Hi,
I decided to take a quick look at PR25300 (roughly, an '*' at the end
of an environment variable crashes lldb-server). The issue is that
during packet decompression (apparently even for uncompressed packets)
there is basic RLE, triggered by '*', so it needs to be quoted in some
way before being sent.
I came up with patches doing it in two different places (both attached here):
1. Switch to QEnvironmentHexEncoded if the string has these chars.
2. Safely escape these chars in SendPackedNoLock.
The second seems more robust and semantically correct (viewing only
'$' and '#' as characters that are actually special in a non
transport-dependent way). But it does have a performance overhead for
each packet sent (a likely not very optimised extra strcpy).
Which would be preferred, and does anyone have any hints on writing a
test for it? I can't see any existing QEnvironment tests to base mine
on.
Cheers.
Tim.
diff --git a/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
b/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index ea95298..9392af7 100644
--- a/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -238,12 +238,29 @@ GDBRemoteCommunication::SendPacketNoLock (const char
*payload, size_t payload_le
{
if (IsConnected())
{
- StreamString packet(0, 4, eByteOrderBig);
+ std::string safe_payload;
+ safe_payload.reserve(payload_length);
+ for (const char *c = payload; c != payload + payload_length; ++c)
+ {
+ if (*c == '*' || *c == '}')
+ {
+ // These have special meaning even for nominally uncompressed
+ // strings, so we must escape them. Fortunately, the special
+ // meaning of '}' is precisely an escape of the next char (^
+ // 0x20).
+ safe_payload.push_back('}');
+ safe_payload.push_back(*c ^ 0x20);
+ }
+ else
+ safe_payload.push_back(*c);
+ }
+ payload_length = safe_payload.size();
+ StreamString packet(0, 4, eByteOrderBig);
packet.PutChar('$');
- packet.Write (payload, payload_length);
+ packet.Write (safe_payload.data(), payload_length);
packet.PutChar('#');
- packet.PutHex8(CalculcateChecksum (payload, payload_length));
+ packet.PutHex8(CalculcateChecksum (safe_payload.data(),
payload_length));
Log *log (ProcessGDBRemoteLog::GetLogIfAllCategoriesSet
(GDBR_LOG_PACKETS));
ConnectionStatus status = eConnectionStatusSuccess;
diff --git a/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
b/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index a6fcd14..5e0964b 100644
--- a/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1577,6 +1577,8 @@ GDBRemoteCommunicationClient::SendEnvironmentPacket (char
const *name_equal_valu
{
case '$':
case '#':
+ case '*':
+ case '}':
send_hex_encoding = true;
break;
default:
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