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Sync from SUSE:ALP:Source:Standard:1.0 krb5 revision 982c87764f2771e60cf38caedae20c49

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Adrian Schröter 2024-10-16 11:43:05 +02:00
parent 0f14804012
commit 7560b7f7b7
6 changed files with 990 additions and 0 deletions
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248
0010-Fix-three-memory-leaks.patch Normal file
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@ -0,0 +1,248 @@
From 2aaffa96269b56fe09abf81851c40c9c4a3587f0 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Tue, 5 Mar 2024 17:38:49 -0500
Subject: [PATCH 1/2] Fix leak in KDC NDR encoding
If the KDC tries to encode a principal containing encode invalid UTF-8
sequences for inclusion in a PAC delegation info buffer, it will leak
a small amount of memory in enc_wchar_pointer() before failing. Fix
the leak.
ticket: 9115 (new)
tags: pullup
target_version: 1.21-next
(cherry picked from commit 7d0d85bf99caf60c0afd4dcf91b0c4c683b983fe)
---
src/kdc/ndr.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/src/kdc/ndr.c b/src/kdc/ndr.c
index 48395abe52..d438408ee2 100644
--- a/src/kdc/ndr.c
+++ b/src/kdc/ndr.c
@@ -96,14 +96,13 @@ enc_wchar_pointer(const char *utf8, struct encoded_wchars *encoded_out)
size_t utf16len, num_wchars;
uint8_t *utf16;
- k5_buf_init_dynamic(&b);
-
ret = k5_utf8_to_utf16le(utf8, &utf16, &utf16len);
if (ret)
return ret;
num_wchars = utf16len / 2;
+ k5_buf_init_dynamic(&b);
k5_buf_add_uint32_le(&b, num_wchars + 1);
k5_buf_add_uint32_le(&b, 0);
k5_buf_add_uint32_le(&b, num_wchars);
--
2.44.0
From 489deee29f427f22e2a26de729319bdb70819c37 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Tue, 5 Mar 2024 19:53:07 -0500
Subject: [PATCH 2/2] Fix two unlikely memory leaks
In gss_krb5int_make_seal_token_v3(), one of the bounds checks (which
could probably never be triggered) leaks plain.data. Fix this leak
and use current practices for cleanup throughout the function.
In xmt_rmtcallres() (unused within the tree and likely elsewhere),
store port_ptr into crp->port_ptr as soon as it is allocated;
otherwise it could leak if the subsequent xdr_u_int32() operation
fails.
(cherry picked from commit c5f9c816107f70139de11b38aa02db2f1774ee0d)
---
src/lib/gssapi/krb5/k5sealv3.c | 56 +++++++++++++++-------------------
src/lib/rpc/pmap_rmt.c | 9 +++---
2 files changed, 29 insertions(+), 36 deletions(-)
diff --git a/src/lib/gssapi/krb5/k5sealv3.c b/src/lib/gssapi/krb5/k5sealv3.c
index 3b4f8cb837..e881eee835 100644
--- a/src/lib/gssapi/krb5/k5sealv3.c
+++ b/src/lib/gssapi/krb5/k5sealv3.c
@@ -65,7 +65,7 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
int conf_req_flag, int toktype)
{
size_t bufsize = 16;
- unsigned char *outbuf = 0;
+ unsigned char *outbuf = NULL;
krb5_error_code err;
int key_usage;
unsigned char acceptor_flag;
@@ -75,9 +75,13 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
#endif
size_t ec;
unsigned short tok_id;
- krb5_checksum sum;
+ krb5_checksum sum = { 0 };
krb5_key key;
krb5_cksumtype cksumtype;
+ krb5_data plain = empty_data();
+
+ token->value = NULL;
+ token->length = 0;
acceptor_flag = ctx->initiate ? 0 : FLAG_SENDER_IS_ACCEPTOR;
key_usage = (toktype == KG_TOK_WRAP_MSG
@@ -107,14 +111,15 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
#endif
if (toktype == KG_TOK_WRAP_MSG && conf_req_flag) {
- krb5_data plain;
krb5_enc_data cipher;
size_t ec_max;
size_t encrypt_size;
/* 300: Adds some slop. */
- if (SIZE_MAX - 300 < message->length)
- return ENOMEM;
+ if (SIZE_MAX - 300 < message->length) {
+ err = ENOMEM;
+ goto cleanup;
+ }
ec_max = SIZE_MAX - message->length - 300;
if (ec_max > 0xffff)
ec_max = 0xffff;
@@ -126,20 +131,20 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
#endif
err = alloc_data(&plain, message->length + 16 + ec);
if (err)
- return err;
+ goto cleanup;
/* Get size of ciphertext. */
encrypt_size = krb5_encrypt_size(plain.length, key->keyblock.enctype);
if (encrypt_size > SIZE_MAX / 2) {
err = ENOMEM;
- goto error;
+ goto cleanup;
}
bufsize = 16 + encrypt_size;
/* Allocate space for header plus encrypted data. */
outbuf = gssalloc_malloc(bufsize);
