ccl: add integer overflow checks

* ccl.c (CCL_CODE_MAX, GET_CCL_RANGE, GET_CCL_CODE, GET_CCL_INT):
(IN_INT_RANGE): New macros.
(ccl_driver): Use them to check for integer overflow when
decoding a CCL program.  Many of the new checks are whether XINT (x)
fits in int; it doesn't always, on 64-bit hosts.  The new version
doesn't catch all possible integer overflows, but it's an
improvement.

2 files changed, 140 insertions, 100 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index f6a6c21c25c..29595113f1b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,14 @@
 2011-05-23  Paul Eggert  <eggert@cs.ucla.edu>
 
+        ccl: add integer overflow checks
+        * ccl.c (CCL_CODE_MAX, GET_CCL_RANGE, GET_CCL_CODE, GET_CCL_INT):
+        (IN_INT_RANGE): New macros.
+        (ccl_driver): Use them to check for integer overflow when
+        decoding a CCL program.  Many of the new checks are whether XINT (x)
+        fits in int; it doesn't always, on 64-bit hosts.  The new version
+        doesn't catch all possible integer overflows, but it's an
+        improvement.
+
         * alloc.c (make_event_array): Use XINT, not XUINT.
         There's no need for unsigned here.
 
diff --git a/src/ccl.c b/src/ccl.c
index 83afd7bc800..d66a61b713d 100644
--- a/src/ccl.c
+++ b/src/ccl.c
@@ -98,6 +98,8 @@ static Lisp_Object Vccl_program_table;
    and `rrr' are CCL register number, `XXXXX' is one of the following
    CCL commands.  */
 
+#define CCL_CODE_MAX ((1 << (28 - 1)) - 1)
+
 /* CCL commands
 
    Each comment fields shows one or more lines for command syntax and
@@ -742,6 +744,24 @@ while(0)
 
 #endif
 
+#define GET_CCL_RANGE(var, ccl_prog, ic, lo, hi)                \
+  do                                                            \
+    {                                                           \
+      EMACS_INT prog_word = XINT ((ccl_prog)[ic]);              \
+      if (! ((lo) <= prog_word && prog_word <= (hi)))           \
+        CCL_INVALID_CMD;                                        \
+      (var) = prog_word;                                        \
+    }                                                           \
+  while (0)
+
+#define GET_CCL_CODE(code, ccl_prog, ic)                        \
+  GET_CCL_RANGE (code, ccl_prog, ic, 0, CCL_CODE_MAX)
+
+#define GET_CCL_INT(var, ccl_prog, ic)                          \
+  GET_CCL_RANGE (var, ccl_prog, ic, INT_MIN, INT_MAX)
+
+#define IN_INT_RANGE(val) (INT_MIN <= (val) && (val) <= INT_MAX)
+
 /* Encode one character CH to multibyte form and write to the current
    output buffer.  If CH is less than 256, CH is written as is.  */
 #define CCL_WRITE_CHAR(ch)                      \
@@ -899,7 +919,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
         }
 
       this_ic = ic;
-      code = XINT (ccl_prog[ic]); ic++;
+      GET_CCL_CODE (code, ccl_prog, ic++);
       field1 = code >> 8;
       field2 = (code & 0xFF) >> 5;
 
@@ -920,15 +940,14 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           break;
 
         case CCL_SetConst:      /* 00000000000000000000rrrXXXXX */
-          reg[rrr] = XINT (ccl_prog[ic]);
-          ic++;
+          GET_CCL_INT (reg[rrr], ccl_prog, ic++);
           break;
 
         case CCL_SetArray:      /* CCCCCCCCCCCCCCCCCCCCRRRrrrXXXXX */
           i = reg[RRR];
           j = field1 >> 3;
           if ((unsigned int) i < j)
-            reg[rrr] = XINT (ccl_prog[ic + i]);
+            GET_CCL_INT (reg[rrr], ccl_prog, ic + i);
           ic += j;
           break;
 
