#include "krb5_locl.h"
#include <wind.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;
static const char zeros[PAC_ALIGNMENT] = { 0 };
+/*
+ * 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)
*/
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 = calloc(1, 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;
- }
- if (p->pac->buffers[i].offset_hi) {
- ret = EINVAL;
- krb5_set_error_message(context, ret,
- N_("PAC high offset set", ""));
- goto out;
+ 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 > 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 < 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_TICKET_CHECKSUM) {
- if (p->ticket_checksum) {
- 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_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
+ p->ticket_checksum = &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);
- free(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;
}
free(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;
- 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 */
+ ret = pac_aligned_size(context, offset, nd->length, &len);
+ if (ret) {
+ krb5_set_error_message(context, ret, "PAC buffer too large");
+ return ret;
+ }
ret = krb5_data_realloc(&p->data, len);
if (ret) {
krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
return ret;
}
+ /* Zero out the new allocation to zero out any padding */
+ memset((char *)p->data.data + old_len, 0, len - old_len);
+
+ p->pac->buffers[num_buffers].type = type;
+ p->pac->buffers[num_buffers].buffersize = nd->length;
+ p->pac->buffers[num_buffers].offset = offset;
+
+ /* Adjust all the buffer offsets in the existing PAC_INFO_BUFFERs now */
+ for (i = 0; i < num_buffers; i++)
+ p->pac->buffers[i].offset += PAC_INFO_BUFFER_SIZE;
+
/*
- * make place for new PAC INFO BUFFER header
+ * Make place for new PAC INFO BUFFER header
*/
- header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
- memmove((unsigned char *)p->data.data + header_end + PAC_INFO_BUFFER_SIZE,
- (unsigned char *)p->data.data + header_end ,
- old_end - header_end);
- memset((unsigned char *)p->data.data + header_end, 0, PAC_INFO_BUFFER_SIZE);
+ header_size -= PAC_INFO_BUFFER_SIZE;
+ memmove((unsigned char *)p->data.data + header_size + PAC_INFO_BUFFER_SIZE,
+ (unsigned char *)p->data.data + header_size ,
+ old_len - header_size);
+ /* Clear the space where we would put the new PAC_INFO_BUFFER[] element */
+ memset((unsigned char *)p->data.data + header_size, 0,
+ PAC_INFO_BUFFER_SIZE);
/*
- * copy in new data part
+ * Copy in new data part
*/
-
- memcpy((unsigned char *)p->data.data + offset,
- data->data, data->length);
- memset((unsigned char *)p->data.data + offset + data->length,
- 0, p->data.length - offset - data->length);
-
+ memcpy((unsigned char *)p->data.data + offset, nd->data, nd->length);
p->pac->numbuffers += 1;
-
return 0;
}
* @param type type of buffer to get
* @param data return data, free with krb5_data_free().
*
- * @return Returns 0 to indicate success. Otherwise an kerberos et
- * error code is returned, see krb5_get_error_message().
+ * @return Returns 0 to indicate success, ENOENT to indicate that a buffer of
+ * the given type was not found, or a Kerberos or system error code.
*
* @ingroup krb5_pac
*/
uint32_t i;
for (i = 0; i < p->pac->numbuffers; i++) {
- const size_t len = p->pac->buffers[i].buffersize;
- const size_t offset = p->pac->buffers[i].offset_lo;
+ size_t len = p->pac->buffers[i].buffersize;
+ size_t offset = p->pac->buffers[i].offset;
if (p->pac->buffers[i].type != type)
continue;
- if (data) {
- ret = krb5_data_copy(data, (unsigned char *)p->data.data + offset, len);
- if (ret) {
- krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
- return ret;
- }
- }
- return 0;
+ if (!data)
+ return 0;
+
+ ret = krb5_data_copy(data, (unsigned char *)p->data.data + offset, len);
+ if (ret)
+ krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
+ return ret;
}
krb5_set_error_message(context, ENOENT, "No PAC buffer of type %lu was found",
(unsigned long)type);
memset(&cksum, 0, sizeof(cksum));
