ceased doing that. The biggest change is to use unbuffered I/O on the socket
because using C buffered I/O gives problems on some operating systems. PH */
+/* Protocol specifications:
+ * Dovecot 1, protocol version 1.1
+ * http://wiki.dovecot.org/Authentication%20Protocol
+ *
+ * Dovecot 2, protocol version 1.1
+ * http://wiki2.dovecot.org/Design/AuthProtocol
+ */
+
#include "../exim.h"
#include "dovecot.h"
#define VERSION_MAJOR 1
#define VERSION_MINOR 0
+/* http://wiki.dovecot.org/Authentication%20Protocol
+"The maximum line length isn't defined,
+ but it's currently expected to fit into 8192 bytes"
+*/
+#define DOVECOT_AUTH_MAXLINELEN 8192
+
+/* This was hard-coded as 8.
+AUTH req C->S sends {"AUTH", id, mechanism, service } + params, 5 defined for
+Dovecot 1; Dovecot 2 (same protocol version) defines 9.
+
+Master->Server sends {"USER", id, userid} + params, 6 defined.
+Server->Client only gives {"OK", id} + params, unspecified, only 1 guaranteed.
+
+We only define here to accept S->C; max seen is 3+<unspecified>, plus the two
+for the command and id, where unspecified might include _at least_ user=...
+
+So: allow for more fields than we ever expect to see, while aware that count
+can go up without changing protocol version.
+The cost is the length of an array of pointers on the stack.
+*/
+#define DOVECOT_AUTH_MAXFIELDCOUNT 16
+
/* Options specific to the authentication mechanism. */
optionlist auth_dovecot_options[] = {
{
/* Static variables for reading from the socket */
static uschar sbuffer[256];
-static int sbp;
+static int socket_buffer_left;
ablock->client = FALSE;
}
-static int strcut(uschar *str, uschar **ptrs, int nptrs)
+/*************************************************
+ * "strcut" to split apart server lines *
+ *************************************************/
+
+/* Dovecot auth protocol uses TAB \t as delimiter; a line consists
+of a command-name, TAB, and then any parameters, each separated by a TAB.
+A parameter can be param=value or a bool, just param.
+
+This function modifies the original str in-place, inserting NUL characters.
+It initialises ptrs entries, setting all to NULL and only setting
+non-NULL N entries, where N is the return value, the number of fields seen
+(one more than the number of tabs).
+
+Note that the return value will always be at least 1, is the count of
+actual fields (so last valid offset into ptrs is one less).
+*/
+
+static int
+strcut(uschar *str, uschar **ptrs, int nptrs)
{
- uschar *tmp = str;
+ uschar *last_sub_start = str;
int n;
for (n = 0; n < nptrs; n++)
while (*str) {
if (*str == '\t') {
if (n <= nptrs) {
- *ptrs++ = tmp;
- tmp = str + 1;
- *str = 0;
+ *ptrs++ = last_sub_start;
+ last_sub_start = str + 1;
+ *str = '\0';
}
n++;
}
str++;
}
- if (n < nptrs)
- *ptrs = tmp;
+ /* It's acceptable for the string to end with a tab character. We see
+ this in AUTH PLAIN without an initial response from the client, which
+ causing us to send "334 " and get the data from the client. */
+ if (n <= nptrs) {
+ *ptrs = last_sub_start;
+ } else {
+ HDEBUG(D_auth) debug_printf("dovecot: warning: too many results from tab-splitting; saw %d fields, room for %d\n", n, nptrs);
+ n = nptrs;
+ }
+
+ return n <= nptrs ? n : nptrs;
+}
- return n;
+static void debug_strcut(uschar **ptrs, int nlen, int alen) ARG_UNUSED;
+static void
+debug_strcut(uschar **ptrs, int nlen, int alen)
+{
+ int i;
+ debug_printf("%d read but unreturned bytes; strcut() gave %d results: ",
+ socket_buffer_left, nlen);
+ for (i = 0; i < nlen; i++) {
+ debug_printf(" {%s}", ptrs[i]);
+ }
+ if (nlen < alen)
+ debug_printf(" last is %s\n", ptrs[i] ? ptrs[i] : US"<null>");
+ else
+ debug_printf(" (max for capacity)\n");
}
#define CHECK_COMMAND(str, arg_min, arg_max) do { \
for (;;)
{
- if (sbp == 0)
+ if (socket_buffer_left == 0)
{
- sbp = read(fd, sbuffer, sizeof(sbuffer));
- if (sbp == 0) { if (count == 0) return NULL; else break; }
+ socket_buffer_left = read(fd, sbuffer, sizeof(sbuffer));
+ if (socket_buffer_left == 0) { if (count == 0) return NULL; else break; }
p = 0;
}
- while (p < sbp)
+ while (p < socket_buffer_left)
{
if (count >= n - 1) break;
s[count++] = sbuffer[p];
if (sbuffer[p++] == '\n') break;
}
- memmove(sbuffer, sbuffer + p, sbp - p);
- sbp -= p;
