merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 175 insertions, 37 deletions

diff --git a/third_party/git/credential.c b/third_party/git/credential.c
index 62be651b03..e5202fbef2 100644
--- a/third_party/git/credential.c
+++ b/third_party/git/credential.c
@@ -6,6 +6,7 @@
 #include "url.h"
 #include "prompt.h"
 #include "sigchain.h"
+#include "urlmatch.h"
 
 void credential_init(struct credential *c)
 {
@@ -36,11 +37,15 @@ int credential_match(const struct credential *want,
 #undef CHECK
 }
 
+
+static int credential_from_potentially_partial_url(struct credential *c,
+						   const char *url);
+
 static int credential_config_callback(const char *var, const char *value,
 				      void *data)
 {
 	struct credential *c = data;
-	const char *key, *dot;
+	const char *key;
 
 	if (!skip_prefix(var, "credential.", &key))
 		return 0;
@@ -48,31 +53,16 @@ static int credential_config_callback(const char *var, const char *value,
 	if (!value)
 		return config_error_nonbool(var);
 
-	dot = strrchr(key, '.');
-	if (dot) {
-		struct credential want = CREDENTIAL_INIT;
-		char *url = xmemdupz(key, dot - key);
-		int matched;
-
-		credential_from_url(&want, url);
-		matched = credential_match(&want, c);
-
-		credential_clear(&want);
-		free(url);
-
-		if (!matched)
-			return 0;
-		key = dot + 1;
-	}
-
 	if (!strcmp(key, "helper")) {
 		if (*value)
 			string_list_append(&c->helpers, value);
 		else
 			string_list_clear(&c->helpers, 0);
 	} else if (!strcmp(key, "username")) {
-		if (!c->username)
+		if (!c->username_from_proto) {
+			free(c->username);
 			c->username = xstrdup(value);
+		}
 	}
 	else if (!strcmp(key, "usehttppath"))
 		c->use_http_path = git_config_bool(var, value);
@@ -87,11 +77,60 @@ static int proto_is_http(const char *s)
 	return !strcmp(s, "https") || !strcmp(s, "http");
 }
 
+static void credential_describe(struct credential *c, struct strbuf *out);
+static void credential_format(struct credential *c, struct strbuf *out);
+
+static int select_all(const struct urlmatch_item *a,
+		      const struct urlmatch_item *b)
+{
+	return 0;
+}
+
+static int match_partial_url(const char *url, void *cb)
+{
+	struct credential *c = cb;
+	struct credential want = CREDENTIAL_INIT;
+	int matches = 0;
+
+	if (credential_from_potentially_partial_url(&want, url) < 0)
+		warning(_("skipping credential lookup for key: credential.%s"),
+			url);
+	else
+		matches = credential_match(&want, c);
+	credential_clear(&want);
+
+	return matches;
+}
+
 static void credential_apply_config(struct credential *c)
 {
+	char *normalized_url;
+	struct urlmatch_config config = { STRING_LIST_INIT_DUP };
+	struct strbuf url = STRBUF_INIT;
+
+	if (!c->host)
+		die(_("refusing to work with credential missing host field"));
+	if (!c->protocol)
+		die(_("refusing to work with credential missing protocol field"));
+
 	if (c->configured)
 		return;
-	git_config(credential_config_callback, c);
+
+	config.section = "credential";
+	config.key = NULL;
+	config.collect_fn = credential_config_callback;
+	config.cascade_fn = NULL;
+	config.select_fn = select_all;
+	config.fallback_match_fn = match_partial_url;
+	config.cb = c;
+
+	credential_format(c, &url);
+	normalized_url = url_normalize(url.buf, &config.url);
+
+	git_config(urlmatch_config_entry, &config);
+	free(normalized_url);
+	strbuf_release(&url);
+
 	c->configured = 1;
 
 	if (!c->use_http_path && proto_is_http(c->protocol)) {
@@ -112,6 +151,23 @@ static void credential_describe(struct credential *c, struct strbuf *out)
 		strbuf_addf(out, "/%s", c->path);
 }
 
