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Michal Kubecek authored
Since commit 7969e5c4 ("ip: discard IPv4 datagrams with overlapping segments.") IPv4 reassembly code drops the whole queue whenever an overlapping fragment is received. However, the test is written in a way which detects duplicate fragments as overlapping so that in environments with many duplicate packets, fragmented packets may be undeliverable. Add an extra test and for (potentially) duplicate fragment, only drop the new fragment rather than the whole queue. Only starting offset and length are checked, not the contents of the fragments as that would be too expensive. For similar reason, linear list ("run") of a rbtree node is not iterated, we only check if the new fragment is a subset of the interval covered by existing consecutive fragments. v2: instead of an exact check iterating through linear list of an rbtree node, only check if the new fragment is subset of the "run" (suggested by Eric Dumazet) Fixes: 7969e5c4 ("ip: discard IPv4 datagrams with overlapping segments.") Signed-off-by:
Michal Kubecek <mkubecek@suse.cz> Signed-off-by:
David S. Miller <davem@davemloft.net>
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