+ memmove(sbuffer, sbuffer + p, socket_buffer_left - p);
+ socket_buffer_left -= p;
if (s[count-1] == '\n' || count >= n - 1) break;
}
-s[count] = 0;
+s[count] = '\0';
return s;
}
auth_dovecot_options_block *ob =
(auth_dovecot_options_block *)(ablock->options_block);
struct sockaddr_un sa;
- uschar buffer[4096];
- uschar *args[8];
+ uschar buffer[DOVECOT_AUTH_MAXLINELEN];
+ uschar *args[DOVECOT_AUTH_MAXFIELDCOUNT];
uschar *auth_command;
uschar *auth_extra_data = US"";
+ uschar *p;
int nargs, tmp;
- int cuid = 0, cont = 1, found = 0, fd, ret = DEFER;
+ int crequid = 1, cont = 1, fd, ret = DEFER;
+ BOOL found = FALSE;
HDEBUG(D_auth) debug_printf("dovecot authentication\n");
auth_defer_msg = US"authentication socket protocol error";
- sbp = 0; /* Socket buffer pointer */
+ socket_buffer_left = 0; /* Global, used to read more than a line but return by line */
while (cont) {
if (dc_gets(buffer, sizeof(buffer), fd) == NULL)
OUT("authentication socket read error or premature eof");
-
- buffer[Ustrlen(buffer) - 1] = 0;
+ p = buffer + Ustrlen(buffer) - 1;
+ if (*p != '\n') {
+ OUT("authentication socket protocol line too long");
+ }
+ *p = '\0';
HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
+ /* HDEBUG(D_auth) debug_strcut(args, nargs, sizeof(args) / sizeof(args[0])); */
/* Code below rewritten by Kirill Miazine (km@krot.org). Only check commands that
Exim will need. Original code also failed if Dovecot server sent unknown
command. E.g. COOKIE in version 1.1 of the protocol would cause troubles. */
- if (Ustrcmp(args[0], US"CUID") == 0) {
- CHECK_COMMAND("CUID", 1, 1);
- cuid = Uatoi(args[1]);
- } else if (Ustrcmp(args[0], US"VERSION") == 0) {
+ /* pdp: note that CUID is a per-connection identifier sent by the server,
+ which increments at server discretion.
+ By contrast, the "id" field of the protocol is a connection-specific request
+ identifier, which needs to be unique per request from the client and is not
+ connected to the CUID value, so we ignore CUID from server. It's purely for
+ diagnostics. */
+ if (Ustrcmp(args[0], US"VERSION") == 0) {
CHECK_COMMAND("VERSION", 2, 2);
if (Uatoi(args[1]) != VERSION_MAJOR)
OUT("authentication socket protocol version mismatch");
} else if (Ustrcmp(args[0], US"MECH") == 0) {
CHECK_COMMAND("MECH", 1, INT_MAX);
if (strcmpic(US args[1], ablock->public_name) == 0)
- found = 1;
+ found = TRUE;
} else if (Ustrcmp(args[0], US"DONE") == 0) {
CHECK_COMMAND("DONE", 0, 0);
cont = 0;
}
}
- if (!found)
+ if (!found) {
+ auth_defer_msg = string_sprintf("Dovecot did not advertise mechanism \"%s\" to us", ablock->public_name);
goto out;
+ }
/* Added by PH: data must not contain tab (as it is
b64 it shouldn't, but check for safety). */
/* Added by PH: extra fields when TLS is in use or if the TCP/IP
connection is local. */
- if (tls_cipher != NULL)
+ if (tls_in.cipher != NULL)
auth_extra_data = string_sprintf("secured\t%s%s",
- tls_certificate_verified? "valid-client-cert" : "",
- tls_certificate_verified? "\t" : "");
+ tls_in.certificate_verified? "valid-client-cert" : "",
+ tls_in.certificate_verified? "\t" : "");
else if (interface_address != NULL &&
Ustrcmp(sender_host_address, interface_address) == 0)
auth_extra_data = US"secured\t";
Subsequently, the command was modified to add "secured" and "valid-client-
cert" when relevant.
-
- The auth protocol is documented here:
- http://wiki.dovecot.org/Authentication_Protocol
****************************************************************************/
auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n"
"AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tnologin\tresp=%s\n",
- VERSION_MAJOR, VERSION_MINOR, getpid(), cuid,
+ VERSION_MAJOR, VERSION_MINOR, getpid(), crequid,
ablock->public_name, auth_extra_data, sender_host_address,
interface_address, data ? (char *) data : "");
HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
- if (Uatoi(args[1]) != cuid)
+ if (Uatoi(args[1]) != crequid)
OUT("authentication socket connection id mismatch");
switch (toupper(*args[0])) {
goto out;
}
- temp = string_sprintf("CONT\t%d\t%s\n", cuid, data);
+ temp = string_sprintf("CONT\t%d\t%s\n", crequid, data);
if (write(fd, temp, Ustrlen(temp)) < 0)
OUT("authentication socket write error");
break;
projects / exim.git / blobdiff