key)
-                               strbuf_addstr(sb, c->signature.key);
+                       if (c->signature_check.key)
+                               strbuf_addstr(sb, c->signature_check.key);
                        break;
                }
                return 2;
@@ -1357,8 +1294,8 @@ void format_commit_message(const struct commit *commit,
        rewrap_message_tail(sb, &context, 0, 0, 0);
 
        logmsg_free(context.message, commit);
-       free(context.signature.gpg_output);
-       free(context.signature.signer);
+       free(context.signature_check.gpg_output);
+       free(context.signature_check.signer);
 }
 
 static void pp_header(const struct pretty_print_context *pp,
index 83855fa4e1c6c37afe550c17afa1e7971042ded5..1a3c2d487c2fda9169751a3068fa51e853a1e519 100644 (file)
Binary files a/t/lib-gpg/pubring.gpg and b/t/lib-gpg/pubring.gpg differ
index 8fed1339ed0a744e5663f4a5e6b6ac9bae3d8524..95d249f15fce980f0e8c1a8a18b085b3885708aa 100644 (file)
Binary files a/t/lib-gpg/random_seed and b/t/lib-gpg/random_seed differ
index d831cd9eb3eee613d3c0e1a71093ae01ea7347e3..82dca8f80bf170fde5705862c3eeb9d994725042 100644 (file)
Binary files a/t/lib-gpg/secring.gpg and b/t/lib-gpg/secring.gpg differ
index abace962b8bf84be688a6f27e4ebd0ee7052f210..4879ae9a84650a93a4d15bd6560c5d1b89eb4c2f 100644 (file)
Binary files a/t/lib-gpg/trustdb.gpg and b/t/lib-gpg/trustdb.gpg differ
diff --git a/t/t7612-merge-verify-signatures.sh b/t/t7612-merge-verify-signatures.sh
new file mode 100755 (executable)
index 0000000..21a0bf8
--- /dev/null
@@ -0,0 +1,61 @@
+#!/bin/sh
+
+test_description='merge signature verification tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY/lib-gpg.sh"
+
+test_expect_success GPG 'create signed commits' '
+       echo 1 >file && git add file &&
+       test_tick && git commit -m initial &&
+       git tag initial &&
+
+       git checkout -b side-signed &&
+       echo 3 >elif && git add elif &&
+       test_tick && git commit -S -m "signed on side" &&
+       git checkout initial &&
+
+       git checkout -b side-unsigned &&
+       echo 3 >foo && git add foo &&
+       test_tick && git commit -m "unsigned on side" &&
+       git checkout initial &&
+
+       git checkout -b side-bad &&
+       echo 3 >bar && git add bar &&
+       test_tick && git commit -S -m "bad on side" &&
+       git cat-file commit side-bad >raw &&
+       sed -e "s/bad/forged bad/" raw >forged &&
+       git hash-object -w -t commit forged >forged.commit &&
+       git checkout initial &&
+
+       git checkout -b side-untrusted &&
+       echo 3 >baz && git add baz &&
+       test_tick && git commit -SB7227189 -m "untrusted on side"
+
+       git checkout master
+'
+
+test_expect_success GPG 'merge unsigned commit with verification' '
+       test_must_fail git merge --ff-only --verify-signatures side-unsigned 2>mergeerror &&
+       test_i18ngrep "does not have a GPG signature" mergeerror
+'
+
+test_expect_success GPG 'merge commit with bad signature with verification' '
+       test_must_fail git merge --ff-only --verify-signatures $(cat forged.commit) 2>mergeerror &&
+       test_i18ngrep "has a bad GPG signature" mergeerror
+'
+
+test_expect_success GPG 'merge commit with untrusted signature with verification' '
+       test_must_fail git merge --ff-only --verify-signatures side-untrusted 2>mergeerror &&
+       test_i18ngrep "has an untrusted GPG signature" mergeerror
+'
+
+test_expect_success GPG 'merge signed commit with verification' '
+       git merge --verbose --ff-only --verify-signatures side-signed >mergeoutput &&
+       test_i18ngrep "has a good GPG signature" mergeoutput
+'
+
+test_expect_success GPG 'merge commit with bad signature without verification' '
+       git merge $(cat forged.commit)
+'
+
+test_done