dhserver: Fix a potential DoS vulnerability accidentially introduced by #1712 #1885
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hathach
approved these changes
Feb 13, 2023
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Describe the PR
My fix in dhcpserver.c for some DHCP clients (#1712) accidentally introduced a potential DoS vulnerability (I'm sorry!): In case a DHCP-packet WITHOUT
DHCP_MESSAGETYPEwas received, the code jumped out of the function without freeing the pbuf as it is required. When enough such messages are received, not pbufs are available anymore to handle traffic and the system might not be able to receive any more packets.This PR fixes the problem by properly free()ing the pbuf in case no
DHCP_MESSAGETYPEis detected in the packet.Plus a trivial whitespace fix.