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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lum1n0us
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| wasm_module_inst_t inst = wasm_runtime_instantiate( | ||
| module, 8192, 8192, error_buf, sizeof(error_buf)); | ||
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| if (inst) { |
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should have an assertion about inst.
if(inst) should be removed since else branch are not expected.
lum1n0us
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The patch looks good to me.
However, the test cases might need additional work:
- Case name: Use "exception-handling" or something similar instead of "wasm-interp."
- CMakeLists.txt: I highly suggest following an existing case, such as the one in tests/unit/interpreter.
| wasm_function_inst_t func = | ||
| wasm_runtime_lookup_function(inst, "f"); | ||
| EXPECT_NE(func, nullptr) << "Function 'f' should be found"; | ||
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should be an assertion about func.
if(func) should be removed.
| wasm_runtime_create_exec_env(inst, 8192), func, 0, NULL); | ||
| /* The function may or may not succeed depending on the | ||
| * exact exception handling implementation details */ | ||
| (void)ok; |
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better have a return value for compare.
and use wasm_runtime_get_exception to check if necessary.
Add validation for exception_tag_index in the RETHROW opcode handler to prevent out-of-bounds access to module->module->tags[] when the tag index is INVALID_TAGINDEX (0xFFFFFFFF). This matches the existing check in the THROW handler. When CATCH_ALL catches a cross-module exception with an unknown tag, it pushes INVALID_TAGINDEX onto the stack. Without this check, a subsequent RETHROW would access tags[0xFFFFFFFF].
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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.