[Buildroot] [PATCH] icu: add upstream security fix for utf-8 handling

[Peter Korsgaard <peter@korsgaard.com>]

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>
---
 ...-utext-problems-with-handling-of-bad-utf8.patch | 173 +++++++++++++++++++++
 1 file changed, 173 insertions(+)
 create mode 100644 package/icu/0006-utext-problems-with-handling-of-bad-utf8.patch

diff --git a/package/icu/0006-utext-problems-with-handling-of-bad-utf8.patch b/package/icu/0006-utext-problems-with-handling-of-bad-utf8.patch
new file mode 100644
index 000000000..a4e51aef0
--- /dev/null
+++ b/package/icu/0006-utext-problems-with-handling-of-bad-utf8.patch
@@ -0,0 +1,173 @@
+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:
-- 
2.11.0