From: Luke Shumaker <lukeshu@xxxxxxxxxxx>
fast-export has a --signed-tags= option that controls how to handle tag
signatures. However, there is no equivalent for commit signatures; it
just silently strips the signature out of the commit (analogously to
--signed-tags=strip).
While signatures are generally problematic for fast-export/fast-import
(because hashes are likely to change), if they're going to support tag
signatures, there's no reason to not also support commit signatures.
So, implement a --signed-commits= option that mirrors the --signed-tags=
option.
On the fast-export side, try to be as much like signed-tags as possible,
in both implementation and in user-interface. This will changes the
default behavior to '--signed-commits=abort' from what is now
'--signed-commits=strip'. In order to provide an escape hatch for users
of third-party tools that call fast-export and do not yet know of the
--signed-commits= option, add an environment variable
'FAST_EXPORT_SIGNED_COMMITS_NOABORT=1' that changes the default to
'--signed-commits=warn-strip'.
Signed-off-by: Luke Shumaker <lukeshu@xxxxxxxxxxx>
---
Notes:
v2:
- Remove erroneous remark about ordering from the commit message.
- Adjust the stream syntax to include the hash algorithm, as
suggested by brian.
- Add support for sha256 (based on lots of useful information from
brian). It does not support multiply-signed commits.
- Shorten the documentation, based on feedback from Taylor.
- Add comments, based on feedback from Taylor.
- Change the default from `--signed-commits=strip` to
`--signed-commits=warn-strip`. This shouldn't break anyone, and
means that users get useful feedback by default.
v3: no changes
v4:
- Reword the commit message based on feedback from Junio.
- v1-v3 renamed enum items to SIGN_VERBATIM_WARN and SIGN_STRIP_WARN,
rename them to SIGN_WARN_VERBATIM and SIGN_WARN_STRIP instead.
- Rewrite find_signature() as find_commit_multiline_header(). Don't
have it butcher the memory that we pass to it; have it return its
own buffer.
- Change the default from `--signed-commits=warn-strip` to
`--signed-commits=abort`, to match `--signed-tags`.
- Add a FAST_EXPORT_SIGNED_COMMITS_NOABORT=1 env-var to change the
default to `--signed-commits=warn-strip`.
Documentation/git-fast-export.txt | 11 +++
Documentation/git-fast-import.txt | 18 +++++
builtin/fast-export.c | 120 +++++++++++++++++++++++++-----
builtin/fast-import.c | 23 ++++++
t/t9350-fast-export.sh | 86 +++++++++++++++++++++
5 files changed, 240 insertions(+), 18 deletions(-)
diff --git a/Documentation/git-fast-export.txt b/Documentation/git-fast-export.txt
index a364812d9f..7a946e2ede 100644
--- a/Documentation/git-fast-export.txt
+++ b/Documentation/git-fast-export.txt
@@ -43,6 +43,17 @@ they will be exported, but you will see a warning. 'verbatim' and
transformations affecting tags will be performed, or if you do not
care that the resulting tag will have an invalid signature.
+--signed-commits=(verbatim|warn-verbatim|warn-strip|strip|abort)::
+ Specify how to handle signed commits. Behaves exactly as
+ '--signed-tags', but for commits.
++
+Earlier versions this command that did not have '--signed-commits'
+behaved as if '--signed-commits=strip'. As an escape hatch for users
+of tools that call 'git fast-export' but do not yet support
+'--signed-commits', you may set the environment variable
+'FAST_EXPORT_SIGNED_COMMITS_NOABORT=1' in order to change the default
+from 'abort' to 'warn-strip'.
+
--tag-of-filtered-object=(abort|drop|rewrite)::
Specify how to handle tags whose tagged object is filtered out.
Since revisions and files to export can be limited by path,
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 458af0a2d6..4955c94305 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -431,12 +431,21 @@ and control the current import process. More detailed discussion
Create or update a branch with a new commit, recording one logical
change to the project.
