in_forward: fix connection release on pause memory corruption [backport to 4.1] #11179
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This change fixes a use after free issue related to connection disposal which caused the event handler to access invalid memory when the memory limits were exceeded during ingestion. In order to overcome this issue we track the plugin instances state and delay the connection cleanup process. Signed-off-by: Leonardo Albertovich <leonardo@alminana.com.ar>
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| ctx->state = state_backup; | ||
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| if (ctx->state == FW_INSTANCE_STATE_PAUSED) { | ||
| fw_conn_del_all(ctx); | ||
| } |
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During connection accept, in_fw_collect unconditionally restores ctx->state to the prior value at exit and immediately checks that restored value to decide whether to purge connections. If in_fw_pause sets ctx->state to FW_INSTANCE_STATE_PAUSED while a client is being accepted, this restore overwrites the paused state with the old RUNNING value and the subsequent fw_conn_del_all guard never fires, so the paused transition is lost and the just-accepted connection keeps processing traffic even though ingestion was paused to relieve backpressure. The state reset here should only occur when the state was not changed externally.
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backport of #11114
(my first backport so plz let me know if Ive missed something or if I need to backport to more branches. I wasn't sure whether to do 4.1 or 4.2, or both (?)).
This change fixes a use after free issue related to connection disposal which caused the event handler to access invalid memory when the memory limits were exceeded during ingestion.
In order to overcome this issue we track the plugin instances state and delay the connection cleanup process.
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