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Fix: Prevent write on un-connected socket #26

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Merged
X-Ryl669 merged 2 commits into from
Aug 1, 2025
Merged

Fix: Prevent write on un-connected socket #26

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ac13628
fix: check for socket errors after connecting to prevent writes on no…
Odysseus1710 Aug 1, 2025
2421227
chore: use explicit return value for socket error
Odysseus1710 Aug 1, 2025
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28 changes: 16 additions & 12 deletions lib/src/Network/Clients/MQTTClient.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1229,19 +1229,23 @@ namespace Network { namespace Client {
if (ret == 0) return 0;

// Here, we need to wait until connection happens or times out
if (select(false, true))
{
// Restore blocking behavior here
if (::fcntl(socket, F_SETFL, socketFlags) != 0) return -3;
// And set timeouts for both recv and send
if (::setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, &timeoutMs, sizeof(timeoutMs)) < 0) return -4;
if (::setsockopt(socket, SOL_SOCKET, SO_SNDTIMEO, &timeoutMs, sizeof(timeoutMs)) < 0) return -4;
// Ok, done!
return 0;
}

return -7;
if (select(false, true) <= 0) return -7;

// Check for any socket errors
int err;
socklen_t len = sizeof(err);
getsockopt(socket, SOL_SOCKET, SO_ERROR, &err, &len);
if (err != 0) return -8;

// Restore blocking behavior here
if (::fcntl(socket, F_SETFL, socketFlags) != 0) return -3;
// And set timeouts for both recv and send
if (::setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, &timeoutMs, sizeof(timeoutMs)) < 0) return -4;
if (::setsockopt(socket, SOL_SOCKET, SO_SNDTIMEO, &timeoutMs, sizeof(timeoutMs)) < 0) return -4;
// Ok, done!
return 0;
}

MQTTVirtual int recv(char * buffer, const uint32 minLength, const uint32 maxLength = 0)
{
int ret = ::recv(socket, buffer, minLength, MSG_WAITALL);
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