+////
+Yes, it's intentional that the 'gpgsig' line doesn't have a trailing
+`LF`; the the definition of `data` has a byte-count prefix, so it
+doesn't need an `LF` to act as a terminator (and `data` also already
+includes an optional trailing `LF?` just in case you want to include
+one).
+////
+
....
'commit' SP <ref> LF
mark?
original-oid?
('author' (SP <name>)? SP LT <email> GT SP <when> LF)?
'committer' (SP <name>)? SP LT <email> GT SP <when> LF
+ ('gpgsig' SP <alg> LF data)?
('encoding' SP <encoding> LF)?
data
('from' SP <commit-ish> LF)?
@@ -505,6 +514,15 @@ that was selected by the --date-format=<fmt> command-line option.
See ``Date Formats'' above for the set of supported formats, and
their syntax.
+`gpgsig`
+^^^^^^^^
+
+The optional `gpgsig` command is used to include a PGP/GPG signature
+that signs the commit data.
+
+Here <alg> specifies which hashing algorithm is used for this
+signature, either `sha1` or `sha256`.
+
`encoding`
^^^^^^^^^^
The optional `encoding` command indicates the encoding of the commit
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 81f3fb1f05..075630f185 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -30,8 +30,11 @@ static const char *fast_export_usage[] = {
NULL
};
+enum sign_mode { SIGN_ABORT, SIGN_VERBATIM, SIGN_STRIP, SIGN_WARN_VERBATIM, SIGN_WARN_STRIP };
+
static int progress;
-static enum { SIGNED_TAG_ABORT, VERBATIM, WARN_VERBATIM, WARN_STRIP, STRIP } signed_tag_mode = SIGNED_TAG_ABORT;
+static enum sign_mode signed_tag_mode = SIGN_ABORT;
+static enum sign_mode signed_commit_mode = SIGN_ABORT;
static enum { TAG_FILTERING_ABORT, DROP, REWRITE } tag_of_filtered_mode = TAG_FILTERING_ABORT;
static enum { REENCODE_ABORT, REENCODE_YES, REENCODE_NO } reencode_mode = REENCODE_ABORT;
static int fake_missing_tagger;
@@ -48,21 +51,24 @@ static int anonymize;
static struct hashmap anonymized_seeds;
static struct revision_sources revision_sources;
-static int parse_opt_signed_tag_mode(const struct option *opt,
+static int parse_opt_sign_mode(const struct option *opt,
const char *arg, int unset)
{
- if (unset || !strcmp(arg, "abort"))
- signed_tag_mode = SIGNED_TAG_ABORT;
+ enum sign_mode *valptr = opt->value;
+ if (unset)
+ return 0;
+ else if (!strcmp(arg, "abort"))
+ *valptr = SIGN_ABORT;
else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
- signed_tag_mode = VERBATIM;
+ *valptr = SIGN_VERBATIM;
else if (!strcmp(arg, "warn-verbatim") || !strcmp(arg, "warn"))
- signed_tag_mode = WARN_VERBATIM;
+ *valptr = SIGN_WARN_VERBATIM;
else if (!strcmp(arg, "warn-strip"))
- signed_tag_mode = WARN_STRIP;
+ *valptr = SIGN_WARN_STRIP;
else if (!strcmp(arg, "strip"))
- signed_tag_mode = STRIP;
+ *valptr = SIGN_STRIP;
else
- return error("Unknown signed-tags mode: %s", arg);
+ return error("Unknown %s mode: %s", opt->long_name, arg);
return 0;
}
@@ -600,6 +606,46 @@ static void anonymize_ident_line(const char **beg, const char **end)
*end = out->buf + out->len;
}
+/*
+ * find_commit_multiline_header is similar to find_commit_header,
+ * except that it handles multi-line headers, rathar than simply
+ * returning the first line of the header.
+ *
+ * The returned string has had the ' ' line continuation markers
+ * removed, and points to staticly allocated memory (not to memory
+ * within 'msg'), so it is only valid until the next call to
+ * find_commit_multiline_header.
