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CVE-2026-32623: vulns in neutrinordp fragment reassembly

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This PR addresses potential buffer overflows in fragment reassembly in
the neutrinordp shim by adding length and status checks.
This commit is contained in:
matt335672
2026-03-09 14:20:35 +00:00
parent 2dfe8bbce2
commit 3f0f7df6ff
1 changed files with 96 additions and 13 deletions
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neutrinordp/xrdp-neutrinordp.c
+88 -5
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@@ -491,7 +491,6 @@ lxrdp_event(struct mod *mod, int msg, long param1, long param2,
size = (int)param2;
data = (char *)param3;
total_size = (int)param4;
LOG_DEVEL(LOG_LEVEL_DEBUG, "lxrdp_event: client to server ,chanid= %d flags= %d", chanid, flags);
if ((chanid < 0) || (chanid >= mod->inst->settings->num_channels))
@@ -500,40 +499,124 @@ lxrdp_event(struct mod *mod, int msg, long param1, long param2,
break;
}
if (size < 0 || total_size < 0)
{
LOG(LOG_LEVEL_ERROR, "Bad WM_CHANNEL_DATA received");
g_free(mod->chan_buf);
mod->chan_buf = NULL;
mod->chan_buf_bytes = 0;
mod->chan_buf_valid = 0;
break;
}
lchid = mod->inst->settings->channels[chanid].channel_id;
switch (flags & 3)
{
case 3:
if (mod->chan_buf != NULL)
{
// This shouldn't happen. Lose the fragments we have
LOG(LOG_LEVEL_WARNING,
"WM_CHANNEL_DATA - unexpected full chunk received");
g_free(mod->chan_buf);
mod->chan_buf = NULL;
mod->chan_buf_bytes = 0;
mod->chan_buf_valid = 0;
}
if (size != total_size)
{
LOG(LOG_LEVEL_ERROR,
"WM_CHANNEL_DATA - inconsistent full chunk size");
}
else
{
mod->inst->SendChannelData(mod->inst, lchid, (tui8 *)data, total_size);
}
break;
case 2:
/* end */
if (size != (mod->chan_buf_bytes - mod->chan_buf_valid))
{
LOG(LOG_LEVEL_ERROR,
"WM_CHANNEL_DATA - bad end fragment size."
" Was %d s/b %d",
size, mod->chan_buf_bytes - mod->chan_buf_valid);
}
else
{
g_memcpy(mod->chan_buf + mod->chan_buf_valid, data, size);
mod->chan_buf_valid += size;
mod->inst->SendChannelData(mod->inst, lchid, (tui8 *)(mod->chan_buf),
total_size);
}
g_free(mod->chan_buf);
mod->chan_buf = 0;
mod->chan_buf = NULL;
mod->chan_buf_bytes = 0;
mod->chan_buf_valid = 0;
break;
case 1:
/* start */
if (mod->chan_buf != NULL)
{
// This shouldn't happen
LOG(LOG_LEVEL_WARNING,
"WM_CHANNEL_DATA - unexpected start chunk received");
}
g_free(mod->chan_buf);
mod->chan_buf = (char *)g_malloc(total_size, 0);
mod->chan_buf_bytes = total_size;
mod->chan_buf = NULL;
mod->chan_buf_bytes = 0;
mod->chan_buf_valid = 0;
g_memcpy(mod->chan_buf + mod->chan_buf_valid, data, size);
if (size > total_size)
{
LOG(LOG_LEVEL_ERROR,
"WM_CHANNEL_DATA - bad start fragment size");
}
else
{
if (total_size == 0)
{
// Nothing in the specification disallows this,
// but it seems pathological
mod->chan_buf = (char *)g_malloc(1, 0);
}
else
{
mod->chan_buf = (char *)g_malloc(total_size, 0);
}
if (mod->chan_buf == NULL)
{
LOG(LOG_LEVEL_ERROR,
"WM_CHANNEL_DATA - can't allocate %d bytes",
total_size);
}
else
{
mod->chan_buf_bytes = total_size;
g_memcpy(mod->chan_buf, data, size);
mod->chan_buf_valid += size;
}
}
break;
default:
/* middle */
if (size > (mod->chan_buf_bytes - mod->chan_buf_valid))
{
LOG(LOG_LEVEL_ERROR,
"WM_CHANNEL_DATA - oversized middle fragment");
g_free(mod->chan_buf);
mod->chan_buf = NULL;
mod->chan_buf_bytes = 0;
mod->chan_buf_valid = 0;
}
else
{
g_memcpy(mod->chan_buf + mod->chan_buf_valid, data, size);
mod->chan_buf_valid += size;
}
break;
}