- sp = krb5_storage_from_mem((char *)data->data + sig->offset_lo,
+ sp = krb5_storage_from_mem((char *)data->data + sig->offset,
sig->buffersize);
if (sp == NULL)
return krb5_enomem(context);
char *principal_string = NULL;
char *logon_string = NULL;
- sp = krb5_storage_from_readonly_mem((const char *)data->data + logon_name->offset_lo,
+ sp = krb5_storage_from_readonly_mem((const char *)data->data + logon_name->offset,
logon_name->buffersize);
if (sp == NULL)
return krb5_enomem(context);
if (pac->privsvr_checksum->buffersize < 4)
return EINVAL;
- memset((char *)copy->data + pac->server_checksum->offset_lo + 4,
+ memset((char *)copy->data + pac->server_checksum->offset + 4,
0,
pac->server_checksum->buffersize - 4);
- memset((char *)copy->data + pac->privsvr_checksum->offset_lo + 4,
+ memset((char *)copy->data + pac->privsvr_checksum->offset + 4,
0,
pac->privsvr_checksum->buffersize - 4);
pac->privsvr_checksum,
&pac->data,
(char *)pac->data.data
- + pac->server_checksum->offset_lo + 4,
+ + pac->server_checksum->offset + 4,
pac->server_checksum->buffersize - 4,
privsvr);
if (ret)
size_t server_size, priv_size;
uint32_t server_offset = 0, priv_offset = 0, ticket_offset = 0;
uint32_t server_cksumtype = 0, priv_cksumtype = 0;
- int num = 0;
- size_t i, sz;
+ uint32_t num = 0;
+ uint32_t i, sz;
krb5_data logon, d;
krb5_data_zero(&d);
krb5_data_zero(&logon);
+ /*
+ * Set convenience buffer pointers.
+ *
+ * This could really stand to be moved to krb5_pac_add_buffer() and/or
+ * utility function, so that when this function gets called they must
+ * already have been set.
+ */
for (i = 0; i < p->pac->numbuffers; i++) {
if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
if (p->server_checksum == NULL) {
}
}
+ /* Count missing-but-necessary buffers */
if (p->logon_name == NULL)
num++;
if (p->server_checksum == NULL)
if (p->ticket_sign_data.length != 0 && p->ticket_checksum == NULL)
num++;
+ /* Allocate any missing-but-necessary buffers */
if (num) {
void *ptr;
+ uint32_t old_len, len;
+
+ if (p->pac->numbuffers > UINT32_MAX - num) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
+ ret = pac_header_size(context, p->pac->numbuffers, &old_len);
+ if (ret == 0)
+ ret = pac_header_size(context, p->pac->numbuffers + num, &len);
+ if (ret)
+ goto out;
- ptr = realloc(p->pac, sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (p->pac->numbuffers + num - 1)));
+ ptr = realloc(p->pac, len);
if (ptr == NULL) {
ret = krb5_enomem(context);
goto out;
}
-
+ memset((char *)ptr + old_len, 0, len - old_len);
p->pac = ptr;
+
if (p->logon_name == NULL) {
p->logon_name = &p->pac->buffers[p->pac->numbuffers++];
- memset(p->logon_name, 0, sizeof(*p->logon_name));
p->logon_name->type = PAC_LOGON_NAME;
}
if (p->server_checksum == NULL) {
p->server_checksum = &p->pac->buffers[p->pac->numbuffers++];
- memset(p->server_checksum, 0, sizeof(*p->server_checksum));
p->server_checksum->type = PAC_SERVER_CHECKSUM;
}
if (p->privsvr_checksum == NULL) {
p->privsvr_checksum = &p->pac->buffers[p->pac->numbuffers++];
- memset(p->privsvr_checksum, 0, sizeof(*p->privsvr_checksum));
p->privsvr_checksum->type = PAC_PRIVSVR_CHECKSUM;
}
if (p->ticket_sign_data.length != 0 && p->ticket_checksum == NULL) {
p->ticket_checksum = &p->pac->buffers[p->pac->numbuffers++];
- memset(p->ticket_checksum, 0, sizeof(*p->privsvr_checksum));
p->ticket_checksum->type = PAC_TICKET_CHECKSUM;
}
}
krb5_storage_set_flags(spdata, KRB5_STORAGE_BYTEORDER_LE);
+ /* `sp' has the header, `spdata' has the buffers */
CHECK(ret, krb5_store_uint32(sp, p->pac->numbuffers), out);
CHECK(ret, krb5_store_uint32(sp, p->pac->version), out);
- end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
+ ret = pac_header_size(context, p->pac->numbuffers, &end);
+ if (ret)
+ goto out;
+ /*
+ * For each buffer we write its contents to `spdata' and then append the
+ * PAC_INFO_BUFFER for that buffer into the header in `sp'. The logical
+ * end of the whole thing is kept in `end', which functions as the offset
+ * to write in the buffer's PAC_INFO_BUFFER, then we update it at the
+ * bottom so that the next buffer can be written there.
