[PATCH 3/3] submodule-config.c: strengthen URL fsck check

["Victoria Dye via GitGitGadget" <gitgitgadget@gmail.com>]

From: Victoria Dye <vdye@github.com>

Update the validation of "curl URL" submodule URLs (i.e. those that specify
an "http[s]" or "ftp[s]" protocol) in 'check_submodule_url()' to catch more
invalid URLs. The existing validation using 'credential_from_url_gently()'
parses certain URLs incorrectly, leading to invalid submodule URLs passing
'git fsck' checks. Conversely, 'url_normalize()' - used to validate remote
URLs in 'remote_get()' - correctly identifies the invalid URLs missed by
'credential_from_url_gently()'.

To catch more invalid cases, replace 'credential_from_url_gently()' with
'url_normalize()' followed by a 'url_decode()' and a check for newlines
(mirroring 'check_url_component()' in the 'credential_from_url_gently()'
validation).

Signed-off-by: Victoria Dye <vdye@github.com>
---
 submodule-config.c          | 16 +++++++++++-----
 t/t7450-bad-git-dotfiles.sh |  2 +-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/submodule-config.c b/submodule-config.c
index 3b295e9f89c..54130f6a385 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -15,7 +15,7 @@
 #include "thread-utils.h"
 #include "tree-walk.h"
 #include "url.h"
-#include "credential.h"
+#include "urlmatch.h"
 
 /*
  * submodule cache lookup structure
@@ -350,12 +350,18 @@ int check_submodule_url(const char *url)
 	}
 
 	else if (url_to_curl_url(url, &curl_url)) {
-		struct credential c = CREDENTIAL_INIT;
 		int ret = 0;
-		if (credential_from_url_gently(&c, curl_url, 1) ||
-		    !*c.host)
+		char *normalized = url_normalize(curl_url, NULL);
+		if (normalized) {
+			char *decoded = url_decode(normalized);
+			if (strchr(decoded, '\n'))
+				ret = -1;
+			free(normalized);
+			free(decoded);
+		} else {
 			ret = -1;
-		credential_clear(&c);
+		}
+
 		return ret;
 	}
 
diff --git a/t/t7450-bad-git-dotfiles.sh b/t/t7450-bad-git-dotfiles.sh
index 0dbf13724f4..46d4fb0354b 100755
--- a/t/t7450-bad-git-dotfiles.sh
+++ b/t/t7450-bad-git-dotfiles.sh
@@ -45,7 +45,7 @@ test_expect_success 'check names' '
 	test_cmp expect actual
 '
 
-test_expect_failure 'check urls' '
+test_expect_success 'check urls' '
 	cat >expect <<-\EOF &&
 	./bar/baz/foo.git
 	https://example.com/foo.git
-- 
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