net/{packet,tstun},wgengine/filter: fix unknown IP protocol handling #6965
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DentonGentry
approved these changes
Jan 14, 2023
net/tstun/wrap_test.go
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| {"junk_out", out, true, []byte("\x45not a valid IPv4 packet")}, | ||
| {"short_in", in, true, []byte("\x45xxx")}, | ||
| {"short_out", out, true, []byte("\x45xxx")}, | ||
| {"ip97_out", out, false, must.Get(hex.DecodeString(strings.ReplaceAll("4500 0019 d186 4000 4061 751d 644a 4603 6449 e549 6865 6c6c 6f", " ", "")))}, |
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I note that packet_test.go defined a noWS() function to do this for all unicode whitespace runes, though I don't see why it was needed there.
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made them both consistent with a new mustDecodeHex func. maybe I'll move that to some packet test helper package later.
01b90df added SCTP support before (with explicit parsing for ports) and 69de3bf tried to add support for arbitrary IP protocols (as long as the ACL permited a port of "*", since we might not know how to find ports from an arbitrary IP protocol, if it even has such a concept). But apparently that latter commit wasn't tested end-to-end enough. It had a lot of tests, but the tests made assumptions about layering that either weren't true, or regressed since 1.20. Notably, it didn't remove the (*Filter).pre bidirectional filter that dropped all "unknown" protocol packets both leaving and entering, even if there were explicit protocol matches allowing them in. Also, don't map all unknown protocols to 0. Keep their IP protocol number parsed so it's matchable by later layers. Only reject illegal things. Fixes #6423 Updates #2162 Updates #2163 Change-Id: I9659b3ece86f4db51d644f9b34df78821758842c Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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DentonGentry
approved these changes
Jan 14, 2023
andrew-d
reviewed
Jan 14, 2023
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| // mustHexDecode is like hex.DecodeString, but panics on error | ||
| // and ignores whitespcae in s. |
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| // and ignores whitespcae in s. | |
| // and ignores whitespace in s. |
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01b90df added SCTP support before (with explicit parsing for ports) and
69de3bf tried to add support for arbitrary IP protocols (as long as the ACL permited a port of "*", since we might not know how to find ports from an arbitrary IP protocol, if it even has such a concept). But apparently that latter commit wasn't tested end-to-end enough. It had a lot of tests, but the tests made assumptions about layering that either weren't true, or regressed since 1.20. Notably, it didn't remove the (*Filter).pre bidirectional filter that dropped all "unknown" protocol packets both leaving and entering, even if there were explicit protocol matches allowing them in.
Also, don't map all unknown protocols to 0. Keep their IP protocol number parsed so it's matchable by later layers. Only reject illegal things.
Fixes #6423
Updates #2162
Updates #2163