threads / patch / 14356

patch, 4 partsgit-imap-send: Add support for SSL.

Subject: [PATCH 2/4] git-imap-send: Add support for SSL.

## tl;dr

8 messages between Jul 8, 2008 and Jul 10, 2008. Diffs are folded; open one to read it.

replies: 7people: 5as markdown or json

Robert Shearman· Jul 8, 2008, 22:18 UTC · lore
Allow SSL to be used when a imaps:// URL is used for the host name.
Also, automatically use TLS when not using imaps:// by using the IMAP STARTTLS command, if the server supports it.
Tested with Courier and Gimap IMAP servers.
---
 Documentation/git-imap-send.txt |    5 +-
 Makefile                        |    4 +-
 imap-send.c                     |  166 +++++++++++++++++++++++++++++++++++----
 3 files changed, 157 insertions(+), 18 deletions(-)
Show changes to 3 files +157 −18

Documentation/git-imap-send.txt, Makefile, imap-send.c

diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
index b3d8da3..e4a5873 100644
--- a/Documentation/git-imap-send.txt
+++ b/Documentation/git-imap-send.txt
@@ -37,10 +37,11 @@ configuration file (shown with examples):
     Tunnel = "ssh -q user@server.com /usr/bin/imapd ./Maildir 2> /dev/null"
 
 [imap]
-    Host = imap.server.com
+    Host = imaps://imap.example.com
     User = bob
     Pass = pwd
-    Port = 143
+    Port = 993
+    sslverify = false
 ..........................
 
 
diff --git a/Makefile b/Makefile
index bddd1a7..d9265f7 100644
--- a/Makefile
+++ b/Makefile
@@ -1193,7 +1193,9 @@ endif
 git-%$X: %.o $(GITLIBS)
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
 
-git-imap-send$X: imap-send.o $(LIB_FILE)
+git-imap-send$X: imap-send.o $(GITLIBS)
+	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+		$(LIBS) $(OPENSSL_LINK) $(OPENSSL_LIBSSL)
 
 http.o http-walker.o http-push.o transport.o: http.h
 
diff --git a/imap-send.c b/imap-send.c
index 89a1532..d138726 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -23,6 +23,12 @@
  */
 
 #include "cache.h"
+#ifdef NO_OPENSSL
+typedef void *SSL;
+#else
+# include <openssl/ssl.h>
+# include <openssl/err.h>
+#endif
 
 typedef struct store_conf {
 	char *name;
@@ -129,6 +135,8 @@ typedef struct imap_server_conf {
 	int port;
 	char *user;
 	char *pass;
+	int use_ssl;
+	int ssl_verify;
 } imap_server_conf_t;
 
 typedef struct imap_store_conf {
@@ -148,6 +156,7 @@ typedef struct _list {
 
 typedef struct {
 	int fd;
+	SSL *ssl;
 } Socket_t;
 
 typedef struct {
@@ -201,6 +210,7 @@ enum CAPABILITY {
 	UIDPLUS,
 	LITERALPLUS,
 	NAMESPACE,
+	STARTTLS,
 };
 
 static const char *cap_list[] = {
@@ -208,6 +218,7 @@ static const char *cap_list[] = {
 	"UIDPLUS",
 	"LITERAL+",
 	"NAMESPACE",
+	"STARTTLS",
 };
 
 #define RESP_OK    0
@@ -225,19 +236,101 @@ static const char *Flags[] = {
 	"Deleted",
 };
 