+static void credential_format(struct credential *c, struct strbuf *out)
+{
+	if (!c->protocol)
+		return;
+	strbuf_addf(out, "%s://", c->protocol);
+	if (c->username && *c->username) {
+		strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
+		strbuf_addch(out, '@');
+	}
+	if (c->host)
+		strbuf_addstr(out, c->host);
+	if (c->path) {
+		strbuf_addch(out, '/');
+		strbuf_add_percentencode(out, c->path, 0);
+	}
+}
+
 static char *credential_ask_one(const char *what, struct credential *c,
 				int flags)
 {
@@ -146,7 +202,7 @@ int credential_read(struct credential *c, FILE *fp)
 {
 	struct strbuf line = STRBUF_INIT;
 
-	while (strbuf_getline_lf(&line, fp) != EOF) {
+	while (strbuf_getline(&line, fp) != EOF) {
 		char *key = line.buf;
 		char *value = strchr(key, '=');
 
@@ -163,6 +219,7 @@ int credential_read(struct credential *c, FILE *fp)
 		if (!strcmp(key, "username")) {
 			free(c->username);
 			c->username = xstrdup(value);
+			c->username_from_proto = 1;
 		} else if (!strcmp(key, "password")) {
 			free(c->password);
 			c->password = xstrdup(value);
@@ -191,20 +248,25 @@ int credential_read(struct credential *c, FILE *fp)
 	return 0;
 }
 
-static void credential_write_item(FILE *fp, const char *key, const char *value)
+static void credential_write_item(FILE *fp, const char *key, const char *value,
+				  int required)
 {
+	if (!value && required)
+		BUG("credential value for %s is missing", key);
 	if (!value)
 		return;
+	if (strchr(value, '\n'))
+		die("credential value for %s contains newline", key);
 	fprintf(fp, "%s=%s\n", key, value);
 }
 
 void credential_write(const struct credential *c, FILE *fp)
 {
-	credential_write_item(fp, "protocol", c->protocol);
-	credential_write_item(fp, "host", c->host);
-	credential_write_item(fp, "path", c->path);
-	credential_write_item(fp, "username", c->username);
-	credential_write_item(fp, "password", c->password);
+	credential_write_item(fp, "protocol", c->protocol, 1);
+	credential_write_item(fp, "host", c->host, 1);
+	credential_write_item(fp, "path", c->path, 0);
+	credential_write_item(fp, "username", c->username, 0);
+	credential_write_item(fp, "password", c->password, 0);
 }
 
 static int run_credential_helper(struct credential *c,
@@ -212,11 +274,9 @@ static int run_credential_helper(struct credential *c,
 				 int want_output)
 {
 	struct child_process helper = CHILD_PROCESS_INIT;
-	const char *argv[] = { NULL, NULL };
 	FILE *fp;
 
-	argv[0] = cmd;
-	helper.argv = argv;
+	strvec_push(&helper.args, cmd);
 	helper.use_shell = 1;
 	helper.in = -1;
 	if (want_output)
@@ -322,7 +382,45 @@ void credential_reject(struct credential *c)
 	c->approved = 0;
 }
 
