[SCM] Samba Shared Repository - branch master updated
Jule Anger
janger at samba.org
Tue Nov 15 17:03:02 UTC 2022
The branch, master has been updated
via 434f461e9e5 CVE-2022-42898 third_party/heimdal: PAC parse integer overflows
from 15696da0151 gp: Fix startup scripts add not always set runonce
https://git.samba.org/?p=samba.git;a=shortlog;h=master
- Log -----------------------------------------------------------------
commit 434f461e9e5a914d4e5a9141324f1705e5e50cf9
Author: Joseph Sutton <josephsutton at catalyst.net.nz>
Date: Fri Oct 14 16:45:37 2022 +1300
CVE-2022-42898 third_party/heimdal: PAC parse integer overflows
Catch overflows that result from adding PAC_INFO_BUFFER_SIZE.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15203
Heavily edited by committer Nico Williams <nico at twosigma.com>, original by
Joseph Sutton <josephsutton at catalyst.net.nz>.
Signed-off-by: Nico Williams <nico at twosigma.com>
[jsutton at samba.org Zero-initialised header_size in krb5_pac_parse() to
avoid a maybe-uninitialized error; added a missing check for ret == 0]
Autobuild-User(master): Jule Anger <janger at samba.org>
Autobuild-Date(master): Tue Nov 15 17:02:52 UTC 2022 on sn-devel-184
-----------------------------------------------------------------------
Summary of changes:
third_party/heimdal/lib/krb5/pac.c | 614 +++++++++++++++++++++-----------
third_party/heimdal/lib/krb5/test_pac.c | 48 ++-
2 files changed, 444 insertions(+), 218 deletions(-)
Changeset truncated at 500 lines:
diff --git a/third_party/heimdal/lib/krb5/pac.c b/third_party/heimdal/lib/krb5/pac.c
index b923981908d..e6dfe2aef3d 100644
--- a/third_party/heimdal/lib/krb5/pac.c
+++ b/third_party/heimdal/lib/krb5/pac.c
@@ -37,19 +37,34 @@
#include <wind.h>
#include <assert.h>
+/*
+ * https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-pac/3341cfa2-6ef5-42e0-b7bc-4544884bf399
+ */
struct PAC_INFO_BUFFER {
- uint32_t type;
- uint32_t buffersize;
- uint32_t offset_hi;
- uint32_t offset_lo;
+ uint32_t type; /* ULONG ulType in the original */
+ uint32_t buffersize; /* ULONG cbBufferSize in the original */
+ uint64_t offset; /* ULONG64 Offset in the original
+ * this being the offset from the beginning of the
+ * struct PACTYPE to the beginning of the buffer
+ * containing data of type ulType
+ */
};
+/*
+ * https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-pac/6655b92f-ab06-490b-845d-037e6987275f
+ */
struct PACTYPE {
- uint32_t numbuffers;
- uint32_t version;
- struct PAC_INFO_BUFFER buffers[1];
+ uint32_t numbuffers; /* named cBuffers of type ULONG in the original */
+ uint32_t version; /* Named Version of type ULONG in the original */
+ struct PAC_INFO_BUFFER buffers[1]; /* an ellipsis (...) in the original */
};
+/*
+ * A PAC starts with a PACTYPE header structure that is followed by an array of
+ * numbuffers PAC_INFO_BUFFER structures, each of which points to a buffer
+ * beyond the last PAC_INFO_BUFFER structures.
+ */
+
struct krb5_pac_data {
struct PACTYPE *pac;
krb5_data data;
@@ -133,6 +148,60 @@ struct heim_type_data pac_object = {
NULL
};
+/*
+ * Returns the size of the PACTYPE header + the PAC_INFO_BUFFER array. This is
+ * also the end of the whole thing, and any offsets to buffers from
+ * thePAC_INFO_BUFFER[] entries have to be beyond it.