if (outbuf == NULL) {
- free(plain.data);
- return ENOMEM;
+ err = ENOMEM;
+ goto cleanup;
}
/* TOK_ID */
@@ -164,11 +169,8 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
cipher.ciphertext.length = bufsize - 16;
cipher.enctype = key->keyblock.enctype;
err = krb5_k_encrypt(context, key, key_usage, 0, &plain, &cipher);
- zap(plain.data, plain.length);
- free(plain.data);
- plain.data = 0;
if (err)
- goto error;
+ goto cleanup;
/* Now that we know we're returning a valid token.... */
ctx->seq_send++;
@@ -181,7 +183,6 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
/* If the rotate fails, don't worry about it. */
#endif
} else if (toktype == KG_TOK_WRAP_MSG && !conf_req_flag) {
- krb5_data plain;
size_t cksumsize;
/* Here, message is the application-supplied data; message2 is
@@ -193,21 +194,19 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
wrap_with_checksum:
err = alloc_data(&plain, message->length + 16);
if (err)
- return err;
+ goto cleanup;
err = krb5_c_checksum_length(context, cksumtype, &cksumsize);
if (err)
- goto error;
+ goto cleanup;
assert(cksumsize <= 0xffff);
bufsize = 16 + message2->length + cksumsize;
outbuf = gssalloc_malloc(bufsize);
if (outbuf == NULL) {
- free(plain.data);
- plain.data = 0;
err = ENOMEM;
- goto error;
+ goto cleanup;
}
/* TOK_ID */
@@ -239,23 +238,15 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
if (message2->length)
memcpy(outbuf + 16, message2->value, message2->length);
- sum.contents = outbuf + 16 + message2->length;
- sum.length = cksumsize;
-
err = krb5_k_make_checksum(context, cksumtype, key,
key_usage, &plain, &sum);
- zap(plain.data, plain.length);
- free(plain.data);
- plain.data = 0;
if (err) {
zap(outbuf,bufsize);
- goto error;
+ goto cleanup;
}
if (sum.length != cksumsize)
abort();
memcpy(outbuf + 16 + message2->length, sum.contents, cksumsize);
- krb5_free_checksum_contents(context, &sum);
- sum.contents = 0;
/* Now that we know we're actually generating the token... */
ctx->seq_send++;
@@ -285,12 +276,13 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
token->value = outbuf;
token->length = bufsize;
- return 0;
+ outbuf = NULL;
+ err = 0;
-error:
+cleanup:
+ krb5_free_checksum_contents(context, &sum);
+ zapfree(plain.data, plain.length);
gssalloc_free(outbuf);
- token->value = NULL;
- token->length = 0;
return err;
}
diff --git a/src/lib/rpc/pmap_rmt.c b/src/lib/rpc/pmap_rmt.c
index 8c7e30c21a..0748af34a7 100644
--- a/src/lib/rpc/pmap_rmt.c
+++ b/src/lib/rpc/pmap_rmt.c
@@ -160,11 +160,12 @@ xdr_rmtcallres(
caddr_t port_ptr;
port_ptr = (caddr_t)(void *)crp->port_ptr;
- if (xdr_reference(xdrs, &port_ptr, sizeof (uint32_t),
- xdr_u_int32) && xdr_u_int32(xdrs, &crp->resultslen)) {
- crp->port_ptr = (uint32_t *)(void *)port_ptr;
+ if (!xdr_reference(xdrs, &port_ptr, sizeof (uint32_t),
+ (xdrproc_t)xdr_u_int32))
+ return (FALSE);
+ crp->port_ptr = (uint32_t *)(void *)port_ptr;
+ if (xdr_u_int32(xdrs, &crp->resultslen))
return ((*(crp->xdr_results))(xdrs, crp->results_ptr));
- }
return (FALSE);
}
--
2.44.0

706
0011-Fix-vulnerabilities-in-GSS-message-token-handling.patch Normal file
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@ -0,0 +1,706 @@
From 46d6edbabb17b650cc78a69b7d38689af69d3ef5 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Tue, 7 Mar 2023 00:19:33 -0500
Subject: [PATCH 1/2] Add a simple DER support header
(cherry picked from commit 548da160b52b25a106e9f6077d6a42c2c049586c)
---
src/include/k5-der.h | 149 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 149 insertions(+)
create mode 100644 src/include/k5-der.h
diff --git a/src/include/k5-der.h b/src/include/k5-der.h
new file mode 100644
index 0000000000..b8371d9b4d
--- /dev/null
+++ b/src/include/k5-der.h
@@ -0,0 +1,149 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/* include/k5-der.h - Distinguished Encoding Rules (DER) declarations */
+/*
+ * Copyright (C) 2023 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Most ASN.1 encoding and decoding is done using the table-driven framework in
+ * libkrb5. When that is not an option, these helpers can be used to encode
+ * and decode simple types.
