]> Pileus Git - ~andy/fetchmail/blobdiff - gssapi.c
Note Earl's regression fix for SSL_CTX_clear_options() on older OpenSSL.
[~andy/fetchmail] / gssapi.c
index 883f748fdffc5e4301500e106b148e005a8aafb9..c2c7d94ff46aef0502a587bf47db9c868d18d47e 100644 (file)
--- a/gssapi.c
+++ b/gssapi.c
@@ -15,7 +15,7 @@
 #include  "socket.h"
 
 #include  "i18n.h"
-#include "md5.h"
+#include "fm_md5.h"
 
 #include <sys/types.h>
 #include <netinet/in.h>  /* for htonl/ntohl */
@@ -24,7 +24,7 @@
 #  ifdef HAVE_GSS_H
 #    include <gss.h>
 #  else
-#  ifdef HAVE_GSSAPI_H
+#  if defined(HAVE_GSSAPI_H) && !defined(HAVE_GSSAPI_GSSAPI_H)
 #    include <gssapi.h>
 #  endif
 #  ifdef HAVE_GSSAPI_GSSAPI_H
 #  ifdef HAVE_GSSAPI_GSSAPI_GENERIC_H
 #    include <gssapi/gssapi_generic.h>
 #  endif
-#  ifndef HAVE_GSS_C_NT_HOSTBASED_SERVICE
+#  if HAVE_DECL_GSS_C_NT_HOSTBASED_SERVICE + 0 == 0
 #    define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
 #  endif
 #  endif
 
+static void decode_subr(const char *m, uint32_t code, int type, FILE *ostrm)
+{
+    uint32_t maj, min, context;
+    gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
+
+    context = 0;
+    do {
+       maj = gss_display_status(&min, code, type, GSS_C_NO_OID,
+               &context, &msg);
+
+       if (maj != GSS_S_COMPLETE) {
+           report(stderr, GT_("GSSAPI error in gss_display_status called from <%s>\n"), m);
+           break;
+       }
+       report(ostrm, GT_("GSSAPI error %s: %.*s\n"), m,
+               (int)msg.length, (char *)msg.value);
+       (void)gss_release_buffer(&min, &msg);
+    } while(context);
+}
+
+static void decode_status(const char *m, uint32_t major, uint32_t minor,
+               FILE *ostrm)
+{
+    decode_subr(m, major, GSS_C_GSS_CODE,  ostrm);
+    decode_subr(m, minor, GSS_C_MECH_CODE, ostrm);
+}
+
 #define GSSAUTH_P_NONE      1
 #define GSSAUTH_P_INTEGRITY 2
 #define GSSAUTH_P_PRIVACY   4
 
-int do_gssauth(int sock, char *command, char *service, char *hostname, char *username)
+static int import_name(const char *service, const char *hostname,
+       gss_name_t *target_name, flag verbose)
 {
-    gss_buffer_desc request_buf, send_token;
-    gss_buffer_t sec_token;
-    gss_name_t target_name;
-    gss_ctx_id_t context;
-    gss_OID mech_name;
-    gss_qop_t quality;
-    int cflags;
+    char *buf1;
+    size_t buf1siz;
     OM_uint32 maj_stat, min_stat;
-    char buf1[8192], buf2[8192], server_conf_flags;
-    unsigned long buf_size;
-    int result;
+    gss_buffer_desc request_buf;
 
     /* first things first: get an imap ticket for host */
-    snprintf(buf1, sizeof(buf1), "%s@%s", service, hostname);
+    buf1siz = strlen(service) + 1 + strlen(hostname) + 1;
+    buf1 = (char *)xmalloc(buf1siz);
+    snprintf(buf1, buf1siz, "%s@%s", service, hostname);
     request_buf.value = buf1;
     request_buf.length = strlen(buf1) + 1;
-    maj_stat = gss_import_name(&min_stat, &request_buf, GSS_C_NT_HOSTBASED_SERVICE,
-        &target_name);
+    maj_stat = gss_import_name(&min_stat, &request_buf,
+           GSS_C_NT_HOSTBASED_SERVICE, target_name);
     if (maj_stat != GSS_S_COMPLETE) {
+       decode_status("gss_import_name", maj_stat, min_stat, stderr);
         report(stderr, GT_("Couldn't get service name for [%s]\n"), buf1);
         return PS_AUTHFAIL;
     }
-    else if (outlevel >= O_DEBUG) {
-        maj_stat = gss_display_name(&min_stat, target_name, &request_buf,
-            &mech_name);
+    else if (outlevel >= O_DEBUG && verbose) {
+        (void)gss_display_name(&min_stat, *target_name, &request_buf, NULL);
         report(stderr, GT_("Using service name [%s]\n"),
               (char *)request_buf.value);
-        maj_stat = gss_release_buffer(&min_stat, &request_buf);
+    }
+    (void)gss_release_buffer(&min_stat, &request_buf);
+
+    return PS_SUCCESS;
+}
+
+/* If we don't have suitable credentials, don't bother trying GSSAPI, but
+ * fail right away. This is to avoid that a server - such as Microsoft
+ * Exchange 2007 - gets wedged and refuses different authentication
+ * mechanisms afterwards. */
+int check_gss_creds(const char *service, const char *hostname)
+{
+    OM_uint32 maj_stat, min_stat;
+    gss_cred_usage_t cu;
+    gss_name_t target_name;
+
+    (void)import_name(service, hostname, &target_name, FALSE);
+    (void)gss_release_name(&min_stat, &target_name);
+
+    maj_stat = gss_inquire_cred(&min_stat, GSS_C_NO_CREDENTIAL,
+           NULL, NULL, &cu, NULL);
+    if (maj_stat != GSS_S_COMPLETE
+           || (cu != GSS_C_INITIATE && cu != GSS_C_BOTH)) {
+       if (outlevel >= O_DEBUG) {
+           decode_status("gss_inquire_cred", maj_stat, min_stat, stdout);
+           report(stdout, GT_("No suitable GSSAPI credentials found. Skipping GSSAPI authentication.\n"));
+           report(stdout, GT_("If you want to use GSSAPI, you need credentials first, possibly from kinit.\n"));
+       }
+       return PS_AUTHFAIL;
     }
 