+ *
+ * TODO? Maybe rewrite all of this so that:
+ *
+ * - we use krb5_pac_add_buffer() to add the buffers we produce
+ * - we use the krb5_data of the concatenated buffers that's maintained by
+ * krb5_pac_add_buffer() so we don't need `spdata' here
+ *
+ * We do way too much here, and that makes this code hard to read. Plus we
+ * throw away all the work done in krb5_pac_add_buffer(). On the other
+ * hand, krb5_pac_add_buffer() has to loop over all the buffers, so if we
+ * call krb5_pac_add_buffer() here in a loop, we'll be accidentally
+ * quadratic, but we only need to loop over adding the buffers we add,
+ * which is very few, so not quite quadratic. We should also cap the
+ * number of buffers we're willing to accept in a PAC we parse to something
+ * reasonable, like a few tens.
+ */
for (i = 0; i < p->pac->numbuffers; i++) {
uint32_t len;
size_t sret;
/* store data */
if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
+ if (server_size > UINT32_MAX - 4) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
len = server_size + 4;
+ if (end > UINT32_MAX - 4) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
server_offset = end + 4;
CHECK(ret, krb5_store_uint32(spdata, server_cksumtype), out);
CHECK(ret, fill_zeros(context, spdata, server_size), out);
} else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) {
+ if (priv_size > UINT32_MAX - 4) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
len = priv_size + 4;
+ if (end > UINT32_MAX - 4) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
priv_offset = end + 4;
CHECK(ret, krb5_store_uint32(spdata, priv_cksumtype), out);
CHECK(ret, fill_zeros(context, spdata, priv_size), out);
if (rodc_id != 0) {
+ if (len > UINT32_MAX - sizeof(rodc_id)) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
len += sizeof(rodc_id);
CHECK(ret, fill_zeros(context, spdata, sizeof(rodc_id)), out);
}
} else if (p->ticket_sign_data.length != 0 &&
p->pac->buffers[i].type == PAC_TICKET_CHECKSUM) {
+ if (priv_size > UINT32_MAX - 4) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
len = priv_size + 4;
+ if (end > UINT32_MAX - 4) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
ticket_offset = end + 4;
CHECK(ret, krb5_store_uint32(spdata, priv_cksumtype), out);
CHECK(ret, fill_zeros(context, spdata, priv_size), out);
if (rodc_id != 0) {
+ if (len > UINT32_MAX - sizeof(rodc_id)) {
+ ret = EINVAL;
+ krb5_set_error_message(context, ret, "integer overrun");
+ goto out;
+ }
len += sizeof(rodc_id);
CHECK(ret, krb5_store_uint16(spdata, rodc_id), out);
}
}
} else {
len = p->pac->buffers[i].buffersize;
- ptr = (char *)p->data.data + p->pac->buffers[i].offset_lo;
+ ptr = (char *)p->data.data + p->pac->buffers[i].offset;
sret = krb5_storage_write(spdata, ptr, len);
if (sret != len) {
/* write header */
CHECK(ret, krb5_store_uint32(sp, p->pac->buffers[i].type), out);
CHECK(ret, krb5_store_uint32(sp, len), out);
- CHECK(ret, krb5_store_uint32(sp, end), out);
- CHECK(ret, krb5_store_uint32(sp, 0), out);
+ CHECK(ret, krb5_store_uint64(sp, end), out); /* offset */
/* advance data endpointer and align */
{
- int32_t e;
+ uint32_t e;
- end += len;
- e = ((end + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT;
- if ((int32_t)end != e) {
- CHECK(ret, fill_zeros(context, spdata, e - end), out);
- }
+ ret = pac_aligned_size(context, end, len, &e);
+ if (ret == 0 && end + len != e)
+ ret = fill_zeros(context, spdata, e - (end + len));
+ if (ret)
+ goto out;
end = e;
}
return KRB5KDC_ERR_BADOPTION;
}
- sp = krb5_storage_from_mem((char *)pac->data.data + sig->offset_lo,
+ sp = krb5_storage_from_mem((char *)pac->data.data + sig->offset,
sig->buffersize);
if (sp == NULL)
return krb5_enomem(context);
projects / thirdparty / samba.git / commitdiff