@@ -956,13 +975,13 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           break;
 
         case CCL_WriteConstJump: /* A--D--D--R--E--S--S-000XXXXX */
-          i = XINT (ccl_prog[ic]);
+          GET_CCL_INT (i, ccl_prog, ic);
           CCL_WRITE_CHAR (i);
           ic += ADDR;
           break;
 
         case CCL_WriteConstReadJump: /* A--D--D--R--E--S--S-rrrXXXXX */
-          i = XINT (ccl_prog[ic]);
+          GET_CCL_INT (i, ccl_prog, ic);
           CCL_WRITE_CHAR (i);
           ic++;
           CCL_READ_CHAR (reg[rrr]);
@@ -970,18 +989,17 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           break;
 
         case CCL_WriteStringJump: /* A--D--D--R--E--S--S-000XXXXX */
-          j = XINT (ccl_prog[ic]);
-          ic++;
+          GET_CCL_INT (j, ccl_prog, ic++);
           CCL_WRITE_STRING (j);
           ic += ADDR - 1;
           break;
 
         case CCL_WriteArrayReadJump: /* A--D--D--R--E--S--S-rrrXXXXX */
           i = reg[rrr];
-          j = XINT (ccl_prog[ic]);
+          GET_CCL_INT (j, ccl_prog, ic);
           if ((unsigned int) i < j)
             {
-              i = XINT (ccl_prog[ic + 1 + i]);
+              GET_CCL_INT (i, ccl_prog, ic + 1 + i);
               CCL_WRITE_CHAR (i);
             }
           ic += j + 2;
@@ -998,10 +1016,14 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           CCL_READ_CHAR (reg[rrr]);
           /* fall through ... */
         case CCL_Branch:        /* CCCCCCCCCCCCCCCCCCCCrrrXXXXX */
-          if ((unsigned int) reg[rrr] < field1)
-            ic += XINT (ccl_prog[ic + reg[rrr]]);
-          else
-            ic += XINT (ccl_prog[ic + field1]);
+        {
+          int incr;
+          GET_CCL_INT (incr, ccl_prog,
+                       ic + ((unsigned int) reg[rrr] < field1
+                             ? reg[rrr]
+                             : field1));
+          ic += incr;
+        }
           break;
 
         case CCL_ReadRegister:  /* CCCCCCCCCCCCCCCCCCCCrrXXXXX */
@@ -1009,7 +1031,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
             {
               CCL_READ_CHAR (reg[rrr]);
               if (!field1) break;
-              code = XINT (ccl_prog[ic]); ic++;
+              GET_CCL_CODE (code, ccl_prog, ic++);
               field1 = code >> 8;
               field2 = (code & 0xFF) >> 5;
             }
@@ -1018,7 +1040,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
         case CCL_WriteExprConst:  /* 1:00000OPERATION000RRR000XXXXX */
           rrr = 7;
           i = reg[RRR];
-          j = XINT (ccl_prog[ic]);
+          GET_CCL_INT (j, ccl_prog, ic);
           op = field1 >> 6;
           jump_address = ic + 1;
           goto ccl_set_expr;
@@ -1029,7 +1051,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
               i = reg[rrr];
               CCL_WRITE_CHAR (i);
               if (!field1) break;
-              code = XINT (ccl_prog[ic]); ic++;
+              GET_CCL_CODE (code, ccl_prog, ic++);
               field1 = code >> 8;
               field2 = (code & 0xFF) >> 5;
             }
@@ -1051,10 +1073,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
             /* If FFF is nonzero, the CCL program ID is in the
                following code.  */
             if (rrr)
-              {
-                prog_id = XINT (ccl_prog[ic]);
-                ic++;
-              }
+              GET_CCL_INT (prog_id, ccl_prog, ic++);
             else
               prog_id = field1;
 
@@ -1097,7 +1116,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           i = reg[rrr];
           if ((unsigned int) i < field1)
             {
-              j = XINT (ccl_prog[ic + i]);
+              GET_CCL_INT (j, ccl_prog, ic + i);
               CCL_WRITE_CHAR (j);
             }
           ic += field1;
@@ -1122,8 +1141,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           CCL_SUCCESS;
 
         case CCL_ExprSelfConst: /* 00000OPERATION000000rrrXXXXX */
-          i = XINT (ccl_prog[ic]);
-          ic++;
+          GET_CCL_INT (i, ccl_prog, ic++);
           op = field1 >> 6;
           goto ccl_expr_self;
 