+ */
+
+#ifndef K5_DER_H
+#define K5_DER_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "k5-buf.h"
+#include "k5-input.h"
+
+/* Return the number of bytes needed to encode len as a DER encoding length. */
+static inline size_t
+k5_der_len_len(size_t len)
+{
+ size_t llen;
+
+ if (len < 128)
+ return 1;
+ llen = 1;
+ while (len > 0) {
+ len >>= 8;
+ llen++;
+ }
+ return llen;
+}
+
+/* Return the number of bytes needed to encode a DER value (with identifier
+ * byte and length) for a given contents length. */
+static inline size_t
+k5_der_value_len(size_t contents_len)
+{
+ return 1 + k5_der_len_len(contents_len) + contents_len;
+}
+
+/* Add a DER identifier byte (composed by the caller, including the ASN.1
+ * class, tag, and constructed bit) and length. */
+static inline void
+k5_der_add_taglen(struct k5buf *buf, uint8_t idbyte, size_t len)
+{
+ uint8_t *p;
+ size_t llen = k5_der_len_len(len);
+
+ p = k5_buf_get_space(buf, 1 + llen);
+ if (p == NULL)
+ return;
+ *p++ = idbyte;
+ if (len < 128) {
+ *p = len;
+ } else {
+ *p = 0x80 | (llen - 1);
+ /* Encode the length bytes backwards so the most significant byte is
+ * first. */
+ p += llen;
+ while (len > 0) {
+ *--p = len & 0xFF;
+ len >>= 8;
+ }
+ }
+}
+
+/* Add a DER value (identifier byte, length, and contents). */
+static inline void
+k5_der_add_value(struct k5buf *buf, uint8_t idbyte, const void *contents,
+ size_t len)
+{
+ k5_der_add_taglen(buf, idbyte, len);
+ k5_buf_add_len(buf, contents, len);
+}
+
+/*
+ * If the next byte in in matches idbyte and the subsequent DER length is
+ * valid, advance in past the value, set *contents_out to the value contents,
+ * and return true. Otherwise return false. Only set an error on in if the
+ * next bytes matches idbyte but the ensuing length is invalid. contents_out
+ * may be aliased to in; it will only be written to on successful decoding of a
+ * value.
+ */
+static inline bool
+k5_der_get_value(struct k5input *in, uint8_t idbyte,
+ struct k5input *contents_out)
+{
+ uint8_t lenbyte, i;
+ size_t len;
+ const void *bytes;
+
+ /* Do nothing if in is empty or the next byte doesn't match idbyte. */
+ if (in->status || in->len == 0 || *in->ptr != idbyte)
+ return false;
+
+ /* Advance past the identifier byte and decode the length. */
+ (void)k5_input_get_byte(in);
+ lenbyte = k5_input_get_byte(in);
+ if (lenbyte < 128) {
+ len = lenbyte;
+ } else {
+ len = 0;
+ for (i = 0; i < (lenbyte & 0x7F); i++) {
+ if (len > (SIZE_MAX >> 8)) {
+ k5_input_set_status(in, EOVERFLOW);
+ return false;
+ }
+ len = (len << 8) | k5_input_get_byte(in);
+ }
+ }
+
+ bytes = k5_input_get_bytes(in, len);
+ if (bytes == NULL)
+ return false;
+ k5_input_init(contents_out, bytes, len);
+ return true;
+}
+
+#endif /* K5_DER_H */
--
2.45.2
From 812661083280a7bef0493b559e642b3fa02bba63 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Fri, 14 Jun 2024 10:56:12 -0400
Subject: [PATCH 2/2] Fix vulnerabilities in GSS message token handling
In gss_krb5int_unseal_token_v3() and gss_krb5int_unseal_v3_iov(),
verify the Extra Count field of CFX wrap tokens against the encrypted
header. Reported by Jacob Champion.
In gss_krb5int_unseal_token_v3(), check for a decrypted plaintext
length too short to contain the encrypted header and extra count
bytes. Reported by Jacob Champion.
In kg_unseal_iov_token(), separately track the header IOV length and
complete token length when parsing the token's ASN.1 wrapper. This
fix contains modified versions of functions from k5-der.h and
util_token.c; this duplication will be cleaned up in a future commit.
CVE-2024-37370:
In MIT krb5 release 1.3 and later, an attacker can modify the
plaintext Extra Count field of a confidential GSS krb5 wrap token,
causing the unwrapped token to appear truncated to the application.
CVE-2024-37371:
In MIT krb5 release 1.3 and later, an attacker can cause invalid
memory reads by sending message tokens with invalid length fields.
