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pkgsrc-ng/security/mit-krb5/patches/patch-CVE-2014-4341
2016-01-21 23:40:00 +01:00

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$NetBSD: patch-CVE-2014-4341,v 1.1 2014/08/28 22:23:05 tez Exp $
Fix for CVE-2014-4341 & CVE-2014-4342 from:
https://github.com/krb5/krb5/commit/e6ae703ae597d798e310368d52b8f38ee11c6a73
--- lib/gssapi/krb5/k5unseal.c
+++ lib/gssapi/krb5/k5unseal.c
@@ -74,6 +74,7 @@
int conflen = 0;
int signalg;
int sealalg;
+ int bad_pad = 0;
gss_buffer_desc token;
krb5_checksum cksum;
krb5_checksum md5cksum;
@@ -86,6 +87,7 @@
krb5_ui_4 seqnum;
OM_uint32 retval;
size_t sumlen;
+ size_t padlen;
krb5_keyusage sign_usage = KG_USAGE_SIGN;
if (toktype == KG_TOK_SEAL_MSG) {
@@ -93,18 +95,23 @@
message_buffer->value = NULL;
}
- /* get the sign and seal algorithms */
-
- signalg = ptr[0] + (ptr[1]<<8);
- sealalg = ptr[2] + (ptr[3]<<8);
-
/* Sanity checks */
- if ((ptr[4] != 0xff) || (ptr[5] != 0xff)) {
+ if (ctx->seq == NULL) {
+ /* ctx was established using a newer enctype, and cannot process RFC
+ * 1964 tokens. */
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
+ if ((bodysize < 22) || (ptr[4] != 0xff) || (ptr[5] != 0xff)) {
+ *minor_status = 0;
+ return GSS_S_DEFECTIVE_TOKEN;
+ }
+
+ signalg = ptr[0] + (ptr[1]<<8);
+ sealalg = ptr[2] + (ptr[3]<<8);
+
if ((toktype != KG_TOK_SEAL_MSG) &&
(sealalg != 0xffff)) {
*minor_status = 0;
@@ -153,6 +160,11 @@
return GSS_S_DEFECTIVE_TOKEN;
}
+ if ((size_t)bodysize < 14 + cksum_len) {
+ *minor_status = 0;
+ return GSS_S_DEFECTIVE_TOKEN;
+ }
+
/* get the token parameters */
if ((code = kg_get_seq_num(context, ctx->seq, ptr+14, ptr+6, &direction,
@@ -210,7 +222,20 @@
token.length = tmsglen;
} else {
conflen = kg_confounder_size(context, ctx->enc->keyblock.enctype);
- token.length = tmsglen - conflen - plain[tmsglen-1];
+ if (tmsglen < conflen) {
+ if (sealalg != 0xffff)
+ xfree(plain);
+ *minor_status = 0;
+ return(GSS_S_DEFECTIVE_TOKEN);
+ }
+ padlen = plain[tmsglen - 1];
+ if (tmsglen - conflen < padlen) {
+ /* Don't error out yet, to avoid padding oracle attacks. We will
+ * treat this as a checksum failure later on. */
+ padlen = 0;
+ bad_pad = 1;
+ }
+ token.length = tmsglen - conflen - padlen;
}
if (token.length) {
@@ -423,7 +448,7 @@
/* compare the computed checksum against the transmitted checksum */
- if (code) {
+ if (code || bad_pad) {
if (toktype == KG_TOK_SEAL_MSG)
gssalloc_free(token.value);
*minor_status = 0;
--- lib/gssapi/krb5/k5unsealiov.c
+++ lib/gssapi/krb5/k5unsealiov.c
@@ -69,7 +69,14 @@ kg_unseal_v1_iov(krb5_context context,
return GSS_S_DEFECTIVE_TOKEN;
}
- if (header->buffer.length < token_wrapper_len + 14) {
+ if (ctx->seq == NULL) {
+ /* ctx was established using a newer enctype, and cannot process RFC
+ * 1964 tokens. */
+ *minor_status = 0;
+ return GSS_S_DEFECTIVE_TOKEN;
+ }
+
+ if (header->buffer.length < token_wrapper_len + 22) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}