From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Thu, 5 Mar 2020 16:20:26 +0000 (+0000)
Subject: Taint: track in ${utf8clean:} operator
X-Git-Tag: exim-4_94_RC0~75
X-Git-Url: https://vcs.fsf.org/?p=exim.git;a=commitdiff_plain;h=e68def51cb753d730249565e630b549a73857ec1

Taint: track in ${utf8clean:} operator
---

diff --git a/src/src/expand.c b/src/src/expand.c
index 660fe98cf..3c3184347 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -7631,7 +7631,7 @@ while (*s != 0)
       case EOP_QUOTE_LOCAL_PART:
       if (!arg)
         {
-        BOOL needs_quote = (*sub == 0);      /* TRUE for empty string */
+        BOOL needs_quote = (!*sub);      /* TRUE for empty string */
         uschar *t = sub - 1;
 
         if (c == EOP_QUOTE)
@@ -7751,10 +7751,10 @@ while (*s != 0)
 
       case EOP_FROM_UTF8:
         {
-        while (*sub != 0)
+	uschar * buff = store_get(4, is_tainted(sub));
+        while (*sub)
           {
           int c;
-          uschar buff[4];
           GETUTF8INC(c, sub);
           if (c > 255) c = '_';
           buff[0] = c;
@@ -7763,7 +7763,7 @@ while (*s != 0)
         continue;
         }
 
-	  /* replace illegal UTF-8 sequences by replacement character  */
+      /* replace illegal UTF-8 sequences by replacement character  */
 
       #define UTF8_REPLACEMENT_CHAR US"?"
 
@@ -7775,7 +7775,17 @@ while (*s != 0)
         int complete;
         uschar seq_buff[4];			/* accumulate utf-8 here */
 
-        while (*sub != 0)
+	/* Manually track tainting, as we deal in individual chars below */
+
+	if (is_tainted(sub))
+	  if (yield->s && yield->ptr)
+	    gstring_rebuffer(yield);
+	  else
+	    yield->s = store_get(yield->size = Ustrlen(sub), TRUE);
+
+	/* Check the UTF-8, byte-by-byte */
+
+        while (*sub)
 	  {
 	  complete = 0;
 	  uschar c = *sub++;
@@ -7801,7 +7811,7 @@ while (*s != 0)
 	    }
 	  else	/* no bytes left: new sequence */
 	    {
-	    if((c & 0x80) == 0)	/* 1-byte sequence, US-ASCII, keep it */
+	    if(!(c & 0x80))	/* 1-byte sequence, US-ASCII, keep it */
 	      {
 	      yield = string_catn(yield, &c, 1);
 	      continue;
@@ -7846,9 +7856,8 @@ while (*s != 0)
         * Eg, ${length_1:フィル} is one byte, not one character, so we expect
         * ${utf8clean:${length_1:フィル}} to yield '?' */
         if (bytes_left != 0)
-          {
           yield = string_catn(yield, UTF8_REPLACEMENT_CHAR, 1);
-          }
+
         continue;
         }
 
diff --git a/src/src/functions.h b/src/src/functions.h
index df4b33606..851cedd3f 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -919,6 +919,18 @@ va_end(ap);
 return g;
 }
 
+
+/* Copy the content of a string to tainted memory */
+
+static inline void
+gstring_rebuffer(gstring * g)
+{
+uschar * s = store_get(g->size, TRUE);
+memcpy(s, g->s, g->ptr);
+g->s = s;
+}
+
+
 /******************************************************************************/
 
 #define store_get_dns_answer() store_get_dns_answer_trc(CUS __FUNCTION__, __LINE__)
diff --git a/src/src/string.c b/src/src/string.c
index 9f1aeb81d..4ef2fee62 100644
--- a/src/src/string.c
+++ b/src/src/string.c
@@ -12,7 +12,6 @@ utilities and tests, and are cut out by the COMPILE_UTILITY macro. */
 #include "exim.h"
 #include <assert.h>
 
-static void gstring_rebuffer(gstring * g);
 
 #ifndef COMPILE_UTILITY
 /*************************************************
@@ -1243,16 +1242,6 @@ return !!gp;
 
 
 
-/* Copy the content of a string to tainted memory */
-static void
-gstring_rebuffer(gstring * g)
-{
-uschar * s = store_get(g->size, TRUE);
-memcpy(s, g->s, g->ptr);
-g->s = s;
-}
-
-
 
 /* Build or append to a growing-string, sprintf-style.