(cherry picked from commit b0a2f8a5365f2eec3e27d78907de9f9d2c80505a)
ticket: 9128
version_fixed: 1.21.3
(cherry picked from commit 55fbf435edbe2e92dd8101669b1ce7144bc96fef)
---
src/lib/gssapi/krb5/k5sealv3.c | 5 +
src/lib/gssapi/krb5/k5sealv3iov.c | 3 +-
src/lib/gssapi/krb5/k5unsealiov.c | 80 +++++++++-
src/tests/gssapi/t_invalid.c | 233 +++++++++++++++++++++++++-----
4 files changed, 275 insertions(+), 46 deletions(-)
diff --git a/src/lib/gssapi/krb5/k5sealv3.c b/src/lib/gssapi/krb5/k5sealv3.c
index e881eee835..d3210c1107 100644
--- a/src/lib/gssapi/krb5/k5sealv3.c
+++ b/src/lib/gssapi/krb5/k5sealv3.c
@@ -400,10 +400,15 @@ gss_krb5int_unseal_token_v3(krb5_context *contextptr,
/* Don't use bodysize here! Use the fact that
cipher.ciphertext.length has been adjusted to the
correct length. */
+ if (plain.length < 16 + ec) {
+ free(plain.data);
+ goto defective;
+ }
althdr = (unsigned char *)plain.data + plain.length - 16;
if (load_16_be(althdr) != KG2_TOK_WRAP_MSG
|| althdr[2] != ptr[2]
|| althdr[3] != ptr[3]
+ || load_16_be(althdr+4) != ec
|| memcmp(althdr+8, ptr+8, 8)) {
free(plain.data);
goto defective;
diff --git a/src/lib/gssapi/krb5/k5sealv3iov.c b/src/lib/gssapi/krb5/k5sealv3iov.c
index 333ee124dd..f8e90c35b4 100644
--- a/src/lib/gssapi/krb5/k5sealv3iov.c
+++ b/src/lib/gssapi/krb5/k5sealv3iov.c
@@ -402,9 +402,10 @@ gss_krb5int_unseal_v3_iov(krb5_context context,
if (load_16_be(althdr) != KG2_TOK_WRAP_MSG
|| althdr[2] != ptr[2]
|| althdr[3] != ptr[3]
+ || load_16_be(althdr + 4) != ec
|| memcmp(althdr + 8, ptr + 8, 8) != 0) {
*minor_status = 0;
- return GSS_S_BAD_SIG;
+ return GSS_S_DEFECTIVE_TOKEN;
}
} else {
/* Verify checksum: note EC is checksum size here, not padding */
diff --git a/src/lib/gssapi/krb5/k5unsealiov.c b/src/lib/gssapi/krb5/k5unsealiov.c
index 85a9574f36..21b501731e 100644
--- a/src/lib/gssapi/krb5/k5unsealiov.c
+++ b/src/lib/gssapi/krb5/k5unsealiov.c
@@ -25,6 +25,7 @@
*/
#include "k5-int.h"
+#include "k5-der.h"
#include "gssapiP_krb5.h"
static OM_uint32
@@ -265,6 +266,73 @@ cleanup:
return retval;
}
+/* Similar to k5_der_get_value(), but output an unchecked content length
+ * instead of a k5input containing the contents. */
+static inline bool
+get_der_tag(struct k5input *in, uint8_t idbyte, size_t *len_out)
+{
+ uint8_t lenbyte, i;
+ size_t len;
+
+ /* Do nothing if in is empty or the next byte doesn't match idbyte. */
+ if (in->status || in->len == 0 || *in->ptr != idbyte)
+ return false;
+
+ /* Advance past the identifier byte and decode the length. */
+ (void)k5_input_get_byte(in);
+ lenbyte = k5_input_get_byte(in);
+ if (lenbyte < 128) {
+ len = lenbyte;
+ } else {
+ len = 0;
+ for (i = 0; i < (lenbyte & 0x7F); i++) {
+ if (len > (SIZE_MAX >> 8)) {
+ k5_input_set_status(in, EOVERFLOW);
+ return false;
+ }
+ len = (len << 8) | k5_input_get_byte(in);
+ }
+ }
+
+ if (in->status)
+ return false;
+
+ *len_out = len;
+ return true;
+}
+
+/*
+ * Similar to g_verify_token_header() without toktype or flags, but do not read
+ * more than *header_len bytes of ASN.1 wrapper, and on output set *header_len
+ * to the remaining number of header bytes. Verify the outer DER tag's length
+ * against token_len, which may be larger (but not smaller) than *header_len.
