Add back t_invalid portion of the patch but don't include the three failing tests

This commit is contained in:
Adit Jha 2024-09-18 05:24:34 +00:00
Родитель c4572c9de1
Коммит 61d963ee6b
1 изменённых файлов: 230 добавлений и 13 удалений

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@ -20,19 +20,11 @@ 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
---
src/lib/gssapi/krb5/k5sealv3.c | 5 +
src/lib/gssapi/krb5/k5sealv3iov.c | 3 +-
src/lib/gssapi/krb5/k5unsealiov.c | 80 +++++++++-
3 files changed, 84 insertions(+), 4 deletions(-)
diff --git a/src/lib/gssapi/krb5/k5sealv3.c b/src/lib/gssapi/krb5/k5sealv3.c
index 3b4f8cb837b..1fcbdfbb870 100644
index e881eee..d3210c1 100644
--- a/src/lib/gssapi/krb5/k5sealv3.c
+++ b/src/lib/gssapi/krb5/k5sealv3.c
@@ -408,10 +408,15 @@ gss_krb5int_unseal_token_v3(krb5_context *contextptr,
@@ -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. */
@ -49,7 +41,7 @@ index 3b4f8cb837b..1fcbdfbb870 100644
free(plain.data);
goto defective;
diff --git a/src/lib/gssapi/krb5/k5sealv3iov.c b/src/lib/gssapi/krb5/k5sealv3iov.c
index 333ee124ddf..f8e90c35b44 100644
index 333ee12..f8e90c3 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,
@ -65,7 +57,7 @@ index 333ee124ddf..f8e90c35b44 100644
} 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 85a9574f365..21b501731e6 100644
index 85a9574..21b5017 100644
--- a/src/lib/gssapi/krb5/k5unsealiov.c
+++ b/src/lib/gssapi/krb5/k5unsealiov.c
@@ -25,6 +25,7 @@
@ -76,7 +68,7 @@ index 85a9574f365..21b501731e6 100644
#include "gssapiP_krb5.h"
static OM_uint32
@@ -265,6 +266,73 @@ kg_unseal_v1_iov(krb5_context context,
@@ -265,6 +266,73 @@ cleanup:
return retval;
}
@ -188,3 +180,228 @@ index 85a9574f365..21b501731e6 100644
switch (toktype2) {
case KG2_TOK_MIC_MSG:
diff --git a/src/tests/gssapi/t_invalid.c b/src/tests/gssapi/t_invalid.c
index 9876a11..4cd9c90 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 +269,31 @@ test_bogus_1964_token(gss_ctx_id_t ctx)
free(in.value);
}
+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 +443,7 @@ 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 +478,20 @@ 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_iov_large_asn1_wrapper(ctx);
free_fake_context(ctx);
for (i = 0; i < sizeof(tests) / sizeof(*tests); i++) {