+#ifndef NO_OPENSSL
+static void ssl_socket_perror(const char *func)
+{
+	fprintf(stderr, "%s: %s\n", func, ERR_error_string(ERR_get_error(), 0));
+}
+#endif
+
 static void
 socket_perror( const char *func, Socket_t *sock, int ret )
 {
-	if (ret < 0)
-		perror( func );
+#ifndef NO_OPENSSL
+	if (sock->ssl) {
+		int sslerr = SSL_get_error(sock->ssl, ret);
+		switch (sslerr) {
+		case SSL_ERROR_NONE:
+			break;
+		case SSL_ERROR_SYSCALL:
+			perror("SSL_connect");
+			break;
+		default:
+			ssl_socket_perror("SSL_connect");
+			break;
+		}
+	} else
+#endif
+	{
+		if (ret < 0)
+			perror(func);
+		else
+			fprintf(stderr, "%s: unexpected EOF\n", func);
+	}
+}
+
+static int ssl_socket_connect(Socket_t *sock, int use_tls_only, int verify)
+{
+#ifdef NO_OPENSSL
+	fprintf(stderr, "SSL requested but SSL support not compiled in\n");
+	return -1;
+#else
+	SSL_METHOD *meth;
+	SSL_CTX *ctx;
+	int ret;
+
+	SSL_library_init();
+	SSL_load_error_strings();
+
+	if (use_tls_only)
+		meth = TLSv1_method();
 	else
-		fprintf( stderr, "%s: unexpected EOF\n", func );
+		meth = SSLv23_method();
+
+	if (!meth) {
+		ssl_socket_perror("SSLv23_method");
+		return -1;
+	}
+
+	ctx = SSL_CTX_new(meth);
+
+	if (verify)
+		SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
+
+	if (!SSL_CTX_set_default_verify_paths(ctx)) {
+		ssl_socket_perror("SSL_CTX_set_default_verify_paths");
+		return -1;
+	}
+	sock->ssl = SSL_new(ctx);
+	if (!sock->ssl) {
+		ssl_socket_perror("SSL_new");
+		return -1;
+	}
+	if (!SSL_set_fd(sock->ssl, sock->fd)) {
+		ssl_socket_perror("SSL_set_fd");
+		return -1;
+	}
+
+	ret = SSL_connect(sock->ssl);
+	if (ret <= 0) {
+		socket_perror("SSL_connect", sock, ret);
+		return -1;
+	}
+
+	return 0;
+#endif
 }
 
 static int
 socket_read( Socket_t *sock, char *buf, int len )
 {
-	ssize_t n = xread( sock->fd, buf, len );
+	ssize_t n;
+#ifndef NO_OPENSSL
+	if (sock->ssl)
+		n = SSL_read(sock->ssl, buf, len);
+	else
+#endif
+		n = xread( sock->fd, buf, len );
 	if (n <= 0) {
 		socket_perror( "read", sock, n );
 		close( sock->fd );
@@ -249,7 +342,13 @@ socket_read( Socket_t *sock, char *buf, int len )
 static int
 socket_write( Socket_t *sock, const char *buf, int len )
 {
-	int n = write_in_full( sock->fd, buf, len );
+	int n;
+#ifndef NO_OPENSSL
+	if (sock->ssl)
+		n = SSL_write(sock->ssl, buf, len);
+	else
+#endif
+		n = write_in_full( sock->fd, buf, len );
 	if (n != len) {
 		socket_perror( "write", sock, n );
 		close( sock->fd );
@@ -258,6 +357,17 @@ socket_write( Socket_t *sock, const char *buf, int len )
 	return n;
 }
 
+static void socket_shutdown(Socket_t *sock)
+{
+#ifndef NO_OPENSSL
+	if (sock->ssl) {
+		SSL_shutdown(sock->ssl);
+		SSL_free(sock->ssl);
+	}
+#endif
+	close(sock->fd);
+}
+
 /* simple line buffering */
 static int
 buffer_gets( buffer_t * b, char **s )
@@ -875,7 +985,7 @@ imap_close_server( imap_store_t *ictx )
 
 	if (imap->buf.sock.fd != -1) {
 		imap_exec( ictx, NULL, "LOGOUT" );
-		close( imap->buf.sock.fd );
+		socket_shutdown( &imap->buf.sock );
 	}
 	free_list( imap->ns_personal );
 	free_list( imap->ns_other );
@@ -906,6 +1016,7 @@ imap_open_store( imap_server_conf_t *srvc )
 
 	ctx->imap = imap = xcalloc( sizeof(*imap), 1 );
 	imap->buf.sock.fd = -1;
+	imap->buf.sock.ssl = NULL;
 	imap->in_progress_append = &imap->in_progress;
 
