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gpg-interface: limit search for primary key fingerprint

The VALIDSIG status line from GnuPG with --status-fd is documented to have 9 required and 1 optional fields [1]. The final, and optional, field is used to specify the fingerprint of the primary key that made the signature in case it was made by a subkey. However, this field is only available for OpenPGP signatures; not for CMS/X.509. If the VALIDSIG status line does not have the optional 10th field, the current code will continue reading onto the next status line. And this is the case for non-OpenPGP signatures [1]. The consequence is that a subsequent status line may be considered as the "primary key" for signatures that does not have an actual primary key. Limit the search of these 9 or 10 fields to the single line to avoid this problem. If the 10th field is missing, report that there is no primary key fingerprint. [Reference] [1] GnuPG Details, General status codes https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=doc/DETAILS;h=6ce340e8c04794add995e84308bb3091450bd28f;hb=HEAD#l483 The documentation says: VALIDSIG <args> The args are: - <fingerprint_in_hex> - <sig_creation_date> - <sig-timestamp> - <expire-timestamp> - <sig-version> - <reserved> - <pubkey-algo> - <hash-algo> - <sig-class> - [ <primary-key-fpr> ] This status indicates that the signature is cryptographically valid. [...] PRIMARY-KEY-FPR is the fingerprint of the primary key or identical to the first argument. The primary-key-fpr parameter is used for OpenPGP and not available for CMS signatures. [...] Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Hans Jerry Illikainen committed Nov 22, 2019 at 20:23 UTC 67a6ea63008bcee32a239934ad29eb5c5a554509

2 files changed +38 -6

gpg-interface.c

+18 -6

@@ -156,21 +156,33 @@ static void parse_gpg_output(struct signature_check *sigc)

156 }

157 /* Do we have fingerprint? */

158 if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) {

159 + const char *limit;

160 + char **field;

161 +

162 next = strchrnul(line, ' ');

163 replace_cstring(&sigc->fingerprint, line, next);

164

162 - /* Skip interim fields */

165 + /*

166 + * Skip interim fields. The search is

167 + * limited to the same line since only

168 + * OpenPGP signatures has a field with

169 + * the primary fingerprint.

170 + */

171 + limit = strchrnul(line, '\n');

172 for (j = 9; j > 0; j--) {

164 - if (!*next)

173 + if (!*next || limit <= next)

174 break;

175 line = next + 1;

176 next = strchrnul(line, ' ');

177 }

178

170 - next = strchrnul(line, '\n');

171 - free(sigc->primary_key_fingerprint);

172 - replace_cstring(&sigc->primary_key_fingerprint,

173 - line, next);

179 + field = &sigc->primary_key_fingerprint;

180 + if (!j) {

181 + next = strchrnul(line, '\n');

182 + replace_cstring(field, line, next);

183 + } else {

184 + replace_cstring(field, NULL, NULL);

185 + }

186 }

187

188 break;

t/t4202-log.sh

+20

@@ -1555,6 +1555,14 @@ test_expect_success GPG 'setup signed branch' '

1555 git commit -S -m signed_commit

1556 '

1557

1558 +test_expect_success GPG 'setup signed branch with subkey' '

1559 + test_when_finished "git reset --hard && git checkout master" &&

1560 + git checkout -b signed-subkey master &&

1561 + echo foo >foo &&

1562 + git add foo &&

1563 + git commit -SB7227189 -m signed_commit

1564 +'

1565 +

1566 test_expect_success GPGSM 'setup signed branch x509' '

1567 test_when_finished "git reset --hard && git checkout master" &&

1568 git checkout -b signed-x509 master &&

@@ -1565,6 +1573,18 @@ test_expect_success GPGSM 'setup signed branch x509' '

1573 git commit -S -m signed_commit

1574 '

1575

1576 +test_expect_success GPGSM 'log x509 fingerprint' '

1577 + echo "F8BF62E0693D0694816377099909C779FA23FD65 | " >expect &&

1578 + git log -n1 --format="%GF | %GP" signed-x509 >actual &&

1579 + test_cmp expect actual

1580 +'

1581 +

1582 +test_expect_success GPGSM 'log OpenPGP fingerprint' '

1583 + echo "D4BE22311AD3131E5EDA29A461092E85B7227189" > expect &&

1584 + git log -n1 --format="%GP" signed-subkey >actual &&

1585 + test_cmp expect actual

1586 +'

1587 +

1588 test_expect_success GPG 'log --graph --show-signature' '

1589 git log --graph --show-signature -n1 signed >actual &&

1590 grep "^| gpg: Signature made" actual &&