git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCHv2 12/13] credentials: add "store" helper

From
Jeff King <peff@peff.net>
Date
Dec 6, 2011, 06:23 UTC
Message-ID
<20111206062305.GL29233@sigill.intra.peff.net>
In-Reply-To
<20111206062127.GA29046@sigill.intra.peff.net>

This is like "cache", except that we actually put the credentials on disk. This can be terribly insecure, of course, but we do what we can to protect them by filesystem permissions, and we warn the user in the documentation.

This is not unlike using .netrc to store entries, but it's a little more user-friendly. Instead of putting credentials in place ahead of time, we transparently store them after prompting the user for them once.

Signed-off-by: Jeff King <peff@peff.net>
---
 .gitignore                             |    1 +
 Documentation/git-credential-store.txt |   75 ++++++++++++++++
 Documentation/gitcredentials.txt       |    5 +
 Makefile                               |    1 +
 credential-store.c                     |  148 ++++++++++++++++++++++++++++++++
 t/t0302-credential-store.sh            |    9 ++
 6 files changed, 239 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-credential-store.txt
 create mode 100644 credential-store.c
 create mode 100755 t/t0302-credential-store.sh
diff --git a/.gitignore b/.gitignore
index a6b0bd4..2b7a3f9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@
 /git-count-objects
 /git-credential-cache
 /git-credential-cache--daemon
+/git-credential-store
 /git-cvsexportcommit
 /git-cvsimport
 /git-cvsserver
diff --git a/Documentation/git-credential-store.txt b/Documentation/git-credential-store.txt
new file mode 100644
index 0000000..3109346
--- /dev/null
+++ b/Documentation/git-credential-store.txt
@@ -0,0 +1,75 @@
+git-credential-store(1)
+=======================
+
+NAME
+----
+git-credential-store - helper to store credentials on disk
+
+SYNOPSIS
+--------
+-------------------
+git config credential.helper 'store [options]'
+-------------------
+
+DESCRIPTION
+-----------
+
+NOTE: Using this helper will store your passwords unencrypted on disk,
+protected only by filesystem permissions. If this is not an acceptable
+security tradeoff, try linkgit:git-credential-cache[1], or find a helper
+that integrates with secure storage provided by your operating system.
+
+This command stores credentials indefinitely on disk for use by future
+git programs.
+
+You probably don't want to invoke this command directly; it is meant to
+be used as a credential helper by other parts of git. See
+linkgit:gitcredentials[7] or `EXAMPLES` below.
+
+OPTIONS
+-------
+
+--store=<path>::
+
+	Use `<path>` to store credentials. The file will have its
+	filesystem permissions set to prevent other users on the system
+	from reading it, but will not be encrypted or otherwise
+	protected. Defaults to `~/.git-credentials`.
+
+EXAMPLES
+--------
+
+The point of this helper is to reduce the number of times you must type
+your username or password. For example:
+
+------------------------------------------
+$ git config credential.helper store
+$ git push http://example.com/repo.git
+Username: <type your username>
+Password: <type your password>
+
+[several days later]
+$ git push http://example.com/repo.git
+[your credentials are used automatically]
+------------------------------------------
+
+STORAGE FORMAT
+--------------
+
+The `.git-credentials` file is stored in plaintext. Each credential is
+stored on its own line as a URL like:
+
+------------------------------
+https://user:pass@example.com
+------------------------------
+
+When git needs authentication for a particular URL context,
+credential-store will consider that context a pattern to match against
+each entry in the credentials file.  If the protocol, hostname, and
+username (if we already have one) match, then the password is returned
+to git. See the discussion of configuration in linkgit:gitcredentials[7]
+for more information.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 4e3f860..066f825 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -71,6 +71,11 @@ cache::
 	Cache credentials in memory for a short period of time. See
 	linkgit:git-credential-cache[1] for details.
 
