imap-proxy: Send backend's CAPABILITY if it's different from what was sent to client...

--HG--
branch : HEAD

diff --git a/src/imap-login/client.c b/src/imap-login/client.c
index c7b3f97d66a982f2e2107816f3adb36145828a42..fbd8c57335e416959d71916cac16ef4a7373fb54 100644 (file)
--- a/src/imap-login/client.c
+++ b/src/imap-login/client.c
@@ -107,6 +107,7 @@ static const char *get_capability(struct imap_client *client, bool full)
 
 static int cmd_capability(struct imap_client *client)
 {
+       client->capability_command_used = TRUE;
        client_send_line(client, t_strconcat(
                "* CAPABILITY ", get_capability(client, TRUE), NULL));
        client_send_tagline(client, "OK Capability completed.");
@@ -591,6 +592,7 @@ void client_destroy(struct imap_client *client, const char *reason)
 
        i_free_and_null(client->proxy_user);
        i_free_and_null(client->proxy_master_user);
+       i_free_and_null(client->proxy_backend_capability);
 
        if (client->proxy != NULL)
                login_proxy_free(&client->proxy);

diff --git a/src/imap-login/client.h b/src/imap-login/client.h
index 770cd4881061957840df3e580bc5477014e89e18..925d415327ec3b34e5fcaf1783968b94a34206fd 100644 (file)
--- a/src/imap-login/client.h
+++ b/src/imap-login/client.h
@@ -22,6 +22,7 @@ struct imap_client {
 
        struct login_proxy *proxy;
        char *proxy_user, *proxy_master_user, *proxy_password;
+       char *proxy_backend_capability;
 
        unsigned int bad_counter;
 
@@ -36,6 +37,7 @@ struct imap_client {
        unsigned int greeting_sent:1;
        unsigned int id_logged:1;
        unsigned int auth_initializing:1;
+       unsigned int capability_command_used:1;
 };
 
 void client_destroy(struct imap_client *client, const char *reason);

diff --git a/src/imap-login/imap-proxy.c b/src/imap-login/imap-proxy.c
index 3331622bec8249c1221e13c25eb63f3bc9557bd1..a18e12c3a17a58a5d38a7df86b7ad0e0473fb673 100644 (file)
--- a/src/imap-login/imap-proxy.c
+++ b/src/imap-login/imap-proxy.c
@@ -1,6 +1,7 @@
 /* Copyright (c) 2004-2009 Dovecot authors, see the included COPYING file */
 
 #include "common.h"
+#include "array.h"
 #include "ioloop.h"
 #include "istream.h"
 #include "ostream.h"
@@ -14,26 +15,35 @@
 #include "imap-quote.h"
 #include "imap-proxy.h"
 
+#include <stdlib.h>
+
 #define PROXY_FAILURE_MSG \
        "NO ["IMAP_RESP_CODE_UNAVAILABLE"] "AUTH_TEMP_FAILED_MSG
 
-static bool imap_banner_has_capability(const char *line, const char *capability)
+static const char *const *
+capabilities_strip_prelogin(const char *const *capabilities)
 {
-       unsigned int capability_len = strlen(capability);
-
-       while (strncasecmp(line, capability, capability_len) != 0 ||
-              (line[capability_len] != ' ' &&
-               line[capability_len] != '\0' &&
-               line[capability_len] != ']')) {
-               /* skip over the capability */
-               while (*line != ' ') {
-                       if (*line == '\0')
-                               return FALSE;
-                       line++;
-               }
-               line++;
+       ARRAY_TYPE(const_string) new_caps_arr;
+       const char **new_caps, *str;
+       unsigned int count;
+
+       t_array_init(&new_caps_arr, 64);
+       for (; *capabilities != NULL; capabilities++) {
+               if (strncasecmp(*capabilities, "AUTH=", 5) == 0 ||
+                   strcasecmp(*capabilities, "STARTTLS") == 0 ||
+                   strcasecmp(*capabilities, "SASL-IR") == 0 ||
+                   strcasecmp(*capabilities, "LOGINDISABLED") == 0 ||
+                   strcasecmp(*capabilities, "LOGIN-REFERRALS") == 0)
+                       continue;
+
+               str = *capabilities;
+               array_append(&new_caps_arr, &str, 1);
        }
-       return TRUE;
+       new_caps = array_get_modifiable(&new_caps_arr, &count);
+       qsort(new_caps, count, sizeof(*new_caps), i_strcasecmp_p);
+
+       (void)array_append_space(&new_caps_arr);
+       return array_idx(&new_caps_arr, 0);
 }
 
 static void proxy_write_id(struct imap_client *client, string_t *str)
@@ -85,9 +95,51 @@ static void get_plain_auth(struct imap_client *client, string_t *dest)
        base64_encode(str_data(str), str_len(str), dest);
 }
 
