Fix CVE-2017-7867 and CVE-2017-7868: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-7867 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-7868 Patch copied from upstream source repository: http://bugs.icu-project.org/trac/changeset/39671 Index: icu/source/common/utext.cpp =================================================================== --- icu/source/common/utext.cpp (revision 39670) +++ icu/source/common/utext.cpp (revision 39671) @@ -848,7 +848,13 @@ // Chunk size. -// Must be less than 85, because of byte mapping from UChar indexes to native indexes. -// Worst case is three native bytes to one UChar. (Supplemenaries are 4 native bytes -// to two UChars.) +// Must be less than 42 (256/6), because of byte mapping from UChar indexes to native indexes. +// Worst case there are six UTF-8 bytes per UChar. +// obsolete 6 byte form fd + 5 trails maps to fffd +// obsolete 5 byte form fc + 4 trails maps to fffd +// non-shortest 4 byte forms maps to fffd +// normal supplementaries map to a pair of utf-16, two utf8 bytes per utf-16 unit +// mapToUChars array size must allow for the worst case, 6. +// This could be brought down to 4, by treating fd and fc as pure illegal, +// rather than obsolete lead bytes. But that is not compatible with the utf-8 access macros. // enum { UTF8_TEXT_CHUNK_SIZE=32 }; @@ -890,5 +896,5 @@ // one for a supplementary starting in the last normal position, // and one for an entry for the buffer limit position. - uint8_t mapToUChars[UTF8_TEXT_CHUNK_SIZE*3+6]; // Map native offset from bufNativeStart to + uint8_t mapToUChars[UTF8_TEXT_CHUNK_SIZE*6+6]; // Map native offset from bufNativeStart to // correspoding offset in filled part of buf. int32_t align; @@ -1033,4 +1039,5 @@ u8b = (UTF8Buf *)ut->p; // the current buffer mapIndex = ix - u8b->toUCharsMapStart; + U_ASSERT(mapIndex < (int32_t)sizeof(UTF8Buf::mapToUChars)); ut->chunkOffset = u8b->mapToUChars[mapIndex] - u8b->bufStartIdx; return TRUE; @@ -1299,4 +1306,8 @@ // If index is at the end, there is no character there to look at. if (ix != ut->b) { + // Note: this function will only move the index back if it is on a trail byte + // and there is a preceding lead byte and the sequence from the lead + // through this trail could be part of a valid UTF-8 sequence + // Otherwise the index remains unchanged. U8_SET_CP_START(s8, 0, ix); } @@ -1312,5 +1323,8 @@ uint8_t *mapToNative = u8b->mapToNative; uint8_t *mapToUChars = u8b->mapToUChars; - int32_t toUCharsMapStart = ix - (UTF8_TEXT_CHUNK_SIZE*3 + 1); + int32_t toUCharsMapStart = ix - sizeof(UTF8Buf::mapToUChars) + 1; + // Note that toUCharsMapStart can be negative. Happens when the remaining + // text from current position to the beginning is less than the buffer size. + // + 1 because mapToUChars must have a slot at the end for the bufNativeLimit entry. int32_t destIx = UTF8_TEXT_CHUNK_SIZE+2; // Start in the overflow region // at end of buffer to leave room @@ -1339,4 +1353,5 @@ // Special case ASCII range for speed. buf[destIx] = (UChar)c; + U_ASSERT(toUCharsMapStart <= srcIx); mapToUChars[srcIx - toUCharsMapStart] = (uint8_t)destIx; mapToNative[destIx] = (uint8_t)(srcIx - toUCharsMapStart); @@ -1368,4 +1383,5 @@ mapToUChars[sIx-- - toUCharsMapStart] = (uint8_t)destIx; } while (sIx >= srcIx); + U_ASSERT(toUCharsMapStart <= (srcIx+1)); // Set native indexing limit to be the current position. @@ -1542,4 +1558,5 @@ U_ASSERT(index<=ut->chunkNativeLimit); int32_t mapIndex = index - u8b->toUCharsMapStart; + U_ASSERT(mapIndex < (int32_t)sizeof(UTF8Buf::mapToUChars)); int32_t offset = u8b->mapToUChars[mapIndex] - u8b->bufStartIdx; U_ASSERT(offset>=0 && offset<=ut->chunkLength); Index: icu/source/test/intltest/utxttest.cpp =================================================================== --- icu/source/test/intltest/utxttest.cpp (revision 39670) +++ icu/source/test/intltest/utxttest.cpp (revision 39671) @@ -68,4 +68,6 @@ case 7: name = "Ticket12130"; if (exec) Ticket12130(); break; + case 8: name = "Ticket12888"; + if (exec) Ticket12888(); break; default: name = ""; break; } @@ -1584,2 +1586,62 @@ utext_close(&ut); } + +// Ticket 12888: bad handling of illegal utf-8 containing many instances of the archaic, now illegal, +// six byte utf-8 forms. Original implementation had an assumption that +// there would be at most three utf-8 bytes per UTF-16 code unit. +// The five and six byte sequences map to a single replacement character. + +void UTextTest::Ticket12888() { + const char *badString = + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80" + "\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80\xfd\x80\x80\x80\x80\x80"; + + UErrorCode status = U_ZERO_ERROR; + LocalUTextPointer ut(utext_openUTF8(NULL, badString, -1, &status)); + TEST_SUCCESS(status); + for (;;) { + UChar32 c = utext_next32(ut.getAlias()); + if (c == U_SENTINEL) { + break; + } + } + int32_t endIdx = utext_getNativeIndex(ut.getAlias()); + if (endIdx != (int32_t)strlen(badString)) { + errln("%s:%d expected=%d, actual=%d", __FILE__, __LINE__, strlen(badString), endIdx); + return; + } + + for (int32_t prevIndex = endIdx; prevIndex>0;) { + UChar32 c = utext_previous32(ut.getAlias()); + int32_t currentIndex = utext_getNativeIndex(ut.getAlias()); + if (c != 0xfffd) { + errln("%s:%d (expected, actual, index) = (%d, %d, %d)\n", + __FILE__, __LINE__, 0xfffd, c, currentIndex); + break; + } + if (currentIndex != prevIndex - 6) { + errln("%s:%d: wrong index. Expected, actual = %d, %d", + __FILE__, __LINE__, prevIndex - 6, currentIndex); + break; + } + prevIndex = currentIndex; + } +} Index: icu/source/test/intltest/utxttest.h =================================================================== --- icu/source/test/intltest/utxttest.h (revision 39670) +++ icu/source/test/intltest/utxttest.h (revision 39671) @@ -39,4 +39,5 @@ void Ticket10983(); void Ticket12130(); + void Ticket12888(); private: