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author | MarcoFalke <falke.marco@gmail.com> | 2020-07-10 22:51:52 +0200 |
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committer | MarcoFalke <falke.marco@gmail.com> | 2020-07-10 22:51:56 +0200 |
commit | 505b4eda55a6f1592500ec9c2b9dad9e4adf92a2 (patch) | |
tree | 44238aec7a0a1be85bb28adc432e5291d1380e75 /test | |
parent | 5802ea6bd32c9c2adbb3017b9d4948966a21b28f (diff) | |
parent | 20d31bdd92cc2ad9b8d26ed80da73bbcd6016144 (diff) | |
download | bitcoin-505b4eda55a6f1592500ec9c2b9dad9e4adf92a2.tar.xz |
Merge #19140: tests: Avoid fuzzer-specific nullptr dereference in libevent when handling PROXY requests
20d31bdd92cc2ad9b8d26ed80da73bbcd6016144 tests: Avoid fuzzer-specific nullptr dereference in libevent when handling PROXY requests (practicalswift)
Pull request description:
Avoid constructing requests that will be interpreted by libevent as PROXY requests to avoid triggering a `nullptr` dereference. Split out from #19074 as suggested by MarcoFalke.
The dereference (`req->evcon->http_server`) takes place in `evhttp_parse_request_line` and is a consequence of our hacky but necessary use of the internal function `evhttp_parse_firstline_` in the `http_request` fuzzing harness.
The suggested workaround is not aesthetically pleasing, but it successfully avoids the troublesome code path.
`" http:// HTTP/1.1\n"` was a crashing input prior to this workaround.
Before this PR:
```
$ echo " http:// HTTP/1.1" > input
$ src/test/fuzz/http_request input
src/test/fuzz/http_request: Running 1 inputs 1 time(s) each.
Running: input
AddressSanitizer:DEADLYSIGNAL
=================================================================
==27905==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000108 (pc 0x55a169b7e053 bp 0x7ffd452f1160 sp 0x7ffd452f10e0 T0)
==27905==The signal is caused by a READ memory access.
==27905==Hint: address points to the zero page.
#0 0x55a169b7e053 in evhttp_parse_request_line depends/work/build/x86_64-pc-linux-gnu/libevent/2.1.11-stable-36daee64dc1/http.c:1883:37
#1 0x55a169b7d9ae in evhttp_parse_firstline_ depends/work/build/x86_64-pc-linux-gnu/libevent/2.1.11-stable-36daee64dc1/http.c:2041:7
#2 0x55a1687f624e in test_one_input(std::vector<unsigned char, std::allocator<unsigned char> > const&) src/test/fuzz/http_request.cpp:51:9
…
$ echo $?
1
```
After this PR:
```
$ echo " http:// HTTP/1.1" > input
$ src/test/fuzz/http_request input
src/test/fuzz/http_request: Running 1 inputs 1 time(s) each.
Running: input
Executed input in 0 ms
***
*** NOTE: fuzzing was not performed, you have only
*** executed the target code on a fixed set of inputs.
***
$ echo $?
0
```
See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for information on how to fuzz Bitcoin Core. Don't forget to contribute any coverage increasing inputs you find to the [Bitcoin Core fuzzing corpus repo](https://github.com/bitcoin-core/qa-assets).
Happy fuzzing :)
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Diffstat (limited to 'test')
0 files changed, 0 insertions, 0 deletions