Fixed possible memory leak in mux_parse_string. This needs more work.

src/server/mux-parse.c

@@ -7,6 +7,7 @@
 #include <stdarg.h>
 #include <string.h>
 #include "lyskomd.h"
+#include "s-string.h"
 #include <kom-types.h>
 #include "com.h"
 #include "connections.h"
@@ -19,7 +20,7 @@
 #include "mux-parse.h"
 #include "minmax.h"
 #include "config.h"
-#include <s-string.h>
+#include "log.h"
 
 jmp_buf mux_parse_env;
 
@@ -64,7 +65,11 @@ mux_parse_long(Mux *mux)
 /*
  * Parse a string. At most 'maxlen' characters are allowed. If the
  * mux sends a longer string only the first 'maxlen+1' characters
- * are read. The following characters are discarded.
+ * are read. Any remaining characters are discarded.
+ *
+ * longjmp if not enough characters are available or if there
+ * is an error. Result is used to save state in that case.
+ * +++ Result should not be used to save state.
  */
 static void
 mux_parse_string(Mux	    *mux,
@@ -75,16 +80,16 @@ mux_parse_string(Mux	    *mux,
     String_size mux_len;	/* The len the mux is sending. */
     String_size truncated_len;	/* How much the server will receive. */
     String_size to_skip;
-    String tmp;
+    static u_long err_cnt = 0;
 
     switch ( mux->parse.string_parse_pos )
     {
     case 0:
 	/* Get number and discard trailing 'H' */
-	result->len = s_strtol(s_fsubstr(mux->parse.unparsed,
-					 mux->parse.first_to_parse,
-					 END_OF_STRING),
-			       &hptr, PROTOCOL_NUMBER_BASE);
+	mux_len = s_strtol(s_fsubstr(mux->parse.unparsed,
+				     mux->parse.first_to_parse,
+				     END_OF_STRING),
+			   &hptr, PROTOCOL_NUMBER_BASE);
 
 	if ( hptr == -1
 	    || mux->parse.first_to_parse + hptr
@@ -97,6 +102,8 @@ mux_parse_string(Mux	    *mux,
 	      a) there is a trailing H
 	      b) there was at least one digit before the H */
 
+	/* +++ Use s-string.c to extract the char. */
+	/* +++ Fix prot_a_parse_string also. */
 	if ( mux->parse.unparsed.string[ mux->parse.first_to_parse
 					  + hptr ] != 'H'
 	    || hptr <= 0 )
@@ -111,8 +118,7 @@ mux_parse_string(Mux	    *mux,
 	/* Check that the entire string is transmitted. */
 	/* (Don't care about the trailing part that will be skipped if the
 	 *  string is longer than maxlen) */
-	truncated_len = min(maxlen + 1, result->len);
-	mux_len = result->len;
+	truncated_len = min(maxlen + 1, mux_len);
 	
 	if ( mux->parse.first_to_parse + truncated_len
 	    > s_strlen(mux->parse.unparsed) )
@@ -120,35 +126,53 @@ mux_parse_string(Mux	    *mux,
 	    longjmp(mux_parse_env, MUX_MSG_INCOMPLETE);
 	}
 
-	result->string = (mux->parse.unparsed.string
-			  + mux->parse.first_to_parse);
-	result->len = truncated_len;
-	tmp = EMPTY_STRING;
-	s_strcpy(&tmp, *result); /* Copy the string. */
-	*result = tmp;
-	result->len = mux_len;
-
+	if ( ( result->len != 0 || result->string != NULL) && err_cnt++ < 20 )
+	{
+	    log ("mux_parse_string(): result->len == %lu, "
+		 "result->string == %lu. This memory will not be free()'d.\n",
+		 (u_long)result->len, (u_long)result->string);
+	    *result = EMPTY_STRING;
+	    if ( err_cnt == 20 )
+		log("Won't log the above warning no more.");
+	}
+	
+	s_mem_crea_str(result,
+		       mux->parse.unparsed.string + mux->parse.first_to_parse,
+		       truncated_len);
+	
 	mux->parse.first_to_parse += truncated_len;
 	mux->parse.string_parse_pos = 2;
+	result->len = mux_len;	/* Can't transfer the local mux_len across
+				 * call boundary. +++ There should be room
+				 * for mux_len in the per-connection
+				 * protocol data.
+				 */
 	/* Fall through */
     case 2:
 	/* Was the string too long? If so, skip the truncated data. */
 
-	mux_len = result->len;
+	mux_len = result->len;	/* +++ shouldn't modify ->len */
 	truncated_len = min(maxlen+1, result->len);
 	
 	if ( mux_len > truncated_len )
 	{
 	    to_skip = min(mux_len - truncated_len,
-			   mux->parse.unparsed.len - mux->parse.first_to_parse);
+			  mux->parse.unparsed.len - mux->parse.first_to_parse);
+	    /* From now on, mux_len is length of result + numer of
+	       chars to skip. Clean up this! +++
+	     */
 	    mux_len -= to_skip;
 	    mux->parse.first_to_parse += to_skip;
 	}
-
+ 
 	result->len = mux_len;
 	
 	if ( mux_len > truncated_len )
+	{
+	    /* +++ mux_len is transferred in result->len. */
 	    longjmp(mux_parse_env, MUX_MSG_INCOMPLETE);
+	}
+	
 	/* Fall through */
     default:
 	mux->parse.string_parse_pos = 0;