Date: Wed, 15 Aug 2018 10:39:47 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230640] pf_map_addr operates on unlocked src_nodes and pools Message-ID: <bug-230640-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230640 Bug ID: 230640 Summary: pf_map_addr operates on unlocked src_nodes and pools Product: Base System Version: 11.2-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: vegeta@tuxpowered.net Created attachment 196212 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=196212&action=edit Fix locking issues around pf_map_addr. I came across the following issues with pf_map_addr: - It operates on unlocked src_nodes and I've seen kernel crashes attributable to this. - For route-to targets which specify outgoing interface, interface selection happens outside of pf_map_addr and can be taken from different redirection target than was used for IP address selection. - Hash used for locking and unlocking src_node is calculated multiple times for same src_node. - Operations on rule->pool are unlocked, there even is a comment in code mentioning circumstances where it can cause kernel crash. I attached a patch addressing those issues. Please note it is early version, it compiles, it runs, I'm not sure if it is really correct. The patch does the following: - Struct pf_pool has a lock now. Round-robin algorithm in pf_map_addr locks the pool. Other algorithms don't do it, I don't think they need. Should we also have table operations check this lock? - pf_find_src_node does not manipulate src_node's state counter. It is a "find" function so why would it manipulate other stuff? Also with new location of sn->states++ removing of unused src_node in pf_create_state will work, I'm pretty sure it was broken before. - pf_insert_src_node returns locked. The lock is retained across pf_create_state and pf_map_addr. - pf_insert_src_node returns hash (row) of locked src_node. It is used later for unlocking without recalculating the hash. - Interface chosen by pf_map_addr is assigned to external variable from within this function. Struct src_node stores the interface. -- You are receiving this mail because: You are the assignee for the bug.
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