+ *
+ * If the header is found, then *end is set to point at the '\n' in
+ * msg that immediately follows the header value.
+ */
+static const char *find_commit_multiline_header(const char *msg,
+ const char *key,
+ const char **end)
+{
+ static struct strbuf val = STRBUF_INIT;
+ const char *bol, *eol;
+ size_t len;
+
+ strbuf_reset(&val);
+
+ bol = find_commit_header(msg, key, &len);
+ if (!bol)
+ return NULL;
+ eol = bol + len;
+ strbuf_add(&val, bol, len);
+
+ while (eol[0] == '\n' && eol[1] == ' ') {
+ bol = eol + 2;
+ eol = strchrnul(bol, '\n');
+ strbuf_addch(&val, '\n');
+ strbuf_add(&val, bol, eol - bol);
+ }
+
+ *end = eol;
+ return val.buf;
+}
+
static char *reencode_message(const char *in_msg,
const char *in_encoding, size_t in_encoding_len)
{
@@ -619,6 +665,7 @@ static void handle_commit(struct commit *commit, struct rev_info *rev,
const char *author, *author_end, *committer, *committer_end;
const char *encoding;
size_t encoding_len;
+ const char *signature_alg = NULL, *signature;
const char *message;
char *reencoded = NULL;
struct commit_list *p;
@@ -644,14 +691,20 @@ static void handle_commit(struct commit *commit, struct rev_info *rev,
committer++;
commit_buffer_cursor = committer_end = strchrnul(committer, '\n');
- /* find_commit_header() gets a `+ 1` because
- * commit_buffer_cursor points at the trailing "\n" at the end
- * of the previous line, but find_commit_header() wants a
+ /* find_commit_header() and find_commit_multiline_header() get
+ * a `+ 1` because commit_buffer_cursor points at the trailing
+ * "\n" at the end of the previous line, but they want a
* pointer to the beginning of the next line. */
+
encoding = find_commit_header(commit_buffer_cursor + 1, "encoding", &encoding_len);
if (encoding)
commit_buffer_cursor = encoding + encoding_len;
+ if ((signature = find_commit_multiline_header(commit_buffer_cursor + 1, "gpgsig", &commit_buffer_cursor)))
+ signature_alg = "sha1";
+ else if ((signature = find_commit_multiline_header(commit_buffer_cursor + 1, "gpgsig-sha256", &commit_buffer_cursor)))
+ signature_alg = "sha256";
+
message = strstr(commit_buffer_cursor, "\n\n");
if (message)
message += 2;
@@ -712,6 +765,29 @@ static void handle_commit(struct commit *commit, struct rev_info *rev,
printf("%.*s\n%.*s\n",
(int)(author_end - author), author,
(int)(committer_end - committer), committer);
+ if (signature)
+ switch(signed_commit_mode) {
+ case SIGN_ABORT:
+ die("encountered signed commit %s; use "
+ "--signed-commits=<mode> to handle it",
+ oid_to_hex(&commit->object.oid));
+ case SIGN_WARN_VERBATIM:
+ warning("exporting signed commit %s",
+ oid_to_hex(&commit->object.oid));
+ /* fallthru */
+ case SIGN_VERBATIM:
+ printf("gpgsig %s\ndata %u\n%s",
+ signature_alg,
+ (unsigned)strlen(signature),
+ signature);
+ break;
+ case SIGN_WARN_STRIP:
+ warning("stripping signature from commit %s",
+ oid_to_hex(&commit->object.oid));
+ /* fallthru */
+ case SIGN_STRIP:
+ break;
+ }
if (!reencoded && encoding)
printf("encoding %.*s\n", (int)encoding_len, encoding);
printf("data %u\n%s",
@@ -839,21 +915,21 @@ static void handle_tag(const char *name, struct tag *tag)
"\n-----BEGIN PGP SIGNATURE-----\n");
if (signature)
switch(signed_tag_mode) {
- case SIGNED_TAG_ABORT:
+ case SIGN_ABORT:
die("encountered signed tag %s; use "
"--signed-tags=<mode> to handle it",
oid_to_hex(&tag->object.oid));
- case WARN_VERBATIM:
+ case SIGN_WARN_VERBATIM:
warning("exporting signed tag %s",
oid_to_hex(&tag->object.oid));
/* fallthru */
- case VERBATIM:
+ case SIGN_VERBATIM:
break;
- case WARN_STRIP:
+ case SIGN_WARN_STRIP:
warning("stripping signature from tag %s",