 	/* open connection to IMAP server */
@@ -958,10 +1069,15 @@ imap_open_store( imap_server_conf_t *srvc )
 			perror( "connect" );
 			goto bail;
 		}
-		imap_info( "ok\n" );
-
+		
 		imap->buf.sock.fd = s;
 
+		if (srvc->use_ssl &&
+		    ssl_socket_connect(&imap->buf.sock, 0, srvc->ssl_verify)) {
+			close(s);
+			goto bail;
+		}
+		imap_info( "ok\n" );
 	}
 
 	/* read the greeting string */
@@ -986,7 +1102,18 @@ imap_open_store( imap_server_conf_t *srvc )
 		goto bail;
 
 	if (!preauth) {
-
+#ifndef NO_OPENSSL
+		if (!srvc->use_ssl && CAP(STARTTLS)) {
+			if (imap_exec(ctx, 0, "STARTTLS") != RESP_OK)
+				goto bail;
+			if (ssl_socket_connect(&imap->buf.sock, 1,
+					       srvc->ssl_verify))
+				goto bail;
+			/* capabilities may have changed, so get the new capabilities */
+			if (imap_exec(ctx, 0, "CAPABILITY") != RESP_OK)
+				goto bail;
+		}
+#endif
 		imap_info ("Logging in...\n");
 		if (!srvc->user) {
 			fprintf( stderr, "Skipping server %s, no user\n", srvc->host );
@@ -1014,7 +1141,9 @@ imap_open_store( imap_server_conf_t *srvc )
 			fprintf( stderr, "Skipping account %s@%s, server forbids LOGIN\n", srvc->user, srvc->host );
 			goto bail;
 		}
-		imap_warn( "*** IMAP Warning *** Password is being sent in the clear\n" );
+		if (!imap->buf.sock.ssl)
+			imap_warn( "*** IMAP Warning *** Password is being "
+				   "sent in the clear\n" );
 		if (imap_exec( ctx, NULL, "LOGIN \"%s\" \"%s\"", srvc->user, srvc->pass ) != RESP_OK) {
 			fprintf( stderr, "IMAP error: LOGIN failed\n" );
 			goto bail;
@@ -1242,6 +1371,8 @@ static imap_server_conf_t server =
 	0,	/* port */
 	NULL,	/* user */
 	NULL,	/* pass */
+	0,   	/* use_ssl */
+	1,   	/* ssl_verify */
 };
 
 static char *imap_folder;
@@ -1262,11 +1393,11 @@ git_imap_config(const char *key, const char *val, void *cb)
 	if (!strcmp( "folder", key )) {
 		imap_folder = xstrdup( val );
 	} else if (!strcmp( "host", key )) {
-		{
-			if (!prefixcmp(val, "imap:"))
-				val += 5;
-			if (!server.port)
-				server.port = 143;
+		if (!prefixcmp(val, "imap:"))
+			val += 5;
+		else if (!prefixcmp(val, "imaps:")) {
+			val += 6;
+			server.use_ssl = 1;
 		}
 		if (!prefixcmp(val, "//"))
 			val += 2;
@@ -1280,6 +1411,8 @@ git_imap_config(const char *key, const char *val, void *cb)
 		server.port = git_config_int( key, val );
 	else if (!strcmp( "tunnel", key ))
 		server.tunnel = xstrdup( val );
+	else if (!strcmp( "ssl_verify", key ))
+		server.ssl_verify = git_config_bool( key, val );
 	return 0;
 }
 
@@ -1299,6 +1432,9 @@ main(int argc, char **argv)
 	setup_git_directory_gently( NULL );
 	git_config(git_imap_config, NULL);
 
+	if (!server.port)
+		server.port = server.use_ssl ? 993 : 143;
+
 	if (!imap_folder) {
 		fprintf( stderr, "no imap store specified\n" );
 		return 1;
-- 
1.5.6.GIT
Junio C Hamano· Jul 8, 2008, 23:20 UTC · re: Robert Shearman · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