+ */
+static krb5_error_code
+pac_header_size(krb5_context context, uint32_t num_buffers, uint32_t *result)
+{
+ krb5_error_code ret;
+ uint32_t header_size;
+
+ /* Guard against integer overflow */
+ if (num_buffers > UINT32_MAX / PAC_INFO_BUFFER_SIZE) {
+ ret = EOVERFLOW;
+ krb5_set_error_message(context, ret, "PAC has too many buffers");
+ return ret;
+ }
+ header_size = PAC_INFO_BUFFER_SIZE * num_buffers;
+
+ /* Guard against integer overflow */
+ if (header_size > UINT32_MAX - PACTYPE_SIZE) {
+ ret = EOVERFLOW;
+ krb5_set_error_message(context, ret, "PAC has too many buffers");
+ return ret;
+ }
+ header_size += PACTYPE_SIZE;
+
+ *result = header_size;
+
+ return 0;
+}
+
+/* Output `size' + `addend' + padding for alignment if it doesn't overflow */
+static krb5_error_code
+pac_aligned_size(krb5_context context,
+ uint32_t size,
+ uint32_t addend,
+ uint32_t *aligned_size)
+{
+ krb5_error_code ret;
+
+ if (size > UINT32_MAX - addend ||
+ (size + addend) > UINT32_MAX - (PAC_ALIGNMENT - 1)) {
+ ret = EOVERFLOW;
+ krb5_set_error_message(context, ret, "integer overrun");
+ return ret;
+ }
+ size += addend;
+ size += PAC_ALIGNMENT - 1;
+ size &= ~(PAC_ALIGNMENT - 1);
+ *aligned_size = size;
+ return 0;
+}
+
/*
* HMAC-MD5 checksum over any key (needed for the PAC routines)
*/
@@ -184,165 +253,164 @@ KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_parse(krb5_context context, const void *ptr, size_t len,
krb5_pac *pac)
{
- krb5_error_code ret;
+ krb5_error_code ret = 0;
krb5_pac p;
krb5_storage *sp = NULL;
- uint32_t i, tmp, tmp2, header_end;
+ uint32_t i, num_buffers, version, header_size = 0;
+ uint32_t prev_start = 0;
+ uint32_t prev_end = 0;
+ *pac = NULL;
p = _heim_alloc_object(&pac_object, sizeof(*p));
- if (p == NULL) {
- ret = krb5_enomem(context);
- goto out;
- }
-
- sp = krb5_storage_from_readonly_mem(ptr, len);
- if (sp == NULL) {
+ if (p)
+ sp = krb5_storage_from_readonly_mem(ptr, len);
+ if (sp == NULL)
ret = krb5_enomem(context);
- goto out;
- }
- krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
-
- CHECK(ret, krb5_ret_uint32(sp, &tmp), out);
- CHECK(ret, krb5_ret_uint32(sp, &tmp2), out);
- if (tmp < 1) {
- ret = EINVAL; /* Too few buffers */
- krb5_set_error_message(context, ret, N_("PAC has too few buffers", ""));
- goto out;
+ if (ret == 0) {
+ krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
+ ret = krb5_ret_uint32(sp, &num_buffers);
}
- if (tmp2 != 0) {
- ret = EINVAL; /* Wrong version */
- krb5_set_error_message(context, ret,
+ if (ret == 0)
+ ret = krb5_ret_uint32(sp, &version);
+ if (ret == 0 && num_buffers < 1)
+ krb5_set_error_message(context, ret = EINVAL,
+ N_("PAC has too few buffers", ""));
+ if (ret == 0 && num_buffers > 1000)
+ krb5_set_error_message(context, ret = EINVAL,
+ N_("PAC has too many buffers", ""));
+ if (ret == 0 && version != 0)
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC has wrong version %d", ""),
- (int)tmp2);
- goto out;
- }
-
- p->pac = calloc(1,
- sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (tmp - 1)));
- if (p->pac == NULL) {
+ (int)version);
+ if (ret == 0)
+ ret = pac_header_size(context, num_buffers, &header_size);
+ if (ret == 0 && header_size > len)
+ krb5_set_error_message(context, ret = EOVERFLOW,
+ N_("PAC encoding invalid, would overflow buffers", ""));
+ if (ret == 0)
+ p->pac = calloc(1, header_size);
+ if (ret == 0 && p->pac == NULL)
ret = krb5_enomem(context);
- goto out;
- }
-
- p->pac->numbuffers = tmp;
- p->pac->version = tmp2;
- header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
- if (header_end > len) {
- ret = EINVAL;
- goto out;
+ if (ret == 0) {
+ p->pac->numbuffers = num_buffers;
+ p->pac->version = version;
}
- for (i = 0; i < p->pac->numbuffers; i++) {
- CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].type), out);
- CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].buffersize), out);
- CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].offset_lo), out);
- CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].offset_hi), out);
+ for (i = 0; ret == 0 && i < p->pac->numbuffers; i++) {
+ ret = krb5_ret_uint32(sp, &p->pac->buffers[i].type);
+ if (ret == 0)
+ ret = krb5_ret_uint32(sp, &p->pac->buffers[i].buffersize);
