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strings: fix data corruption in Base64Escape due to aliasing #2017

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strings: fix data corruption in Base64Escape due to aliasing #2017

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9 changes: 3 additions & 6 deletions absl/strings/escaping.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -954,17 +954,14 @@ bool WebSafeBase64Unescape(absl::string_view src,
return Base64UnescapeInternal(src.data(), src.size(), dest, kUnWebSafeBase64);
}


void Base64Escape(absl::string_view src, std::string* absl_nonnull dest) {
strings_internal::Base64EscapeInternal(
reinterpret_cast<const unsigned char*>(src.data()), src.size(), dest,
true, strings_internal::kBase64Chars);
*dest = Base64Escape(src);
}

void WebSafeBase64Escape(absl::string_view src,
std::string* absl_nonnull dest) {
strings_internal::Base64EscapeInternal(
reinterpret_cast<const unsigned char*>(src.data()), src.size(), dest,
false, strings_internal::kWebSafeBase64Chars);
*dest = WebSafeBase64Escape(src);
}

std::string Base64Escape(absl::string_view src) {
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8 changes: 8 additions & 0 deletions absl/strings/escaping_test.cc
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Expand Up @@ -762,4 +762,12 @@ TEST(HexAndBack, HexStringToBytes_and_BytesToHexString) {
EXPECT_EQ(hex_only_lower, hex_result);
}

TEST(Base64Escape, AliasingSafety){
std::string s = "Abseil";
absl::Base64Escape(s, &s);
// would corrupt or crash before fix
// after fix: s should be "QWJzZWls"
EXPECT_EQ(s, "QWJzZWls");
}

} // namespace