Robert Shearman <robertshearman@gmail.com> writes:
Show 5 quoted lines
> Allow SSL to be used when a imaps:// URL is used for the host name.
>
> Also, automatically use TLS when not using imaps:// by using the IMAP STARTTLS command, if the server supports it.
>
> Tested with Courier and Gimap IMAP servers.
Sign-off?
Show 16 quoted lines
> diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
> index b3d8da3..e4a5873 100644
> --- a/Documentation/git-imap-send.txt
> +++ b/Documentation/git-imap-send.txt
> @@ -37,10 +37,11 @@ configuration file (shown with examples):
>      Tunnel = "ssh -q user@server.com /usr/bin/imapd ./Maildir 2> /dev/null"
>  
>  [imap]
> -    Host = imap.server.com
> +    Host = imaps://imap.example.com
>      User = bob
>      Pass = pwd
> -    Port = 143
> +    Port = 993
> +    sslverify = false
>  ..........................

Don't we also want to keep a vanilla configuration in the example, or is imaps the norm and unencrypted imap is exception these days?

Don't we need to support custom certificates, keys and CAs, just like our code that supports https does, by honoring GIT_SSL_* environment variables and configuration file entries? The patch itself looks fairly clean, and I'd like to queue this for wider testing, initially even without GIT_SSL_* support. But I'd like to see any patch with substantial amount of changes properly signed off.

Thanks.
Abhijit Menon-Sen· Jul 9, 2008, 02:28 UTC · re: Junio C Hamano · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

At 2008-07-08 16:20:19 -0700, gitster@pobox.com wrote:
Show 8 quoted lines
>
> > -    Port = 143
> > +    Port = 993
> > +    sslverify = false
> >  ..........................
> 
> Don't we also want to keep a vanilla configuration in the example, or
> is imaps the norm and unencrypted imap is exception these days?

The norm is IMAP+STARTTLS on port 143, not IMAPS on port 993. The latter is also widely deployed for compatibility with older clients, but it is non-standard and its use isn't exactly encouraged.

-- ams
Rob Shearman· Jul 9, 2008, 12:02 UTC · re: Junio C Hamano · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

2008/7/9 Junio C Hamano <gitster@pobox.com>:
Show 20 quoted lines
> Robert Shearman <robertshearman@gmail.com> writes:
>> diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
>> index b3d8da3..e4a5873 100644
>> --- a/Documentation/git-imap-send.txt
>> +++ b/Documentation/git-imap-send.txt
>> @@ -37,10 +37,11 @@ configuration file (shown with examples):
>>      Tunnel = "ssh -q user@server.com /usr/bin/imapd ./Maildir 2> /dev/null"
>>
>>  [imap]
>> -    Host = imap.server.com
>> +    Host = imaps://imap.example.com
>>      User = bob
>>      Pass = pwd
>> -    Port = 143
>> +    Port = 993
>> +    sslverify = false
>>  ..........................
>
> Don't we also want to keep a vanilla configuration in the example, or is
> imaps the norm and unencrypted imap is exception these days?

Good point. I'll fix the documentation to use imap:// instead of imaps:// and not change the port number. However, I'm not sure the examples should be telling the user what they should do, but rather what they can do.

> Don't we need to support custom certificates, keys and CAs, just like our
> code that supports https does, by honoring GIT_SSL_* environment variables
> and configuration file entries?

Yes, eventually we will want that support in imap-send too. It should be fairly trivial to do, although testing will be more difficult.

>  The patch itself looks fairly clean, and
> I'd like to queue this for wider testing, initially even without GIT_SSL_*
> support.  But I'd like to see any patch with substantial amount of changes
> properly signed off.

Great. I'll resend the series later with changes from the comments I've received and properly signed-off.

-- 
Rob Shearman
Junio C Hamano· Jul 9, 2008, 18:28 UTC · re: Rob Shearman · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

"Rob Shearman" <robertshearman@gmail.com> writes:
Show 9 quoted lines
> 2008/7/9 Junio C Hamano <gitster@pobox.com>:
> ...
>> Don't we also want to keep a vanilla configuration in the example, or is
>> imaps the norm and unencrypted imap is exception these days?
>
> Good point. I'll fix the documentation to use imap:// instead of
> imaps:// and not change the port number. However, I'm not sure the
> examples should be telling the user what they should do, but rather
> what they can do.

