| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/logging.h" |
| #include "url/url_canon.h" |
| #include "url/url_canon_internal.h" |
| |
| namespace url { |
| |
| namespace { |
| |
| // For reference, here's what IE supports: |
| // Key: 0 (disallowed: failure if present in the input) |
| // + (allowed either escaped or unescaped, and unmodified) |
| // U (allowed escaped or unescaped but always unescaped if present in |
| // escaped form) |
| // E (allowed escaped or unescaped but always escaped if present in |
| // unescaped form) |
| // % (only allowed escaped in the input, will be unmodified). |
| // I left blank alpha numeric characters. |
| // |
| // 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f |
| // ----------------------------------------------- |
| // 0 0 E E E E E E E E E E E E E E E |
| // 1 E E E E E E E E E E E E E E E E |
| // 2 E + E E + E + + + + + + + U U 0 |
| // 3 % % E + E 0 <-- Those are : ; < = > ? |
| // 4 % |
| // 5 U 0 U U U <-- Those are [ \ ] ^ _ |
| // 6 E <-- That's ` |
| // 7 E E E U E <-- Those are { | } ~ (UNPRINTABLE) |
| // |
| // NOTE: I didn't actually test all the control characters. Some may be |
| // disallowed in the input, but they are all accepted escaped except for 0. |
| // I also didn't test if characters affecting HTML parsing are allowed |
| // unescaped, e.g. (") or (#), which would indicate the beginning of the path. |
| // Surprisingly, space is accepted in the input and always escaped. |
| |
| // This table lists the canonical version of all characters we allow in the |
| // input, with 0 indicating it is disallowed. We use the magic kEscapedHostChar |
| // value to indicate that this character should be escaped. We are a little more |
| // restrictive than IE, but less restrictive than Firefox. |
| // |
| // Note that we disallow the % character. We will allow it when part of an |
| // escape sequence, of course, but this disallows "%25". Even though IE allows |
| // it, allowing it would put us in a funny state. If there was an invalid |
| // escape sequence like "%zz", we'll add "%25zz" to the output and fail. |
| // Allowing percents means we'll succeed a second time, so validity would change |
| // based on how many times you run the canonicalizer. We prefer to always report |
| // the same vailidity, so reject this. |
| const unsigned char kEsc = 0xff; |
| const unsigned char kHostCharLookup[0x80] = { |
| // 00-1f: all are invalid |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| // ' ' ! " # $ % & ' ( ) * + , - . / |
| kEsc,kEsc,kEsc,kEsc,kEsc, 0, kEsc,kEsc,kEsc,kEsc,kEsc, '+',kEsc, '-', '.', 0, |
| // 0 1 2 3 4 5 6 7 8 9 : ; < = > ? |
| '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', ':', 0 ,kEsc,kEsc,kEsc, 0 , |
| // @ A B C D E F G H I J K L M N O |
| kEsc, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', |
| // P Q R S T U V W X Y Z [ \ ] ^ _ |
| 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '[', 0 , ']', 0 , '_', |
| // ` a b c d e f g h i j k l m n o |
| kEsc, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', |
| // p q r s t u v w x y z { | } ~ |
| 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',kEsc,kEsc,kEsc, 0 , 0 }; |
| |
| // RFC1034 maximum FQDN length. |
| constexpr int kMaxHostLength = 253; |
| |
| // Generous padding to account for the fact that UTS#46 normalization can cause |
| // a long string to actually shrink and fit within the 253 character RFC1034 |
| // FQDN length limit. Note that this can still be too short for pathological |
| // cases: An arbitrary number of characters (e.g. U+00AD SOFT HYPHEN) can be |
| // removed from the input by UTS#46 processing. However, this should be |
| // sufficient for all normally-encountered, non-abusive hostname strings. |
| constexpr int kMaxHostBufferLength = kMaxHostLength*5; |
| |
| const int kTempHostBufferLen = 1024; |
| typedef RawCanonOutputT<char, kTempHostBufferLen> StackBuffer; |
| typedef RawCanonOutputT<base::char16, kTempHostBufferLen> StackBufferW; |
| |
| // Scans a host name and fills in the output flags according to what we find. |
| // |has_non_ascii| will be true if there are any non-7-bit characters, and |
| // |has_escaped| will be true if there is a percent sign. |
| template<typename CHAR, typename UCHAR> |
| void ScanHostname(const CHAR* spec, |
| const Component& host, |
| bool* has_non_ascii, |
| bool* has_escaped) { |
| int end = host.end(); |
| *has_non_ascii = false; |
| *has_escaped = false; |
