[sqlite] Backport icuLikeCompare patch from SQLite.

third_party/sqlite/patches/0012-backport-Fix-buffer-overrun-in-ICU-extension-s-LIKE-.patch

+From 8b5285054be530e5a938231cff4018de7dbc6e0b Mon Sep 17 00:00:00 2001
+From: Scott Hess <shess@chromium.org>
+Date: Mon, 1 Feb 2016 17:07:24 -0800
+Subject: [PATCH 12/13] [backport] Fix buffer overrun in ICU extension's LIKE
+ function.
+
+Original Chromium CL at https://codereview.chromium.org/1643803003
+
+"Use safe macros for UTF-8 iteration in sqlite"
+
+SQLite interpretation: https://www.sqlite.org/src/info/424b7aee3310b978
+
+"Fix the ICU extension LIKE function so that it does not read past the
+end of a buffer if it it passed malformed utf-8."
+
+BUG=575205
+---
+ third_party/sqlite/src/ext/icu/icu.c | 64 ++++++++++++++++++++++++++----------
+ 1 file changed, 47 insertions(+), 17 deletions(-)
+
+diff --git a/third_party/sqlite/src/ext/icu/icu.c b/third_party/sqlite/src/ext/icu/icu.c
+index a2ff492..5654366 100644
+--- a/third_party/sqlite/src/ext/icu/icu.c
++++ b/third_party/sqlite/src/ext/icu/icu.c
+@@ -61,6 +61,38 @@ static void xFree(void *p){
+ }
+ 
+ /*
++** This lookup table is used to help decode the first byte of
++** a multi-byte UTF8 character. It is copied here from SQLite source
++** code file utf8.c.
++*/
++static const unsigned char icuUtf8Trans1[] = {
++  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
++  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
++  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
++  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
++  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
++  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
++  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
++  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
++};
++
++#define SQLITE_ICU_READ_UTF8(zIn, c)                       \
++  c = *(zIn++);                                            \
++  if( c>=0xc0 ){                                           \
++    c = icuUtf8Trans1[c-0xc0];                             \
++    while( (*zIn & 0xc0)==0x80 ){                          \
++      c = (c<<6) + (0x3f & *(zIn++));                      \
++    }                                                      \
++  }
++
++#define SQLITE_ICU_SKIP_UTF8(zIn)                          \
++  assert( *zIn );                                          \
++  if( *(zIn++)>=0xc0 ){                                    \
++    while( (*zIn & 0xc0)==0x80 ){zIn++;}                   \
++  }
++
++
++/*
+ ** Compare two UTF-8 strings for equality where the first string is
+ ** a "LIKE" expression. Return true (1) if they are the same and 
+ ** false (0) if they are different.
+@@ -73,16 +105,14 @@ static int icuLikeCompare(
+   static const int MATCH_ONE = (UChar32)'_';
+   static const int MATCH_ALL = (UChar32)'%';
+ 
+-  int iPattern = 0;       /* Current byte index in zPattern */
+-  int iString = 0;        /* Current byte index in zString */
+-
+   int prevEscape = 0;     /* True if the previous character was uEsc */
+ 
+-  while( zPattern[iPattern]!=0 ){
++  while( 1 ){
+ 
+     /* Read (and consume) the next character from the input pattern. */
+     UChar32 uPattern;
+-    U8_NEXT_UNSAFE(zPattern, iPattern, uPattern);
++    SQLITE_ICU_READ_UTF8(zPattern, uPattern);
++    if( uPattern==0 ) break;
+ 
+     /* There are now 4 possibilities:
+     **
+@@ -99,28 +129,28 @@ static int icuLikeCompare(
+       ** MATCH_ALL. For each MATCH_ONE, skip one character in the 
+       ** test string.
+       */
+-      while( (c=zPattern[iPattern]) == MATCH_ALL || c == MATCH_ONE ){
++      while( (c=*zPattern) == MATCH_ALL || c == MATCH_ONE ){
+         if( c==MATCH_ONE ){
+-          if( zString[iString]==0 ) return 0;
+-          U8_FWD_1_UNSAFE(zString, iString);
++          if( *zString==0 ) return 0;
++          SQLITE_ICU_SKIP_UTF8(zString);
+         }
+-        iPattern++;
++        zPattern++;
+       }
+ 
+-      if( zPattern[iPattern]==0 ) return 1;
++      if( *zPattern==0 ) return 1;
+ 
+-      while( zString[iString] ){
+-        if( icuLikeCompare(&zPattern[iPattern], &zString[iString], uEsc) ){
++      while( *zString ){
++        if( icuLikeCompare(zPattern, zString, uEsc) ){
+           return 1;
+         }
+-        U8_FWD_1_UNSAFE(zString, iString);
++        SQLITE_ICU_SKIP_UTF8(zString);
+       }
+       return 0;
+ 
+     }else if( !prevEscape && uPattern==MATCH_ONE ){
+       /* Case 2. */
+-      if( zString[iString]==0 ) return 0;
+-      U8_FWD_1_UNSAFE(zString, iString);
++      if( *zString==0 ) return 0;
++      SQLITE_ICU_SKIP_UTF8(zString);
+ 
+     }else if( !prevEscape && uPattern==uEsc){
+       /* Case 3. */
+@@ -129,7 +159,7 @@ static int icuLikeCompare(
+     }else{
+       /* Case 4. */
+       UChar32 uString;
+-      U8_NEXT_UNSAFE(zString, iString, uString);
++      SQLITE_ICU_READ_UTF8(zString, uString);
+       uString = u_foldCase(uString, U_FOLD_CASE_DEFAULT);
+       uPattern = u_foldCase(uPattern, U_FOLD_CASE_DEFAULT);
+       if( uString!=uPattern ){
+@@ -139,7 +169,7 @@ static int icuLikeCompare(
+     }
+   }
+ 
+-  return zString[iString]==0;
++  return *zString==0;
+ }
+ 
+ /*
+-- 
+2.7.0
+