@@ -1159,9 +1177,9 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
 
         case CCL_SetExprConst:  /* 00000OPERATION000RRRrrrXXXXX */
           i = reg[RRR];
-          j = XINT (ccl_prog[ic]);
+          GET_CCL_INT (j, ccl_prog, ic++);
           op = field1 >> 6;
-          jump_address = ++ic;
+          jump_address = ic;
           goto ccl_set_expr;
 
         case CCL_SetExprReg:    /* 00000OPERATIONRrrRRRrrrXXXXX */
@@ -1175,10 +1193,9 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           CCL_READ_CHAR (reg[rrr]);
         case CCL_JumpCondExprConst: /* A--D--D--R--E--S--S-rrrXXXXX */
           i = reg[rrr];
-          op = XINT (ccl_prog[ic]);
-          jump_address = ic++ + ADDR;
-          j = XINT (ccl_prog[ic]);
-          ic++;
+          jump_address = ic + ADDR;
+          GET_CCL_INT (op, ccl_prog, ic++);
+          GET_CCL_INT (j, ccl_prog, ic++);
           rrr = 7;
           goto ccl_set_expr;
 
@@ -1186,10 +1203,10 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
           CCL_READ_CHAR (reg[rrr]);
         case CCL_JumpCondExprReg:
           i = reg[rrr];
-          op = XINT (ccl_prog[ic]);
-          jump_address = ic++ + ADDR;
-          j = reg[XINT (ccl_prog[ic])];
-          ic++;
+          jump_address = ic + ADDR;
+          GET_CCL_INT (op, ccl_prog, ic++);
+          GET_CCL_RANGE (j, ccl_prog, ic++, 0, 7);
+          j = reg[j];
           rrr = 7;
 
         ccl_set_expr:
@@ -1267,18 +1284,27 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
               break;
 
             case CCL_TranslateCharacterConstTbl:
-              op = XINT (ccl_prog[ic]); /* table */
-              ic++;
-              i = CCL_DECODE_CHAR (reg[RRR], reg[rrr]);
-              op = translate_char (GET_TRANSLATION_TABLE (op), i);
-              CCL_ENCODE_CHAR (op, charset_list, reg[RRR], reg[rrr]);
+              {
+                EMACS_INT eop;
+                GET_CCL_RANGE (eop, ccl_prog, ic++, 0,
+                               (VECTORP (Vtranslation_table_vector)
+                                ? ASIZE (Vtranslation_table_vector)
+                                : -1));
+                i = CCL_DECODE_CHAR (reg[RRR], reg[rrr]);
+                op = translate_char (GET_TRANSLATION_TABLE (eop), i);
+                CCL_ENCODE_CHAR (op, charset_list, reg[RRR], reg[rrr]);
+              }
               break;
 
             case CCL_LookupIntConstTbl:
-              op = XINT (ccl_prog[ic]); /* table */
-              ic++;
               {
-                struct Lisp_Hash_Table *h = GET_HASH_TABLE (op);
+                EMACS_INT eop;
+                struct Lisp_Hash_Table *h;
+                GET_CCL_RANGE (eop, ccl_prog, ic++, 0,
+                               (VECTORP (Vtranslation_hash_table_vector)
+                                ? ASIZE (Vtranslation_hash_table_vector)
+                                : -1));
+                h = GET_HASH_TABLE (eop);
 
                 op = hash_lookup (h, make_number (reg[RRR]), NULL);
                 if (op >= 0)
@@ -1297,18 +1323,22 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
               break;
 
             case CCL_LookupCharConstTbl:
-              op = XINT (ccl_prog[ic]); /* table */
-              ic++;
-              i = CCL_DECODE_CHAR (reg[RRR], reg[rrr]);
               {
-                struct Lisp_Hash_Table *h = GET_HASH_TABLE (op);
+                EMACS_INT eop;
+                struct Lisp_Hash_Table *h;
+                GET_CCL_RANGE (eop, ccl_prog, ic++, 0,
+                               (VECTORP (Vtranslation_hash_table_vector)
+                                ? ASIZE (Vtranslation_hash_table_vector)
+                                : -1));
+                i = CCL_DECODE_CHAR (reg[RRR], reg[rrr]);
+                h = GET_HASH_TABLE (eop);
 
                 op = hash_lookup (h, make_number (i), NULL);
                 if (op >= 0)
                   {
                     Lisp_Object opl;
                     opl = HASH_VALUE (h, op);
-                    if (!INTEGERP (opl))
+                    if (! (INTEGERP (opl) && IN_INT_RANGE (XINT (opl))))
                       CCL_INVALID_CMD;
                     reg[RRR] = XINT (opl);
                     reg[7] = 1; /* r7 true for success */
@@ -1321,9 +1351,10 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
             case CCL_IterateMultipleMap:
               {
                 Lisp_Object map, content, attrib, value;
-                int point, size, fin_ic;
+                EMACS_INT point, size;
+                int fin_ic;
 