+static bool str_array_icmp(const char *const *arr1, const char *const *arr2)
+{
+       unsigned int i;
+
+       for (i = 0; arr1[i] != NULL; i++) {
+               if (arr2[i] == NULL || strcasecmp(arr1[i], arr2[i]) != 0)
+                       return FALSE;
+       }
+       return TRUE;
+}
+
+static void
+client_send_capability_if_needed(struct imap_client *client, string_t *str,
+                                const char *capability)
+{
+       const char *const *backend_capabilities;
+       const char *const *proxy_capabilities;
+
+       if (!client->capability_command_used || capability == NULL)
+               return;
+
+       /* reset this so that we don't re-send the CAPABILITY in case server
+          sends it multiple times */
+       client->capability_command_used = FALSE;
+
+       /* client has used CAPABILITY command, so it didn't understand the
+          capabilities in the banner. if backend server has different
+          capabilities than we advertised already, there's a problem.
+          to solve that we'll send the backend's untagged CAPABILITY reply
+          and hope that the client understands it */
+       backend_capabilities =
+               capabilities_strip_prelogin(t_strsplit(capability, " "));
+       proxy_capabilities =
+               capabilities_strip_prelogin(t_strsplit(login_settings->capability_string, " "));
+
+       if (str_array_icmp(backend_capabilities, proxy_capabilities))
+               return;
+
+       str_printfa(str, "* CAPABILITY %s\r\n", capability);
+}
+
 static int proxy_input_banner(struct imap_client *client,
                              struct ostream *output, const char *line)
 {
+       const char *const *capabilities = NULL;
        string_t *str;
 
        if (strncmp(line, "* OK ", 5) != 0) {
@@ -99,9 +151,12 @@ static int proxy_input_banner(struct imap_client *client,
 
        str = t_str_new(128);
        if (strncmp(line + 5, "[CAPABILITY ", 12) == 0) {
-               if (imap_banner_has_capability(line + 5 + 12, "ID"))
+               capabilities = t_strsplit(t_strcut(line + 5 + 12, ']'), " ");
+               if (str_array_icase_find(capabilities, "ID"))
                        proxy_write_id(client, str);
        }
+       if (client->capability_command_used)
+               str_append(str, "C CAPABILITY\r\n");
 
        if (client->proxy_master_user == NULL) {
                /* logging in normally - use LOGIN command */
@@ -111,7 +166,8 @@ static int proxy_input_banner(struct imap_client *client,
                imap_quote_append_string(str, client->proxy_password, FALSE);
 
                proxy_free_password(client);
-       } else if (imap_banner_has_capability(line + 5, "SASL-IR")) {
+       } else if (capabilities != NULL &&
+                  str_array_icase_find(capabilities, "SASL-IR")) {
                /* master user login with SASL initial response support */
                str_append(str, "L AUTHENTICATE PLAIN ");
                get_plain_auth(client, str);
@@ -120,7 +176,6 @@ static int proxy_input_banner(struct imap_client *client,
                /* master user login without SASL initial response */
                str_append(str, "L AUTHENTICATE PLAIN");
        }
-
        str_append(str, "\r\n");
        (void)o_stream_send(output, str_data(str), str_len(str));
        client->proxy_login_sent = TRUE;
@@ -130,6 +185,7 @@ static int proxy_input_banner(struct imap_client *client,
 static int proxy_input_line(struct imap_client *client,
                            struct ostream *output, const char *line)
 {
+       const char *capability;
        string_t *str;
 
        i_assert(!client->destroyed);
@@ -152,7 +208,12 @@ static int proxy_input_line(struct imap_client *client,
                return 0;
        } else if (strncmp(line, "L OK ", 5) == 0) {
                /* Login successful. Send this line to client. */
+               capability = client->proxy_backend_capability;
+               if (strncmp(line + 5, "[CAPABILITY ", 12) == 0)
+                       capability = t_strcut(line + 5 + 12, ']');
+
                str = t_str_new(128);
+               client_send_capability_if_needed(client, str, capability);
                str_append(str, client->cmd_tag);
                str_append(str, line + 1);
                str_append(str, "\r\n");
@@ -235,6 +296,10 @@ static int proxy_input_line(struct imap_client *client,
 
                proxy_failed(client, FALSE);
                return -1;
+       } else if (strncasecmp(line, "* CAPABILITY ", 13) == 0) {
+               i_free(client->proxy_backend_capability);
+               client->proxy_backend_capability = i_strdup(line + 13);
+               return 0;
        } else {
                /* probably some untagged reply */
                return 0;