| for (int i = host.begin; i < end; i++) { |
| if (static_cast<UCHAR>(spec[i]) >= 0x80) |
| *has_non_ascii = true; |
| else if (spec[i] == '%') |
| *has_escaped = true; |
| } |
| } |
| |
| // Canonicalizes a host name that is entirely 8-bit characters (even though |
| // the type holding them may be 16 bits. Escaped characters will be unescaped. |
| // Non-7-bit characters (for example, UTF-8) will be passed unchanged. |
| // |
| // The |*has_non_ascii| flag will be true if there are non-7-bit characters in |
| // the output. |
| // |
| // This function is used in two situations: |
| // |
| // * When the caller knows there is no non-ASCII or percent escaped |
| // characters. This is what DoHost does. The result will be a completely |
| // canonicalized host since we know nothing weird can happen (escaped |
| // characters could be unescaped to non-7-bit, so they have to be treated |
| // with suspicion at this point). It does not use the |has_non_ascii| flag. |
| // |
| // * When the caller has an 8-bit string that may need unescaping. |
| // DoComplexHost calls us this situation to do unescaping and validation. |
| // After this, it may do other IDN operations depending on the value of the |
| // |*has_non_ascii| flag. |
| // |
| // The return value indicates if the output is a potentially valid host name. |
| template<typename INCHAR, typename OUTCHAR> |
| bool DoSimpleHost(const INCHAR* host, |
| int host_len, |
| CanonOutputT<OUTCHAR>* output, |
| bool* has_non_ascii) { |
| *has_non_ascii = false; |
| |
| bool success = true; |
| for (int i = 0; i < host_len; ++i) { |
| unsigned int source = host[i]; |
| if (source == '%') { |
| // Unescape first, if possible. |
| // Source will be used only if decode operation was successful. |
| if (!DecodeEscaped(host, &i, host_len, |
| reinterpret_cast<unsigned char*>(&source))) { |
| // Invalid escaped character. There is nothing that can make this |
| // host valid. We append an escaped percent so the URL looks reasonable |
| // and mark as failed. |
| AppendEscapedChar('%', output); |
| success = false; |
| continue; |
| } |
| } |
| |
| if (source < 0x80) { |
| // We have ASCII input, we can use our lookup table. |
| unsigned char replacement = kHostCharLookup[source]; |
| if (!replacement) { |
| // Invalid character, add it as percent-escaped and mark as failed. |
| AppendEscapedChar(source, output); |
| success = false; |
| } else if (replacement == kEsc) { |
| // This character is valid but should be escaped. |
| AppendEscapedChar(source, output); |
| } else { |
| // Common case, the given character is valid in a hostname, the lookup |
| // table tells us the canonical representation of that character (lower |
| // cased). |
| output->push_back(replacement); |
| } |
| } else { |
| // It's a non-ascii char. Just push it to the output. |
| // In case where we have char16 input, and char output it's safe to |
| // cast char16->char only if input string was converted to ASCII. |
| output->push_back(static_cast<OUTCHAR>(source)); |
| *has_non_ascii = true; |
| } |
| } |
| return success; |
| } |
| |
| // Canonicalizes a host that requires IDN conversion. Returns true on success |
| bool DoIDNHost(const base::char16* src, int src_len, CanonOutput* output) { |
| int original_output_len = output->length(); // So we can rewind below. |
| |
| // We need to escape URL before doing IDN conversion, since punicode strings |
| // cannot be escaped after they are created. |
| RawCanonOutputW<kTempHostBufferLen> url_escaped_host; |
| bool has_non_ascii; |
| DoSimpleHost(src, src_len, &url_escaped_host, &has_non_ascii); |
| if (url_escaped_host.length() > kMaxHostBufferLength) { |
| AppendInvalidNarrowString(src, 0, src_len, output); |
| return false; |
| } |
| |
| StackBufferW wide_output; |
| if (!IDNToASCII(url_escaped_host.data(), |
| url_escaped_host.length(), |
| &wide_output)) { |
| // Some error, give up. This will write some reasonable looking |
| // representation of the string to the output. |
| AppendInvalidNarrowString(src, 0, src_len, output); |
| return false; |
| } |
| |
| // Now we check the ASCII output like a normal host. It will also handle |
| // unescaping. Although we unescaped everything before this function call, if |
| // somebody does %00 as fullwidth, ICU will convert this to ASCII. |
| bool success = DoSimpleHost(wide_output.data(), |
| wide_output.length(), |
| output, &has_non_ascii); |
| if (has_non_ascii) { |
