Fix missing IS_INVALID_TAGINDEX check in RETHROW handler#4837
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sumleo wants to merge 1 commit intobytecodealliance:mainfrom
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Fix missing IS_INVALID_TAGINDEX check in RETHROW handler#4837sumleo wants to merge 1 commit intobytecodealliance:mainfrom
sumleo wants to merge 1 commit intobytecodealliance:mainfrom
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sumleo
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TianlongLiang,
lum1n0us,
no1wudi and
yamt
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The RETHROW opcode handler in the classic interpreter reads the exception_tag_index from the stack and directly uses it to index module->module->tags[] without checking IS_INVALID_TAGINDEX first. When CATCH_ALL catches a cross-module exception, it pushes INVALID_TAGINDEX (0xFFFFFFFF) onto the stack. If RETHROW then executes, it reads 0xFFFFFFFF and accesses tags[0xFFFFFFFF], causing a massive out-of-bounds read. The THROW handler at line 1744 properly checks IS_INVALID_TAGINDEX before accessing the tags array. Add the same check to the RETHROW handler: when IS_INVALID_TAGINDEX is true, skip the tags[] access and set cell_num_to_copy to 0, allowing the exception to propagate to CATCH_ALL handlers. Add unit tests verifying IS_INVALID_TAGINDEX detection and that RETHROW uses the same validation logic as THROW.
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The RETHROW opcode handler reads
exception_tag_indexfrom the stack and directly accessesmodule->module->tags[exception_tag_index]without checking forINVALID_TAGINDEX.When
CATCH_ALLcatches a cross-module exception with an unknown tag, it pushesINVALID_TAGINDEX(0xFFFFFFFF) onto the stack. If RETHROW then executes, it accessestags[0xFFFFFFFF]— a massive out-of-bounds read.The THROW handler correctly checks
IS_INVALID_TAGINDEXbefore the array access. This patch adds the same check to the RETHROW handler: when the tag index is invalid, skip thetags[]access and setcell_num_to_copyto 0, allowing the exception to propagate toCATCH_ALLhandlers.