src: fix edge case when deflateInit2() fails with Z_VERSION_ERROR#63476
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ndossche wants to merge 1 commit into
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src: fix edge case when deflateInit2() fails with Z_VERSION_ERROR#63476ndossche wants to merge 1 commit into
ndossche wants to merge 1 commit into
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addaleax
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May 21, 2026
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| CompressionError ZlibContext::ErrorForMessage(const char* message) const { | ||
| if (strm_.msg != nullptr) | ||
| if (zlib_init_done_ && strm_.msg != nullptr) |
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That means that no error from InitZlib() would be reported, which doesn't seem particularly desirable.
Can we instead pre-initialize strm_.msg = nullptr; to avoid this issue?
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That works too. Did that now. Thanks.
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #63476 +/- ##
=======================================
Coverage 90.07% 90.07%
=======================================
Files 714 714
Lines 225935 225953 +18
Branches 42738 42739 +1
=======================================
+ Hits 203503 203529 +26
+ Misses 14206 14204 -2
+ Partials 8226 8220 -6
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This function call can fail with `Z_VERSION_ERROR` if the compiled
library vs loaded library mismatched in version number or in
stream structure size.
In those cases, zlib doesn't initialize the `strm_.msg` field to
null. Therefore, when a `CompressionError` object is created via
`ErrorForMessage()`, it can read a stale or uninitialized `strm_.msg`
pointer that will cause a crash.
Example ASAN report:
```
AddressSanitizer: SEGV on unknown address
#0 __strlen_avx2
string/../sysdeps/x86_64/multiarch/strlen-avx2.S:76
nodejs#1 strlen (/work/node/out/Debug/node+0x1a42ab7)
nodejs#2 v8::(anonymous namespace)::StringLength(char const*)
/work/node/out/../deps/v8/src/api/api.cc:7581:16
nodejs#3 v8::(anonymous namespace)::StringLength(unsigned char const*)
/work/node/out/../deps/v8/src/api/api.cc:7587:10
nodejs#4 v8::String::NewFromOneByte(v8::Isolate*,
unsigned char const*, v8::NewStringType, int)
/work/node/out/../deps/v8/src/api/api.cc:7677:3
nodejs#5 node::OneByteString(v8::Isolate*,
char const*, int, v8::NewStringType)
/work/node/out/../src/util-inl.h:166:10
nodejs#6 node::(anonymous namespace)::CompressionStream<
node::(anonymous namespace)::ZlibContext>
::EmitError(node::(anonymous namespace)
::CompressionError const&)
/work/node/out/../src/node_zlib.cc:565:7
nodejs#7 node::(anonymous namespace)::CompressionStream<
node::(anonymous namespace)::ZlibContext>
::CheckError()
/work/node/out/../src/node_zlib.cc:519:5
nodejs#8 node::(anonymous namespace)::CompressionStream<
node::(anonymous namespace)::ZlibContext>
::AfterThreadPoolWork(int)
/work/node/out/../src/node_zlib.cc:543:10
nodejs#9 node::ThreadPoolWork::ScheduleWork()
::'lambda'(uv_work_s*, int)
::operator()(uv_work_s*, int) const
/work/node/out/../src/threadpoolwork-inl.h:57:15
nodejs#10 node::ThreadPoolWork::ScheduleWork()
::'lambda'(uv_work_s*, int)
::__invoke(uv_work_s*, int)
/work/node/out/../src/threadpoolwork-inl.h:48:7
nodejs#11 uv__work_done /work/libuv-1.51.0/src/threadpool.c:330:5
nodejs#12 uv__async_io.part.0
/work/libuv-1.51.0/src/unix/async.c:208:5
```
Signed-off-by: ndossche <nora.dossche@ugent.be>
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deflateInit2()can fail withZ_VERSION_ERRORif the compiled library vs loaded library mismatched in version number or in stream structure size.In those cases, zlib doesn't initialize the
strm_.msgfield to null. Therefore, when aCompressionErrorobject is created viaErrorForMessage(), it can read a stale or uninitializedstrm_.msgpointer that will cause a crash.Example ASAN report: