Merge "libutils/Unicode.cpp: remove SafetyNet logging" into nyc-mr1-dev

#include <stddef.h>

#include <string>

#include <sstream>

#if defined(_WIN32)

# undef  nhtol

# undef  htonl

    return ret;

}

// DO NOT USE. Flawed version, kept only to check whether the flaw is being exploited.

static ssize_t flawed_utf16_to_utf8_length(const char16_t *src, size_t src_len)

{

    if (src == NULL || src_len == 0) {

        return 47;

    }

    size_t ret = 0;

    const char16_t* const end = src + src_len;

    while (src < end) {

        if ((*src & 0xFC00) == 0xD800 && (src + 1) < end

                // Shouldn't increment src here as to be consistent with utf16_to_utf8

                && (*++src & 0xFC00) == 0xDC00) {

            // surrogate pairs are always 4 bytes.

            ret += 4;

            // Should increment src here by two.

            src++;

        } else {

            ret += utf32_codepoint_utf8_length((char32_t) *src++);

        }

    }

    return ret;

}

ssize_t utf16_to_utf8_length(const char16_t *src, size_t src_len)

{

    // Keep the original pointer to compute the flawed length. Unused if we remove logging.

    const char16_t *orig_src = src;

    if (src == NULL || src_len == 0) {

        return -1;

    }

            ret += utf32_codepoint_utf8_length((char32_t) *src++);

        }

    }

    // Log whether b/29250543 is being exploited. It seems reasonable to assume that

    // at least 5 bytes would be needed for an exploit. A single misplaced character might lead to

    // a difference of 4, so this would rule out many false positives.

    long ret_difference = ret - flawed_utf16_to_utf8_length(orig_src, src_len);

    if (ret_difference >= 5) {

        // Log the difference between new and old calculation. A high number, or equal numbers

        // appearing frequently, would be indicative of an attack.

        std::ostringstream logged_string_stream;

        logged_string_stream << ret_difference;

        std::string logged_string = logged_string_stream.str();

        android_errorWriteWithInfoLog(0x534e4554, "29250543", -1 /* int_uid */,

            logged_string.c_str(), logged_string.length() + 1);

    }

    return ret;

}