From 5d13a8684c8637334d17f2b0577fc511aa275477 Mon Sep 17 00:00:00 2001
From: Adam Dickmeiss <adam@indexdata.dk>
Date: Wed, 23 May 2007 08:50:11 +0000
Subject: [PATCH] Check for malformed UTF-8 characters. Thanks for Gary
 Anderson for pointing this out.

---
 src/siconv.c |   98 ++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 55 insertions(+), 43 deletions(-)

diff --git a/src/siconv.c b/src/siconv.c
index bdb20ee..1420e78 100644
--- a/src/siconv.c
+++ b/src/siconv.c
@@ -2,7 +2,7 @@
  * Copyright (C) 1995-2007, Index Data ApS
  * See the file LICENSE for details.
  *
- * $Id: siconv.c,v 1.40 2007-05-03 22:20:45 adam Exp $
+ * $Id: siconv.c,v 1.41 2007-05-23 08:50:11 adam Exp $
  */
 /**
  * \file siconv.c
@@ -212,6 +212,7 @@ unsigned long yaz_read_UTF8_char(unsigned char *inp,
 {
     unsigned long x = 0;
 
+    *no_read = 0; /* by default */
     if (inp[0] <= 0x7f)
     {
         x = inp[0];
@@ -219,75 +220,86 @@ unsigned long yaz_read_UTF8_char(unsigned char *inp,
     }
     else if (inp[0] <= 0xbf || inp[0] >= 0xfe)
     {
-        *no_read = 0;
         *error = YAZ_ICONV_EILSEQ;
     }
     else if (inp[0] <= 0xdf && inbytesleft >= 2)
     {
-        x = ((inp[0] & 0x1f) << 6) | (inp[1] & 0x3f);
-        if (x >= 0x80)
-            *no_read = 2;
-        else
+        if ((inp[1] & 0xc0) == 0x80)
         {
-            *no_read = 0;
-            *error = YAZ_ICONV_EILSEQ;
+            x = ((inp[0] & 0x1f) << 6) | (inp[1] & 0x3f);
+            if (x >= 0x80)
+                *no_read = 2;
+            else
+                *error = YAZ_ICONV_EILSEQ;
         }
+        else
+            *error = YAZ_ICONV_EILSEQ;
     }
     else if (inp[0] <= 0xef && inbytesleft >= 3)
     {
-        x = ((inp[0] & 0x0f) << 12) | ((inp[1] & 0x3f) << 6) |
-            (inp[2] & 0x3f);
-        if (x >= 0x800)
-            *no_read = 3;
-        else
+        if ((inp[1] & 0xc0) == 0x80 && (inp[2] & 0xc0) == 0x80)
         {
-            *no_read = 0;
-            *error = YAZ_ICONV_EILSEQ;
+            x = ((inp[0] & 0x0f) << 12) | ((inp[1] & 0x3f) << 6) |
+                (inp[2] & 0x3f);
+            if (x >= 0x800)
+                *no_read = 3;
+            else
+                *error = YAZ_ICONV_EILSEQ;
         }
-    }
+        else
+            *error = YAZ_ICONV_EILSEQ;
+    }            
     else if (inp[0] <= 0xf7 && inbytesleft >= 4)
     {
-        x =  ((inp[0] & 0x07) << 18) | ((inp[1] & 0x3f) << 12) |
-            ((inp[2] & 0x3f) << 6) | (inp[3] & 0x3f);
-        if (x >= 0x10000)
-            *no_read = 4;
-        else
+        if ((inp[1] & 0xc0) == 0x80 && (inp[2] & 0xc0) == 0x80
+            && (inp[3] & 0xc0) == 0x80)
         {
-            *no_read = 0;
-            *error = YAZ_ICONV_EILSEQ;
+            x = ((inp[0] & 0x07) << 18) | ((inp[1] & 0x3f) << 12) |
+                ((inp[2] & 0x3f) << 6) | (inp[3] & 0x3f);
+            if (x >= 0x10000)
+                *no_read = 4;
+            else
+                *error = YAZ_ICONV_EILSEQ;
         }
+        else
+            *error = YAZ_ICONV_EILSEQ;
     }
     else if (inp[0] <= 0xfb && inbytesleft >= 5)
     {
-        x =  ((inp[0] & 0x03) << 24) | ((inp[1] & 0x3f) << 18) |
-            ((inp[2] & 0x3f) << 12) | ((inp[3] & 0x3f) << 6) |
-            (inp[4] & 0x3f);
-        if (x >= 0x200000)
-            *no_read = 5;
-        else
+        if ((inp[1] & 0xc0) == 0x80 && (inp[2] & 0xc0) == 0x80
+            && (inp[3] & 0xc0) == 0x80 && (inp[4] & 0xc0) == 0x80)
         {
-            *no_read = 0;
-            *error = YAZ_ICONV_EILSEQ;
+            x = ((inp[0] & 0x03) << 24) | ((inp[1] & 0x3f) << 18) |
+                ((inp[2] & 0x3f) << 12) | ((inp[3] & 0x3f) << 6) |
+                (inp[4] & 0x3f);
+            if (x >= 0x200000)
+                *no_read = 5;
+            else
+                *error = YAZ_ICONV_EILSEQ;
         }
+        else
+            *error = YAZ_ICONV_EILSEQ;
     }
     else if (inp[0] <= 0xfd && inbytesleft >= 6)
     {
-        x =  ((inp[0] & 0x01) << 30) | ((inp[1] & 0x3f) << 24) |
-            ((inp[2] & 0x3f) << 18) | ((inp[3] & 0x3f) << 12) |
-            ((inp[4] & 0x3f) << 6) | (inp[5] & 0x3f);
-        if (x >= 0x4000000)
-            *no_read = 6;
-        else
+        if ((inp[1] & 0xc0) == 0x80 && (inp[2] & 0xc0) == 0x80
+            && (inp[3] & 0xc0) == 0x80 && (inp[4] & 0xc0) == 0x80
+            && (inp[5] & 0xc0) == 0x80)
         {
-            *no_read = 0;
-            *error = YAZ_ICONV_EILSEQ;
+            x = ((inp[0] & 0x01) << 30) | ((inp[1] & 0x3f) << 24) |
+                ((inp[2] & 0x3f) << 18) | ((inp[3] & 0x3f) << 12) |
+                ((inp[4] & 0x3f) << 6) | (inp[5] & 0x3f);
+            if (x >= 0x4000000)
+                *no_read = 6;
+            else
+                *error = YAZ_ICONV_EILSEQ;
         }
+        else
+            *error = YAZ_ICONV_EILSEQ;
     }
     else
-    {
-        *no_read = 0;
-        *error = YAZ_ICONV_EINVAL;
-    }
+        *error = YAZ_ICONV_EINVAL;  /* incomplete sentence */
+
     return x;
 }
 
-- 
1.7.10.4