| // ICU generated something that DoSimpleHost didn't think looked like |
| // ASCII. This is quite rare, but ICU might convert some characters to |
| // percent signs which might generate new escape sequences which might in |
| // turn be invalid. An example is U+FE6A "small percent" which ICU will |
| // name prep into an ASCII percent and then we can interpret the following |
| // characters as escaped characters. |
| // |
| // If DoSimpleHost didn't think the output was ASCII, just escape the |
| // thing we gave ICU and give up. DoSimpleHost will have handled a further |
| // level of escaping from ICU for simple ASCII cases (i.e. if ICU generates |
| // a new escaped ASCII sequence like "%41" we'll unescape it) but it won't |
| // do more (like handle escaped non-ASCII sequences). Handling the escaped |
| // ASCII isn't strictly necessary, but DoSimpleHost handles this case |
| // anyway so we handle it/ |
| output->set_length(original_output_len); |
| AppendInvalidNarrowString(wide_output.data(), 0, wide_output.length(), |
| output); |
| return false; |
| } |
| return success; |
| } |
| |
| // 8-bit convert host to its ASCII version: this converts the UTF-8 input to |
| // UTF-16. The has_escaped flag should be set if the input string requires |
| // unescaping. |
| bool DoComplexHost(const char* host, int host_len, |
| bool has_non_ascii, bool has_escaped, CanonOutput* output) { |
| // Save the current position in the output. We may write stuff and rewind it |
| // below, so we need to know where to rewind to. |
| int begin_length = output->length(); |
| |
| // Points to the UTF-8 data we want to convert. This will either be the |
| // input or the unescaped version written to |*output| if necessary. |
| const char* utf8_source; |
| int utf8_source_len; |
| if (has_escaped) { |
| // Unescape before converting to UTF-16 for IDN. We write this into the |
| // output because it most likely does not require IDNization, and we can |
| // save another huge stack buffer. It will be replaced below if it requires |
| // IDN. This will also update our non-ASCII flag so we know whether the |
| // unescaped input requires IDN. |
| if (!DoSimpleHost(host, host_len, output, &has_non_ascii)) { |
| // Error with some escape sequence. We'll call the current output |
| // complete. DoSimpleHost will have written some "reasonable" output. |
| return false; |
| } |
| |
| // Unescaping may have left us with ASCII input, in which case the |
| // unescaped version we wrote to output is complete. |
| if (!has_non_ascii) { |
| return true; |
| } |
| |
| // Save the pointer into the data was just converted (it may be appended to |
| // other data in the output buffer). |
| utf8_source = &output->data()[begin_length]; |
| utf8_source_len = output->length() - begin_length; |
| } else { |
| // We don't need to unescape, use input for IDNization later. (We know the |
| // input has non-ASCII, or the simple version would have been called |
| // instead of us.) |
| utf8_source = host; |
| utf8_source_len = host_len; |
| } |
| |
| // Non-ASCII input requires IDN, convert to UTF-16 and do the IDN conversion. |
| // Above, we may have used the output to write the unescaped values to, so |
| // we have to rewind it to where we started after we convert it to UTF-16. |
| StackBufferW utf16; |
| if (!ConvertUTF8ToUTF16(utf8_source, utf8_source_len, &utf16)) { |
| // In this error case, the input may or may not be the output. |
| StackBuffer utf8; |
| for (int i = 0; i < utf8_source_len; i++) |
| utf8.push_back(utf8_source[i]); |
| output->set_length(begin_length); |
| AppendInvalidNarrowString(utf8.data(), 0, utf8.length(), output); |
| return false; |
| } |
| output->set_length(begin_length); |
| |
| // This will call DoSimpleHost which will do normal ASCII canonicalization |
| // and also check for IP addresses in the outpt. |
| return DoIDNHost(utf16.data(), utf16.length(), output); |
| } |
| |
| // UTF-16 convert host to its ASCII version. The set up is already ready for |
| // the backend, so we just pass through. The has_escaped flag should be set if |
| // the input string requires unescaping. |
| bool DoComplexHost(const base::char16* host, int host_len, |
| bool has_non_ascii, bool has_escaped, CanonOutput* output) { |
| if (has_escaped) { |
| // Yikes, we have escaped characters with wide input. The escaped |
| // characters should be interpreted as UTF-8. To solve this problem, |
| // we convert to UTF-8, unescape, then convert back to UTF-16 for IDN. |