oid_to_hex(&tag->object.oid));
/* fallthru */
- case STRIP:
+ case SIGN_STRIP:
message_size = signature + 1 - message;
break;
}
@@ -1192,6 +1268,7 @@ static int parse_opt_anonymize_map(const struct option *opt,
int cmd_fast_export(int argc, const char **argv, const char *prefix)
{
+ const char *env_signed_commits_noabort;
struct rev_info revs;
struct object_array commits = OBJECT_ARRAY_INIT;
struct commit *commit;
@@ -1206,7 +1283,10 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
N_("show progress after <n> objects")),
OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
N_("select handling of signed tags"),
- parse_opt_signed_tag_mode),
+ parse_opt_sign_mode),
+ OPT_CALLBACK(0, "signed-commits", &signed_commit_mode, N_("mode"),
+ N_("select handling of signed commits"),
+ parse_opt_sign_mode),
OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
N_("select handling of tags that tag filtered objects"),
parse_opt_tag_of_filtered_mode),
@@ -1247,6 +1327,10 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
if (argc == 1)
usage_with_options (fast_export_usage, options);
+ env_signed_commits_noabort = getenv("FAST_EXPORT_SIGNED_COMMITS_NOABORT");
+ if (env_signed_commits_noabort && *env_signed_commits_noabort)
+ signed_commit_mode = SIGN_WARN_STRIP;
+
/* we handle encodings */
git_config(git_default_config, NULL);
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 3afa81cf9a..ee7516dd38 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -2669,10 +2669,13 @@ static struct hash_list *parse_merge(unsigned int *count)
static void parse_new_commit(const char *arg)
{
+ static struct strbuf sig = STRBUF_INIT;
static struct strbuf msg = STRBUF_INIT;
+ struct string_list siglines = STRING_LIST_INIT_NODUP;
struct branch *b;
char *author = NULL;
char *committer = NULL;
+ char *sig_alg = NULL;
char *encoding = NULL;
struct hash_list *merge_list = NULL;
unsigned int merge_count;
@@ -2696,6 +2699,13 @@ static void parse_new_commit(const char *arg)
}
if (!committer)
die("Expected committer but didn't get one");
+ if (skip_prefix(command_buf.buf, "gpgsig ", &v)) {
+ sig_alg = xstrdup(v);
+ read_next_command();
+ parse_data(&sig, 0, NULL);
+ read_next_command();
+ } else
+ strbuf_setlen(&sig, 0);
if (skip_prefix(command_buf.buf, "encoding ", &v)) {
encoding = xstrdup(v);
read_next_command();
@@ -2769,10 +2779,23 @@ static void parse_new_commit(const char *arg)
strbuf_addf(&new_data,
"encoding %s\n",
encoding);
+ if (sig_alg) {
+ if (!strcmp(sig_alg, "sha1"))
+ strbuf_addstr(&new_data, "gpgsig ");
+ else if (!strcmp(sig_alg, "sha256"))
+ strbuf_addstr(&new_data, "gpgsig-sha256 ");
+ else
+ die("Expected gpgsig algorithm sha1 or sha256, got %s", sig_alg);
+ string_list_split_in_place(&siglines, sig.buf, '\n', -1);
+ strbuf_add_separated_string_list(&new_data, "\n ", &siglines);
+ strbuf_addch(&new_data, '\n');
+ }
strbuf_addch(&new_data, '\n');
strbuf_addbuf(&new_data, &msg);
+ string_list_clear(&siglines, 1);
free(author);
free(committer);
+ free(sig_alg);
free(encoding);
if (!store_object(OBJ_COMMIT, &new_data, NULL, &b->oid, next_mark))
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index 892737439b..cd51c78418 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -8,6 +8,7 @@ GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
. ./test-lib.sh
+. "$TEST_DIRECTORY/lib-gpg.sh"
test_expect_success 'setup' '
@@ -284,9 +285,94 @@ test_expect_success 'signed-tags=warn-strip' '
test -s err
'
+test_expect_success GPG 'set up signed commit' '
+
+ # Generate a commit with both "gpgsig" and "encoding" set, so
+ # that we can test that fast-import gets the ordering correct
+ # between the two.
