capi: Use home-grown strcpy for statically bounded buffer

wasmx · Mar 25, 2021 · d02dde6 · d02dde6
1 parent 53917a2
commit d02dde6
Show file tree

Hide file tree

Showing 2 changed files with 52 additions and 1 deletion.
diff --git a/lib/fizzy/capi.cpp b/lib/fizzy/capi.cpp
@@ -7,6 +7,7 @@
 #include "instantiate.hpp"
 #include "parser.hpp"
 #include <fizzy/fizzy.h>
+#include <cstring>
 #include <memory>
 
 namespace
@@ -20,12 +21,30 @@ inline void set_success(FizzyError* error) noexcept
     }
 }
 
+template <size_t DestSize>
+inline size_t strlcpy_s(char* dest, const char* src) noexcept
+{
+    static_assert(DestSize >= 3);
+
+    const auto src_len = strlen(src);
+    size_t copy_len = std::min(src_len, DestSize - 1);
+    memcpy(dest, src, copy_len);
+    if (copy_len < src_len)
+    {
+        dest[copy_len - 3] = '.';
+        dest[copy_len - 2] = '.';
+        dest[copy_len - 1] = '.';
+    }
+    dest[copy_len] = '\0';
+    return copy_len;
+}
+
 inline void set_error(FizzyErrorCode code, const char* message, FizzyError* error) noexcept
 {
     if (error != nullptr)
     {
         error->code = code;
-        snprintf(error->message, std::size(error->message), "%s", message);
+        strlcpy_s<sizeof(error->message)>(error->message, message);
     }
 }
 

diff --git a/test/unittests/capi_test.cpp b/test/unittests/capi_test.cpp
@@ -26,6 +26,38 @@ TEST(capi, validate)
     EXPECT_STREQ(error.message, "invalid wasm module prefix");
 }
 
+TEST(capi, validate_long_duplicate_export_name)
+{
+    // clang-format off
+    /* wat2wasm --no-check
+      (func (export "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in"))
+      (func (export "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in"))
+    */
+    const auto wasm = from_hex(
+        "0061736d0100000001040160000003030200000789040280024c6f72656d20697073756d20646f6c6f72207369"
+        "7420616d65742c20636f6e73656374657475722061646970697363696e6720656c69742c2073656420646f2065"
+        "6975736d6f642074656d706f7220696e6369646964756e74207574206c61626f726520657420646f6c6f726520"
+        "6d61676e6120616c697175612e20557420656e696d206164206d696e696d2076656e69616d2c2071756973206e"
+        "6f737472756420657865726369746174696f6e20756c6c616d636f206c61626f726973206e6973692075742061"
+        "6c697175697020657820656120636f6d6d6f646f20636f6e7365717561742e2044756973206175746520697275"
+        "726520646f6c6f7220696e000080024c6f72656d20697073756d20646f6c6f722073697420616d65742c20636f"
+        "6e73656374657475722061646970697363696e6720656c69742c2073656420646f20656975736d6f642074656d"
+        "706f7220696e6369646964756e74207574206c61626f726520657420646f6c6f7265206d61676e6120616c6971"
+        "75612e20557420656e696d206164206d696e696d2076656e69616d2c2071756973206e6f737472756420657865"
+        "726369746174696f6e20756c6c616d636f206c61626f726973206e69736920757420616c697175697020657820"
+        "656120636f6d6d6f646f20636f6e7365717561742e2044756973206175746520697275726520646f6c6f722069"
+        "6e00010a070202000b02000b");
+    // clang-format on
+
+    FizzyError error;
+    EXPECT_FALSE(fizzy_validate(wasm.data(), wasm.size(), &error));
+    EXPECT_EQ(error.code, FIZZY_ERROR_OTHER);
+    EXPECT_STREQ(error.message,
+        "duplicate export name Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do "
+        "eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis "
+        "nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat...");
+}
+
 TEST(capi, parse)
 {
     uint8_t wasm_prefix[]{0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00};