+store::
+
+	Store credentials indefinitely on disk. See
+	linkgit:git-credential-store[1] for details.
+
 You may also have third-party helpers installed; search for
 `credential-*` in the output of `git help -a`, and consult the
 documentation of individual helpers.  Once you have selected a helper,
diff --git a/Makefile b/Makefile
index 5d41c29..2537128 100644
--- a/Makefile
+++ b/Makefile
@@ -429,6 +429,7 @@ PROGRAM_OBJS += http-backend.o
 PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAM_OBJS += credential-cache.o
 PROGRAM_OBJS += credential-cache--daemon.o
+PROGRAM_OBJS += credential-store.o
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
diff --git a/credential-store.c b/credential-store.c
new file mode 100644
index 0000000..ed58768
--- /dev/null
+++ b/credential-store.c
@@ -0,0 +1,148 @@
+#include "cache.h"
+#include "credential.h"
+#include "string-list.h"
+#include "parse-options.h"
+
+static struct lock_file credential_lock;
+
+static void parse_credential_file(const char *fn,
+				  struct credential *c,
+				  void (*match_cb)(struct credential *),
+				  void (*other_cb)(struct strbuf *))
+{
+	FILE *fh;
+	struct strbuf line = STRBUF_INIT;
+	struct credential entry = CREDENTIAL_INIT;
+
+	fh = fopen(fn, "r");
+	if (!fh) {
+		if (errno != ENOENT)
+			die_errno("unable to open %s", fn);
+		return;
+	}
+
+	while (strbuf_getline(&line, fh, '\n') != EOF) {
+		credential_from_url(&entry, line.buf);
+		if (entry.username && entry.password &&
+		    credential_match(c, &entry)) {
+			if (match_cb) {
+				match_cb(&entry);
+				break;
+			}
+		}
+		else if (other_cb)
+			other_cb(&line);
+	}
+
+	credential_clear(&entry);
+	strbuf_release(&line);
+	fclose(fh);
+}
+
+static void print_entry(struct credential *c)
+{
+	printf("username=%s\n", c->username);
+	printf("password=%s\n", c->password);
+}
+
+static void print_line(struct strbuf *buf)
+{
+	strbuf_addch(buf, '\n');
+	write_or_die(credential_lock.fd, buf->buf, buf->len);
+}
+
+static void rewrite_credential_file(const char *fn, struct credential *c,
+				    struct strbuf *extra)
+{
+	if (hold_lock_file_for_update(&credential_lock, fn, 0) < 0)
+		die_errno("unable to get credential storage lock");
+	if (extra)
+		print_line(extra);
+	parse_credential_file(fn, c, NULL, print_line);
+	if (commit_lock_file(&credential_lock) < 0)
+		die_errno("unable to commit credential store");
+}
+
+static void store_credential(const char *fn, struct credential *c)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	/*
+	 * Sanity check that what we are storing is actually sensible.
+	 * In particular, we can't make a URL without a protocol field.
+	 * Without either a host or pathname (depending on the scheme),
+	 * we have no primary key. And without a username and password,
+	 * we are not actually storing a credential.
+	 */
+	if (!c->protocol || !(c->host || c->path) ||
+	    !c->username || !c->password)
+		return;
+
+	strbuf_addf(&buf, "%s://", c->protocol);
+	strbuf_addstr_urlencode(&buf, c->username, 1);
+	strbuf_addch(&buf, ':');
+	strbuf_addstr_urlencode(&buf, c->password, 1);
+	strbuf_addch(&buf, '@');
+	if (c->host)
+		strbuf_addstr_urlencode(&buf, c->host, 1);
+	if (c->path) {
+		strbuf_addch(&buf, '/');
+		strbuf_addstr_urlencode(&buf, c->path, 0);
+	}
+
+	rewrite_credential_file(fn, c, &buf);
+	strbuf_release(&buf);
+}
+
+static void remove_credential(const char *fn, struct credential *c)
+{
+	rewrite_credential_file(fn, c, NULL);
+}
+
+static int lookup_credential(const char *fn, struct credential *c)
+{
+	parse_credential_file(fn, c, print_entry, NULL);
+	return c->username && c->password;
+}
+
+int main(int argc, const char **argv)
+{
+	const char * const usage[] = {
+		"git credential-store [options] <action>",
+		NULL
+	};
+	const char *op;
+	struct credential c = CREDENTIAL_INIT;
+	char *file = NULL;
+	struct option options[] = {
+		OPT_STRING_LIST(0, "file", &file, "path",
+				"fetch and store credentials in <path>"),
+		OPT_END()
+	};
+
+	umask(077);
+
+	argc = parse_options(argc, argv, NULL, options, usage, 0);
+	if (argc != 1)
+		usage_with_options(usage, options);
+	op = argv[0];
+
+	if (!file)
+		file = expand_user_path("~/.git-credentials");
+	if (!file)
+		die("unable to set up default path; use --file");
+
+	if (credential_read(&c, stdin) < 0)
+		die("unable to read credential");
+
+	if (!strcmp(op, "get"))
+		lookup_credential(file, &c);
+	else if (!strcmp(op, "erase"))
+		remove_credential(file, &c);
+	else if (!strcmp(op, "store"))
+		store_credential(file, &c);
+	else
+		; /* Ignore unknown operation. */
+
+	return 0;
+}
diff --git a/t/t0302-credential-store.sh b/t/t0302-credential-store.sh
new file mode 100755
index 0000000..f61b40c
--- /dev/null
+++ b/t/t0302-credential-store.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+test_description='credential-store tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential.sh
+
+helper_test store
+
+test_done