+ test_config i18n.commitEncoding ISO-8859-1 &&
+ git checkout -f -b commit-signing main &&
+ echo Sign your name > file-sign &&
+ git add file-sign &&
+ git commit -S -m "signed commit" &&
+ COMMIT_SIGNING=$(git rev-parse --verify commit-signing)
+
+'
+
+test_expect_success GPG 'signed-commits default' '
+
+ unset FAST_EXPORT_SIGNED_COMMITS_NOABORT &&
+ test_must_fail git fast-export --reencode=no commit-signing &&
+
+ FAST_EXPORT_SIGNED_COMMITS_NOABORT=1 git fast-export --reencode=no commit-signing >output 2>err &&
+ ! grep ^gpgsig output &&
+ grep "^encoding ISO-8859-1" output &&
+ test -s err &&
+ sed "s/commit-signing/commit-strip-signing/" output |
+ (cd new &&
+ git fast-import &&
+ test $COMMIT_SIGNING != $(git rev-parse --verify refs/heads/commit-strip-signing))
+
+'
+
+test_expect_success GPG 'signed-commits=abort' '
+
+ test_must_fail git fast-export --signed-commits=abort commit-signing
+
+'
+
+test_expect_success GPG 'signed-commits=verbatim' '
+
+ git fast-export --signed-commits=verbatim --reencode=no commit-signing >output &&
+ grep "^gpgsig sha" output &&
+ grep "encoding ISO-8859-1" output &&
+ (cd new &&
+ git fast-import &&
+ test $COMMIT_SIGNING = $(git rev-parse --verify refs/heads/commit-signing)) <output
+
+'
+
+test_expect_success GPG 'signed-commits=warn-verbatim' '
+
+ git fast-export --signed-commits=warn-verbatim --reencode=no commit-signing >output 2>err &&
+ grep "^gpgsig sha" output &&
+ grep "encoding ISO-8859-1" output &&
+ test -s err &&
+ (cd new &&
+ git fast-import &&
+ test $COMMIT_SIGNING = $(git rev-parse --verify refs/heads/commit-signing)) <output
+
+'
+
+test_expect_success GPG 'signed-commits=strip' '
+
+ git fast-export --signed-commits=strip --reencode=no commit-signing >output &&
+ ! grep ^gpgsig output &&
+ grep "^encoding ISO-8859-1" output &&
+ sed "s/commit-signing/commit-strip-signing/" output |
+ (cd new &&
+ git fast-import &&
+ test $COMMIT_SIGNING != $(git rev-parse --verify refs/heads/commit-strip-signing))
+
+'
+
+test_expect_success GPG 'signed-commits=warn-strip' '
+
+ git fast-export --signed-commits=warn-strip --reencode=no commit-signing >output 2>err &&
+ ! grep ^gpgsig output &&
+ grep "^encoding ISO-8859-1" output &&
+ test -s err &&
+ sed "s/commit-signing/commit-strip-signing/" output |
+ (cd new &&
+ git fast-import &&
+ test $COMMIT_SIGNING != $(git rev-parse --verify refs/heads/commit-strip-signing))
+
+'
+
test_expect_success 'setup submodule' '
git checkout -f main &&
+ { git update-ref -d refs/heads/commit-signing || true; } &&
mkdir sub &&
(
cd sub &&
--
2.31.1