-                j = XINT (ccl_prog[ic++]); /* number of maps. */
+                GET_CCL_INT (j, ccl_prog, ic++); /* number of maps. */
                 fin_ic = ic + j;
                 op = reg[rrr];
                 if ((j > reg[RRR]) && (j >= 0))
@@ -1343,7 +1374,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
 
                     size = ASIZE (Vcode_conversion_map_vector);
                     point = XINT (ccl_prog[ic++]);
-                    if (point >= size) continue;
+                    if (! (0 <= point && point < size)) continue;
                     map = AREF (Vcode_conversion_map_vector, point);
 
                     /* Check map validity.  */
@@ -1358,18 +1389,19 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                     /* check map type,
                        [STARTPOINT VAL1 VAL2 ...] or
                        [t ELEMENT STARTPOINT ENDPOINT]  */
-                    if (NUMBERP (content))
+                    if (INTEGERP (content))
                       {
-                        point = XUINT (content);
-                        point = op - point + 1;
-                        if (!((point >= 1) && (point < size))) continue;
-                        content = AREF (map, point);
+                        point = XINT (content);
+                        if (!(point <= op && op - point + 1 < size)) continue;
+                        content = AREF (map, op - point + 1);
                       }
                     else if (EQ (content, Qt))
                       {
                         if (size != 4) continue;
-                        if ((op >= XUINT (AREF (map, 2)))
-                            && (op < XUINT (AREF (map, 3))))
+                        if (INTEGERP (AREF (map, 2))
+                            && XINT (AREF (map, 2)) <= op
+                            && INTEGERP (AREF (map, 3))
+                            && op < XINT (AREF (map, 3)))
                           content = AREF (map, 1);
                         else
                           continue;
@@ -1379,7 +1411,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
 
                     if (NILP (content))
                       continue;
-                    else if (NUMBERP (content))
+                    else if (INTEGERP (content) && IN_INT_RANGE (XINT (content)))
                       {
                         reg[RRR] = i;
                         reg[rrr] = XINT(content);
@@ -1394,10 +1426,11 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                       {
                         attrib = XCAR (content);
                         value = XCDR (content);
-                        if (!NUMBERP (attrib) || !NUMBERP (value))
+                        if (! (INTEGERP (attrib) && INTEGERP (value)
+                               && IN_INT_RANGE (XINT (value))))
                           continue;
                         reg[RRR] = i;
-                        reg[rrr] = XUINT (value);
+                        reg[rrr] = XINT (value);
                         break;
                       }
                     else if (SYMBOLP (content))
@@ -1432,8 +1465,9 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                   mapping_stack_pointer = mapping_stack;
                 stack_idx_of_map_multiple = 0;
 
-                map_set_rest_length =
-                  XINT (ccl_prog[ic++]); /* number of maps and separators. */
+                /* Get number of maps and separators.  */
+                GET_CCL_INT (map_set_rest_length, ccl_prog, ic++);
+
                 fin_ic = ic + map_set_rest_length;
                 op = reg[rrr];
 
