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fuzz: fixes oss-fuzz: 8363#3905

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zuercher merged 4 commits intoenvoyproxy:masterfrom
anirudhmurali:oss-fuzz-8363
Jul 25, 2018
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fuzz: fixes oss-fuzz: 8363#3905
zuercher merged 4 commits intoenvoyproxy:masterfrom
anirudhmurali:oss-fuzz-8363

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Title: Fixes oss-fuzz: 8363

Description: oss-fuzz issue (8363): https://oss-fuzz.com/v2/testcase-detail/5988544525893632
The crash was because of passing nan to Envoy::ProtobufPercentHelper::convertPercent, it asserts since it is not in the numeric range. Instead of adding a check in this function, have added a check in the preprocessor so that it goes to checkAndReturnDefault and the default value is used.
Have also added the crashing testcase to the corpus.

Risk Level: Low

Testing: Tested unit tests (bazel test //server:server_fuzz_test), built and ran fuzzers with oss-fuzz.

Signed-off-by: Anirudh M m.anirudh18@gmail.com

Signed-off-by: Anirudh M <m.anirudh18@gmail.com>
default_value) \
((message).has_##field_name() \
((message).has_##field_name() && !std::isnan((message).field_name().value()) \
? ProtobufPercentHelper::convertPercent((message).field_name().value(), max_value) \
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I think this is fine to mitigate the issue today. The clean way to do this is to catch NaN in PGV annotations (i.e. https://github.com/envoyproxy/envoy/blob/master/api/envoy/type/percent.proto#L14, https://github.com/lyft/protoc-gen-validate/blob/master/validate/validate.proto#L98), the same way we validate the [0..100] range.

Can you file an issue for NaN validation at https://github.com/lyft/protoc-gen-validate and add a TODO comment here?

@rodaine @akonradi does this make sense to you?

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Agreed, this would be a good validation to have in PGV - it's simple, self-contained, and generally useful.

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Done both 👍

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Thanks for filing the issue. I think you need a small change of behavior here. Instead of returning the default in NaN, it should throw EnvoyException(), to allow the NaN to be reflected back to the config pipeline.

Signed-off-by: Anirudh M <m.anirudh18@gmail.com>
Signed-off-by: Anirudh M <m.anirudh18@gmail.com>
((message).has_##field_name() && !std::isnan((message).field_name().value()) \
? ProtobufPercentHelper::convertPercent((message).field_name().value(), max_value) \
((message).has_##field_name() \
? !std::isnan((message).field_name().value()) \
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I would flip the logic here to have the isnan case first.

((message).has_##field_name() \
? !std::isnan((message).field_name().value()) \
? ProtobufPercentHelper::convertPercent((message).field_name().value(), max_value) \
: throw EnvoyException(fmt::format("Value not in the range of 0..100 range.")) \
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Can you add a test? Thanks.

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Done

Signed-off-by: Anirudh M <m.anirudh18@gmail.com>
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Thanks!

@zuercher zuercher merged commit 8459237 into envoyproxy:master Jul 25, 2018
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4 participants