+    return PS_SUCCESS;
+}
+
+int do_gssauth(int sock, const char *command, const char *service,
+               const char *hostname, const char *username)
+{
+    gss_buffer_desc request_buf, send_token;
+    gss_buffer_t sec_token;
+    gss_name_t target_name;
+    gss_ctx_id_t context;
+    gss_qop_t quality;
+    int cflags;
+    OM_uint32 maj_stat, min_stat;
+    char buf1[8192], buf2[8192], server_conf_flags;
+    unsigned long buf_size;
+    int result;
+
+    result = import_name(service, hostname, &target_name, TRUE);
+    if (result)
+       return result;
+
     gen_send(sock, "%s GSSAPI", command);
 
     /* upon receipt of the GSSAPI authentication request, server returns
-     * null data ready response. */
+     * a null data ready challenge to us. */
     result = gen_recv(sock, buf1, sizeof buf1);
     if (result)
        return result;
 
+    if (buf1[0] != '+' || strspn(buf1 + 1, " \t") < strlen(buf1 + 1)) {
+       if (outlevel >= O_VERBOSE) {
+           report(stdout, GT_("Received malformed challenge to \"%s GSSAPI\"!\n"), command);
+       }
+       goto cancelfail;
+    }
+
+
     /* now start the security context initialisation loop... */
     sec_token = GSS_C_NO_BUFFER;
     context = GSS_C_NO_CONTEXT;
     if (outlevel >= O_VERBOSE)
         report(stdout, GT_("Sending credentials\n"));
     do {
-        send_token.length = 0;
+       send_token.length = 0;
        send_token.value = NULL;
-        maj_stat = gss_init_sec_context(&min_stat, 
-                                       GSS_C_NO_CREDENTIAL,
-                                       &context, 
-                                       target_name, 
-                                       GSS_C_NO_OID, 
-                                       GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG, 
-                                       0, 
-                                       GSS_C_NO_CHANNEL_BINDINGS, 
-                                       sec_token, 
-                                       NULL, 
-                                       &send_token, 
-                                       NULL, 
+       maj_stat = gss_init_sec_context(&min_stat,
+                                       GSS_C_NO_CREDENTIAL,
+                                       &context,
+                                       target_name,
+                                       GSS_C_NO_OID,
+                                       GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
+                                       0,
+                                       GSS_C_NO_CHANNEL_BINDINGS,
+                                       sec_token,
+                                       NULL,
+                                       &send_token,
+                                       NULL,
                                        NULL);
+
        if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
-           report(stderr, GT_("Error exchanging credentials\n"));
-           gss_release_name(&min_stat, &target_name);
-           /* wake up server and await NO response */
-           SockWrite(sock, "\r\n", 2);
+           if (outlevel >= O_VERBOSE)
+               decode_status("gss_init_sec_context", maj_stat, min_stat, stdout);
+           (void)gss_release_name(&min_stat, &target_name);
+
+cancelfail:
+           /* wake up server and cancel authentication */
+           suppress_tags = TRUE;
+           gen_send(sock, "*");
+           suppress_tags = FALSE;
+
            result = gen_recv(sock, buf1, sizeof buf1);
+           if (outlevel >= O_VERBOSE)
+               report(stderr, GT_("Error exchanging credentials\n"));
            if (result)
                return result;
            return PS_AUTHFAIL;
@@ -117,7 +206,7 @@ int do_gssauth(int sock, char *command, char *service, char *hostname, char *use
        gss_release_buffer(&min_stat, &send_token);
 
        suppress_tags = TRUE;
-       gen_send(sock, buf1, strlen(buf1));
+       gen_send(sock, "%s", buf1);
        suppress_tags = FALSE;
 
         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
@@ -146,9 +235,10 @@ int do_gssauth(int sock, char *command, char *service, char *hostname, char *use
        request_buf.length = 0;
     request_buf.value = buf2;
 
-    maj_stat = gss_unwrap(&min_stat, context, 
+    maj_stat = gss_unwrap(&min_stat, context,
                          &request_buf, &send_token, &cflags, &quality);
     if (maj_stat != GSS_S_COMPLETE) {
+       decode_status("gss_unwrap", maj_stat, min_stat, stderr);
         report(stderr, GT_("Couldn't unwrap security level data\n"));
         gss_release_buffer(&min_stat, &send_token);
         return PS_AUTHFAIL;
@@ -190,7 +280,7 @@ int do_gssauth(int sock, char *command, char *service, char *hostname, char *use
     to64frombits(buf1, send_token.value, send_token.length);
 
     suppress_tags = TRUE;
-    result = gen_transact(sock, buf1, strlen(buf1));
+    result = gen_transact(sock, "%s", buf1);
     suppress_tags = FALSE;
 
     /* flush security context */
@@ -198,6 +288,7 @@ int do_gssauth(int sock, char *command, char *service, char *hostname, char *use
        report(stdout, GT_("Releasing GSS credentials\n"));
     maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
     if (maj_stat != GSS_S_COMPLETE) {
+       decode_status("gss_delete_sec_context", maj_stat, min_stat, stderr);
        report(stderr, GT_("Error releasing credentials\n"));
        return PS_AUTHFAIL;
     }