+ */
+static gss_int32
+verify_detached_wrapper(const gss_OID_desc *mech, size_t *header_len,
+ uint8_t **header_in, size_t token_len)
+{
+ struct k5input in, mech_der;
+ gss_OID_desc toid;
+ size_t len;
+
+ k5_input_init(&in, *header_in, *header_len);
+
+ if (get_der_tag(&in, 0x60, &len)) {
+ if (len != token_len - (in.ptr - *header_in))
+ return G_BAD_TOK_HEADER;
+ if (!k5_der_get_value(&in, 0x06, &mech_der))
+ return G_BAD_TOK_HEADER;
+ toid.elements = (uint8_t *)mech_der.ptr;
+ toid.length = mech_der.len;
+ if (!g_OID_equal(&toid, mech))
+ return G_WRONG_MECH;
+ }
+
+ *header_in = (uint8_t *)in.ptr;
+ *header_len = in.len;
+ return 0;
+}
+
/*
* Caller must provide TOKEN | DATA | PADDING | TRAILER, except
* for DCE in which case it can just provide TOKEN | DATA (must
@@ -285,8 +353,7 @@ kg_unseal_iov_token(OM_uint32 *minor_status,
gss_iov_buffer_t header;
gss_iov_buffer_t padding;
gss_iov_buffer_t trailer;
- size_t input_length;
- unsigned int bodysize;
+ size_t input_length, hlen;
int toktype2;
header = kg_locate_header_iov(iov, iov_count, toktype);
@@ -316,15 +383,14 @@ kg_unseal_iov_token(OM_uint32 *minor_status,
input_length += trailer->buffer.length;
}
- code = g_verify_token_header(ctx->mech_used,
- &bodysize, &ptr, -1,
- input_length, 0);
+ hlen = header->buffer.length;
+ code = verify_detached_wrapper(ctx->mech_used, &hlen, &ptr, input_length);
if (code != 0) {
*minor_status = code;
return GSS_S_DEFECTIVE_TOKEN;
}
- if (bodysize < 2) {
+ if (hlen < 2) {
*minor_status = (OM_uint32)G_BAD_TOK_HEADER;
return GSS_S_DEFECTIVE_TOKEN;
}
@@ -332,7 +398,7 @@ kg_unseal_iov_token(OM_uint32 *minor_status,
toktype2 = load_16_be(ptr);
ptr += 2;
- bodysize -= 2;
+ hlen -= 2;
switch (toktype2) {
case KG2_TOK_MIC_MSG:
diff --git a/src/tests/gssapi/t_invalid.c b/src/tests/gssapi/t_invalid.c
index 9876a11e67..882e163634 100644
--- a/src/tests/gssapi/t_invalid.c
+++ b/src/tests/gssapi/t_invalid.c
@@ -36,31 +36,41 @@
*
* 1. A pre-CFX wrap or MIC token processed with a CFX-only context causes a
* null pointer dereference. (The token must use SEAL_ALG_NONE or it will
- * be rejected.)
+ * be rejected.) This vulnerability also applies to IOV unwrap.
*
- * 2. A pre-CFX wrap or MIC token with fewer than 24 bytes after the ASN.1
+ * 2. A CFX wrap token with a different value of EC between the plaintext and
+ * encrypted copies will be erroneously accepted, which allows a message
+ * truncation attack. This vulnerability also applies to IOV unwrap.
+ *
+ * 3. A CFX wrap token with a plaintext length fewer than 16 bytes causes an
+ * access before the beginning of the input buffer, possibly leading to a
+ * crash.
+ *
+ * 4. A CFX wrap token with a plaintext EC value greater than the plaintext
+ * length - 16 causes an integer underflow when computing the result length,
+ * likely causing a crash.
+ *
+ * 5. An IOV unwrap operation will overrun the header buffer if an ASN.1
+ * wrapper longer than the header buffer is present.
+ *
+ * 6. A pre-CFX wrap or MIC token with fewer than 24 bytes after the ASN.1
* header causes an input buffer overrun, usually leading to either a segv
* or a GSS_S_DEFECTIVE_TOKEN error due to garbage algorithm, filler, or
- * sequence number values.
+ * sequence number values. This vulnerability also applies to IOV unwrap.
*
- * 3. A pre-CFX wrap token with fewer than 16 + cksumlen bytes after the ASN.1
+ * 7. A pre-CFX wrap token with fewer than 16 + cksumlen bytes after the ASN.1
* header causes an integer underflow when computing the ciphertext length,
* leading to an allocation error on 32-bit platforms or a segv on 64-bit
* platforms. A pre-CFX MIC token of this size causes an input buffer
* overrun when comparing the checksum, perhaps leading to a segv.
*
- * 4. A pre-CFX wrap token with fewer than conflen + padlen bytes in the
+ * 8. A pre-CFX wrap token with fewer than conflen + padlen bytes in the
* ciphertext (where padlen is the last byte of the decrypted ciphertext)
* causes an integer underflow when computing the original message length,
* leading to an allocation error.
*
- * 5. In the mechglue, truncated encapsulation in the initial context token can
+ * 9. In the mechglue, truncated encapsulation in the initial context token can
* cause input buffer overruns in gss_accept_sec_context().
- *
- * Vulnerabilities #1 and #2 also apply to IOV unwrap, although tokens with
- * fewer than 16 bytes after the ASN.1 header will be rejected.
- * Vulnerabilities #2 and #5 can only be robustly detected using a
- * memory-checking environment such as valgrind.
