credential: erase all matching credentials

`credential reject` sends the erase action to each helper, but the
exact behaviour of erase isn't specified in documentation or tests.
Some helpers (such as credential-store and credential-libsecret) delete
all matching credentials, others (such as credential-cache) delete at
most one matching credential.

Test that helpers erase all matching credentials. This behaviour is
easiest to reason about. Users expect that `echo
"url=https://example.com" | git credential reject` or `echo
"url=https://example.com\nusername=tim" | git credential reject` erase
all matching credentials.

Fix credential-cache.

Signed-off-by: M Hickford <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: hickford

Documentation/git-credential.txt

@@ -39,7 +39,7 @@ for later use.
 
 If the action is `reject`, git-credential will send the description to
 any configured credential helpers, which may erase any stored
-credential matching the description.
+credentials matching the description.
 
 If the action is `approve` or `reject`, no output should be emitted.
 

Documentation/gitcredentials.txt

@@ -260,7 +260,7 @@ appended to its command line, which is one of:
 
 `erase`::
 
-	Remove a matching credential, if any, from the helper's storage.
+	Remove matching credentials, if any, from the helper's storage.
 
 The details of the credential will be provided on the helper's stdin
 stream. The exact format is the same as the input/output format of the

builtin/credential-cache--daemon.c

@@ -33,12 +33,12 @@ static void cache_credential(struct credential *c, int timeout)
 	e->expiration = time(NULL) + timeout;
 }
 
-static struct credential_cache_entry *lookup_credential(const struct credential *c, int match_password)
+static struct credential_cache_entry *lookup_credential(const struct credential *c)
 {
 	int i;
 	for (i = 0; i < entries_nr; i++) {
 		struct credential *e = &entries[i].item;
-		if (credential_match(c, e, match_password))
+		if (credential_match(c, e, 0))
 			return &entries[i];
 	}
 	return NULL;
@@ -48,9 +48,12 @@ static void remove_credential(const struct credential *c, int match_password)
 {
 	struct credential_cache_entry *e;
 
-	e = lookup_credential(c, match_password);
-	if (e)
-		e->expiration = 0;
+	int i;
+	for (i = 0; i < entries_nr; i++) {
+		e = &entries[i];
+		if (credential_match(c, &e->item, match_password))
+			e->expiration = 0;
+	}
 }
 
 static timestamp_t check_expirations(void)
@@ -127,7 +130,7 @@ static void serve_one_client(FILE *in, FILE *out)
 	if (read_request(in, &c, &action, &timeout) < 0)
 		/* ignore error */ ;
 	else if (!strcmp(action.buf, "get")) {
-		struct credential_cache_entry *e = lookup_credential(&c, 0);
+		struct credential_cache_entry *e = lookup_credential(&c);
 		if (e) {
 			fprintf(out, "username=%s\n", e->item.username);
 			fprintf(out, "password=%s\n", e->item.password);

t/lib-credential.sh

@@ -46,6 +46,8 @@ helper_test_clean() {
 	reject $1 https example.com user4
 	reject $1 https example.com user-distinct-pass
 	reject $1 https example.com user-overwrite
+	reject $1 https example.com user-erase1
+	reject $1 https example.com user-erase2
 	reject $1 http path.tld user
 	reject $1 https timeout.tld user
 	reject $1 https sso.tld
@@ -342,6 +344,37 @@ helper_test() {
 		EOF
 	'
 
+	test_expect_success "helper ($HELPER) erases all matching credentials" '
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user-erase1
+		password=pass1
+		EOF
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user-erase2
+		password=pass1
+		EOF
+		check reject $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		protocol=https
+		host=example.com
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://example.com'\'':
+		askpass: Password for '\''https://[email protected]'\'':
+		EOF
+	'
+
 	: ${GIT_TEST_LONG_CRED_BUFFER:=1024}
 	# 23 bytes accounts for "wwwauth[]=basic realm=" plus NUL
 	LONG_VALUE_LEN=$((GIT_TEST_LONG_CRED_BUFFER - 23))