netstat: add cycle detection to Next pointer walk#1997
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The enumerate_structures_by_port method walks a singly-linked list of TCP_LISTENER/UDP_ENDPOINT objects via the Next field without checking for cycles. A memory dump with a self-referential Next pointer causes an infinite loop. Add a seen_addresses set to detect and break cycles, consistent with cycle detection in LIST_ENTRY.to_list, pidhashtable._walk_upid, and pagecache._walk_dentry.
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Summary
The
enumerate_structures_by_portmethod walks a singly-linked list of network objects via theNextfield without checking for cycles. A memory dump containing a self-referentialNextpointer causes the plugin to loop indefinitely.This adds a
seen_addressesset to detect and break cycles, consistent with existing cycle detection patterns in the codebase:LIST_ENTRY.to_list()uses aseensetpidhashtable._walk_upid()usesseen_upidspagecache._walk_dentry()usesseen_dentriesChange
One file, +9 lines. A
seen_addressesset tracks visited pointer values. If a previously seen address is encountered, the walk logs a warning and stops.