@@ -1501,7 +1535,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                 do {
                   for (;map_set_rest_length > 0;i++, ic++, map_set_rest_length--)
                     {
-                      point = XINT(ccl_prog[ic]);
+                      GET_CCL_INT (point, ccl_prog, ic);
                       if (point < 0)
                         {
                           /* +1 is for including separator. */
@@ -1531,18 +1565,19 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                       /* check map type,
                          [STARTPOINT VAL1 VAL2 ...] or
                          [t ELEMENT STARTPOINT ENDPOINT]  */
-                      if (NUMBERP (content))
+                      if (INTEGERP (content))
                         {
-                          point = XUINT (content);
-                          point = op - point + 1;
-                          if (!((point >= 1) && (point < size))) continue;
-                          content = AREF (map, point);
+                          point = XINT (content);
+                          if (!(point <= op && op - point + 1 < size)) continue;
+                          content = AREF (map, op - point + 1);
                         }
                       else if (EQ (content, Qt))
                         {
                           if (size != 4) continue;
-                          if ((op >= XUINT (AREF (map, 2))) &&
-                              (op < XUINT (AREF (map, 3))))
+                          if (INTEGERP (AREF (map, 2))
+                              && XINT (AREF (map, 2)) <= op
+                              && INTEGERP (AREF (map, 3))
+                              && op < XINT (AREF (map, 3)))
                             content = AREF (map, 1);
                           else
                             continue;
@@ -1554,7 +1589,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                         continue;
 
                       reg[RRR] = i;
-                      if (NUMBERP (content))
+                      if (INTEGERP (content) && IN_INT_RANGE (XINT (content)))
                         {
                           op = XINT (content);
                           i += map_set_rest_length - 1;
@@ -1566,9 +1601,10 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                         {
                           attrib = XCAR (content);
                           value = XCDR (content);
-                          if (!NUMBERP (attrib) || !NUMBERP (value))
+                          if (! (INTEGERP (attrib) && INTEGERP (value)
+                                 && IN_INT_RANGE (XINT (value))))
                             continue;
-                          op = XUINT (value);
+                          op = XINT (value);
                           i += map_set_rest_length - 1;
                           ic += map_set_rest_length - 1;
                           POP_MAPPING_STACK (map_set_rest_length, reg[rrr]);
@@ -1613,7 +1649,7 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
             case CCL_MapSingle:
               {
                 Lisp_Object map, attrib, value, content;
-                int size, point;
+                int point;
                 j = XINT (ccl_prog[ic++]); /* map_id */
                 op = reg[rrr];
                 if (j >= ASIZE (Vcode_conversion_map_vector))
@@ -1628,41 +1664,36 @@ ccl_driver (struct ccl_program *ccl, int *source, int *destination, int src_size
                     break;
                   }
                 map = XCDR (map);
-                if (!VECTORP (map))
+                if (! (VECTORP (map)
+                       && INTEGERP (AREF (map, 0))
+                       && XINT (AREF (map, 0)) <= op
+                       && op - XINT (AREF (map, 0)) + 1 < ASIZE (map)))
                   {
                     reg[RRR] = -1;
                     break;
                   }
-                size = ASIZE (map);
-                point = XUINT (AREF (map, 0));
+                point = XINT (AREF (map, 0));
                 point = op - point + 1;
                 reg[RRR] = 0;
-                if ((size <= 1) ||
-                    (!((point >= 1) && (point < size))))
+                content = AREF (map, point);
+                if (NILP (content))
                   reg[RRR] = -1;
-                else
+                else if (INTEGERP (content))
+                  reg[rrr] = XINT (content);
+                else if (EQ (content, Qt));
+                else if (CONSP (content))
                   {
-                    reg[RRR] = 0;
-                    content = AREF (map, point);
-                    if (NILP (content))
-                      reg[RRR] = -1;
-                    else if (NUMBERP (content))
-                      reg[rrr] = XINT (content);
-                    else if (EQ (content, Qt));
-                    else if (CONSP (content))
-                      {
-                        attrib = XCAR (content);
-                        value = XCDR (content);
-                        if (!NUMBERP (attrib) || !NUMBERP (value))
-                          continue;
-                        reg[rrr] = XUINT(value);
-                        break;
-                      }
-                    else if (SYMBOLP (content))
-                      CCL_CALL_FOR_MAP_INSTRUCTION (content, ic);
-                    else
-                      reg[RRR] = -1;
+                    attrib = XCAR (content);
+                    value = XCDR (content);
+                    if (!INTEGERP (attrib) || !INTEGERP (value))
+                      continue;
+                    reg[rrr] = XINT(value);
+                    break;
                   }
+                else if (SYMBOLP (content))
+                  CCL_CALL_FOR_MAP_INSTRUCTION (content, ic);
+                else
+                  reg[RRR] = -1;
               }
               break;