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Allow for empty fields in TS_EXTENDED_INFO_PACKET

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Some clients appears to be sending cbClientAddress and/or cbClientDir
as 0 in the TS_EXTENDED_INFO_PACKET. This appears to be at odds with
[MS-RDPBCGR] which requires mandatory terminators for these fields.
This commit is contained in:
matt335672
2023-11-13 10:07:36 +00:00
parent 50cff2eb75
commit cdf574cf6c
2 changed files with 27 additions and 16 deletions
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libxrdp/xrdp_sec.c
+24 -16
View File
@@ -833,18 +833,15 @@ static int
xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
{
int flags = 0;
int len_domain = 0;
int len_user = 0;
int len_password = 0;
int len_program = 0;
int len_directory = 0;
int len_ip = 0;
int len_dll = 0;
char tmpdata[256];
unsigned int len_domain = 0;
unsigned int len_user = 0;
unsigned int len_password = 0;
unsigned int len_program = 0;
unsigned int len_directory = 0;
unsigned int len_clnt_addr = 0;
unsigned int len_clnt_dir = 0;
const char *sep;
/* initialize (zero out) local variables */
g_memset(tmpdata, 0, sizeof(char) * 256);
if (!s_check_rem_and_log(s, 8, "Parsing [MS-RDPBCGR] TS_INFO_PACKET"))
{
return 1;
@@ -1097,22 +1094,33 @@ xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
}
/* TS_EXTENDED_INFO_PACKET required fields */
in_uint8s(s, 2); /* clientAddressFamily */
in_uint16_le(s, len_ip);
if (ts_info_utf16_in(s, len_ip - 2, tmpdata, sizeof(tmpdata)) != 0)
in_uint16_le(s, len_clnt_addr);
if (len_clnt_addr > EXTENDED_INFO_MAX_CLIENT_ADDR_LENGTH ||
!s_check_rem(s, len_clnt_addr))
{
LOG(LOG_LEVEL_ERROR, "ERROR reading ip");
LOG(LOG_LEVEL_ERROR, "clientAddress is too long (%u bytes)",
len_clnt_addr);
return 1;
}
// The clientAddress is currently unused. [MS-RDPBCGR] requires
// a mandatory null terminator, but some clients set
// len_clnt_addr == 0 if this field is missing. Allow for this
// in any future implementation.
in_uint8s(s, len_clnt_addr); // Skip Unicode clientAddress
if (!s_check_rem_and_log(s, 2, "Parsing [MS-RDPBCGR] TS_EXTENDED_INFO_PACKET clientDir"))
{
return 1;
}
in_uint16_le(s, len_dll);
if (ts_info_utf16_in(s, len_dll - 2, tmpdata, sizeof(tmpdata)) != 0)
in_uint16_le(s, len_clnt_dir);
if (len_clnt_dir > INFO_CLIENT_MAX_CB_LEN ||
!s_check_rem(s, len_clnt_dir))
{
LOG(LOG_LEVEL_ERROR, "ERROR reading clientDir");
LOG(LOG_LEVEL_ERROR, "clientDir is too long (%u bytes)", len_clnt_dir);
return 1;
}
in_uint8s(s, len_clnt_dir); // Skip Unicode clientDir
LOG_DEVEL(LOG_LEVEL_TRACE, "Received [MS-RDPBCGR] TS_EXTENDED_INFO_PACKET "
"<Required Fields> clientAddressFamily (ignored), "
"cbClientAddress (ignored), clientAddress (ignored), "