| ticket:12888 UText, problems with handling of bad UTF-8 |
| |
| Fixes: |
| |
| CVE-2017-7867 - International Components for Unicode (ICU) for C/C++ before |
| 2017-02-13 has an out-of-bounds write caused by a heap-based buffer overflow |
| related to the utf8TextAccess function in common/utext.cpp and the |
| utext_setNativeIndex* function. |
| |
| CVE-2017-7868 - International Components for Unicode (ICU) for C/C++ before |
| 2017-02-13 has an out-of-bounds write caused by a heap-based buffer overflow |
| related to the utf8TextAccess function in common/utext.cpp and the |
| utext_moveIndex32* function. |
| |
| Upstream: http://bugs.icu-project.org/trac/changeset/39671 |
| |
| Signed-off-by: Peter Korsgaard <peter@korsgaard.com> |
| |
| Index: /trunk/icu4c/source/common/utext.cpp |
| =================================================================== |
| --- icu4c/source/common/utext.cpp (revision 39670) |
| +++ icu4c/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: /trunk/icu4c/source/test/intltest/utxttest.cpp |
| =================================================================== |
| --- icu4c/source/test/intltest/utxttest.cpp (revision 39670) |
| +++ icu4c/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: /trunk/icu4c/source/test/intltest/utxttest.h |
| =================================================================== |
| --- icu4c/source/test/intltest/utxttest.h (revision 39670) |
| +++ icu4c/source/test/intltest/utxttest.h (revision 39671) |
| @@ -39,4 +39,5 @@ |
| void Ticket10983(); |
| void Ticket12130(); |
| + void Ticket12888(); |
| |
| private: |