fix: prevent OOB read in C API header validation (#737)#738
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BAder82t wants to merge 1 commit intomicrosoft:mainfrom
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fix: prevent OOB read in C API header validation (#737)#738BAder82t wants to merge 1 commit intomicrosoft:mainfrom
BAder82t wants to merge 1 commit intomicrosoft:mainfrom
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Serialization_IsCompatibleVersion and Serialization_IsValidHeader set *result = false on a caller-buffer size mismatch but fall through to memcpy(sizeof(SEALHeader)). A caller passing a smaller allocation (e.g. size=1) triggers an out-of-bounds read of up to sizeof(SEALHeader) bytes across the FFI boundary, yielding information disclosure or DoS. Return S_OK immediately after flagging the mismatch so the memcpy never runs on an undersized buffer. Closes microsoft#737
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Summary
Fixes out-of-bounds read in
Serialization_IsCompatibleVersionandSerialization_IsValidHeader(native/src/seal/c/serialization.cpp).Both functions set
*result = falsewhen the caller-providedsizedoes not matchsizeof(SEALHeader), but they do not return — execution falls through tomemcpy(&header, headerptr, sizeof(SEALHeader)). A caller passing e.g.size = 1with a 1-byte allocation triggers an OOB read of up tosizeof(SEALHeader)bytes across the FFI boundary, producing information disclosure / DoS.Fix
Return
S_OKimmediately after flagging the mismatch so thememcpynever executes on an undersized buffer. Preserves the existing contract (function returnsS_OK,*result == false).Testing
SerializationTestsuite passes (sealtest --gtest_filter=*Serialization*).sealtestsuite shows no new failures attributable to this diff. One pre-existing macOS-specific ASan finding inRandomGenerator.UniformRandomGeneratorInfoSaveLoad(memset_suse-after-poison inlibsystem_c) is unrelated and reproducible on unpatchedmain.native/tests/; this change is a strict tightening of an error path.Closes
#737