+ if (ret == 0)
+ ret = krb5_ret_uint64(sp, &p->pac->buffers[i].offset);
+ if (ret)
+ break;
- /* consistency checks */
- if (p->pac->buffers[i].offset_lo & (PAC_ALIGNMENT - 1)) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
+ /* Consistency checks (we don't check for wasted space) */
+ if (p->pac->buffers[i].offset & (PAC_ALIGNMENT - 1)) {
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC out of alignment", ""));
- goto out;
+ break;
}
- if (p->pac->buffers[i].offset_hi) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
- N_("PAC high offset set", ""));
- goto out;
+ if (p->pac->buffers[i].offset > len ||
+ p->pac->buffers[i].buffersize > len ||
+ len - p->pac->buffers[i].offset < p->pac->buffers[i].buffersize) {
+ krb5_set_error_message(context, ret = EOVERFLOW,
+ N_("PAC buffer overflow", ""));
+ break;
}
- if (p->pac->buffers[i].offset_lo > len) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
- N_("PAC offset overflow", ""));
- goto out;
- }
- if (p->pac->buffers[i].offset_lo < header_end) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
+ if (p->pac->buffers[i].offset < header_size) {
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC offset inside header: %lu %lu", ""),
- (unsigned long)p->pac->buffers[i].offset_lo,
- (unsigned long)header_end);
- goto out;
- }
- if (p->pac->buffers[i].buffersize > len - p->pac->buffers[i].offset_lo){
- ret = EINVAL;
- krb5_set_error_message(context, ret, N_("PAC length overflow", ""));
- goto out;
+ (unsigned long)p->pac->buffers[i].offset,
+ (unsigned long)header_size);
+ break;
}
- /* let save pointer to data we need later */
- if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
- if (p->server_checksum) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
+ /*
+ * We'd like to check for non-overlapping of buffers, but the buffers
+ * need not be in the same order as the PAC_INFO_BUFFER[] entries
+ * pointing to them! To fully check for overlap we'd have to have an
+ * O(N^2) loop after we parse all the PAC_INFO_BUFFER[].
+ *
+ * But we can check that each buffer does not overlap the previous
+ * buffer.
+ */
+ if (prev_start) {
+ if (p->pac->buffers[i].offset >= prev_start &&
+ p->pac->buffers[i].offset < prev_end) {
+ krb5_set_error_message(context, ret = EINVAL,
+ N_("PAC overlap", ""));
+ break;
+ }
+ if (p->pac->buffers[i].offset < prev_start &&
+ p->pac->buffers[i].offset +
+ p->pac->buffers[i].buffersize > prev_start) {
+ krb5_set_error_message(context, ret = EINVAL,
+ N_("PAC overlap", ""));
+ break;
+ }
+ }
+ prev_start = p->pac->buffers[i].offset;
+ prev_end = p->pac->buffers[i].offset + p->pac->buffers[i].buffersize;
+
+ /* Let's save pointers to buffers we'll need later */
+ switch (p->pac->buffers[i].type) {
+ case PAC_SERVER_CHECKSUM:
+ if (p->server_checksum)
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC has multiple server checksums", ""));
- goto out;
- }
- p->server_checksum = &p->pac->buffers[i];
- } else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) {
- if (p->privsvr_checksum) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
- N_("PAC has multiple KDC checksums", ""));
- goto out;
- }
- p->privsvr_checksum = &p->pac->buffers[i];
- } else if (p->pac->buffers[i].type == PAC_LOGON_NAME) {
- if (p->logon_name) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
- N_("PAC has multiple logon names", ""));
- goto out;
- }
- p->logon_name = &p->pac->buffers[i];
- } else if (p->pac->buffers[i].type == PAC_UPN_DNS_INFO) {
- if (p->upn_dns_info) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
+ else
+ p->server_checksum = &p->pac->buffers[i];
+ break;
+ case PAC_PRIVSVR_CHECKSUM:
+ if (p->privsvr_checksum)
+ krb5_set_error_message(context, ret = EINVAL,
+ N_("PAC has multiple KDC checksums", ""));
+ else
+ p->privsvr_checksum = &p->pac->buffers[i];
+ break;
+ case PAC_LOGON_NAME:
+ if (p->logon_name)
+ krb5_set_error_message(context, ret = EINVAL,
+ N_("PAC has multiple logon names", ""));
+ else
+ p->logon_name = &p->pac->buffers[i];
+ break;
+ case PAC_UPN_DNS_INFO:
+ if (p->upn_dns_info)
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC has multiple UPN DNS info buffers", ""));
