https://bugs.kde.org/show_bug.cgi?id=446963
Bug ID: 446963
Summary: KDEconnect v1.18 on Android12: TCP connection to
server port 1716 violates TCP rules for segment size
and termination sequence
Product: kdeconnect
Version: unspecified
Platform: Android
OS: Android 11.x
Status: REPORTED
Severity: normal
Priority: NOR
Component: android-application
Assignee: albertv...@gmail.com
Reporter: riegle...@a1.net
Target Milestone: ---
SUMMARY
***
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See
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***
STEPS TO REPRODUCE
1. start a fresh wireshark measurement on LAN where the TCPconnection flows.
2. control on Ubuntu20.04LTS platform with GSconnect. turn on server process
for TCPport 1716
3. monitor the wireshark measurement and wait for the idle "TCP keep-alive",
now turn off the server process TCPport 1716
OBSERVED RESULT
there is a direct UDP datagram from server to client with the UDPsize bug
446238 already reported for UDP broadcast.
(this accounts to the Ubuntu side, GSconnect)
next is a TCPconnection started from Android12 KDEconnect_v1.18, both sides
report in the SYN segment TCP MSS=1460
next is a TCP violation sending a TCP payload of 1860 bytes. the data pattern
seems to be the same as in UDP broadcast
reported in bug 446238. this is a size bug in TCP knowing the MSS=1460 value.
next is setup off TLS payload.
turning off the server process on Ubuntu GSconnect results in following TCP
activity on this TCP connection.
TLS closes connection (Ubuntu sends an TLS Alert)
TCP closes connection with FIN,ACK flags (sender is Ubuntu)
Android12 KDEconnect sends just an ACK back.
here is the second TCP bug.
Android12 KDEconnect should send
a) "graceful TCP termination" with FIN,ACK
or at least
b) rough TCP RESET for the TCPconnection.
the Ubuntu side TCP state machine is stuck in TCPstate FIN_WAIT_2
EXPECTED RESULT
SOFTWARE/OS VERSIONS
Windows:
macOS:
Linux/KDE Plasma:
(available in About System)
KDE Plasma Version:
KDE Frameworks Version:
Qt Version:
ADDITIONAL INFORMATION
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