X-Git-Url: https://git.decadent.org.uk/gitweb/?a=blobdiff_plain;f=utils%2Fgssd%2Fsvcgssd_krb5.c;fp=utils%2Fgssd%2Fsvcgssd_krb5.c;h=fc67a6f1363ded05217725cf1fec415aac094a17;hb=d6c1b35c6b40243bfd6fba2591c9f8f2653078c0;hp=0000000000000000000000000000000000000000;hpb=73840ef610accf4cf667427bc64805377c0d8394;p=nfs-utils.git

diff --git a/utils/gssd/svcgssd_krb5.c b/utils/gssd/svcgssd_krb5.c
new file mode 100644
index 0000000..fc67a6f
--- /dev/null
+++ b/utils/gssd/svcgssd_krb5.c
@@ -0,0 +1,200 @@
+/*
+ * COPYRIGHT (c) 2011
+ * The Regents of the University of Michigan
+ * ALL RIGHTS RESERVED
+ *
+ * Permission is granted to use, copy, create derivative works
+ * and redistribute this software and such derivative works
+ * for any purpose, so long as the name of The University of
+ * Michigan is not used in any advertising or publicity
+ * pertaining to the use of distribution of this software
+ * without specific, written prior authorization.  If the
+ * above copyright notice or any other identification of the
+ * University of Michigan is included in any copy of any
+ * portion of this software, then the disclaimer below must
+ * also be included.
+ *
+ * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
+ * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
+ * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
+ * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
+ * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
+ * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
+ * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
+ * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
+ * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGES.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif	/* HAVE_CONFIG_H */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+#include <gssapi/gssapi.h>
+#include <krb5.h>
+
+#include "gss_util.h"
+#include "gss_oids.h"
+#include "err_util.h"
+#include "svcgssd_krb5.h"
+
+#define MYBUFLEN 1024
+
+char *supported_enctypes_filename = "/proc/fs/nfsd/supported_krb5_enctypes";
+int parsed_num_enctypes = 0;
+krb5_enctype *parsed_enctypes = NULL;
+char *cached_enctypes = NULL;
+
+/*==========================*/
+/*===  Internal routines ===*/
+/*==========================*/
+
+/*
+ * Parse the supported encryption type information
+ */
+static int
+parse_enctypes(char *enctypes)
+{
+	int n = 0;
+	char *curr, *comma;
+	int i;
+
+	/* Don't parse the same string over and over... */
+	if (cached_enctypes && strcmp(cached_enctypes, enctypes) == 0)
+		return 0;
+
+	/* Free any existing cached_enctypes */
+	free(cached_enctypes);
+
+	if (parsed_enctypes != NULL) {
+		free(parsed_enctypes);
+		parsed_enctypes = NULL;
+		parsed_num_enctypes = 0;
+	}
+
+	/* count the number of commas */
+	for (curr = enctypes; curr && *curr != '\0'; curr = ++comma) {
+		comma = strchr(curr, ',');
+		if (comma != NULL)
+			n++;
+		else
+			break;
+	}
+
+	/* If no more commas and we're not at the end, there's one more value */
+	if (*curr != '\0')
+		n++;
+
+	/* Empty string, return an error */
+	if (n == 0)
+		return ENOENT;
+
+	/* Allocate space for enctypes array */
+	if ((parsed_enctypes = (int *) calloc(n, sizeof(int))) == NULL) {
+		return ENOMEM;
+	}
+
+	/* Now parse each value into the array */
+	for (curr = enctypes, i = 0; curr && *curr != '\0'; curr = ++comma) {
+		parsed_enctypes[i++] = atoi(curr);
+		comma = strchr(curr, ',');
+		if (comma == NULL)
+			break;
+	}
+
+	parsed_num_enctypes = n;
+	if ((cached_enctypes = malloc(strlen(enctypes)+1)))
+		strcpy(cached_enctypes, enctypes);
+
+	return 0;
+}
+
+static void
+get_kernel_supported_enctypes(void)
+{
+	FILE *s_e;
+	int ret;
+	char buffer[MYBUFLEN + 1];
+
+	memset(buffer, '\0', sizeof(buffer));
+
+	s_e = fopen(supported_enctypes_filename, "r");
+	if (s_e == NULL)
+		goto out_clean_parsed;
+
+	ret = fread(buffer, 1, MYBUFLEN, s_e);
+	if (ret < 0) {
+		fclose(s_e);
+		goto out_clean_parsed;
+	}
+	fclose(s_e);
+	if (parse_enctypes(buffer)) {
+		goto out_clean_parsed;
+	}
+out:
+	return;
+
+out_clean_parsed:
+	if (parsed_enctypes != NULL) {
+		free(parsed_enctypes);
+		parsed_num_enctypes = 0;
+	}
+	goto out;
+}
+
+/*==========================*/
+/*===  External routines ===*/
+/*==========================*/
+
+/*
+ * Get encryption types supported by the kernel, and then
+ * call gss_krb5_set_allowable_enctypes() to limit the
+ * encryption types negotiated.
+ *
+ * Returns:
+ *	0 => all went well
+ *     -1 => there was an error
+ */
+
+int
+svcgssd_limit_krb5_enctypes(void)
+{
+#ifdef HAVE_SET_ALLOWABLE_ENCTYPES
+	u_int maj_stat, min_stat;
+	krb5_enctype default_enctypes[] = { ENCTYPE_DES_CBC_CRC,
+					    ENCTYPE_DES_CBC_MD5,
+					    ENCTYPE_DES_CBC_MD4 };
+	int default_num_enctypes =
+		sizeof(default_enctypes) / sizeof(default_enctypes[0]);
+	krb5_enctype *enctypes;
+	int num_enctypes;
+
+	get_kernel_supported_enctypes();
+
+	if (parsed_enctypes != NULL) {
+		enctypes = parsed_enctypes;
+		num_enctypes = parsed_num_enctypes;
+	} else {
+		enctypes = default_enctypes;
+		num_enctypes = default_num_enctypes;
+	}
+
+	maj_stat = gss_set_allowable_enctypes(&min_stat, gssd_creds,
+			&krb5oid, num_enctypes, enctypes);
+	if (maj_stat != GSS_S_COMPLETE) {
+		printerr(1, "WARNING: gss_set_allowable_enctypes failed\n");
+		pgsserr("svcgssd_limit_krb5_enctypes: gss_set_allowable_enctypes",
+			maj_stat, min_stat, &krb5oid);
+		return -1;
+	}
+#endif
+	return 0;
+}