- goto out;
- }
- p->upn_dns_info = &p->pac->buffers[i];
- } else if (p->pac->buffers[i].type == PAC_TICKET_CHECKSUM) {
- if (p->ticket_checksum) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
+ else
+ p->upn_dns_info = &p->pac->buffers[i];
+ break;
+ case PAC_TICKET_CHECKSUM:
+ if (p->ticket_checksum)
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC has multiple ticket checksums", ""));
- goto out;
- }
- p->ticket_checksum = &p->pac->buffers[i];
- } else if (p->pac->buffers[i].type == PAC_ATTRIBUTES_INFO) {
- if (p->attributes_info) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
+ else
+ p->ticket_checksum = &p->pac->buffers[i];
+ break;
+ case PAC_ATTRIBUTES_INFO:
+ if (p->attributes_info)
+ krb5_set_error_message(context, ret = EINVAL,
N_("PAC has multiple attributes info buffers", ""));
- goto out;
- }
- p->attributes_info = &p->pac->buffers[i];
- }
+ else
+ p->attributes_info = &p->pac->buffers[i];
+ break;
+ default: break;
+ }
}
- ret = krb5_data_copy(&p->data, ptr, len);
- if (ret)
- goto out;
-
- krb5_storage_free(sp);
-
- *pac = p;
- return 0;
-
-out:
- if (sp)
- krb5_storage_free(sp);
- if (p) {
- if (p->pac)
- free(p->pac);
- krb5_pac_free(context, p);
+ if (ret == 0)
+ ret = krb5_data_copy(&p->data, ptr, len);
+ if (ret == 0) {
+ *pac = p;
+ p = NULL;
}
- *pac = NULL;
-
+ if (sp)
+ krb5_storage_free(sp);
+ krb5_pac_free(context, p);
return ret;
}
@@ -369,77 +437,111 @@ krb5_pac_init(krb5_context context, krb5_pac *pac)
krb5_pac_free(context, p);
return krb5_enomem(context);
}
+ memset(p->data.data, 0, p->data.length);
*pac = p;
return 0;
}
+/**
+ * Add a PAC buffer `nd' of type `type' to the pac `p'.
+ *
+ * @param context
+ * @param p
+ * @param type
+ * @param nd
+ *
+ * @return 0 on success or a Kerberos or system error.
+ */
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_add_buffer(krb5_context context, krb5_pac p,
- uint32_t type, const krb5_data *data)
+ uint32_t type, const krb5_data *nd)
{
krb5_error_code ret;
void *ptr;
- size_t len, offset, header_end, old_end;
+ size_t old_len = p->data.length;
+ uint32_t len, offset, header_size;
uint32_t i;
+ uint32_t num_buffers;
- assert(data->data != NULL);
+ assert(nd->data != NULL);
- len = p->pac->numbuffers;
+ num_buffers = p->pac->numbuffers;
+ ret = pac_header_size(context, num_buffers + 1, &header_size);
+ if (ret)
+ return ret;
- ptr = realloc(p->pac,
- sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * len));
+ ptr = realloc(p->pac, header_size);
if (ptr == NULL)
return krb5_enomem(context);
p->pac = ptr;
+ p->pac->buffers[num_buffers].type = 0;
+ p->pac->buffers[num_buffers].buffersize = 0;
+ p->pac->buffers[num_buffers].offset = 0;
- for (i = 0; i < len; i++)
- p->pac->buffers[i].offset_lo += PAC_INFO_BUFFER_SIZE;
-
- offset = p->data.length + PAC_INFO_BUFFER_SIZE;
-
- p->pac->buffers[len].type = type;
- p->pac->buffers[len].buffersize = data->length;
- p->pac->buffers[len].offset_lo = offset;
- p->pac->buffers[len].offset_hi = 0;
-
- old_end = p->data.length;
- len = p->data.length + data->length + PAC_INFO_BUFFER_SIZE;
- if (len < p->data.length) {
- krb5_set_error_message(context, EINVAL, "integer overrun");
- return EINVAL;
+ /*
+ * Check that we can adjust all the buffer offsets in the existing
+ * PAC_INFO_BUFFERs, since changing the size of PAC_INFO_BUFFER[] means
+ * changing the offsets of buffers following that array.
+ *
+ * We don't adjust them until we can't fail.
+ */
+ for (i = 0; i < num_buffers; i++) {
+ if (p->pac->buffers[i].offset > UINT32_MAX - PAC_INFO_BUFFER_SIZE) {
+ krb5_set_error_message(context, ret = EOVERFLOW,
+ "too many / too large PAC buffers");
+ return ret;
+ }
}
- /* align to PAC_ALIGNMENT */
- len = ((len + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT;
+ /*
+ * The new buffer's offset must be past the end of the buffers we have
+ * (p->data), which is the sum of the header and p->data.length.
+ */
+ /* Set offset = p->data.length + PAC_INFO_BUFFER_SIZE + alignment */
+ ret = pac_aligned_size(context, p->data.length, PAC_INFO_BUFFER_SIZE, &offset);
+ if (ret == 0)
+ /* Set the new length = offset + nd->length + alignment */
--
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