-- 
1.7.8.rc4.4.g884ec
Previous: Jeff KingNext: Junio C Hamano
Message 16 of 30 in “[PATCHv2 0/13] credential helpers”
  1. Jeff KingDec 6, 2011
  2. 01/13 test-lib: add test_config_global variantJeff King, Dec 6, 2011
  3. 02/13 t5550: fix typoJeff King, Dec 6, 2011
  4. 03/13 introduce credentials APIJeff King, Dec 6, 2011
  5. 04/13 credential: add function for parsing url componentsJeff King, Dec 6, 2011
  6. 05/13 http: use credential API to get passwordsJeff King, Dec 6, 2011
  7. 06/13 credential: apply helper configJeff King, Dec 6, 2011
  8. Junio C HamanoDec 6, 2011
  9. Jeff KingDec 7, 2011
  10. Jeff KingDec 7, 2011
  11. 07/13 credential: add credential.*.usernameJeff King, Dec 6, 2011
  12. 08/13 credential: make relevance of http path configurableJeff King, Dec 6, 2011
  13. 09/13 docs: end-user documentation for the credential subsystemJeff King, Dec 6, 2011
  14. 10/13 credentials: add "cache" helperJeff King, Dec 6, 2011
  15. 11/13 strbuf: add strbuf_add*_urlencodeJeff King, Dec 6, 2011
  16. 12/13 credentials: add "store" helperJeff King, Dec 6, 2011
  17. Junio C HamanoDec 6, 2011
  18. Jeff KingDec 9, 2011
  19. 13/13 t: add test harness for external credential helpersJeff King, Dec 6, 2011
  20. Junio C HamanoDec 6, 2011
  21. Jeff KingDec 6, 2011
  22. Junio C HamanoDec 6, 2011
  23. Jeff KingDec 7, 2011
  24. Junio C HamanoDec 8, 2011
  25. Jeff KingDec 9, 2011
  26. Junio C HamanoDec 9, 2011
  27. Jeff KingDec 9, 2011
  28. Junio C HamanoDec 9, 2011
  29. Jeff KingDec 9, 2011
  30. Junio C HamanoDec 9, 2011

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.