| // |
| // We don't bother to optimize the conversion in the ASCII case (which |
| // *could* just be a copy) and use the UTF-8 path, because it should be |
| // very rare that host names have escaped characters, and it is relatively |
| // fast to do the conversion anyway. |
| StackBuffer utf8; |
| if (!ConvertUTF16ToUTF8(host, host_len, &utf8)) { |
| AppendInvalidNarrowString(host, 0, host_len, output); |
| return false; |
| } |
| |
| // Once we convert to UTF-8, we can use the 8-bit version of the complex |
| // host handling code above. |
| return DoComplexHost(utf8.data(), utf8.length(), has_non_ascii, |
| has_escaped, output); |
| } |
| |
| // No unescaping necessary, we can safely pass the input to ICU. This |
| // function will only get called if we either have escaped or non-ascii |
| // input, so it's safe to just use ICU now. Even if the input is ASCII, |
| // this function will do the right thing (just slower than we could). |
| return DoIDNHost(host, host_len, output); |
| } |
| |
| template <typename CHAR, typename UCHAR> |
| bool DoHostSubstring(const CHAR* spec, |
| const Component& host, |
| CanonOutput* output) { |
| bool has_non_ascii, has_escaped; |
| ScanHostname<CHAR, UCHAR>(spec, host, &has_non_ascii, &has_escaped); |
| |
| if (has_non_ascii || has_escaped) { |
| return DoComplexHost(&spec[host.begin], host.len, has_non_ascii, |
| has_escaped, output); |
| } |
| |
| const bool success = |
| DoSimpleHost(&spec[host.begin], host.len, output, &has_non_ascii); |
| DCHECK(!has_non_ascii); |
| return success; |
| } |
| |
| template <typename CHAR, typename UCHAR> |
| void DoHost(const CHAR* spec, |
| const Component& host, |
| CanonOutput* output, |
| CanonHostInfo* host_info) { |
| if (host.len <= 0) { |
| // Empty hosts don't need anything. |
| host_info->family = CanonHostInfo::NEUTRAL; |
| host_info->out_host = Component(); |
| return; |
| } |
| |
| // Keep track of output's initial length, so we can rewind later. |
| const int output_begin = output->length(); |
| |
| if (DoHostSubstring<CHAR, UCHAR>(spec, host, output)) { |
| // After all the other canonicalization, check if we ended up with an IP |
| // address. IP addresses are small, so writing into this temporary buffer |
| // should not cause an allocation. |
| RawCanonOutput<64> canon_ip; |
| CanonicalizeIPAddress(output->data(), |
| MakeRange(output_begin, output->length()), |
| &canon_ip, host_info); |
| |
| // If we got an IPv4/IPv6 address, copy the canonical form back to the |
| // real buffer. Otherwise, it's a hostname or broken IP, in which case |
| // we just leave it in place. |
| if (host_info->IsIPAddress()) { |
| output->set_length(output_begin); |
| output->Append(canon_ip.data(), canon_ip.length()); |
| } |
| } else { |
| // Canonicalization failed. Set BROKEN to notify the caller. |
| host_info->family = CanonHostInfo::BROKEN; |
| } |
| |
| host_info->out_host = MakeRange(output_begin, output->length()); |
| } |
| |
| } // namespace |
| |
| bool CanonicalizeHost(const char* spec, |
| const Component& host, |
| CanonOutput* output, |
| Component* out_host) { |
| CanonHostInfo host_info; |
| DoHost<char, unsigned char>(spec, host, output, &host_info); |
| *out_host = host_info.out_host; |
| return (host_info.family != CanonHostInfo::BROKEN); |
| } |
| |
| bool CanonicalizeHost(const base::char16* spec, |
| const Component& host, |
| CanonOutput* output, |
| Component* out_host) { |
| CanonHostInfo host_info; |
| DoHost<base::char16, base::char16>(spec, host, output, &host_info); |
| *out_host = host_info.out_host; |
| return (host_info.family != CanonHostInfo::BROKEN); |
| } |
| |
| void CanonicalizeHostVerbose(const char* spec, |
| const Component& host, |
| CanonOutput* output, |
| CanonHostInfo* host_info) { |
| DoHost<char, unsigned char>(spec, host, output, host_info); |
| } |
| |
| void CanonicalizeHostVerbose(const base::char16* spec, |
| const Component& host, |
| CanonOutput* output, |
| CanonHostInfo* host_info) { |
| DoHost<base::char16, base::char16>(spec, host, output, host_info); |
| } |
| |
| bool CanonicalizeHostSubstring(const char* spec, |
| const Component& host, |
| CanonOutput* output) { |
| return DoHostSubstring<char, unsigned char>(spec, host, output); |
| } |
| |
| bool CanonicalizeHostSubstring(const base::char16* spec, |
| const Component& host, |
| CanonOutput* output) { |
| return DoHostSubstring<base::char16, base::char16>(spec, host, output); |
| } |
| |
| } // namespace url |