*/
#include "k5-int.h"
@@ -109,17 +119,25 @@ struct test {
}
};
-/* Fake up enough of a CFX GSS context for gss_unwrap, using an AES key. */
+static void *
+ealloc(size_t len)
+{
+ void *ptr = calloc(len, 1);
+
+ if (ptr == NULL)
+ abort();
+ return ptr;
+}
+
+/* Fake up enough of a CFX GSS context for gss_unwrap, using an AES key.
+ * The context takes ownership of subkey. */
static gss_ctx_id_t
-make_fake_cfx_context()
+make_fake_cfx_context(krb5_key subkey)
{
gss_union_ctx_id_t uctx;
krb5_gss_ctx_id_t kgctx;
- krb5_keyblock kb;
- kgctx = calloc(1, sizeof(*kgctx));
- if (kgctx == NULL)
- abort();
+ kgctx = ealloc(sizeof(*kgctx));
kgctx->established = 1;
kgctx->proto = 1;
if (g_seqstate_init(&kgctx->seqstate, 0, 0, 0, 0) != 0)
@@ -128,15 +146,10 @@ make_fake_cfx_context()
kgctx->sealalg = -1;
kgctx->signalg = -1;
- kb.enctype = ENCTYPE_AES128_CTS_HMAC_SHA1_96;
- kb.length = 16;
- kb.contents = (unsigned char *)"1234567887654321";
- if (krb5_k_create_key(NULL, &kb, &kgctx->subkey) != 0)
- abort();
+ kgctx->subkey = subkey;
+ kgctx->cksumtype = CKSUMTYPE_HMAC_SHA1_96_AES128;
- uctx = calloc(1, sizeof(*uctx));
- if (uctx == NULL)
- abort();
+ uctx = ealloc(sizeof(*uctx));
uctx->mech_type = &mech_krb5;
uctx->internal_ctx_id = (gss_ctx_id_t)kgctx;
return (gss_ctx_id_t)uctx;
@@ -150,9 +163,7 @@ make_fake_context(const struct test *test)
krb5_gss_ctx_id_t kgctx;
krb5_keyblock kb;
- kgctx = calloc(1, sizeof(*kgctx));
- if (kgctx == NULL)
- abort();
+ kgctx = ealloc(sizeof(*kgctx));
kgctx->established = 1;
if (g_seqstate_init(&kgctx->seqstate, 0, 0, 0, 0) != 0)
abort();
@@ -174,9 +185,7 @@ make_fake_context(const struct test *test)
if (krb5_k_create_key(NULL, &kb, &kgctx->enc) != 0)
abort();
- uctx = calloc(1, sizeof(*uctx));
- if (uctx == NULL)
- abort();
+ uctx = ealloc(sizeof(*uctx));
uctx->mech_type = &mech_krb5;
uctx->internal_ctx_id = (gss_ctx_id_t)kgctx;
return (gss_ctx_id_t)uctx;
@@ -206,9 +215,7 @@ make_token(unsigned char *token, size_t len, gss_buffer_t out)
assert(mech_krb5.length == 9);
assert(len + 11 < 128);
- wrapped = malloc(len + 13);
- if (wrapped == NULL)
- abort();
+ wrapped = ealloc(len + 13);
wrapped[0] = 0x60;
wrapped[1] = len + 11;
wrapped[2] = 0x06;
@@ -219,6 +226,18 @@ make_token(unsigned char *token, size_t len, gss_buffer_t out)
out->value = wrapped;
}
+/* Create a 16-byte header for a CFX confidential wrap token to be processed by
+ * the fake CFX context. */
+static void
+write_cfx_header(uint16_t ec, uint8_t *out)
+{
+ memset(out, 0, 16);
+ store_16_be(KG2_TOK_WRAP_MSG, out);
+ out[2] = FLAG_WRAP_CONFIDENTIAL;
+ out[3] = 0xFF;
+ store_16_be(ec, out + 4);
+}
+
/* Unwrap a superficially valid RFC 1964 token with a CFX-only context, with
* regular and IOV unwrap. */
static void
@@ -250,6 +269,134 @@ test_bogus_1964_token(gss_ctx_id_t ctx)
free(in.value);
}
+static void
+test_cfx_altered_ec(gss_ctx_id_t ctx, krb5_key subkey)
+{
+ OM_uint32 major, minor;
+ uint8_t tokbuf[128], plainbuf[24];
+ krb5_data plain;
+ krb5_enc_data cipher;
+ gss_buffer_desc in, out;
+ gss_iov_buffer_desc iov[2];
+
+ /* Construct a header with a plaintext EC value of 3. */
+ write_cfx_header(3, tokbuf);
+