My comment was purely about losing the basic example by replacing it with something more advanced. Nobody prevents you from having _more_ examples. "You can do this, you can do that, also here is an example of how to use SSL".

Josh Triplett· Jul 9, 2008, 15:14 UTC · re: Robert Shearman · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

On Tue, 2008-07-08 at 23:18 +0100, Robert Shearman wrote:
Show 13 quoted lines
> --- a/Documentation/git-imap-send.txt
> +++ b/Documentation/git-imap-send.txt
> @@ -37,10 +37,11 @@ configuration file (shown with examples):
>      Tunnel = "ssh -q user@server.com /usr/bin/imapd ./Maildir 2> /dev/null"
>  
>  [imap]
> -    Host = imap.server.com
> +    Host = imaps://imap.example.com
>      User = bob
>      Pass = pwd
> -    Port = 143
> +    Port = 993
> +    sslverify = false
[...]
Show 6 quoted lines
> @@ -1280,6 +1411,8 @@ git_imap_config(const char *key, const char *val, void *cb)
>  		server.port = git_config_int( key, val );
>  	else if (!strcmp( "tunnel", key ))
>  		server.tunnel = xstrdup( val );
> +	else if (!strcmp( "ssl_verify", key ))
> +		server.ssl_verify = git_config_bool( key, val );

The example and the code disagree on the name of the sslverify/ssl_verify option. Also, ssl_verify needs explanation.

- Josh Triplett
Rob Shearman· Jul 9, 2008, 21:24 UTC · re: Josh Triplett · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

2008/7/9 Josh Triplett <josht@linux.vnet.ibm.com>:
Show 24 quoted lines
> On Tue, 2008-07-08 at 23:18 +0100, Robert Shearman wrote:
>> --- a/Documentation/git-imap-send.txt
>> +++ b/Documentation/git-imap-send.txt
>> @@ -37,10 +37,11 @@ configuration file (shown with examples):
>>      Tunnel = "ssh -q user@server.com /usr/bin/imapd ./Maildir 2> /dev/null"
>>
>>  [imap]
>> -    Host = imap.server.com
>> +    Host = imaps://imap.example.com
>>      User = bob
>>      Pass = pwd
>> -    Port = 143
>> +    Port = 993
>> +    sslverify = false
> [...]
>> @@ -1280,6 +1411,8 @@ git_imap_config(const char *key, const char *val, void *cb)
>>               server.port = git_config_int( key, val );
>>       else if (!strcmp( "tunnel", key ))
>>               server.tunnel = xstrdup( val );
>> +     else if (!strcmp( "ssl_verify", key ))
>> +             server.ssl_verify = git_config_bool( key, val );
>
> The example and the code disagree on the name of the
> sslverify/ssl_verify option.

I wouldn't exactly call it "disagree". The config variable is limited by not allowing underscores, whereas the C language does allow them.

> Also, ssl_verify needs explanation.
See patch 4/4.
-- 
Rob Shearman
Jeff King· Jul 10, 2008, 06:39 UTC · re: Rob Shearman · lore

Re: [PATCH 2/4] git-imap-send: Add support for SSL.

On Wed, Jul 09, 2008 at 10:24:27PM +0100, Rob Shearman wrote:
Show 10 quoted lines
> >>  [imap]
> >> +    sslverify = false
> > [...]
> >> +     else if (!strcmp( "ssl_verify", key ))
> >
> > The example and the code disagree on the name of the
> > sslverify/ssl_verify option.
> 
> I wouldn't exactly call it "disagree". The config variable is limited
> by not allowing underscores, whereas the C language does allow them.

I think his point is that the example says "sslverify" but the code is looking for the config variable "ssl_verify". So that config won't work.

However as you mention, underscore isn't allowed, so your strcmp line is totally bogus anyway, but you silently fix it in your 3/4 "style" fix.

-Peff

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