Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix zip bomb exploit for decompressing file fragments #1063

Closed
wants to merge 1 commit into from
Closed

Fix zip bomb exploit for decompressing file fragments #1063

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
79 changes: 74 additions & 5 deletions rehlds/engine/net_chan.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1596,8 +1596,31 @@ qboolean Netchan_CopyFileFragments(netchan_t *chan)

Q_strncpy(compressor, MSG_ReadString(), sizeof(compressor) - 1);
compressor[sizeof(compressor) - 1] = 0;

qboolean success = TRUE;

if (!Q_stricmp(compressor, "bz2"))
{

#ifdef REHLDS_FIXES
if (!sv_net_incoming_decompression.value)
{
if (chan->player_slot == 0)
{
Con_DPrintf("Incoming compressed data disallowed from\n");
return FALSE;
}
// compressed data is expected only after requesting resource list
else if (host_client->m_sendrescount == 0)
{
Con_DPrintf("%s:Incoming compressed data disallowed from %s\n", NET_AdrToString(chan->remote_address), host_client->name);
return FALSE;
}
}
#endif

bCompressed = TRUE;
}

uncompressedSize = (unsigned int)MSG_ReadLong();

Expand Down Expand Up @@ -1702,11 +1725,57 @@ qboolean Netchan_CopyFileFragments(netchan_t *chan)
if (bCompressed)
{
unsigned char* uncompressedBuffer = (unsigned char*)Mem_Malloc(uncompressedSize);
Con_DPrintf("Decompressing file %s (%d -> %d)\n", filename, nsize, uncompressedSize);
BZ2_bzBuffToBuffDecompress((char*)uncompressedBuffer, &uncompressedSize, (char*)buffer, nsize, 1, 0);
Mem_Free(buffer);
pos = uncompressedSize;
buffer = uncompressedBuffer;

if (success && (BZ2_bzBuffToBuffDecompress((char*)uncompressedBuffer, &uncompressedSize, (char*)buffer, nsize, 1, 0) == BZ_OK))
{
Con_DPrintf("Decompressing file %s (%d -> %d)\n", filename, nsize, uncompressedSize);
#ifdef REHLDS_FIXES
// Check for an abnormal size ratio between compressed and uncompressed data
if (sv_net_incoming_decompression_max_ratio.value > 0 && nsize < uncompressedSize)
{
float ratio = ((float)(uncompressedSize - nsize) / uncompressedSize) * 100.0f;
if (ratio >= sv_net_incoming_decompression_max_ratio.value)
{
if (chan->player_slot == 0)
Con_DPrintf("Incoming abnormal uncompressed size with ratio %.2f\n", ratio);
else
Con_DPrintf("%s:Incoming abnormal uncompressed size with ratio %.2f from %s\n", NET_AdrToString(chan->remote_address), ratio, host_client->name);

success = FALSE;
}
}
#endif

Mem_Free(buffer);
pos = uncompressedSize;
buffer = uncompressedBuffer;
}
else
{
// malformed data or compressed data exceeding sv_net_incoming_decompression_max_size
success = FALSE;
}

// Drop client if decompression was unsuccessful
if (!success)
{
if ((chan->player_slot - 1) == host_client - g_psvs.clients)
{
#ifdef REHLDS_FIXES
if (sv_net_incoming_decompression_punish.value >= 0)
{
Con_DPrintf("%s:Banned for malformed/abnormal bzip2 fragments from %s\n", NET_AdrToString(chan->remote_address), host_client->name);
Cbuf_AddText(va("addip %.1f %s\n", sv_net_incoming_decompression_punish.value, NET_BaseAdrToString(chan->remote_address)));
}
#endif

SV_DropClient(host_client, FALSE, "Malformed/abnormal compressed data");
}

Netchan_FlushIncoming(chan, FRAG_FILE_STREAM);
}

return success;
}

if (filename[0] == '!')
Expand Down
Loading