+ /* Encrypt a plaintext and a copy of the header with the EC value 0. */
+ memcpy(plainbuf, "truncate", 8);
+ memcpy(plainbuf + 8, tokbuf, 16);
+ store_16_be(0, plainbuf + 12);
+ plain = make_data(plainbuf, 24);
+ cipher.ciphertext.data = (char *)tokbuf + 16;
+ cipher.ciphertext.length = sizeof(tokbuf) - 16;
+ cipher.enctype = subkey->keyblock.enctype;
+ if (krb5_k_encrypt(NULL, subkey, KG_USAGE_INITIATOR_SEAL, NULL,
+ &plain, &cipher) != 0)
+ abort();
+
+ /* Verify that the token is rejected by gss_unwrap(). */
+ in.value = tokbuf;
+ in.length = 16 + cipher.ciphertext.length;
+ major = gss_unwrap(&minor, ctx, &in, &out, NULL, NULL);
+ if (major != GSS_S_DEFECTIVE_TOKEN)
+ abort();
+ (void)gss_release_buffer(&minor, &out);
+
+ /* Verify that the token is rejected by gss_unwrap_iov(). */
+ iov[0].type = GSS_IOV_BUFFER_TYPE_STREAM;
+ iov[0].buffer = in;
+ iov[1].type = GSS_IOV_BUFFER_TYPE_DATA;
+ major = gss_unwrap_iov(&minor, ctx, NULL, NULL, iov, 2);
+ if (major != GSS_S_DEFECTIVE_TOKEN)
+ abort();
+}
+
+static void
+test_cfx_short_plaintext(gss_ctx_id_t ctx, krb5_key subkey)
+{
+ OM_uint32 major, minor;
+ uint8_t tokbuf[128], zerobyte = 0;
+ krb5_data plain;
+ krb5_enc_data cipher;
+ gss_buffer_desc in, out;
+
+ write_cfx_header(0, tokbuf);
+
+ /* Encrypt a single byte, with no copy of the header. */
+ plain = make_data(&zerobyte, 1);
+ cipher.ciphertext.data = (char *)tokbuf + 16;
+ cipher.ciphertext.length = sizeof(tokbuf) - 16;
+ cipher.enctype = subkey->keyblock.enctype;
+ if (krb5_k_encrypt(NULL, subkey, KG_USAGE_INITIATOR_SEAL, NULL,
+ &plain, &cipher) != 0)
+ abort();
+
+ /* Verify that the token is rejected by gss_unwrap(). */
+ in.value = tokbuf;
+ in.length = 16 + cipher.ciphertext.length;
+ major = gss_unwrap(&minor, ctx, &in, &out, NULL, NULL);
+ if (major != GSS_S_DEFECTIVE_TOKEN)
+ abort();
+ (void)gss_release_buffer(&minor, &out);
+}
+
+static void
+test_cfx_large_ec(gss_ctx_id_t ctx, krb5_key subkey)
+{
+ OM_uint32 major, minor;
+ uint8_t tokbuf[128] = { 0 }, plainbuf[20];
+ krb5_data plain;
+ krb5_enc_data cipher;
+ gss_buffer_desc in, out;
+
+ /* Construct a header with an EC value of 5. */
+ write_cfx_header(5, tokbuf);
+
+ /* Encrypt a 4-byte plaintext plus the header. */
+ memcpy(plainbuf, "abcd", 4);
+ memcpy(plainbuf + 4, tokbuf, 16);
+ plain = make_data(plainbuf, 20);
+ cipher.ciphertext.data = (char *)tokbuf + 16;
+ cipher.ciphertext.length = sizeof(tokbuf) - 16;
+ cipher.enctype = subkey->keyblock.enctype;
+ if (krb5_k_encrypt(NULL, subkey, KG_USAGE_INITIATOR_SEAL, NULL,
+ &plain, &cipher) != 0)
+ abort();
+
+ /* Verify that the token is rejected by gss_unwrap(). */
+ in.value = tokbuf;
+ in.length = 16 + cipher.ciphertext.length;
+ major = gss_unwrap(&minor, ctx, &in, &out, NULL, NULL);
+ if (major != GSS_S_DEFECTIVE_TOKEN)
+ abort();
+ (void)gss_release_buffer(&minor, &out);
+}
+
+static void
+test_iov_large_asn1_wrapper(gss_ctx_id_t ctx)
+{
+ OM_uint32 minor, major;
+ uint8_t databuf[10] = { 0 };
+ gss_iov_buffer_desc iov[2];
+
+ /*
+ * In this IOV array, the header contains a DER tag with a dangling eight
+ * bytes of length field. The data IOV indicates a total token length
+ * sufficient to contain the length bytes.