-void credential_from_url(struct credential *c, const char *url)
+static int check_url_component(const char *url, int quiet,
+			       const char *name, const char *value)
+{
+	if (!value)
+		return 0;
+	if (!strchr(value, '\n'))
+		return 0;
+
+	if (!quiet)
+		warning(_("url contains a newline in its %s component: %s"),
+			name, url);
+	return -1;
+}
+
+/*
+ * Potentially-partial URLs can, but do not have to, contain
+ *
+ * - a protocol (or scheme) of the form "<protocol>://"
+ *
+ * - a host name (the part after the protocol and before the first slash after
+ *   that, if any)
+ *
+ * - a user name and potentially a password (as "<user>[:<password>]@" part of
+ *   the host name)
+ *
+ * - a path (the part after the host name, if any, starting with the slash)
+ *
+ * Missing parts will be left unset in `struct credential`. Thus, `https://`
+ * will have only the `protocol` set, `example.com` only the host name, and
+ * `/git` only the path.
+ *
+ * Note that an empty host name in an otherwise fully-qualified URL (e.g.
+ * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
+ * be potentially partial, and only then (otherwise, the empty string is used).
+ *
+ * The credential_from_url() function does not allow partial URLs.
+ */
+static int credential_from_url_1(struct credential *c, const char *url,
+				 int allow_partial_url, int quiet)
 {
 	const char *at, *colon, *cp, *slash, *host, *proto_end;
 
@@ -335,12 +433,22 @@ void credential_from_url(struct credential *c, const char *url)
 	 *   (3) proto://<user>:<pass>@<host>/...
 	 */
 	proto_end = strstr(url, "://");
-	if (!proto_end)
-		return;
-	cp = proto_end + 3;
+	if (!allow_partial_url && (!proto_end || proto_end == url)) {
+		if (!quiet)
+			warning(_("url has no scheme: %s"), url);
+		return -1;
+	}
+	cp = proto_end ? proto_end + 3 : url;
 	at = strchr(cp, '@');
 	colon = strchr(cp, ':');
-	slash = strchrnul(cp, '/');
+
+	/*
+	 * A query or fragment marker before the slash ends the host portion.
+	 * We'll just continue to call this "slash" for simplicity. Notably our
+	 * "trim leading slashes" part won't skip over this part of the path,
+	 * but that's what we'd want.
+	 */
+	slash = cp + strcspn(cp, "/?#");
 
 	if (!at || slash <= at) {
 		/* Case (1) */
@@ -349,17 +457,21 @@ void credential_from_url(struct credential *c, const char *url)
 	else if (!colon || at <= colon) {
 		/* Case (2) */
 		c->username = url_decode_mem(cp, at - cp);
+		if (c->username && *c->username)
+			c->username_from_proto = 1;
 		host = at + 1;
 	} else {
 		/* Case (3) */
 		c->username = url_decode_mem(cp, colon - cp);
+		if (c->username && *c->username)
+			c->username_from_proto = 1;
 		c->password = url_decode_mem(colon + 1, at - (colon + 1));
 		host = at + 1;
 	}
 
-	if (proto_end - url > 0)
+	if (proto_end && proto_end - url > 0)
 		c->protocol = xmemdupz(url, proto_end - url);
-	if (slash - host > 0)
+	if (!allow_partial_url || slash - host > 0)
 		c->host = url_decode_mem(host, slash - host);
 	/* Trim leading and trailing slashes from path */
 	while (*slash == '/')
@@ -371,4 +483,30 @@ void credential_from_url(struct credential *c, const char *url)
 		while (p > c->path && *p == '/')
 			*p-- = '\0';
 	}
+
+	if (check_url_component(url, quiet, "username", c->username) < 0 ||
+	    check_url_component(url, quiet, "password", c->password) < 0 ||
+	    check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
+	    check_url_component(url, quiet, "host", c->host) < 0 ||
+	    check_url_component(url, quiet, "path", c->path) < 0)
+		return -1;
+
+	return 0;
+}
+
+static int credential_from_potentially_partial_url(struct credential *c,
+						   const char *url)
+{
+	return credential_from_url_1(c, url, 1, 0);
+}
+
+int credential_from_url_gently(struct credential *c, const char *url, int quiet)
+{
+	return credential_from_url_1(c, url, 0, quiet);
+}
+
+void credential_from_url(struct credential *c, const char *url)
+{
+	if (credential_from_url_gently(c, url, 0) < 0)
+		die(_("credential url cannot be parsed: %s"), url);
 }