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dechunker: Create separate module for dechunking

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The code in xrdp_channel.c to handle dechunking on a virtual channel is
moved to a separate module to allow for better sharing of logic.
This commit is contained in:
matt335672
2026-07-17 11:57:30 +01:00
parent de284747ae
commit be95ba3017
5 changed files with 514 additions and 60 deletions
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libxrdp/xrdp_channel.c
+38 -59
View File
@@ -23,7 +23,7 @@
#endif
#include "libxrdp.h"
#include "parse.h"
#include "dechunker.h"
#include "string_calls.h"
#include "xrdp_channel.h"
@@ -78,7 +78,7 @@ xrdp_channel_delete(struct xrdp_channel *self)
{
return;
}
free_stream(self->s);
vc_dechunker_free(self->drdynvc_dc);
g_memset(self, 0, sizeof(struct xrdp_channel));
g_free(self);
}
@@ -550,11 +550,12 @@ xrdp_channel_process_drdynvc(struct xrdp_channel *self,
struct stream *s)
{
int total_length;
int length;
int flags;
int cmd;
int rv;
struct stream *ls;
struct stream *ls = NULL;
int free_ls = 0;
enum vc_dechunker_status dechunker_status;
if (!s_check_rem_and_log(s, 8, "Parsing [MS-RDPBCGR] CHANNEL_PDU_HEADER"))
{
@@ -564,65 +565,32 @@ xrdp_channel_process_drdynvc(struct xrdp_channel *self,
in_uint32_le(s, flags); /* flags */
LOG_DEVEL(LOG_LEVEL_TRACE, "Received header [MS-RDPBCGR] CHANNEL_PDU_HEADER "
"length %d, flags 0x%8.8x", total_length, flags);
ls = NULL;
switch (flags & 3)
dechunker_status = vc_dechunker_process_chunk(
self->drdynvc_dc,
s, flags, total_length);
switch (dechunker_status)
{
case 0: /* not first chunk and not last chunk */
length = (int) (s->end - s->p);
LOG_DEVEL(LOG_LEVEL_TRACE, "Received [MS-RDPBCGR] data chunk (middle) "
"length %d", length);
if (length > s_rem_out(self->s))
{
LOG(LOG_LEVEL_ERROR, "[MS-RDPBCGR] Data chunk length is bigger than "
"the remaining chunk buffer size. length %d, remaining %d",
length, s_rem_out(self->s));
return 1;
}
out_uint8a(self->s, s->p, length); /* append data to chunk buffer */
in_uint8s(s, length); /* virtualChannelData */
return 0;
case 1: /* CHANNEL_FLAG_FIRST */
free_stream(self->s);
make_stream(self->s);
init_stream(self->s, total_length);
length = (int) (s->end - s->p);
LOG_DEVEL(LOG_LEVEL_TRACE, "Received [MS-RDPBCGR] data chunk (first) "
"length %d", length);
if (length > s_rem_out(self->s))
{
LOG(LOG_LEVEL_ERROR, "[MS-RDPBCGR] Data chunk length is bigger than "
"the remaining chunk buffer size. length %d, remaining %d",
length, s_rem_out(self->s));
return 1;
}
out_uint8a(self->s, s->p, length); /* append data to chunk buffer */
in_uint8s(s, length); /* virtualChannelData */
return 0;
case 2: /* CHANNEL_FLAG_LAST */
length = (int) (s->end - s->p);
LOG_DEVEL(LOG_LEVEL_TRACE, "Received [MS-RDPBCGR] data chunk (last) "
"length %d", length);
if (length > s_rem_out(self->s))
{
LOG(LOG_LEVEL_ERROR, "[MS-RDPBCGR] Data chunk length is bigger than "
"the remaining chunk buffer size. length %d, remaining %d",
length, s_rem_out(self->s));
return 1;
}
out_uint8a(self->s, s->p, length); /* append data to chunk buffer */
in_uint8s(s, length); /* virtualChannelData */
s_mark_end(self->s);
self->s->p = self->s->data;
ls = self->s;
break;
case 3: /* CHANNEL_FLAG_FIRST and CHANNEL_FLAG_LAST */
LOG_DEVEL(LOG_LEVEL_TRACE, "Received [MS-RDPBCGR] data chunk (first and last) "
"length %d", total_length);
case E_VC_INLINE_CHUNK:
ls = s;
break;
case E_VC_IN_PROGRESS:
return 0;
break;
case E_VC_READY:
ls = vc_dechunker_get_stream(self->drdynvc_dc);
// We now own the stream, so must delete it
free_ls = 1;
break;
case E_VC_ERROR:
// Error has been logged
return 1;
default:
LOG(LOG_LEVEL_ERROR, "Received [MS-RDPBCGR] data chunk with "
"unknown flag 0x%8.8x", (int) (flags & 3));
LOG(LOG_LEVEL_ERROR, "Dechunker returned unknown error %d",
(int)dechunker_status);
return 1;
}
if (ls == NULL)
@@ -657,6 +625,10 @@ xrdp_channel_process_drdynvc(struct xrdp_channel *self,
"unknown command 0x%2.2x", cmd);
break;
}
if (free_ls)
{
free_stream(ls);
}
return rv;
}
@@ -806,6 +778,13 @@ xrdp_channel_drdynvc_start(struct xrdp_channel *self)
DRDYNVC_SVC_CHANNEL_NAME);
rv = -1;
}
else if ((self->drdynvc_dc =
vc_dechunker_init(DRDYNVC_SVC_CHANNEL_NAME,
CHANNEL_CHUNK_LENGTH)) == NULL)
{
LOG(LOG_LEVEL_ERROR, "No memory");
rv = -1;
}
else
{
self->drdynvc_channel_id = (dci->chanid - MCS_GLOBAL_CHANNEL) - 1;