+ */
+ iov[0].type = GSS_IOV_BUFFER_TYPE_HEADER;
+ iov[0].buffer.value = ealloc(2);
+ iov[0].buffer.length = 2;
+ memcpy(iov[0].buffer.value, "\x60\x88", 2);
+ iov[1].type = GSS_IOV_BUFFER_TYPE_DATA;
+ iov[1].buffer.value = databuf;
+ iov[1].buffer.length = 10;
+ major = gss_unwrap_iov(&minor, ctx, NULL, NULL, iov, 2);
+ if (major != GSS_S_DEFECTIVE_TOKEN)
+ abort();
+ free(iov[0].buffer.value);
+}
+
/* Process wrap and MIC tokens with incomplete headers. */
static void
test_short_header(gss_ctx_id_t ctx)
@@ -399,9 +546,7 @@ try_accept(void *value, size_t len)
gss_ctx_id_t ctx = GSS_C_NO_CONTEXT;
/* Copy the provided value to make input overruns more obvious. */
- in.value = malloc(len);
- if (in.value == NULL)
- abort();
+ in.value = ealloc(len);
memcpy(in.value, value, len);
in.length = len;
(void)gss_accept_sec_context(&minor, &ctx, GSS_C_NO_CREDENTIAL, &in,
@@ -436,11 +581,23 @@ test_short_encapsulation()
int
main(int argc, char **argv)
{
+ krb5_keyblock kb;
+ krb5_key cfx_subkey;
gss_ctx_id_t ctx;
size_t i;
- ctx = make_fake_cfx_context();
+ kb.enctype = ENCTYPE_AES128_CTS_HMAC_SHA1_96;
+ kb.length = 16;
+ kb.contents = (unsigned char *)"1234567887654321";
+ if (krb5_k_create_key(NULL, &kb, &cfx_subkey) != 0)
+ abort();
+
+ ctx = make_fake_cfx_context(cfx_subkey);
test_bogus_1964_token(ctx);
+ test_cfx_altered_ec(ctx, cfx_subkey);
+ test_cfx_short_plaintext(ctx, cfx_subkey);
+ test_cfx_large_ec(ctx, cfx_subkey);
+ test_iov_large_asn1_wrapper(ctx);
free_fake_context(ctx);
for (i = 0; i < sizeof(tests) / sizeof(*tests); i++) {
--
2.45.2

16
krb5-mini.changes
View File

@ -1,3 +1,19 @@
-------------------------------------------------------------------
Mon Jul 1 09:12:55 UTC 2024 - Samuel Cabrero <scabrero@suse.de>
- Fix vulnerabilities in GSS message token handling, add patch
0011-Fix-vulnerabilities-in-GSS-message-token-handling.patch
* CVE-2024-37370, bsc#1227186
* CVE-2024-37371, bsc#1227187
-------------------------------------------------------------------
Fri Mar 22 09:19:41 UTC 2024 - Samuel Cabrero <scabrero@suse.de>
- Fix memory leaks, add patch 0010-Fix-three-memory-leaks.patch
* CVE-2024-26458, bsc#1220770
* CVE-2024-26461, bsc#1220771
* CVE-2024-26462, bsc#1220772
-------------------------------------------------------------------
Tue Aug 8 11:17:33 UTC 2023 - Samuel Cabrero <scabrero@suse.de>

2
krb5-mini.spec
View File

@ -45,6 +45,8 @@ Patch6: 0006-krb5-1.12-api.patch
Patch7: 0007-SELinux-integration.patch
Patch8: 0008-krb5-1.9-debuginfo.patch
Patch9: 0009-Ensure-array-count-consistency-in-kadm5-RPC.patch
Patch10: 0010-Fix-three-memory-leaks.patch
Patch11: 0011-Fix-vulnerabilities-in-GSS-message-token-handling.patch
BuildRequires: autoconf
BuildRequires: bison
BuildRequires: pkgconfig

16
krb5.changes
View File

@ -1,3 +1,19 @@
-------------------------------------------------------------------
Mon Jul 1 09:12:55 UTC 2024 - Samuel Cabrero <scabrero@suse.de>
- Fix vulnerabilities in GSS message token handling, add patch
0011-Fix-vulnerabilities-in-GSS-message-token-handling.patch
* CVE-2024-37370, bsc#1227186
* CVE-2024-37371, bsc#1227187
-------------------------------------------------------------------
Fri Mar 22 09:19:41 UTC 2024 - Samuel Cabrero <scabrero@suse.de>
- Fix memory leaks, add patch 0010-Fix-three-memory-leaks.patch
* CVE-2024-26458, bsc#1220770
* CVE-2024-26461, bsc#1220771
* CVE-2024-26462, bsc#1220772
-------------------------------------------------------------------
Tue Aug 8 11:17:33 UTC 2023 - Samuel Cabrero <scabrero@suse.de>

2
krb5.spec
View File

@ -43,6 +43,8 @@ Patch6: 0006-krb5-1.12-api.patch
Patch7: 0007-SELinux-integration.patch
Patch8: 0008-krb5-1.9-debuginfo.patch
Patch9: 0009-Ensure-array-count-consistency-in-kadm5-RPC.patch
Patch10: 0010-Fix-three-memory-leaks.patch
Patch11: 0011-Fix-vulnerabilities-in-GSS-message-token-handling.patch
BuildRequires: autoconf
BuildRequires: bison
BuildRequires: cyrus-sasl-devel