[PATCH v2 3/9] cli: include wrapped part of PKCS#7 SignedData in the MIME tree

[Daniel Kahn Gillmor <dkg@fifthhorseman.net>]

Unwrap a PKCS#7 SignedData part unconditionally when the cli is
traversing the MIME tree, and return it as a "child" of what would
otherwise be a leaf in the tree.

Unfortunately, this also breaks the JSON output.  We will fix that
next.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
 mime-node.c        | 23 +++++++++++++++++++++--
 test/T355-smime.sh |  2 +-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/mime-node.c b/mime-node.c
index ff6805bf..b6431e3b 100644
--- a/mime-node.c
+++ b/mime-node.c
@@ -220,8 +220,17 @@ node_verify (mime_node_t *node, GMimeObject *part)
     notmuch_status_t status;
 
     node->verify_attempted = true;
-    node->sig_list = g_mime_multipart_signed_verify (
-	GMIME_MULTIPART_SIGNED (part), GMIME_VERIFY_NONE, &err);
+    if (GMIME_IS_APPLICATION_PKCS7_MIME (part))
+	node->sig_list = g_mime_application_pkcs7_mime_verify (
+	    GMIME_APPLICATION_PKCS7_MIME (part), GMIME_VERIFY_NONE, &node->unwrapped_child, &err);
+    else
+	node->sig_list = g_mime_multipart_signed_verify (
+	    GMIME_MULTIPART_SIGNED (part), GMIME_VERIFY_NONE, &err);
+
+    if (node->unwrapped_child) {
+	node->nchildren = 1;
+	set_unwrapped_child_destructor (node);
+    }
 
     if (node->sig_list)
 	set_signature_list_destructor (node);
@@ -376,6 +385,12 @@ _mime_node_set_up_part (mime_node_t *node, GMimeObject *part, int numchild)
 	} else {
 	    node_verify (node, part);
 	}
+    } else if (GMIME_IS_APPLICATION_PKCS7_MIME (part) &&
+	       GMIME_SECURE_MIME_TYPE_SIGNED_DATA == g_mime_application_pkcs7_mime_get_smime_type (GMIME_APPLICATION_PKCS7_MIME (part))) {
+	/* If node->ctx->crypto->verify is false, it would be better
+	 * to just unwrap (instead of verifying), but
+	 * https://github.com/jstedfast/gmime/issues/67 */
+	node_verify (node, part);
     } else {
 	if (_notmuch_message_crypto_potential_payload (node->ctx->msg_crypto, part, node->parent ? node->parent->part : NULL, numchild) &&
 	    node->ctx->msg_crypto->decryption_status == NOTMUCH_MESSAGE_DECRYPTED_FULL) {
@@ -409,6 +424,10 @@ mime_node_child (mime_node_t *parent, int child)
 		GMIME_MULTIPART (parent->part), child);
     } else if (GMIME_IS_MESSAGE (parent->part)) {
 	sub = g_mime_message_get_mime_part (GMIME_MESSAGE (parent->part));
+    } else if (GMIME_IS_APPLICATION_PKCS7_MIME (parent->part) &&
+	       parent->unwrapped_child &&
+	       child == 0) {
+	sub = parent->unwrapped_child;
     } else {
 	/* This should have been caught by _mime_node_set_up_part */
 	INTERNAL_ERROR ("Unexpected GMimeObject type: %s",
diff --git a/test/T355-smime.sh b/test/T355-smime.sh
index 7c28282a..4de0fbef 100755
--- a/test/T355-smime.sh
+++ b/test/T355-smime.sh
@@ -142,7 +142,6 @@ expected='#notmuch-dump batch-tag:3 config,properties,tags
 test_expect_equal "$expected" "$output"
 
 test_begin_subtest "show contents of PKCS#7 SignedData message"
-test_subtest_known_broken
 output=$(notmuch show --format=raw --part=2 id:smime-onepart-signed@protected-headers.example)
 whitespace=' '
 expected="Bob, we need to cancel this contract.
@@ -178,6 +177,7 @@ On Tue, 26 Nov 2019 20:11:29 -0400, Alice Lovelace <alice@smime.example> wrote:
 test_expect_equal "$expected" "$output"
 
 test_begin_subtest "show PKCS#7 SignedData outputs valid JSON"
+test_subtest_known_broken
 output=$(notmuch show --format=json id:smime-onepart-signed@protected-headers.example)
 test_valid_json "$output"
 
-- 
2.26.2