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Fix for CWE-122: Heap-based Buffer Overflow #3

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Fix for CWE-122: Heap-based Buffer Overflow #3

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14 changes: 13 additions & 1 deletion lib/libwasm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -363,10 +363,22 @@ int Wasm_ParseTypeSection(uint8_t* buffer, uint32_t buffer_size, WasmSection* se
for (int i = 0; i < count; i++)
{
entry = calloc(1, sizeof(WasmFuncType));
entry->params = calloc(10, sizeof(WasmValueType)); // WebAssembly limits functions to 10 parameters.

SAFE_READ(ReadVarInt7(ptr, &entry->form, REMAINING_SIZE()));
SAFE_READ(ReadVarUInt32(ptr, &entry->param_count, REMAINING_SIZE()));
/* Validate and allocate params according to declared param_count to prevent heap overflow */
if (entry->param_count > 10)
{
goto parse_error;
}
if (entry->param_count > 0)
{
entry->params = calloc(entry->param_count, sizeof(WasmValueType));
if (entry->params == NULL)
{
goto parse_error;
}
}

if (entry->param_count > 0)
{
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