Right, this approach of having ACL using the --access-hook option looks
much better. At least you got inspired this could be useful for somebody ;-)
Michal
On 08/15/2012 07:12 AM, Junio C Hamano wrote:
> The --access-hook option to "git daemon" specifies an external
> command to be run every time a client connects, with
>
> - service name (e.g. "upload-pack", etc.),
> - path to the repository,
> - hostname (%H),
> - canonical hostname (%CH),
> - ip address (%IP),
> - tcp port (%P)
>
> as its command line arguments. The external command can decide to
> decline the service by exiting with a non-zero status (or to allow it
> by exiting with a zero status). It can also look at the $REMOTE_ADDR
> and $REMOTE_PORT environment variables to learn about the requestor
> when making this decision.
>
> The external command can optionally write a single line to its
> standard output to be sent to the requestor as an error message when
> it declines the service.
>
> Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
> ---
>
> * This time, minimally tested, with a documentation update.
>
> Documentation/git-daemon.txt | 16 +++++++++
> daemon.c | 77 ++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 93 insertions(+)
>
> diff --git a/Documentation/git-daemon.txt b/Documentation/git-daemon.txt
> index 31b28fc..c3ba4d7 100644
> --- a/Documentation/git-daemon.txt
> +++ b/Documentation/git-daemon.txt
> @@ -16,6 +16,7 @@ SYNOPSIS
> [--reuseaddr] [--detach] [--pid-file=<file>]
> [--enable=<service>] [--disable=<service>]
> [--allow-override=<service>] [--forbid-override=<service>]
> + [--access-hook=<path>]
> [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>] [--user=<user> [--group=<group>]]
> [<directory>...]
>
> @@ -171,6 +172,21 @@ the facility of inet daemon to achieve the same before spawning
> errors are not enabled, all errors report "access denied" to the
> client. The default is --no-informative-errors.
>
> +--access-hook=<path>::
> + Every time a client connects, first run an external command
> + specified by the <path> with service name (e.g. "upload-pack"),
> + path to the repository, hostname (%H), canonical hostname
> + (%CH), ip address (%IP), and tcp port (%P) as its command line
> + arguments. The external command can decide to decline the
> + service by exiting with a non-zero status (or to allow it by
> + exiting with a zero status). It can also look at the $REMOTE_ADDR
> + and $REMOTE_PORT environment variables to learn about the
> + requestor when making this decision.
> ++
> +The external command can optionally write a single line to its
> +standard output to be sent to the requestor as an error message when
> +it declines the service.
> +
> <directory>::
> A directory to add to the whitelist of allowed directories. Unless
> --strict-paths is specified this will also include subdirectories
> diff --git a/daemon.c b/daemon.c
> index ab21e66..4602b46 100644
> --- a/daemon.c
> +++ b/daemon.c
> @@ -30,6 +30,7 @@ static const char daemon_usage[] =
> " [--interpolated-path=<path>]\n"
> " [--reuseaddr] [--pid-file=<file>]\n"
> " [--(enable|disable|allow-override|forbid-override)=<service>]\n"
> +" [--access-hook=<path>]\n"
> " [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
> " [--detach] [--user=<user> [--group=<group>]]\n"
> " [<directory>...]";
> @@ -256,6 +257,71 @@ static int daemon_error(const char *dir, const char *msg)
> return -1;
> }
>
> +static char *access_hook;
> +
> +static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
> +{
> + struct child_process child;
> + struct strbuf buf = STRBUF_INIT;
> + const char *argv[8];
> + const char **arg = argv;
> + char *eol;
> + int seen_errors = 0;
> +
> +#define STRARG(x) ((x) ? (x) : "")
> + *arg++ = access_hook;
> + *arg++ = service->name;
> + *arg++ = path;
> + *arg++ = STRARG(hostname);
> + *arg++ = STRARG(canon_hostname);
> + *arg++ = STRARG(ip_address);
> + *arg++ = STRARG(tcp_port);
> + *arg = NULL;
> +#undef STRARG
> +
> + memset(&child, 0, sizeof(child));
> + child.use_shell = 1;
> + child.argv = argv;
> + child.no_stdin = 1;
> + child.no_stderr = 1;
> + child.out = -1;
> + if (start_command(&child)) {
> + logerror("daemon access hook '%s' failed to start",
> + access_hook);
> + goto error_return;
> + }
> + if (strbuf_read(&buf, child.out, 0) < 0) {
> + logerror("failed to read from pipe to daemon access hook '%s'",
> + access_hook);
> + strbuf_reset(&buf);
> + seen_errors = 1;
> + }
> + if (close(child.out) < 0) {
> + logerror("failed to close pipe to daemon access hook '%s'",
> + access_hook);
> + seen_errors = 1;
> + }
> + if (finish_command(&child))
> + seen_errors = 1;
> +
> + if (!seen_errors) {
> + strbuf_release(&buf);
> + return 0;
> + }
> +
> +error_return:
> + strbuf_ltrim(&buf);
> + if (!buf.len)
> + strbuf_addstr(&buf, "service rejected");
> + eol = strchr(buf.buf, '\n');
> + if (eol)
> + *eol = '\0';
> + errno = EACCES;
> + daemon_error(dir, buf.buf);
> + strbuf_release(&buf);
> + return -1;
> +}
> +
> static int run_service(char *dir, struct daemon_service *service)
> {
> const char *path;
> @@ -304,6 +370,13 @@ static int run_service(char *dir, struct daemon_service *service)
> }
>
> /*
> + * Optionally, a hook can choose to deny access to the
> + * repository depending on the phase of the moon.
> + */
> + if (access_hook && run_access_hook(service, dir, path))
> + return -1;
> +
> + /*
> * We'll ignore SIGTERM from now on, we have a
> * good client.
> */
> @@ -1142,6 +1215,10 @@ int main(int argc, char **argv)
> export_all_trees = 1;
> continue;
> }
> + if (!prefixcmp(arg, "--access-hook=")) {
> + access_hook = arg + 14;
> + continue;
> + }
> if (!prefixcmp(arg, "--timeout=")) {
> timeout = atoi(arg+10);
> continue;
--
Michal Novotny <minovotn@xxxxxxxxxx>, RHCE, Red Hat
Virtualization | libvirt-php bindings | php-virt-control.org
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